Supra Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
174 Posts
Discussion Starter · #1 ·
hello guys, I have been having this warm start problem for ages now. first let me start by some specs.

94 MKIV US specs TT MT supra.
stock turbos and fuel system.
HKS cams and cat back system.

my problem is. the freaken car will not start easily once it warms up, cold starts are no problem at all, but if I let it warm up and shut her off then try to restart in half an hour or so, it will just keep cranking some times till the battery is drained and it will not start, if I let her cool down for a couple of hours or so, it will start right up.

I have read somewhere in here about a trick that helped me with the hot start problem but that trick does not always work.

the trick is to push the gas peddal all the way while the igntion is on for 15 seconds or so, and she sometimes will start after doing that trick but I would have to tab on the gas peddlal while trying to start her but again that does not always work, it sure does help big time, or it least it acts like it want to start but she will not idle by her own.


I am not sure if it's flooding problem by a leaky injector or it's loosing fuel pressure when it's warm. by doing the hold the throtal wide open while the ignition is on for 15 seconds before starting (cranking) trick some times help, what does that tell you guys???


any help would be greatly appreciated.

thanks
 

·
Registered
Joined
·
872 Posts
check fuel persure VSV. per FSM
 

·
Registered
MKIV TT 6 Speed
Joined
·
1,488 Posts
Check your IACV, battery and alternator. It might be one of those if you’re saying you’re having a problem with warm start ups and idle, your IACV “Idle air control valve” motor might be failing and restricting the proper amount of air into the intake manifold. Colder air is denser and in your case it might just be enough to get the car running with a bad IACV.

Also you’re mentioned after trying to crank it over and over your battery drains it shouldn’t if the battery was in good operating condition. The battery might also be a factor on your problem or even your alternator.
 

·
Registered
Joined
·
481 Posts
This may sound stupid, compared to the other advice everyone has given...but your spark plugs may be shot or coilpacks going bad. Holding the gas wide open on crank cuts the fuel injectors off, so if that trick does work sometimes, your plugs may be fouled causing them to get wet with fuel when you try to crank. So in a nutshell try changing your spark plugs. Hope it helps.
 

·
feeding your habit
Joined
·
4,015 Posts
because you say it's a hot start issue, I'd check the FPR. I'd also suggest checking the wiring under the coilpack cover to make sure there are no broken insulators on the wires or connectors. If those check out OK, then check the coilpacks.

These are the things that I think of when you mention it's only an issue on hot starting.
 

·
Registered
Joined
·
174 Posts
Discussion Starter · #6 ·
thanks for the help guys.

here is what I have done so far and that did not help with the problem at all.

I changed the battery way too many times, if I leave the car for a week or so the battery would just die, the problem ended up to be my radio, so if I unplug the radio fuse, the car better will not drian out as fast.

I have also changed the spark plugs and that did not help either.

cleaned the IACV and that also did not help.

can you guys please tell me what does the trick that I mentioned earlier do, I sear I read it somewhere in here. it's like I go and floor the gas (before starting the car) and turn the ignition on (do not crank tho) and wait for 15 seconds, I then turn the ignition off and let go of the gas peddal and start to crank, if I do this (when I am having the hot start issue) the car would act like it would want to start but it would not idle untill I manual tab the gas pedal while cranking till it eventually starts. so what does trick do???

I bought this car used, and the guy seemed to mess with the canister, it's still there, but there one of the 3 hoses that goes in it is just not there, so maybe this is the source of the problem.

another thing that I found out whoever had it before, decided to cut the second O2 sensor harness off, I know with that year and model you can just leave the second O2 sensor pluged but hangit in the air rather than in the exhaust pipe, so now I just can get another O2 sensor, but the guys cut the 4 wires with the plug off, and I don't want to solder it just like that especially there are 2 white wires that I am affraid I would switch them up and fry the ECU or something.

so could it be the second O2 sensor not pluged or the canister or something else?


one final thing, this problem seems to get worest when the ECU is reset (when the batter dies) but if the batter behaves and the ECU get a couple of day of driving around (learning) the problem seems to be a lot less.


sorry to bug you guys, but I am really pulling my hair out because of this problem, I felt like $hit a couple of times when the car just would not start while I am out with my frineds or the wife, it's like I would stop to eat out or something with my wife, come out and spend long time to start the freaking thing, and sometimes the battery would die before I get to start the freaken thing.

your help is much appreciated guys


thanks
 

·
Registered
Joined
·
872 Posts
check fuel persure VSV. per FSM
did you ever check it? check the IAC too not just clean it.

difficult start when hot check these:
1,sterter signal
2, IAC valve circuit
3,VSV for fuel pressure
4,fuel pump control
5,ingector circuit
6,ignition coil
7,spark plug.
 

·
Registered
Joined
·
707 Posts
98mkiv posted the fix. This is a known issue that comes up every once in a while with the oem fpr. Once it gets hot it lowers the fp below 34 psi and there for the afr's at idle are lean (~15.0:1) and the car is hard to start. Either swap out your fpr from someone who has upgraded their fuel system or have yours checked.
 

·
Registered
Joined
·
707 Posts
You are welcome. Once it's fixed just send us oil as payment :)
 

·
Registered
Joined
·
174 Posts
Discussion Starter · #13 ·
You are welcome. Once it's fixed just send us oil as payment :)
Looool, will do Sir, but if the problem will not be fixed, you will have to start producing more Electric cars cause you ain't gonna be getting no more oil from us :)


Ahmed
 

·
Registered
Joined
·
160 Posts
I know this is an old thread but it helped me out i think. I found that somehow i made the mistake of putting insulating antiseize compound on my plugs. I have no idea why i did that. I cleaned them up and works fine every time. It wasnt bad plugs but dirty threads so my ground sucked ass.
 

·
Registered
Joined
·
174 Posts
Discussion Starter · #15 ·
actually the problem was in the injectors, the guy who had the car before me "I think "blew the motor up and put a JDM motor instead, that means the car had US ECU and Jdm injectors, I changed the injectors with US ones and it has been perfect ever since.


Ahmed
 
1 - 15 of 15 Posts
Top