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scksupe
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after driving about a half an hour or so, and then when i cut the car off then leave it for a while, when i go into the store, then go back out and try to start it, the car idles rough and cuts off then i turn it on again and does the same thing so i press the gas and it putters and then shuts off. then i turn it on again and put it into drive, then press on the gas it accelerates real slow for about a couple of minutes then drives fine, what could this problem be?
 

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scksupe
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Discussion Starter #2
i just changed the fuel filter and the afm. the car is a 86.5 NA
 

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scksupe
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Discussion Starter #3
anyone have any ideas on what this problem could be?
 

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sounds like the same problem i had in a pick up once, it had a pressure soldenoid in the tranny to tellit when to go into overdrive and it was bad causing the car to run fine, then after warm up turn off then back on it would putter, black smoke, ect
..that was the only time i have ever seen that, unless your coolent temp sensor is telling the computer full lean because it is malfunctioned thinking its cold all the time.. hope this helps
 

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Mine does close to this, except usually if I rev it up it'll stop dying, but still idle a bit rough. And if I move a bit in first or reverse, it stops trying to die. But sometimes I still have idle issues.

I'm still checking for vac leaks/exhaust leaks (my IC pipe hose clamps are crappy, they are getting replaced.) and going to check/adjust the tps soon.
 

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Honestly Im interested in hearing a good answer to this too cause it seems to happen in other cars too. My first car was an 88 Ford Taurus POS and it did the same damn thing. For some reasons it seems to be prevalent in automatics? I never have figured it out because I have tried doing every thing I could think of and never could cure the problem. I even took that damn car into 6-7 other mechanics and they couldnt give me an answer either. Someone really should answer this question cause it has bugged the hell out of me for years.
 

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Oldie but a Goodie
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Mine is very intermittent, but virtually the same thing. I can only imagine it's from a vacuum leak but I'm really not sure. Haven't looked into it enough yet.
 

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I can't believe this hasn't been answered definitively by every post so far! I thought many of us knew about this, but since that's apparently not the case, I'm glad I can share something that will dismiss any fears you have about your car not operating correctly. Honestly I'm somewhat surprised this is such a huge mystery...especially the mention of going around asking mechanics, and them not knowing answers! Well, for better or worse, most of you guys don't have anything to fix--at the least, stop worrying about vacuum leaks or TPS adjustment!

This is textbook heat-soak, as was mentioned in the post before me. As was speculated, it can in principle occur on any vehicle, and is more noticable in automatics once placed in gear due to the extra engine load at idle. What happens is that, as the warm engine sits, the engine compartment actually warms up due to lack of active cooling. Soon the fuel in the rail vaporizes, and basically tries to clear out of the area of the injectors and other hot locations. When you restart before the engine has entirely cooled and the fuel condensed again, you're feeding vapor and/or lower liquid pressure to the injectors, and in the nicest cases, get a low and lean idle. My car has never died because of this, but it's not great to let it idle at 500RPM.

This problem is most pronounced on turbocharged cars of any manufacturer--the turbo and related assemblies store a lot of extra heat under the hood which builds up the moment the fan stops pushing fresh air into the compartment. This problem is much worse if you do not let your car idle down properly (as I'm afraid many Supra owners don't), or do not have the watercooling lines attached to the turbocharger (those cooling lines are specifically designed so that heat convection automatically causes coolant to continue to move slowly through the turbo, considerably helping its cool-down). Restarting ~30 minutes after shutdown is, if I understand correctly, often cited as the worst heat soak gets.

A quick fix is a gentle, constant rev to ~1500RPM for a few seconds. Depending on the severity of the heat soak, you may need to be cautious about pushing the throttle, or it could stall. The problem should completely resolve itself pretty quickly, or almost instantaneously after a gentle rev or two.

This is actually completely normal operation, except in cases where it seriously effects drivability (sounds like the case with the original post here). Brand new MKIIIs off the production line had to deal with this, and I believe Toyota engineered some things into the system to make the effect less than it otherwise would be. If heat soak is a big problem for you, ensure that your car is not running hot, and that you idle it down properly. A warmer engine or turbocharger at shutdown will make the problem much worse than it needs to be--also keep in mind that you can heat-torture your engine and components AFTER it is off, because things do INCREASE in temperature once the cooling mechanisms shut off, even though heat generation also stops.

So, if this problem is severe--there was a mention of a case where driving any distance in 1st or reverse tends to make the problem disappear, for instance, which is like my case; something to just deal with--then you probably have some sort of cooling issue or don't idle-down. Good luck all...I'm happy to answer or speculate about anything else related to your specific cases, because it seems so many are bothered by this.
 

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thank you for answering that man. Like I said Ive always wondered what the hell was going on with that. Now that I think about it my wifes Saturn does that sometimes. I never have the problem with my Supra or when I had my G2 Integra but my old Taurus used to do it a lot in the summer time. Great post :bigthumb:
 

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scksupe
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Discussion Starter #13
thanks for the response, finally someone had an answer
 

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wusaint36 said:
[...] my old Taurus used to do it a lot in the summer time.
Definitely. It's great to know the cause of these things, because then everything makes sense. If your car does have heat soak, you can expect it to, for instance, be really bad on hot summer days when you don't have a chance to idle-down and happened to have boosted recently before parking.

As far as dealing with it, I think it is much better to try and get it to go away or at least lessen before moving the car, especially with an automatic. If the problem is only as "severe" as a slighly low idle, you can probably be on your way, but if that idle is rough or anything close to a stall, sit there with it for a while and fix the issue with a few kind revs. And, again, gentle with the revving--the motor is running lean and the ECU quite confused as-is.

As a final note, also be aware of things that put extra load on the engine during this period. Power-steering, espcially at low speeds such as getting out of a parking spot, is an obvious concern...but one that some people don't think about is the alternator load from the headlights being used at night. Postpone turning on your headlights until the engine at least appears stable, if at a low idle.

Interesting comment by Viper. Definitely good support for seafoam, as it would imply that his engine is either running cooler or dealing with shut-down heat more effectively. Beautiful paint, BTW! :bigthumb:

I'm somewhat curious to hear from the people that indeed have bad cases of this problem, such as where the engine will actually stall. Do you guys idle-down the turbos, or have any doubts about your cooling system's effectiveness?
 

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Well my old POS Taurus had cooling troubles sense day one. I was always tracking down some kind of gremlin with the cooling system on that thing. It was a never ending story. Im sure that had a lot to do with the reason that car did it too.
 

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scksupe
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Discussion Starter #17
the supra started sputtering again all of a sudden i cant quiet figure it out. it was doing fine for a while adn know it is acting up again. I CANT FIGURE THIS SUPRA OUT!
 

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SMFL
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malloynx said:
this is why there is a FPR VSV in the vacuum system. to increase FP on hot start-ups
Think about how many people just strip things off their car. Their buddy did it and nothing happened so I will too. :dunno: Then in the middle of summer, it starts acting up for no reason.
 
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