Check Engine light. Codes 4 and 11.

[mahleek87]

Today my check engine light came on in my 86 toyota van while driving but then it went away. Later on I noticed that It came on again while I was driving when I hit the gas while running and got no power but then eventually the power caught up and resulted in a power surge. The van is running kinda roughy. Not too bad but the check engine light comes and goes. Where should I start? I checked the codes and got codes 4 and 11. I find the owners manual so I hope someone can look that up for me and give me some decent advice on what to do.

[JRSJ]

Here ya go :)

Code 4 / Water temp sensor / may be the coolant temperature sensor circuit OR the sensor itself.

Code 11 / Switch / air conditioner switch, TPS circuit, TPS, or neutral start switch.

(I'll wager your TPS is faulty for code 11.)


Here (http://www.toyotavantech.com/techdocs/1986_1987_codes.pdf) is the .PDF file for your codes -- Print it out and keep it in your van :D

[mahleek87]

Where is the coolant temperature sensor circuit located? Or the TPS circuit? Thanks for the help.

[JRSJ]

Where is the coolant temperature sensor circuit located? Or the TPS circuit? Thanks for the help.

The circuit is the electrical connection between the sensors and ECU. Anywhere along that circuit could be an electrical short (chaffed/melted wires, loose connections etc.) I'd start investigating by checking the sensors themselves. The actual location of the Coolant Temperature Sensor is on the radiator fill neck. (I'll take a picture of it tomorrow to show you.)

The TPS (Throttle Position Sensor) is a black plastic box located on the rear side of the throttle body manifold. Removal of the throttle body is required to gain access to that sensor. You will also need a new throttle body gasket to replace the old one. Tim has posted a video on how to calibrate a TPS properly here (http://www.toyotavantech.com/forum/showthread.php?447-Throttle-Position-Sensor-TPS-Canada).

That would be a good starting point -- I wouldn't be surprised if new sensors were all your van needed.

[JRSJ]

http://i8.photobucket.com/albums/a23/timsrv/TVT%20pics/cooling%20system/coolanttempsensor.jpg


As promised, here is the picture showing the location of the coolant temp sensor. I believe it takes a 19mm deep socket or wrench to remove.

JRSJ

(ps. mods, if there is any issue with putting TVT on images I contribute with, please PM me. Just trying to give back to the community.)

[timsrv]

(ps. mods, if there is any issue with putting TVT on images I contribute with, please PM me. Just trying to give back to the community.)

As far as I'm concerned it's awesome. Thanks for your great responses (makes my job easier). I also like the way JRSJ Photos display in the forum. Nice website by the way. Tim

[llamavan]

I'm good with it, too. Various people "lift" photos and post them elsewhere on the internet for all kinds of reasons; having ToyotaVanTech (or better still, ToyotaVanTech.com) on the photos gives people a way to find to this site, and by definition, if they are looking at a van-specific photo, they probably can benefit from locating us. So, THANKS! :thmbup:

Gwen

[JRSJ]

Cheers guys, I'll make sure it says ToyotaVanTech.com in all future posts. :)

I'd like to add one more point to the original thread topic. Its worth noting that the Coolant Temperature Sensor (CTS) has nothing to do with the temperature gauge in your dash cluster. That sensor is located on the passenger side of the cylinder head, beside the distributor cap. The CTS is connected to your vans ECU, and helps it make decisions when the engine is cold. It relays information to the ECU, then from the ECU to the cold start injector. I believe it also has a play in air-to-fuel ratio when cold starting.)

Keep us updated with your findings and any hiccups along the way, mahleek87. :D

JRSJ

[eddieleephd]

Hey guys,
I am not fond of getting parts from Toyota that I can get elsewhere, I am just unsure as to what these models are finicky about.
I know that most Toyota's dislike non OEM Manufactured parts. Toyota wants $90 for the TPS and the best part I can find otherwise is BECK ARNLEY.
What to do Toyota or Beck Arnley. difference is like $40 so not the end of the world. I am opposed to Wells like AutoZone has all around.
Lifetime warranty means piece of crap we have to warranty !!!!

[timsrv]

I've used Beck Arnley TPS units a couple of times on vans. I popped the cover off one once and had a look at the internals. It was stamped "made in Italy" but appeared to be of a quality construction. I guess time will tell if it lasts as long as Toyota. Tim

[JRSJ]

I'm using a Beck Arnley TPS as well. All is well for my van.

[eddieleephd]

Thanks guys,
I appreciate your input!!
Price difference of $30-40.... I have new O2 sensors that are denso so no question about those!!!
Thank Ebay for competition!!!

[eddieleephd]

Ok so I was just looking at this new beck arnley TPS I got from Rockauto and it looks nothing like the one in the video!!
It as well does not seem adjustable, for that matter it looks nothing like the picture I saw on their website???

really it is a little 90 degree looking thing made of plastic WTF.

do your guys both look like they do in the video? if I have to send it back I will just go to toyota!

[JRSJ]

It should look like this:


http://info.rockauto.com/getimage/getimage.php?imagekey=940485&imageurl=http%3A//info.rockauto.com/Airtex/5S5171.jpg

[timsrv]

Yep, the one JRSJ posted is it. Of course the one in my video was attached to the throttle body (removed from the van). After installing and adjusting to the throttle body the entire assembly gets mounted back on the van. Tim

[eddieleephd]

Yeah that is not at all what they sent me!! this is the unfortunate part of ordering online!!
And this part looks nothing like it.
Can someone list a part # on the correct one?

[timsrv]

TPS= Toyota #89452-14020 or Beck Arnley #158-0503

[TinyBird]

Hello everyone, Newbie here, but been owner of for 80's vans... but finally stumped....

Got a code 4, replaced sensor, checked wiring to ecu, checked ecu voltages... checked output from tps,
now here are my clues.


For a year or more, i have round the cts thru a switch i flick when i step on the gas and flick again when idling. by taking the cts in and out of operation I am able to go.... so, I always figured it was the cts, and replaced, fully expecting repair fix, reset code. But code comes right back and did not repair. This lead to checking tps, which i took apart, contacts good, checked voltage on terms, ok.

Then i peeked into the ecu, looking for fried caps, etc., looking good there, plus the readings were ok.

My dearly beloved, which i did a total engine overhaul over 5 years as i became sober. Toyo and zen thing... so, my patience is being tested once again...

my hunch is that still must be wiring for the code to show up right away....

any suggestions or clues?

[timsrv]

That sensor is just a thermistor that changes resistance with temperature (the colder it is the more resistance). It has a range of 100 ohms (at around 250 deg F) to 20,000 ohms (at around 0 deg F). The resistance changes are fairly linear throughout the temp range, so if you have any doubts about it just disconnect and test resistance between the 2 terminals. If the sensor is not installed, then then you should see around 2,000 ohms at room temp. If the sensor is installed, use a thermometer in the filler neck and calculate the resistance based on coolant temp. To check the wires, go to the ECU and pull the connectors off. Set your meter to sound a tone when continuity is detected, then touch one lead to the brown sensor wire and the other lead to the brown wire in the E2 position of the ECU harness. if the circuit is complete the meter will sound a tone. Repeat the these steps for the green sensor wire and the THW position of the ECU harness. If you don't have a manual let me know and I'll post some pics. Tim

[TinyBird]

Thanks, I will do that check tomorrow....but earlier, I found a puzzling thing that sure threw me... One of the wires to sensor goes to the thw of ecu and the other splices, the brown one, into other brown ones that are grounded. This makes no sense to me.... Am I correct that this brown one should not be grounded? Maybe it has been wrong for eons... It's a 4ye engine in an '84 model with a 3ye ecu. maybe somehow the wiring went wrong. I have always had crappy gas mileage. Further puzzled what else has happened that made the problem so bad that is undriveable. I will post back my wiring findings tomorrow. I have a schematic and see that the brwn ties into the Air Flow meter and E2. Geezus what has been going on?

By the way, I bought all new connectors for the fi, cts, tps, cold start, .... I am committed! Going all the way now...

[timsrv]

Yes, brown is ground and s/b tied into other grounds there by the manifold. The E2 position of the ECU should also be tied to that same location. Tim

[TinyBird]

Pooh, was thinking that was the problem, brwn should not be grnd... odd that my skematic does not show it grounded....

oh well, stumped..... cause i know the wires are good to thw and e2, i swapped out maf and the other cold start temp sensor from my spare engine....

any idea what else could keep the code 4 persistent, i mean right away, too... tells me a short or something bad.... i have not double checked engine ground but ran a wire to manifold ground from battery...

clue, when idling, and then open throttle it immediately dies if i don't take the cts out..of circuit...
had throttle body off, all clean...as is tps... if i was getting stray voltage to ground lots of dashlifghts would be going bonkers...

been pondering over this for months and months...... i mean when the switch is flicked, taking sensor in and out, , it dies quick, not like going too rich or lean which would sputter it out.

I have every wire out of the harness to the ecu, doing a total rewire...

i was going to get to the idle air valve underneath manfld but hoping i would not need to go that far... and seems pointless with the trouble code persistent, a leaky intake would not give temp code...

oh well, been desperate before, and know it will be solved one day... you have a great forum, all those other ones are so gamed for marketing, probably facebook behind them.

[TinyBird]

one other thought, that has been a huge problem over many years is that friggin alternator and booby trpped location throwing off voltage due to drippy p/s fluid, been there and done that... but it may be cracked insulator or some lil something...

maybe if i just stuck a 2000 ohm resistor btwn e2 and thw, then add a lil rheostat that i change manually.....

[timsrv]

Sorry for stating the obvious, but did you actually test the thermistor values? These things can be bad right out of the box.........especially if aftermarket.

[TinyBird]

yep, check, but so determined, bought another one...tested good too....

stickin me a fail safe resistor in there tomorrow, see what happens after clearing code....

[timsrv]

Pull the sensor connector off and verify resistance between the two conductors. Once you know what it is (let's say 2000 ohms), put the connector back on then pull the ECU harness and check between E2 & THW positions. You should read the same value as you did on the sensor. The sensor is basically just a resistor and the ECU is an ohm meter. If the sensor is good, and it's resistance can be accurately read from the ECU harness, then there should be no code (assuming it's been cleared after the remedy). If the ECU is calling foul, when in fact there is none, then the ECU itself could be the problem.

If you can't read correct resistance from the ECU harness, then the circuit (wires) are the problem. The biggest suspect would be the connector. Check that thermistor connector with x-ray vision. Make sure the little conductors inside are not deformed and verify the wires aren't chaffed through or broken inside near the connector. Tim

[TinyBird]

alright Perry Mason is going to get to the bottom of this tomorrow.... and report back.... thnk you ... i had every engine part disassemebled and in boxes for 5 years back in the 90's bfore i got my baby put back together and this and my 72 mercedes 240d are my lil darlins.... not so much my neighbors though...

[TinyBird]

Glory bee! got the code 4 light off.... Just went ahead and installed the new connector at sensor and that did it.... must have been an intermittent somewhere that would short when plugged in...

Now on to final tuning up and getting it all in top shape... thanks for the moral support and repeating the obvious on what needs to be done....

Napa had the connectors for $8 the tps was around $16

their echelon line pn 2-18457 and ec173 for tps

[timsrv]

That's awesome! Happy to be able to help. You did the real work though. After 28 years in the intense heat these connectors can certainly become problem areas. Tim

[fuquan]

I am also getting codes 4 and 11.

In cool weather, when my engine is cold, the van runs like total crap. Idles around 500 and the engine shakes, but it does not stall. Once the engine warms up the van runs well.

When timing is set properly the van runs like a very old dog. I have to manually advance the timing to 20 something to get any power out of it.

Checked my water temperature sensor. It tests fine. Have not gotten around to checking my TPS (given its unknown age perhaps I should just replace it). However, today I noticed that I can see the gasket between the throttle body and intake is actually visible! Could this be what is causing my cold engine idle problem?

744

[TinyBird]

After a very long ordeal, I SOLVED mine. the intake plenum gasket, the one between the top and bottom of the entire manifold., was leaking. When engine heats up, stops leaking. I did the senor thing, the tps, and much much more until I tore the ole gal down, and saw some gasket missing.... and then it made sense, once while troubleshooting and fiddlin with stuff, running really bad, i had a misfire and saw a puff of smoke come from the area, and i thought, wtf..... should have paid more attention and got right to it., but skipped over it to my ignorance....
just a thought...I would not be surprised if this is others problem, too.... mine came on real, real slow, hard starting at times...but could get it running by pulling of temp sensors, which was just tricking the ecu..... I rebuilt my 83 , 100% and this is the 1st issue since i did the job, back in 1999...

[fuquan]

TinyBird -- Did Napa Echelon pn 2-18457 fit on your coolant temp sensor? It is described as having a "centered index slot". My CTS has a index slot that is off-center. Did you just push the connector on over the off-set slot?

[RawbSpear]

idle-up temp switch and cold start timing switch is bad. Same problem i just fixed in my van. i had codes 4 and 11.~ My MAS and my TPS gave bad numbers and had to be replaced as well, replacement of TPS got rid of code 11 but did not fix problem:

[fuquan]

idle-up temp switch and cold start timing switch is bad. Same problem i just fixed in my van. i had codes 4 and 11.~ My MAS and my TPS gave bad numbers and had to be replaced as well, replacement of TPS got rid of code 11 but did not fix problem:

Thanks for that tip, Rawb. Looks like you are right. My idle-up temp switch is not checking out - there is resistance (1.15 K ohms) between the terminal and body when oil temp is cold (less than 103 f). Resistance of my cold start timing switch (54 ohms @ 20 deg C) is almost within service manual specs (38 - 44 ohms below 30 deg C). Water temp sensor and cold start injector appear to be OK.

I searched online for an idle-up temp switch but haven't found one. Do you happen to have a part number or online source for that switch?

[fuquan]

idle-up temp switch and cold start timing switch is bad. Same problem i just fixed in my van. i had codes 4 and 11.~ My MAS and my TPS gave bad numbers and had to be replaced as well, replacement of TPS got rid of code 11 but did not fix problem:

Forgive a basic question, but what/where is the MAS or MAFS?

[RawbSpear]

the mas is under the drivers seat. It is attached to the top of the airbox where the filter is.

code 4 is a bad temperature switch. I i were you i would replace all three sensors/ switches on that tree..

here is a 5% off discount code for rock auto. enter it in the how did you hear of us section before checkout. this code is good for 2 weeks starting today: 111312019127243

[fuquan]

the mas is under the drivers seat. It is attached to the top of the airbox where the filter is.

code 4 is a bad temperature switch. I i were you i would replace all three sensors/ switches on that tree..

here is a 5% off discount code for rock auto. enter it in the how did you hear of us section before checkout. this code is good for 2 weeks starting today: 111312019127243




I have seen some vans without a idle-up temp switch. Instead they only have a bolt in that hole on the radiator cap column. Is the idle-up temp switch only on vans with A/C? My van used to have A/C but it was taken out before I got the van. My idle-up temp switch does not have the black cylindrical connector. Instead it has a small spade connector.

[timsrv]

I'm going to clear a couple things up here. The switch Rawb is referring to as the "Idle-up Temperature Switch" is actually the "Water Temperature Switch". These were only installed on vans with factory AC and don't have much to do with the way the van runs. Toyota put these switches there to combat the "Heat Soak" issue that can affect these vans (particularly the ones that might be running AC in hot climates). If you're having trouble with heat soak, then I would recommend pulling the wire from this sensor and permanently attaching it to a ground point (new switches of the correct value are NLA). The result of grounding this wire will be slightly higher fuel pressures for a couple of minutes each time you start the van. This higher pressure will reduce potential runability issues caused by heat soak.

For more information on this subject read THIS THREAD (http://www.toyotavantech.com/forum/showthread.php?289-Is-it-the-infamous-hot-soak) & review the PDF attached to my 1st post. Tim

[RawbSpear]

Tim you are wrong.. I know what i am talking about, i just replaced all of them and had to find out what they are called and what they did so that I could get my car to wrok properly.
The idle up temperature switch I got from TOYOTA!!

Go look in your manual in the FI section DUDE!!!

PS my car works perfectly. thank you

[timsrv]

Tim you are wrong.. I know what i am talking about, i just replaced all of them and had to find out what they are called and what they did so that I could get my car to wrok properly.
The idle up temperature switch I got from TOYOTA!!

Go look in your manual in the FI section DUDE!!!

PS my car works perfectly. thank you

Toyota routinely uses different names for some of these components so you could be correct about them using the term "Idle-up", but the function is as I described (check the service bulletin I linked to). The other component you refer to as "Temperature Switch" with the Airtex / Wells reference is actually a sensor (not a switch). It's possible Toyota may have referred to this component with a different name........somewhere, but as far as function it is not a switch. It is a thermister and it changes resistance based on temperature (no switching action going on). The ECU monitors this one and adjusts fuel mix based on the resistance it sees. This particular sensor is VERY important in regards to driveability issues. If this one is bad the van will run like total crap. The part labeled M.A.S. is actually the AFM (Air Flow Meter).

For the most current tech information on the "Water Temperature Switch" please check the service bulletin I linked to as Toyota published this AFTER the service manuals were printed. Tim

[timsrv]

I wanted to say that discussion is good as it helps develop a working knowledge of how the van works (important when trying to diagnose problems). I just did a search on TVP and found an old thread (similar to this one) from way back in 2008. Here's a link: http://www.toyotavanpeople.com/forum/viewtopic.php?f=2&t=4311 . In my post you will see I'm also calling it the "idle-up / pressure-up temperature switch" :)...........I wonder where I got that from? :doh: :LOL2:. Tim

[fuquan]

I wanted to say that discussion is good as it helps develop a working knowledge of how the van works (important when trying to diagnose problems). I just did a search on TVP and found an old thread (similar to this one) from way back in 2008. Here's a link: http://www.toyotavanpeople.com/forum/viewtopic.php?f=2&t=4311 . In my post you will see I'm also calling it the "idle-up / pressure-up temperature switch" :)...........I wonder where I got that from? :doh: :LOL2:. Tim

Tim and Rawb, this discussion is very educational. I read the linked TVP post and the service bulletin but I'm not sure I understand everything ... maybe someday I will. Tim, your saying that if I am not having a hot-soak issue, and I don't have AC (even though I used to have it), I can safely ignore the water (idle-up) temperature switch? It sounds like I could replace the switch with a plug. Would that be OK? My water temperature switch appears to be bad since there is resistance between the switch's terminal and ground when the engine is cold. Is there any reason to take action?

[timsrv]

If you're not having a heat soak issue then I'd ignore the temp switch. If there's continuity between the switch terminal & ground when the van is cold, that means the switch is bad.........but in this case bad is good :thmbup:. I don't think it matters much what you do regarding that switch. If you ever start having heat soak problems then I'd just cut the wire and ground it out. At that point your switch effectively becomes a "fancy" plug. If a simple plug makes you feel better then do that instead. I pulled my water temp switch and used that spot to put a 220 deg N.O. temp switch. I wired it to a bright LED in my dash. I also put an annoying piezo buzzer on that circuit so I will be alerted if temp ever exceeds 220 deg F. I wired my oil pressure switch to the alarm circuit as well so I get the same annoying warning if oil pressure ever drops below 4psi. If it ever goes off then I'll need to check my gauges to see what caused it (oil pressure or temperature), then immediately take the appropriate action. Tim

[fuquan]

I got rid of code 11 and restored proper timing advance by replacing my TPS. Code 4 disappeared somewhere along the way, perhaps when I insulated chaffed wires at my water temp sensor connector.

Still have a very rough idle when the engine is cold. My cold start injector time switch tests bad. All other EFI components appear to be good. Rawb, you listed Beck/Arnely 1580034 for cold start injector time switch. I can't find this part listed for the van at rockauto.com. Is there a place to cross reference Toyota part numbers with after market part numbers? On Toyodiy.com I see Toyota 89462-30011 "SWITCH, START INJECTOR TIME" for my Canadian issue 87 LE. This part is available for about the same price ($140 - $150) as B/A 1580034. Is there any reason not to go with the Toyota part? Is there an less expensive aftermarket alternative? Can anybody confirm that Toyota part number? I am hesitant to spend $150 without being certain that I am ordering the right part.

Any guidance would be welcome :cnfsd:.

%%% EDIT / UPDATE %%%%
Cheapest place I could find a genuine Toyota cold start injector time switch was 'autohausaz' .com. $136 and free shipping. All other toyota parts websites wanted to charge me $15 - $25 for shipping, and autohausaz had the lowest price I could find by $10 - $20. I ordered it and hope the new switch solves my cold-engine rough idle. Honestly, though, I don't understand exactly how it will. My CSITS is basically a switch that is stuck on. The switch is supposed to be on when cold and off when hot. So my switch is always telling the cold start injector to spray extra fuel, right? Somebody correct me if I am on the wrong track.

Sorry if my posts have taken this thread for a turn away from the code 11 & 4 topic. Please reassign if appropriate.

[dobbobolina]

Hey guys -

first off I have dug through and read everything above - Im kind of wanting some more opinions and wisdom though.

Brand new owner of an 87 4wd automatic, bought it 2 days ago. Im not a mechanic nor do I have much experience with internal combustion engines, I did do some electric conversions on VW's though in the past. Thats about it for my mechanical experience.

Thank you guys for your forum, I have already learned so much.

My wife and I fell in love with this van when we saw it for sale, decided to get rid of the Sequoia for something that represented us a little more accurately =). My wife went and bought it, drove it around for a day without a problem (aside from it taking 5 minutes to start from cold, and a while to warm up). She took off on a trip so I was left with the van today.

Factoids for context:

It took me 15 minutes to get the thing started today, tried cycling the fuel pump (turning the key to on or start 3 times). It was parked on a steep hill so I thought that might have some role in it.

Researched how to get error codes from the ECU, code 4 and 11. Now, the guy I bought it from said it needed a new ECU, he thought the fuel pump was bad, but said he had it tested and the pressure was fine, so chalked it up to an ECU, which he had lying around. I put in the other ECU (he graciously let me have) and one of the vacuum valves kept clicking on and off, and the van would not start. Put the old one back in. It started. I don't think the ECU is an issue.

I decided to load the kids up to buy a new guinea pig from the pet store. Along the way the van completely turned off. We pulled over, it took a few attempts but it started back up, idling very low around 500-600. I test drove it around and it kept losing power. It would drive great sometimes for about 20 seconds, and then the next second I couldn't get it to shift, totally lagging and stalling, sounded like the throttle being completely turned off and back on again. Again - it would drive great for a moment, then stalling / not shifting with it seeming like the throttle was off / on.

We managed to get it home, way back up the hill (going about 15 mph and the engine sounding LOUD). I can't even determine where to start, it felt like the vacuum system losing vacuum, but I checked all the lines and could not find an issue. Also, yes the car had gas.

I know error 11 is not that bad, but could the error code 4 be the most of it? For the most part, Im thinking :

#1 - Fix the water temp sensor issue.
if #1 does not resolve investigate the fuel pump and fuel filter.
If that does not work?

Thanks guys. Really want to get this thing running well.

[dobbobolina]

Pretty sure I found the main issue which seems to be a short in one of the harnesses going to the ECU. Looks like someone had done some work there. While I have the van running, if I move the harness in question just a bit, I can hear one of the VSV valves click, and the motor bogs down / dies. Hopefully redoing these wires will fix the main problem, don't know if it is the also the cause of error 4 and 11. Picking up a new multimeter to test the ECU and sensors.

[dobbobolina]

Status update:

Replaced TPS sensor, this cleared up error code 11. I put a new water temperature thermistor in (other one had no continuity, and new one tested good), unhooked battery, tested codes again, still code 4. Checked the new temperature thermistor and it checked out bad. Weird. Will put another one in.

Since the van still drives like crap, Ive been trying to test anything and everything I can, replaced the ignition coil (without taking off the distributor, which is painful but I don't have a timing light yet.) because the secondary coil had no continuity / resistance. Put it back together, it started up after a minute of trying, which is an improvement.

When I first start the van It barely has any power, idles sometimes at 750 which it should but sometimes at about 1100. Giving it gas makes it sound like its going to die until its warmed up. It will still die on me while driving, starts dropping power intermittently. Shuts off sometimes while driving.

If I tap on the outside of the van where the ECU is while its running, it will shut off. Could not find a short in the harness. Tested with other ECU and it does the same thing. Tested all voltage / resistance at every ECU port. Im at a loss.

[djshimon]

Hey Dob,
Did you ever figure out your problem? I'm having a somewhat similar bogging/rough running when warmed up and Code 4 when I wiggle the wires to the sensor or cold start. I'm gonna check continuity today but I think it's in the wiring right at those sensors.

[tennesseetoyota]

Hello all,

So since I bought my van back in November, it's had an issue where when I first start when the engine is cold, it putters out and dies. I'll then have to start it again, anywhere up to a maximum of four times if it's really cold outside. I haven't thought much of it and have marked it off as a nuisance while I fixed other problems, but now I have time and money to address the problem (hopefully).

Beyond this, after I've driven around for a while then park the van for a bit (for like an hour or so), when I come back to it and start it again it will start but seems a little weak and kind of putters. If I start to drive right away it will struggle a bit but eventually "come-to" and be back to normal. The same will happen if I sit and let it idle for a while until it stops the puttering.

So my question is, what do you all think this is? I think it's likely a vacuum leak, but am not sure. I would appreciate y'alls advice as you are true experts! Thanks!

[Cali Cruiser]

There are several things that it could be, but here are a couple of quick and easy things to do first.

Check your cold-start injector. Remove it, clean it, and test it to confirm it is working properly.
Check your air intake hose for cracks, rips, or damage of any kind.
Replace your fuel filter. If you haven't changed it, I bet the person you bought the van from didn't either.
A full tune up might be a good idea. I suggest spending a few extra bucks for iridium spark plugs.

How many miles are on your van?

[Burntboot]

Always check for stored codes
Always diagnose problems prior to doing other maintenance/repairs

CC's list is a good start, but you still need to know if the computer has logged any faults.

[tennesseetoyota]

Van has 125,000 miles on it.

I checked the codes and observed the following, would they have anything to do with it?

I read the codes by shorting the check engine connector and got what I think are two codes. I pulled the code number 4 and code number 11.

For code number 4, the manual says that it's an open or short circuit in water temperature sensor signal.

For code number 11 , the manual says that "Air conditioner switch ON, idle switch OFF or shift position in any other position other than P or N range during diagnosis check." Which the van was in P when I did the check. The air conditioner is disconnected (the belt is disconnected), so would that have something to do with this code (code number 11, that is)?

I also recently replaced the air intake hose (the big one right on top under the driver seat), so that doesn't seem to be my problem.

Thanks!

Here's a PDF of the diagnostic codes:
6883

[VanCo]

A bad water temp sensor (or messed up sensor plug wiring) would explain your symptoms.

Did you touch the throttle at all while reading the codes? If you take it off idle while the check engine connector is connected it can throw a false 11. If not there is a lot on this forum about the 11 code.

[tennesseetoyota]

After a very long ordeal, I SOLVED mine. the intake plenum gasket, the one between the top and bottom of the entire manifold., was leaking. When engine heats up, stops leaking. I did the senor thing, the tps, and much much more until I tore the ole gal down, and saw some gasket missing.... and then it made sense, once while troubleshooting and fiddlin with stuff, running really bad, i had a misfire and saw a puff of smoke come from the area, and i thought, wtf..... should have paid more attention and got right to it., but skipped over it to my ignorance....
just a thought...I would not be surprised if this is others problem, too.... mine came on real, real slow, hard starting at times...but could get it running by pulling of temp sensors, which was just tricking the ecu..... I rebuilt my 83 , 100% and this is the 1st issue since i did the job, back in 1999...

I'm having an identical problem. What is the intake plenum gasket and where is it located?

[tennesseetoyota]

Soooo, it turned out that there was a cable physically unplugged from the sensor on coolant filler neck:

7006

Plugging this back in resolved the issue of hard starting, now it starts on the first turn and continues to run! Also, both codes are gone and have been gone for the past 200 miles or so

The only issue I'm facing at this point is that, after I park it after driving (for long enough to where the van reaches operating temp) and let it sit for a while (10+ minutes), it has issues starting. It struggles in a similar manner as before, just kind of idling weakly unless I floor the gas pedal, after which I hear a whoosh of air and it idles normally.

Any ideas on what this may be?

[tennesseetoyota]

Hello all! Hope you are well.

After figuring out that the rough start from cold issue was due to one wire being completely disconnected (see below), I have resolved codes 4 and 11 (have driven around 100 miles, codes aren't coming back :)).

7016
Red arrow points to wire that was disconnected. Where the wire connects is circled in red. It's just kind of sitting in there right now. Is there a sensor that's supposed to go there?

Now I am facing the issue that the van has trouble starting after I have driven it around for a while and then parked it for > 15 minutes. It struggles and idles rough for a minute, then if I take off and give it gas I hear a whooshing sound and the van is back to normal.

Any ideas what this might be?

Thanks!

[tennesseetoyota]

That picture is of the coolant filler neck by the way, just for reference.

[BelueJacques]

Could anyone clarify….is that the “idle-up/water temperature switch” that has been mentioned many times as a spot to ground for help with Heat-soak?

[originalkwyjibo]

Yes, that is the one.