Ok, its been a long time since I have posted anything. But Since I have bought the car, I have changed the starter,cap,rotor,plugs,wires,battery,fuel filter, air filter, coolant temp sensor, IAC valve, TPS sensor. I have checked the spark and its fine. The fuel pressure is right where the book says it should be. I checked it at the check valve at the end of the fuel rail and it was fine. I changed out the ECU from a buddies car that runs fantastic, and it changed nothing. I dont know what else to try and im bout ready to give up and sell the freakin car, because its starting to get on my nerves, and noone has been willing to help. Once again I have a 1990 RS 3.1 V6 with 103000 miles and its a automatic.

 

So what are you asking

 

Im asking what the hell I should check or try next! I am at the limits of my mechanical knowledge as far as diagnosis goes. I need help!

 

You failed to mention what the car is doing or not doing. A good description would help expedite a solution to your problems.

 

so what is it doing or not doing?,jimmy

 

ya like how did it run after you changed the cap and rotor rough or semi normal?

 

man thats a long list.. been there. didnt see map sensor tho. But really we need to know what its doing to be able to help.


or you could check the muffler bearings, and blinker fluid.

 

lol muffler bearings.. such a shame they actually exist....

 

OK let me ask this, does the car run?
If it doesn't run, does it start when you spray some ether into the intake?
Have you checked the injector resistance?
Is the spark timing correct? Your distributor rotor should point to the #1 cylinder wire when your #1 piston is at TDC.
If your car is running, but not running right, what is it doing? Do you get any trouble codes? All of this info would be helpful in our ability to make suggestions regarding what approach you may want to take to resolve the issues you have.
Do you have a service and repair manual for the car? If not, I recommend you get one.

 

The car wont run, and I apologize for the language and not saying what it was and was not doing . When I changed the plugs, cap and rotor and wires, it would start and run for like 10 minutes then die and not restart and run. Well, I followed one of the posts I saw and changed the Coolant Temp Sensor and the TPS and the IAC. Nothing, as a matter of fact when I did that, the car will not longer run at all!. I went over it multiple times, and can see nothing of the harness left un-connected, and I have no vacuum leaks that are aparent and I had my brother in law come out and have a look, all the way from Jersey. Hes an ASE cert and performance mechanic so I figured it wouldent hurt. And he made the suggestion fo spraying ether into the throttle body and seeing if it will start. I havent had the chance yet. I do have a shop manuel for it. The SES light DOES NOT come on. When you turn it on it does what its supposed to do, then goes out when you start it. When the car ran before the light still never came on until it died, which is normal I believe. How do you check the resistance of the injectors? The MAP sensor is fine, I pulled my buddies from the same car I got the ECU from. and yet again it made no difference. Thanks guys, for all the help thus far!

 

Unplug the connectors to the fuel injectors and test the resistance of each injector. I don't know exactly what it is supposed to be on the 3.1l v6, but all six injectors should be about the same. On the TPI v8 it is anywhere from 12-16 ohms.
Spray the ether into the intake and see if it starts. If it doesn't you could potentially have a spark timing issue. When you replaced the rotor, did you make sure that you marked the position of the rotor?
If your car starts with the ether, than you know your problem has got to be fuel delivery.

 

This is a good start. You said that the car ran before you changed the Coolant Temp Sensor, IAC, and TPS.. Did you calibrate the TPS and the IAC? When you did have it running was it running smooth or ruff?

 

When the car was running it ran really smooth, except for a slight missfire every now and again. I have NEVER heard of calibrating a TPS or IAC valve in my life! So the answer would be NO lol. and this may seem like a random question but is the 1990 V6 a OBD I system?

 

I guess I should have asked if the TPS was adjustable? Im not real sure on the V6. Your car will be OBD I.

https://www.thirdgen.org/tpimod2

 

Does this car have the VATS (security) system?

 

I honestly couldent tell you if it did or not. I know I have a security light, then when you turn the car on comes on then goes back out. To do the injector test, I gotta take the plenum back off dont I? UGH I hate taking the thing off, that damn EGR hose is a pain! BUT IF the car ran fine before I changed the coolant temp sensor, than wouldent that mean the injectors are NOT to blame? Cause if they were wouldent have dont that before I changed the sensor. What the used to do before I changed the sensor was I would start it up, it would take 3 trys to start it, then it would run GREAT until it idled up to operating temp, then it would just die, no sputtering or backfireing of missing, it would just die. You could try and start it again, but all it would do is crank, and not run. Now the car will just crank and not run period. O yea, when I replaced the sensor and got everything back together, I went to start the car, and IT STARTED and ran for 3 seconds and then I havent been able to get it to start since then.

 

That sounds like a bad fuel pump. Have you checked the pressure?

 

SWAP THE COIL, barrow on from a friend, or replace it . swap the coil!!!

 

The pressure is right where is should be, and the ignitin coil is brand spankin new! Read my inital post to see what all I have replaced.

 

you still have spark? can you hook up the fuel pressure guage, and have some one pour fuel in the tb and keep it running? reason i ask is this is similar to what happened to me. I kept checking the presuure at the start up cycle, and kept getting good readings. bt as the motor would run the pressure would fall off to nothing. ( replaced pump) I kept spinning the guess wheel and replacing parts until i had seen that.

 

Have you rechecked for spark since the car went down totally. Maybe a bad ignition modual or pickup in the dizzy. could have been overheating so it would run till got hot and now just went completely out.

 

Ill go out and check the spark now, but the car does still have spark it just may have died cause of what you said vette Ill check it ASAP. and if the fuel pressure was falling off, it wouldent run as well as it did. So im gearing towards what Vette said about the PU coil and the module.

 

Well guys, I believe I finally found the culpret. Its my fuel pump, my fuel pressure isnt even were it should be when its priming the injectors. After spending all that money, I can honestly say its gunna be worth it in the long run. Ill get some great fuel mileage out of the old girl. Next on the list is a flowmaster exhaust with 2 1/2 pipeing. But before that, is a manifold gasket replacment, since the one on the passenger side is blown, I mean that thing is FUBAR! I gota question to ask too, the 5.7 350 the Iroc Z came with, will the 700R4 tranny I got in there with my 3.1 V6 bolt straight up to the 5.7? I see no reason why it souldent unless the bolt pattern is different. Oh, yea, and the spark was perfectly fine when the car runs and when the car will start but not run. I got some dude in my neiborhood haulin *** in his mustang atm , it sounds like a Fox body 4.9 with flowmaster 40 series on it. Mabye I should chase him down and ask him???

 

So.. it WAS the fuel pump? How does it run now??

 

Like a Top! Other than that friggin exhaust leak, but I need to replace that before it burns up a valve. Im going to running a true duel setup exhaust. Im gunna have the shop custom fab it for me, where the passenger side header is cut off and shortened, with a cat bolted onto it, then a flowmaster Delta 44 series mufflers on each pipe, with the exit point under the car with some dump tips right off the mufflers. But the piping from the cat to the muffler will be 2 1/2 inch. The exhaust is gunna stop at about where the edge of the hatch glass starts. I originally wanted to run side pipes, that exit just before the rear tires. But I will be driving the car everyday to work and all around gods creation. What you guys think about that setup?

 

I doubt it. You have a 60* V6 and I am willing to bet that you are going to need an adapter plate machined in order to match the bolt pattern of a 90* v8.

 

The bellhousing bolt pattern is different from V8 TH700's, as well as being weaker internally.