Acceleration issue

JDM,
I guess I followed it up in this thread : https://www.toyotavantech.com/forum/...ough#post37112
Have you tried spraying water on the distributor-just to rule out somewhere else it could be shorting? If it happens when you spray it and you have another distributor I'd swap 'em. Also how old is your dizzy cap?
From the other thread- I'm thinking after cap, wires and plugs I'd check your coil. I think Papay was right on in that thread-he spray coated his coil in rubber. Not sure how to test the coil for wet shorting besides checking resistance before and after spraying it with a mist.
Also make sure your drain holes in the distributor are clear.`

I remember MAHLEEk had this exact issue symptoms and all and replacing the coil resolved the issue. Additionally maybe the exhaust is plugged or restricted?

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Originally Posted by djshimon

Also how old is your dizzy cap?

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Thank you for the quick response!! The OEM cap is 4 years old and about 30k miles but as for the ignition coil don’t think it was replaced when I originally had a ton of work done when I first got the van??

I’m thinking that has to be the issue!!?? I checked on RockAuto and there’s about 4 different kinds, is there a “part of choice” you would go with or should I order an OEM part?

JPERL,

Thank you for the response I think I’ll be starting with replacing the coil and keep my fingers crossed!

Thank you:thmbup:

JDM

Oem always seems better for Toyota but if it's an exhorbitant cost I'd get an aftermarket coil-others might weigh in here. If you're gonna be taking it out to replace it I'd check resistance on it before and after spraying it with water to see if it has an effect.

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Originally Posted by JDM VANMAN

Update, I’ve replaced the distributor gaskets but still having the acceleration in the rain, still can’t nail it down. I’m hoping that I’m using the correct terminology in this thread so I’m posting a video-

https://youtu.be/V-MdzSdvS8Q

thank you:thmbup:

JDM

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JDM, that looks suspiciously like a "Fuel Cut RPM" system issue. It's not talked about much in the manual, but mentioned briefly on FI-74 (87 service manual). It's an emission feature that turns off the injectors while decelerating. It's controlled by the ECU (Electronic Control Unit) based on the info it's getting from the TPS (Throttle Position Sensor). If/when it does it again, disconnect the TPS to see if the issue goes away. If you can make it come and go by disconnecting/reconnecting the TPS, then it's a bad TPS. If disconnecting the TPS does not affect it, then it's either a short in the harness (between wires IDL & E1 somewhere between the TPS and the ECU) or it's a bad ECU. Good luck and please update with your findings. Tim

PS: Since it's affected by water, you should also check the seal on your TPS connector. If it's damaged there are aftermarket connectors available. Tim

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Originally Posted by JDM VANMAN

Thank you for the quick response!! The OEM cap is 4 years old and about 30k miles but as for the ignition coil don’t think it was replaced when I originally had a ton of work done when I first got the van??

I’m thinking that has to be the issue!!?? I checked on RockAuto and there’s about 4 different kinds, is there a “part of choice” you would go with or should I order an OEM part?

JPERL,

Thank you for the response I think I’ll be starting with replacing the coil and keep my fingers crossed!

Thank you:thmbup:

JDM

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I nabbed this coil off of Amazon.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Seems to be working great so far! The old OEM one had burn marks on the top and the cover was cracked.

I'm not sure if there is a "choice" one, but taking out the old one sure made a difference with the idle. I still had the little rubber gasket under the original dizzy cap though.

Tim,


thank you for the detailed reply as always, Lots of good info!!! But this happens when it’s raining and when I start to accelerate from 1st to 2nd gears, hit a puddle on the right side, and then instantaneous loss of acceleration. I’ll pull over and the idle will be steady except for when I push the accelerator down half way and then it’ll not pass the 2200rpm range.

On any other dry day the van will fire right up and run smooth all day long:thmbup: Although the TPS has never been replaced along with the ignition coil, that’ll be the starting point to help resolve this issue.

Flecker,

thank you for the link on the Delphi coil, I think that’s the one the shop put into my TownAce when I was having issues with that van and it’s been running fine. I wanted to OEM part in the TownAce but they had already diagnosed the issues and repaired it before I could ask for the OEM part.

Thank you I’ll keep you posted!!

JDM

That is a little different than the symptoms i had. From what i remember: When I would hit a puddle the idle would go down to like 500rpm and when i would accelerate it would hesitate/stumble/run like crap at lower rpms until i got it up to about 2500-3000 then it would run ok. It didn't hit a limit like yours that i can remember. Very curious to hear the cause of this but i don't doubt Tim is right.

Yes I don’t doubt Tim either ( I’m no where in the position to do that) but it only happens on acceleration and not deceleration, it’ll last for 6,8,10 minutes I’m guessing where the rpm’s just won’t go over the 2200 mark.

Did you happen to notice any peculiar smells when this happened to you? I would have to say I do smell something but can’t put my nose to what it is, it’s not something easy like burning clutch, radiator fluid.... I’m thinking it’s more of a rich exhaust smell when this happens. Eventually after holding the accelerator for the duration of time and it clears up the rpm’s start climbing back up like normal again and away I go???

Friday I went in to my Tech that works on the van and reviewed the whole scenario with him again and he said they did fill up a bottle and spray it on the distributor cap and in the general area and the van kept idling like normal, they did this when I asked them to replace the gaskets a while ago. I told him it only does it upon acceleration so one person would need to hold the accelerator to 2500 rpm’s while the other sprayed water. He just said “ahhh ok we’ll check it out”


It sucks cause it happens in the rain when I’m going to and from work 6am-9pm and it pitch dark, or I’m on the freeway. Oh and the most important... my lack of wrenching skills.
JDM

Any chance a code showed up? I watched your video again and it's definitely different-mine was like a misfire-not saying it isn't your coil though (can't see from here!). I would probably have someone on the gas and I'd have a sprayer and I'd just go around spraying things one at a time until the problem rears its ugly head again.

No man, every time it’s happened it’s been dark and plus I haven’t taken the time to learn how to pull codes even though there’s a very detailed thread on how to do it. :no:

The very first time it happened I had the van towed off the Express Lanes to the shop and by the time they started to work on it, it fired right up. Only thing I can do is drop it at the shop and pay them to recreate what I’ve been experiencing and get the explanation.

I’ve asked them to use the service connector to pull codes or I could even bring in the FSM but they just looked at me and laughed, not in a melicious way of course, they said they don’t use the Stone Tablets anymore. :LOL2:

JDM

Stone tablet-it's a paperclip! But yeah it's a very simple machine compared to my 2013 Prius-quit laughing! Just thinking if a TPS code was thrown that'd give more Credence to Tim's theory. You should really check your codes it's fun-it's literally putting a paperclip into a yellow dangling connector and turning the van to "on" and counting the blinks. If you miss the blinks, they repeat. Well that's enough pushiness for tonight, until next time!:bluevan:

I watched the video. That's 100% what fuel cut does on acceleration. Basically the computer is getting a signal the throttle is fully closed. It then limits injector output. If this happens when you're accelerating it will act as a kind of rev limiter at 2200 rpm. More than likely a tps wire, tps connector, or bad tps is getting wet and completing the circuit.

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Originally Posted by VanCo

I watched the video. That's 100% what fuel cut does on acceleration. Basically the computer is getting a signal the throttle is fully closed. It then limits injector output. If this happens when you're accelerating it will act as a kind of rev limiter at 2200 rpm. More than likely a tps wire, tps connector, or bad tps is getting wet and completing the circuit.

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I think you nailed it man... When I first started tearing into my van a little over a month ago I ripped off all the access panels and pressure washed all the crapola out of the engine bay. Shortly there after mine started doing the same thing! Idle seems ok, but when I revved it I found it started cutting out in the upper rpm's. I pulled the codes and got a code 2 AND 11. I knew the afm circuit was having issues, the wiring was cut. Fixed that and still got a code 11 after the fact.

Ordered the new beck-arnley tps and everything went back to normal.

I think he needs a new tps. I ripped my throttle body off and cleaned and cleared all the vac ports as well... about a 2 hour job. I will say again, I am a huge fan of putting di-electric grease in ALL my plug fittings, it rules out the potential for faulty wiring connections (at least at the plugs)!

Pull the codes and if you see a code 7 OR 11, just get a new TPS. Amazon- https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

42 bux shipped if you have Prime~!
:dance2:

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Originally Posted by JDM VANMAN

..............but it only happens on acceleration and not deceleration, it’ll last for 6,8,10 minutes I’m guessing where the rpm’s just won’t go over the 2200 mark.

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Yes, it's only supposed to happen on deceleration. Since it's happening on acceleration it would be a malfunction or an "issue" with that system (sorry I didn't make that more clear in my post).

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Originally Posted by JDM VANMAN

It sucks cause it happens in the rain.............
JDM

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And this is why I think you should check the TPS connector seal as well as the TPS and the harness. It could also be an issue with the ECU, but since that's much more sheltered from water splashes that's less likely. I suppose it's possible it could have a problem with humidity inside the ECU box (when conditions are right), but that's somewhat of a stretch. Tim

Tim


No worries, I cling on to everything you say... Tim’s word is The Law when it come to diagnostic explanations but you know you have to talk to me like a 2nd grader because of my lack of wrenching skills!! :cnfsd::cnfsd::cnfsd:


I’m attaching a new video of the codes that came up when I jumped the ODB1 wire.
I got code 4 and 11 and code 7 and 12


I don’t think any codes have ever been cleared but after addressing them I’ll need to clear them out.


djshimon,


Thank you for building up my confidence in how easy it is to read the codes!!! Now teach me how to clear them!! :dance2:


Vanco,


Thank you for chiming your input and explanation this helps not just for me but everyone reading!!


Flecker,


Thank you for your link to a new TPS, I think I’ll order a new connector as well but I can’t seem to figure out which one is the correct one for the TPS?


I’m gonna order the new Ignition Coil, TPS and the TPS connector, thank you all for the inputs and redirects to parts!! Tremendously helpful!!


https://youtu.be/IYLidTY91JY

JDM

4- water temp sensor
5- O2 sensor
7- TPS
11- switch signal


Theres a pdf on here that explains all this... http://www.toyotavantech.com/forum/c...gons-all-years

If those codes are all relevant your prolly at about 100 bux or so for the tps , O2 sensor (if bad, not unplugged) and the temp sensor (if it's bad and not just unplugged).


Again- for the parts...

O2 sensor : https://www.amazon.com/Denso-234-105...ords=o2+sensor

Temp sensor: https://www.amazon.com/Beck-Arnley-1...erature+sensor


The tps is the one jacking with you more than anything though.

I've used the Standard #S745 Connector for the TPS. FWIW, this should be considered a crucial connection and be soldered/shrink tubed to the harness. Wire nuts and/or solderless connectors may work as a temporary fix, but things like this should be sealed and protected as it reduces the risk of future issues.

As mentioned multiple times in other threads, once documented, it's recommended you clear codes then see what comes back. I'm guessing you'll see codes 7 & 11 come back (7 would explain the current problem you're having & 11 is also usually caused by a failing TPS). I sort of doubt 4 will come back as the van would run terrible all the time if that temp sensor was bad. Code 5 may or may not come back. The van can run decent with a bad o2 sensor but your performance and economy will suffer. Just follow the link Flecker gave and that should explain things in more detail. Here's a link that shows how to service and adjust your throttle body and TPS: https://www.toyotavantech.com/forum/...-Throttle-Body. Tim

Even easier to clear codes, disconnect the battery cable from the negative (ground or -) battery terminal for about 30 seconds-60 if you're wanting to be thorough. Don't mess with the positive terminal. Some of your stored codes could be old but the tps one is probably the ongoing.

Tanks guys, I’ve got all the parts ordered and they’ll be showing up in the next couple days!!:thmbup:

JDM