Car Only Runs for a Minute.

[smagnotta]

I don't mean to hijack this thread so I apologize ahead of time...

Hey "thesupraman" - You really seem knowledgeable about the MK3.

My mileage is good - I am getting 23 MPG average which is great because I am old enough (showing my age) to remember in 1987 when the sticker said:
18 city 23 highway

I was wondering about the EGR system. I don't remember the exact part I am trying to describe but it is not the EGR valve. It is the part above it that has 2 vacuum lines - one on each side. I don't know if the mechanic connected the hoses to the right side. There is a "P" and a "Q" side according to my 87 manual. I am wondering how to tell which side is which. In other words does the P side go to the EGR valve or does the Q side? The EGR system is the only one I have not replaced or messed with. The mechanic did not install the EGR block off plate even though I gave him the plate. I wonder if he was worried about it passing emissions in PA and thought it was illegal or something?

 

[thesupraman]

I don't mean to hijack this thread so I apologize ahead of time...

Hey "thesupraman" - You really seem knowledgeable about the MK3.

My mileage is good - I am getting 23 MPG average which is great because I am old enough (showing my age) to remember in 1987 when the sticker said:
18 city 23 highway

I was wondering about the EGR system. I don't remember the exact part I am trying to describe but it is not the EGR valve. It is the part above it that has 2 vacuum lines - one on each side. I don't know if the mechanic connected the hoses to the right side. There is a "P" and a "Q" side according to my 87 manual. I am wondering how to tell which side is which. In other words does the P side go to the EGR valve or does the Q side? The EGR system is the only one I have not replaced or messed with. The mechanic did not install the EGR block off plate even though I gave him the plate. I wonder if he was worried about it passing emissions in PA and thought it was illegal or something?

Hope this helps......PM me if you have any more questions. Yeah, technically if the car came equipped with an EGR system you are legally not allowed to remove it. It is pretty easy to remove if you want to tackle it yourself, and it really cleans up the engine bay(visually). My car passed NJ state inspection with flying colors with the EGR off. Unless the mechanic is up on the MK3, he wouldn't know where to look for the egr anyway. Remove it yourself and take it to another garage for inspection.

 

[YoNkErS87t]

The car has no egr, but i checked the cold start injector anyway. I unplugged it from the harness and it did nothing so i plugged it on the fuel rail just incase it was stuck open. Did nothing.

I just ordered a fuel pump and will order injectors next week. I also bought a fuel filter from the dealer. I hope this solves the problem

 

[thesupraman]

Yeah, I hope it solves the problem too. I finally got a chance to start working on my own car tonite, and found out that the valve did come in contact with the piston. Sooo, I the head does have to come off. Figures. Keep us posted on your progress, I'm very interested to see what the problem is.

 

[YoNkErS87t]

Ummm..I guess try checking all of the air/fuel related sensors at the ecu plug....unless you did already.

How would i check this? Take a volt or ohm meter to the plugs going to the Ecu?

 

[smagnotta]

Hey Yonkers and thesupraman:

What about a complete fuel system cleanup? I had some trouble with my old 87 just due to the age and I went to Monroe of all places and they did an oil change that involves a complete fuel system cleaning. I was skeptical but after that the car's improvement was unbelievable.

Could a professional fuel system cleaning help Yonkers out? Something to try that isn't too costly ($70 at the most)...

 

[Sonex2000]

damn...YO87T. WTF?!?

 

[thesupraman]

Ummm..I guess try checking all of the air/fuel related sensors at the ecu plug....unless you did already.

How would i check this? Take a volt or ohm meter to the plugs going to the Ecu?

Yeah. Check out the link. This way you know exactly what the ecu is seeing, if anything, from the sensors.
http://www.cygnusx1.net/supra/library/TSRM/fi/FI_050.html
Click on "next page" to see what the volt/ohm values are supposed to be.

 

[thesupraman]

Hey Yonkers and thesupraman:

What about a complete fuel system cleanup? I had some trouble with my old 87 just due to the age and I went to Monroe of all places and they did an oil change that involves a complete fuel system cleaning. I was skeptical but after that the car's improvement was unbelievable.

Could a professional fuel system cleaning help Yonkers out? Something to try that isn't too costly ($70 at the most)...

Could be, but I think that yonkers already swapped out his injectors with no luck. The primary thing that the fuel system cleanup targets is the injectors, so if he had the same problem with different injectors, this would most likely not fix his problem. Good idea though :bigthumb:

 

[YoNkErS87t]

The injectors i put in was a set i had laying around the garage. When i put them in they all sounded like crap, but i think the set thats in now has a one or two that are shot. Two of them sounded off, I swapped out the injectors and it was worse, all of them were a dud. So i put back in the original set and they sounded better than before i took them out. I think that they could be the culprit, but i'll see when the fuel pump and filter come. Even though i will get 550cc in the next week or two the pump was the cheaper route to go.

 

[YoNkErS87t]

Replaced the fuel pump and filter yesterday and still nothing. In fact i have another problem. I don't know what you call the thing that holds the fuel pump in the tank, but the high pressure line going to the filter was so rusted that now it has a pin hole leak. This sucks. Another $100 down the drain.

I must have the patience of a saint with this car. Actually I drank myself stupid afterwards and let my friend shoot me with a paintball gun. OUCH!!!!!!!!!

 

[turboa7mgte]

to much fuel usualy means you have a vac leak... its telling the ECu you are putting load on the car and adding fuel. Normaly it raises the RPM's as well. I would see if you can get ahold of a vac gauge and see what kind of vacumm you are getting.

Now on to my next tid bit of info.... I tell people this all the time.... Check your Grounds!!!! I have my grounds double grounded... it sounds stupid but listen to me....

Last year i had a fuel related problem that i cured at the time with my SAFC but it always bothered me what was causing this to happen. One day my car would idle lean the next Rich.... I go to checking things for the 173,836,837 time and it turned out to be a supid little Ground wire that was there but hanging on by a few strands.... I replaced it and POW!!!! back in business!!!

You may also want to check that your 92 sensor signl wire has continuity to the ECU plug. and try your buddys 02 sensor while you are at it...

Good luck!!!
Let us know how it goes!!!

 

[YoNkErS87t]

You do mean the 02 sensor not the 92 sensor, right? Just want to make sure we're on the same page here.

I did swap out his 02 sensor already and it did nothing. And his is brand new.

I also have a vac gauge hooked up right now. It is hooked up to the hose coming off the intake manifold. It reads just below -20. Like 18-19. I know when the car ran fine the vac read at -20psi.

Could it be possible that i have a leak in the throttle body itself, not the gasket?

I will also check signals to the ecu when i get a chance.

 

[turboa7mgte]

lol... yeah 02 sensor...

I guess if you had a cracked TB it would mess up all kinds of shit. it would be like a permanant boost leak... but I think your problem is electrical.

 

[Supraman]

I think TurboA7MGTE has it here. I just found this thread.

I suffered from similar problems, and went through similar frustrations trying to solve the issue... After hours upon hours of checks and research, I stumbled across a mention that the ground wire under the #5 intake runner tends to corrode. I immediately ran out to the garage to check it. The ground point bolt was loose by a good eighth or quarter of an inch! I tightened it up, and the problems vanished! Granted, they came back with much less severity about a day later, when I noticed that the connector was ALSO badly corroded. Sanding it down and torqing it well has eliminated all related problems!

Check it out and let us know!

 

[YoNkErS87t]

Well do so.

When I tore the engine down for the Hg job, I went over the harness and connectors and anything that looked bad was replaced with another harness.

The ones I replaced:

-Cps

-Coil packs

-The 02 sensor looks kinda a bad, but the one from my spair harness fell apart as soon as a touched it so I couldn't replace it. I did check it with a volt meter and it looked good so i just left it. I'm going back and rechecking it though.

Another Question: How many grounds are there on our cars and where?

- Firewall to head
-coilpack to head(i drove with this one not connected for months because it was rotted and the car drove fine, but its connected now)
-Negative battery cable

And what else?

Thanx guys for your help.

 

[Supraman]

Well, in addition to the grounds you listed, there's also the one I was talking about--under the #5 intake runner. Be sure to verify it is not only tight, but very clean and sanded off--this is the most important ground on the car and is almost certainly your problem, if it's a grounding issue. There's also a ground point near the AFM, and a couple near the fuse box. A full listing of locations and functions can be found on pages 26, 28, 30 (etc) and 148...(etc) of the EWDs:

cygnusx1.net/supra/library/Wiring/pages/Page_026.html

cygnusx1.net/supra/library/Wiring/pages/Page_148.html

 

[YoNkErS87t]

Where does the fifth runner ground go to? The Firewall? Probaly a stupid question.

 

[turboa7mgte]

Where does the fifth runner ground go to? The Firewall? Probaly a stupid question.

Varoius sensors, the ECU...

 

[cruzinbill]

hey i am having the 100% exact same problem only one thing differant when the car is tryn to idle i get 0 vacum untill i try to rev it then it drops to negative 18 then goe back 0 and i am 1000000000000000000000000000000000000% sure i have no boost or vacum leaks so no i will check the throttle body and this ground theory wich i think will work after countless hours of reading diagrams this may be it i will know tomorrow morning