Car wont start hot
 

87 7mge manual.
Ive been trying to find out whats wrong with my car for the last 6 months.
When my car is cold it starts easy and runs fine, till I get somewhere. Ill kill it, when I come back to it after sitting 20 mins and the engines still hot it will turn over but wont start. If im lucky I can get it to but it spits and sputters for about 4 miles then clears out. The funny thing is when its running after a cold start the engine cant take full throttle pretty much falling on its face, but once the engine warms up its fast as hell. I cannot find the problem anywhere.

I have tested just about everything in the car and everthing so far checks out. I just did a diagnosis on it and im comming up with 51. If it was the neutral start switch the starter wouldnt even try to start the car. I replaced the o2 sensor, TPS, pickup coils in the dis., wires, plugs, coil, fuel pump, FPR, fuel filter, air filter, and battery cables. I also replaced the grounding straps from the trany to frame, and engine to frame. and I cleaned the grounds comming from the bat. ground to the frame.

I also took a ohm meter to these, MAF, control modual and I also check the wires going from the ecu to the, tps, maf, control modual, o2, and injectors.

Nothing is wrong with this damn thing so why doesnt it want to start when hot. All the hillbilly mechanics around here know nothing about supras. I just want my supra fixed. please help me

when it cranks but wont start, check for spark, if you're getting none, you know where to go from there. If you are, check fuel. Most of the engine is mechanically in sync, so if it is getting spark at the right time, and is getting fuel, it should run.

Sound like a fuel problem. Toyota had a real 'hot hard start' problem back then. The intake valves get very carboned up. Read and do this first. http://www.toyota-supra.info/forums/...injectors.html

It may fix your problem, and certainly is good for your engine.

You MAY have an electrical component that has a bad spot in it that is effected by a hot underhood soak (parking for a while, then trying to start engine). You will have to test parts and 'catch it' in the act.

I might have found the problem :) I did the injector cleaner and carb cleaner in the intake, but it was still messing up so I started to pull the wires and plugs to take a look at them, see if the plugs revealed anything.

Everthing checked out till I got to the last two plugs. The spark plug wells where half filled with oil???? My valve cover gaskets are leaking AGAIN.

I replaced them about 8 months ago and stopped the leak. When they leaked last time it didnt cause my car to mess up, but I knew it would eventually so I replaced them and checked it every week for about 2 months with no signs of a leak. Im sure the day after the last time I checked it, it started leaking again. lol I hope this is it.

Oh and I had one other Q. When you adj the tps, do you set it based on how the engine runs or on ohm resistance. thanks

Set the TPS off of the resistance as stated in the TSRM

Im really close to giving up on the supra, I got it back together and she's still messed up. I fixed the hot start thing. At idle it purrs like a kitten. If you gently press the throttle it will rev up and rev down like normal, but on the rev down if you give it gas to rev back up (like if you where shifting) it missfires and feel like the motor is boged down. If I give it full throttle, It acts like you turned the key off and wont rev up at all. The RPM needle just falls all the way to 0. (dies) A gentle throttle has more of a pull then full throttle. I dont know what to do know.

I took it for a trip about 500 miles. It ran great going there but on the way back it started running bad. When at a stop it idles at 500 rpm, flutters up and down till it dies.
Yeah and its not starting when its hot. Again. I smell fuel when I try to start it, but the spark plugs are white like its running lean. The car runs good when cold and bad when hot. I cant give it full throttle at all or it will start missing.
I looked around on the internet and nobody has a full proof solution to this problem.

Have you cheked your IC piping for leaks?
Try diagnosting the TPS sensor as well. The procedures are in the TSRM.

Im not running a intercooler. The 1st thread posted tells what I have tested.
Im going to a tech school right now, and my instructor told me it sound like my ecu is missing up.
Im going to run a ohm meter over all the terminals again to see what I find, but its too damn hot to be working on my car in the parking lot.
100+ allmost everyday. lol but I'll keep yall posted on what I find.

Im just wondering, what size battery does a 7mge need.

I had a very similar problem with my 87 N/A. I figured out it was my spark plug wire boot not being all the way 'snapped' onto the sparkplug. Made a slight adjustment and fixed my problem.

I just did a ignion rebuild. New distrubutor, cap, rotor, NGK wireset, and bosch platium 4 spark plugs. I ran good for about 300 miles then started messing up again. I was told that sometimes the transistors inside the ecm start going bad and are sometimes affected by heat.

Im not really sure this is the cause, but it would make sence it runs bad and good at random times. sometimes it takes 3 trys to start my car and other times it starts right up and revs to 1500 like its suppost to. Everything is really random and it seems to get worse the hotter the engine gets. (I just checked the coolant and cold start injector time switch yesterday and the ohms are within spec)

oh and it gets better, my car now for no reason at all idles at 400 rpm. Ill pull to a stop light and it idles at 400. green light Ill go to the next light, stop and it will idle at 700<---- this part here has me confused and the idle screw wont raise idle any.

take those bullshit bosch platium plugs out and get ngk and it should fix it or atleast help u out alot

My friend has a video camera so im gonna get some videos and post them that way yall can see what im talking about. Internet troubleshooting isnt gonna help if nobodys had this problem and cant see what the car is doing.

If I dont fix it in the next 2 months im thinking about selling the car and getting a truck. Supras are badass cars and all, but im not experiencing the badassness my car once had. Ive been trying to fix it for over a year now and im running out of money and patience. Im in a tech school for auto mechanics. Doesnt really leave money leftover for my car.

try asking your problem over on Supramania - Home of the Supra
Its not that they have better people or anything, they just have much more activity than this site.

I finally got a timing gun and checked it on the supra. I warmed it up, and jumped the te1 and e1 terminals, and was Idling at 800 RPM. It read about 20 degrees BTDC, which is way out of spec. So I adjusted it to 10 BTDC like the book says, and now it runs even worse. 1000 to 3500 rpms is fine, but no full throttle and no power above 3500 RPM. If I do give it full throttle it missed really bad and wont even accelarate and above 3500 RPM it misses bad but will accelarate as long as I ease into full throttle. WTF is up this doesnt make any sense, I put it where it needs to be and it runs worse than when its out of spec. Its a JDM motor, would that make a difference??? Any ideas? Please help

>carfanatic89 says: Im in a tech school for auto mechanics. Doesnt really leave money leftover for my car.

>If I dont fix it in the next 2 months im thinking about selling the car and getting a truck. Supras are badass cars and all, but im not experiencing the badassness my car once had.

Then stop throwing parts at it and diagnose the issue. This is going to be your career - right? Get to the bottom of it or quit - the world does not need more sub-par mechanics. Sorry to be down on you but honestly you should see this as a challenge and not act already defeated by it.

Since you already replaced the ignition you need to do some diagnosis work before you go out and replace the fuel system. Put a fuel pressure guage on the fuel rail and see what pressure you get. It could be a clogged filter or good old fashon vapor lock causing the issue.

30 psi. and hold that for 3 hours. The vsv's are working and the fuel pump regulator is recieving vacuum. I have built alot of engines and fixed many of my friends vehicles, but their easy to fix problems. Nothing like wont start when hot and will when cold. Makes no sense, Im just frustrated with this car ive been trying to find out whats wrong with it for over a year now. I have taken the car to toyota, and they couldnt find anything. The school im going to has a toyota program and they are clueless as well. Just because I want to get a reliable car inorder to get a relaible job doesnt mean im a shitty mechanic. everything else as far as maintenance has been done by the book. Nobody can help me with the problem and im currently on 3 forums to find the problem.

So the 30psi on the fuel rail is stable - meaning the same reading when it is hot, cold, running well, running like crap?

The vacuum solenoid valves are working - under what conditions were they tested? Back in the day I had a 280Z that acted similarly. A temperature sensor was faulty but bench tested OK - meaning it had the right resistance cold and hot - but it did not remain correct under prolonged heat. The end result was that the engine was enriching the mixture until it thought it warmed up - which it never did. It was eventually found after sitting on a diagnostics machine for about an hour.

Another thought is to monitor your fuel trim and see what the engine thinks is happening with the fuel mix while this is happening.

...or stick a wide band sensor in the exhaust and see if it is rich or lean for yourself when this happens.

I would also recommend the NKG plugs - even a cheap set until you get this solved. When my 280Z was running as I described in my previous post - the NKG plugs were the only ones that could shake off the rich mixture - the rest would just foul until they died.

Thanks that was more helpful, I just took off the timing cover to make sure the cam gears haven't jumped a tooth. everthing checked out and I started it and ran ok. The fuel pressure is to high right now to crack the line, ima let it bleed off some pressure. Then ill put the guage back on to check and get a fuel curve of all conditions and see what I find. As far as a wide band goes, do they make a wideband sensor that will bolt inplace of the old sensor to run a guage and send feedback to the ecm. If so can you tell me where I could buy one. I have ngk wires on right now. I have to wait till next paycheck to get ngk plugs. Im also going to put on a new intake. I think the old ones fine, but it is old and has some stress cracks in it and might be letting un-metered air in the engine. Thanks again, I know im really close to find out whats wrong with her.

won't run
 

It looks like you have done almost everthing. What done to check for vapor lock and or lack of fuel? The fuel filter, the inlet air elecronics?the

I have drivena Supra like yours for almost 150K miles and have never had problem like you describe. I had the head off mine and can not get it running. I gave up and have posted a thread to sell it.

Sorry am not much help. I am sure that someone will come to your aid with a good idea.

Dan Swanson

OMG I finally think I found the problem. I got this wild hair to open up the ECU and I found a resistor that was burned up. Im so happy words cant even begin to describe. I had to stare at the ECU for about 10 mins before I saw it. I literally jumped out of my car and ran around the parking lot. lol All the others are blue and the one burned up is white with black burn marks under underneath and from the edges of the resistor down the wires to the circut board. Here a pic my cameras kinda fuzzy but you can see the difference.

http://c4.ac-images.myspacecdn.com/i...47f525ea3f.jpg

What do I do now. I don't know anyone around where I live to fix this, should I try a computer store? I would like to fix i myself, but I dont know how to solder on circuit boards. Or take the old one off. As a matter of fact how is anyone gonna know what kind of resistor it is. I kinda dont want to by a used one from a salvage yard, it might be in the same condition this one is in, and I damn sure dont have 500 for a refurbished unit. Any advice welcome.

Try to get a clearer picture of the resistor, or tell us the color bands on it. Using that you can find the resistance. Then ohm it out and make sure it really is bad. Im sure a computer store would be able to do it for you, it isnt difficult, and you can just get a replacement resistor of the same value from anywhere like radioshack. If you cant see the colors you are going to have to find someone willing to take theirs apart and get them for you. Make sure that resistor is all thats bad on the whole board, seems like if that would burn out something else might have, and soemthing else might have in one of the chips. You just never know.

Well its one of the ones that doesn't have color bars on it, its just a solid color (blue) with numbers and letters on it. I ran the ohm meter over it and it read Infinite so I know its bad. I took the ECU to an computer electronics store and they said they could fix it easily, only 20 bucks. Which is cool, but theres a problem. I took the ohm meter to one side and it runs to the output terminal for the FPR, which makes no sence how did my car run without a signal voltage to the FPR to tell the relay to turn on??? Im in the dark on that one. Ima get my computer back friday, and put her in and see what happens. Ill keep yall posted

Good to hear they are able to fix it, hope it fixes your problem.

Car won't start hot
 

Carfanatic89.

I am glad to hear you my have found a cheap solution. I am looking forward to hear the out come.\

Dan Swanson

This is my luck. not only did it not fix the problem, but but made it worse. Now my car wont start. It will start rev up as much I want to like 4000 RPM then putters down and dies. Then wont start and I have to wait 30 mins to do I again. Another thing when I brought it to the computer store they couldnt tell the ohm of the original resistor. All it had was a 3 R on it so they guessed it was a 3.6 ohm rating. If I post a better pic of the ECU will somebody open their ECU with the same part number and tell me the was the resistance of the resistor. I would greatly appreciate if someone would. The part number of the ECU is 89661-14091. I would ask somebody around where I live to do this, but I own the only supra in the area.

car won't start
 

carfanatic89,

Sorry, too hear the bad news. If you can post a better pic I will take alook at my ECU and get back with.

Dan Swanson

I dont think im gonna need that, sorry, but I think im giving up on the supra. My dads sick of me not having a reliable car and is giving me his 1980 ford 150 4x4. So the supra is gonna sit for awhile till I can figure out what im gonna do with it. I might keep it and wait till I have the money for a 1jz-gte swap. Or I might sell it. I apreacate everybodys help. I just can make sence of whats wrong with it and im sick of dropping every dime I make into it.

Car wont start hot
 

Carfanatic89,

I know you are frustrated over the problems you have had. It seems like you are close to solving the problem.

I would like know about the info you have on getting ECU's rebuilt/ refurbished in case I have that problem I will no where top go to get help?

Thank you and I wish the best.

Dan Swanson

As far as parts go the 4 best places to buy parts from are: Rockauto.com, Horsepowerfreaks.com, partstrain.com and ebay.com (in that order) . Yeah maybe when I get alittle farther in life I might be able to work on the supra. Im only 19 and I have plenty of time to get another supra or fix this one. But at the moment I need a ride that can take me back and forth to work relaibly. My supra is the reason I got fired and had to come back home to live with my parents. Im ready to get the hell out of the house again. lol

But still it eats me up to not know whats wrong with this car. I love my car and I dont wanna quit, but I have to do whats best for my situation.

Find someone else with a supra and ask if you could borrow their ecu for like 10 minuets, just swap it and see if it solves the problem, if it does there you go, if not move on from there

Your a funny guy, lol im the only and I mean only person with a supra. Im known as the guy who has a supra. there aren't to many people in the country that own a supra. I try to explain the parts and what they do and ppl give me a srange look thats the main reason why if I take it to a local shop. It turns out them asking me questions. lol

Have you tried SupraMania yet? They have a lot more activity and people that know the car inside and out.

I copy pasted everything from these post over there and their telling me that they dont know either.

Carfanatic89
 

I missed the thread where you gave me the parts info. Thank you very much. I understand your situation. I wish you the best. One of the days I hope to see a thread telling us you got your supra running great.

If you think it may sit for a long time you may want to lubricate the the cam, valves and pistons with Marvel Mystery Oil or some similar lubrrcant. Turnig the engine over manually by using the the harmonic balancer bolt would be helpful too. The lubricant will help prevent problems like I have currently, two stuck valves in the number one cylinder. I lubed everything but I was busy and let it set too long withyout lubing the cam followers.

I wish the best.

Dan Swanson

Quoted on Dan:Thanks that was more helpful, I just took off the timing car covers to make sure the cam gears haven't jumped a tooth. everthing checked out and I started it and ran ok. The fuel pressure is to high right now to crack the line, ima let it bleed off some pressure. Then ill put the guage back on to check and get a fuel curve of all conditions and see what I find. As far as a wide band goes, do they make a wideband sensor that will bolt inplace of the old sensor to run a guage and send feedback to the ecm. If so can you tell me where I could buy one. I have ngk wires on right now. I have to wait till next paycheck to get ngk plugs. Im also going to put on a new intake. I think the old ones fine, but it is old and has some stress cracks in it and might be letting un-metered air in the engine. Thanks again, I know im really close to find out whats wrong with her.

Having a very high fuel pressure is quite normal according to your situation. Where are you planning to buy your plugs?

Spark Plug
 

I have the same problem with my Cavalier Z24. Starts no problem when cold, but the minute a drive somewhere and it gets warm, my RPM meter either bounces till it dies, or it just wont start.
If the spark plug wires are turning white, they probably need to be replaced. Check them for thinning. Also, if you popped out your spark plug and found oil, you might be having that problem again. Check it one more time to make sure. You might not have fixed the initial problem.
Someone once told me that as the car gets warm the spark plug wires expand. This might be why you are having problems, if they are old and thinning.