87 showing codes 3 and 11

[pete]

My 87 2wd le with 274,000 mostly struggles to pick up speed down the road and eventually gets goin down the freeway. Sometimes She runs fine but always has horrible gas mileage.

It cuts off for split second when i give it gas (I thought Throttle Position Sensor). It does it every few seconds with the increase of gas pedal pressure. The check engine light flickers on in time with the engine stutter. no other lights show.





Showing codes 3 and 11.



#3 is ignition signal, no signal from ignitor 4 times in succession.
1) ignition circuit (+B,IGF,IGT) 2)ignitor, 3) ECU see FI-32

#11 is switch signal, Air conditioner switch on,idle switch off
1)air conditioner switch, 2)throttle position sensor circuit,3)throttle position sensor, 4)neutral start switch , 5) ECU


pulled the TPS and everything checked out ok with it.


Any Ideas on where I should try next. Anyone had something similar?




Ps.

Caution !!! when putting the sensor back on the throttle shaft because the old plastics are brittle and the metal throttle shaft pushed against the sensor plastic female housing up top where the metal ring is and I forced it down on the shaft and it snaped the ring off and broke the plastic.






Here are the old and new screws for attaching/removing and adjusting sensor on throttle body. The old style phillips strip out and then the whole throttle body has to come out to get it off then you have to grind the head out. Especially after 200,000 miles on salty roads. The upgraded hex heads I bought at lowes hardware. I think they were under a dollar. They can be loosed with a small hex key which is perfect for new TPS adjustment and later maintenance or troubleshooting without throttle body removal:

[timsrv]

Take a look at your EGR modulator. If it's burned or melted then your cat converter is plugged up. The cat converter being plugged won't usually throw a code unless it's a CA vehicle with an EGR temp sensor.........and 88 was the 1st year to have that.

I think the code 3 is left over from something a while back (possibly before you got the van???) If that condition were still there your van wouldn't run. Clear the codes and check it after a few days to be sure it doesn't come back. As for the TPS, IMO any van that has over 100k miles with an unknown history should have the TPS changed just for the sake of preventive maintenance. Even if the TPS tested good it could have been having intermittent issues. Replacing it was the right thing to do. Before looking for other causes for code 11, wait a week and check codes again (I'll bet it doesn't come back). Tim

[pete]

I know it's not the converter because I just went through a converter issue about 2,000 miles ago. The battery was disconnected to clear the codes. Do I still need to pull the EFI fuse too? These codes showed up after clearing them by battery only. I had taken the battery out for a few days and when I drove the van again, they showed up.

[timsrv]

Battery disconnected for 30 seconds or so should clear codes. Did you verify they were cleared before you started back up?

If the codes were clear but came back, then I might suspect a weak igniter or ignition coil. These type of problems can be hard to diagnose. With that many miles it really could be anything. Did code 11 come back after the TPS was replaced? Since I have so many extra parts laying around I will usually swap parts as this is usually the fastest way to figure out a problem. I don't suppose you have that option........do you? If you do, I'd swap MAF sensor 1st (easiest), then ignitor, then coil. I wish I could be of more help. Tim

[pete]

Before the throttle body was taken off and tps out, I put battery back in and drove it with cleared codes. Not sure how long it took for cel to come back on, but when it did 3 and 11 showed. This is an 87 2wd.

Plan to put new tps in tonight.

Did not understand all the angles the shop manual says to do. I know there is a simpler way. I just don't remember where I put my notes.

[timsrv]

Here's a thread where this is discussed: http://www.toyotavantech.com/forum/s...gnition-timing. I get into specifics of TPS adjustment near the top of page 2. If the TPS is new, just ignor angles and set it by using a feeler gauge in the throttle stop. This is the only adjustment you need to make. If you get this one right all the others will fall into place. Tim

[pete]

Thanks for the link to the thread. I do have a question. Probably a stupid one and betrays my ignorance of the throttle and idle system, What if your stop screw has been messed with. I know there was an idle problem a little while ago and i messed around with it. I have experience in dissasembly and cleaning of engine sludge on IAC motors
(a $200.00 part if you haven't learned how to clean them correctly) on 97-01 toyota camrys to solve a very common problem with engine stall at idle. Is this screw the only adjustment for idle? How am i to know my stop screw is set right? I apologize for being ignorant in van idle adjustment and throttle position.

[timsrv]

It's funny you should ask because we had that exact discussion in the last thread I linked you to. Just go to page 2 and read everything below the TPS post I made. I need to make a better post regarding TPS replacement and adjustment that explains this proceedure with the throttle body removed. I'll be doing this job soon an another van so I'll document it then. Tim

PS: I just edited one of the pictures in my TPS post to show the idle adjustment screw location.

[pete]

Thanks,

Still have not got back to finish this work yet. Any day now would be nice.

[robgagnon]

Hi all,
I've spent countless happy hours reading thread after thread, so thanks for that!
Anyhow, code 11 indicates:

#11 is switch signal, Air conditioner switch on,idle switch off
1)air conditioner switch, 2)throttle position sensor circuit,3)throttle position sensor, 4)neutral start switch , 5) ECU

But what does these actually mean?
1) the the AC switch on the dash is actually turned on?
2) I get this
3) I get this too
4) is this just for automatics? does it have anything to do with the clutch depressed switch?
5) ECU - don't take me there!

So I hopefully cleared out the ECU by pulling the fuse for a minute or so and without restarting the engine checked the codes again. Still got 11. Does the ECU know to throw a code even if the car has not been run?

Hmmm, idle switch off. That means I think that the idle switch signal coming from the TPS and the ECU wants the idle switch on? Perhaps my TPS is misadjusted/no good and doesn't provide a idle signal at all even with engine not running and ECU knows it. So I plan to test it out per the great threads on TPS adjustment when time is available.

Would anyone care to direct me to a thread that explains what the TPS does? I know the TPS causes an extra injector cycle when going from idle to non-idle. What else does it do? Can a TPS that does not provide an idle signal cause a van to lack power in general (not just a hesitation on initial acceleration)?

Thanks - Rob

[timsrv]

I'm sure there are situations where code 11 means something else, but every time I've seen it it's been a bad or disconnected TPS. The TPS is a common failed part. I've had a lot of vans, and every single one I purchased with over 100k miles had a bad TPS. If the van has over 100k & you get a code 11, I would just replace the TPS. While the throttle body is off, I would give it a good cleaning. Here's a thread where this is outlined: http://www.toyotavantech.com/forum/s...-Throttle-Body. If you don't want to clean the throttle body, just skip to the end. I posted a video at the end that shows how to adjust the TPS.

As for not being able to clear codes from the ECU, that's an indication the ECU is faulty. If it doesn't clear by pulling the EFI fuse, try disconnecting the battery (leave it disconnected for at least 30 seconds). If that doesn't clear codes, then try another ECU. These can be found on eBay for around $50. FYI, with older vehicles it's a good idea to have a spare anyhow (along with a few other things).

As for what the TPS does, on these vans it's function is pretty basic. It tells the ECU what position the throttle is in. The ECU uses this data to (along with O2 sensor, temperature sensor, and air flow meter data) to deliver the correct fire times to the fuel injectors. The more data the ECU has, the more precise the fuel mix. A precise fuel mix means best possible power & economy while keeping emissions to a bare minimum. The TPS is also an integral part of the Electronic Timing Advance system. A bad TPS will usually render this system inoperative. You can test the advance system by jumping the Check Engine Connector & checking the timing. Once you verify the ignition timing (12 deg BTDC), pull the jumper and recheck timing. If the electronic advance is working the timing should jump to around 20 deg BTDC. Tim

[Don Kihote]

I'm sure there are situations where code 11 means something else, but every time I've seen it it's been a bad or disconnected TPS. The TPS is a common failed part. I've had a lot of vans, and every single one I purchased with over 100k miles had a bad TPS. If the van has over 100k & you get a code 11, I would just replace the TPS. While the throttle body is off, I would give it a good cleaning. Here's a thread where this is outlined: http://www.toyotavantech.com/forum/s...-Throttle-Body. If you don't want to clean the throttle body, just skip to the end. I posted a video at the end that shows how to adjust the TPS.

As for not being able to clear codes from the ECU, that's an indication the ECU is faulty. If it doesn't clear by pulling the EFI fuse, try disconnecting the battery (leave it disconnected for at least 30 seconds). If that doesn't clear codes, then try another ECU. These can be found on eBay for around $50. FYI, with older vehicles it's a good idea to have a spare anyhow (along with a few other things).

As for what the TPS does, on these vans it's function is pretty basic. It tells the ECU what position the throttle is in. The ECU uses this data to (along with O2 sensor, temperature sensor, and air flow meter data) to deliver the correct fire times to the fuel injectors. The more data the ECU has, the more precise the fuel mix. A precise fuel mix means best possible power & economy while keeping emissions to a bare minimum. The TPS is also an integral part of the Electronic Timing Advance system. A bad TPS will usually render this system inoperative. You can test the advance system by jumping the Check Engine Connector & checking the timing. Once you verify the ignition timing (12 deg BTDC), pull the jumper and recheck timing. If the electronic advance is working the timing should jump to around 20 deg BTDC. Tim

Dear Uncle Tim, I try to find but there is no video as you guide here (the bolt words). Please show it to me, I have just replace TPS. Thanks a lot!

[timsrv]

Click on the last image in that post and that should take you to the video (I just tried it and it worked for me). It may take a few seconds to load, so be patient. If that doesn't work, here's another link: http://s8.photobucket.com/user/timsr..._0426.mp4.html