1989 IROC 5.7 TPI all stock.
Car will turn over fine. Typically it will eventullay start (after more than a minute of cranking). Starts with starting fluid and will run afterwards and is driveable but a little sluggish/hesitant. Started replacing parts, fuel filter, fuel pressure regulator, fuel pump. Pump primes to about 48 psi, 48 psi at idle without vacuum on regulator (after using starting fluid to start). If key is left in acc position without starting after priming, or if the key is turned off, the pressure will bleed down about 1 psi per second. Injector(s) stuck open?? Looking for advice.

 

Odd situation seems like. Fuel pressure and bleed off sounds normal. Might try unplugging the MAF sensor and trying to start it. Does it start normally when hot? Bad temp sensor?

 

Thanks for the info, I will try your suggestions tomorrow as I just had it running to move it so I could get another car in the garage since we are expecting bad weather. Typically it starts easier after it has run. I have been dealing with this the last 2 summers and it seems that once it gets running, the 2nd start is easier whether it is up to temp or not. Last summer I had about a 50% chance of it starting within a few cranks, now I have about a 0-1% chance of that, it either needs assistance (starting fluid), or to crank over until the battery is almost dead. Almost acts flooded and is very "rich" smelling once it gets running and takes a minute or two to idle nice, not rough or lopey. If it is not idling smooth and you press the accelerator, it will stumble almost to the point of dying.

 

Unplugged MAF, no change in situation. As far as the temp sensor goes, is there a something that can be referenced to show how many Ohms it should measure for a given temp?

 

Hey i got some value and some places to start looking. I think its your distributor.I think of the distributor you got 5 main components, (pickup coil, coil, rotor, condenser, ignition control module.) i recommend the following but warn you caution, because if you remove the ignition control module, you'll need "special thick white electronic thermo grease" to replace the module or it will fry in about 10 minutes i heard, because of heat. Now that that out the way...... 1. if its starting issue then it possibly the "pickup coil" because it tells the engine what cylinder reference and when to fire. The pickup coil typically shorts out and the permanent magnet built in it, cracks, i had 6 cracks in mine.... 2... Next guess "the COIL"(not pickup coil) sure the coil(not pickup coil) will work but fails very often cause of no starting. I had a coil that would fail only after 4 minutes stalling the car (time to warm up car), even a quick restart and put into drive real quick is would stall and wouldn't restart. But i dont get me wrong, it could the simplest thing like the puny spring or bad insulator under the COIL(not pickup coil) that powers the rotor, or a bad ground for the COIL" or just a plain fried coil. but check this, if the coil went bad then the Ignition control module is counting its days, (they typically should be changed together if one or the other is confirmed bad, because they "fight each other" when one or the other goes bad, but* not always required*, but man i hate being visited by the tow truck in the middle of no where".)....... 3. next is the "ignition control module", the brains of the fire sequence idk really get, i personally call it the points-less chip(meaning points eliminator, back in the day distributor suckd because the points always crapped) . To test this take it to autozone, but get the special module grease and be sure to care for the chip/module. Typically they dont go bad b4 the main COIL,.. 5. "Condenser"/radio frequency killer---not an important part in starting issue. 6. check your contacts and rotor for corrosion and wear. 7. I think the route to take it 1.check wiring to plugs, 2. check MAIN coil's spring, 3. check Main coils resistance( it may in the right resistance range of specs, but fails when hot) 4.get ignition control module testd and thermo grease 5. check the resistance of the pick-up coil 7. do a mild dizzy rebuild and if you do, check to see if you distributor's shaft's endplay is less that 0.015" or shims be needed, (while youre there situation) and replace the pickup coil, main coil, ignition control module. I used mexico parts from autozone, and paid for each part at a time, using their Autozone reward to rack up the points on the card till i was able to get that free 20 bucks credit. sweet. and also do you get any codes from the SES? the resistance of the injectors should be between 11.0---14.0 ohms but be careful removing the injector clips the the connectors. when you replaced the fuel pump did you use a GM pump? DID you use the crappy stock PULSATOR? i recommend a neoprene hose rated for fuel injection with a very high PSI rating and metal clamps. a regular hose will burst after the gas eats the outside rubber, even though is a fuel hose, is protected inside not out, as for the neoprene is fuel breakdown resistance. but your PSI is high, so thats ****..ALso check the TPS voltage, and make sure the MAT sensor is plugged in(under the plenum), after you swapped the regulator, the MAT often goes unplugged during reinstall, check the EGR vacuum hose route, vacuum test the Fuel vapor canister check valve, and stop using starting fluid, it could back fire and burn the MAF when starting (assuming you reinstall the ducting)..oh drinking a beer and sitting on the JOHN thinking with a haynes manual helps a lot. -mikey

 

Thanks for all the info, it will take me a little time to get thru it all and get it checked, I will post again when I make it thru everything. Thanks for all the help. I have definitely been using the drinking approach to this problem. Doesn't seem to make the car start though.

 

I am not agreeing with sick. I would also look at your fuel line check valve. My car which is in my sig, the z-28 tpi is doing the same exact thing yours is and I read a thread about how to check for it. I cannot remember exactly but do a search for fuel line check valve. It is a lot easier than you think. My z is not a dd so I have not got around to it yet, has something to do with clamping the lines in and out of your fuel rail. One of the reasons that I haven't done anything w/ it is that if i pump the pedal a little while turning the motor over it starts to fire and then it clears up, the lopiness that you mentioned. I see you replaced the fuel pump. I believe that the check valve would likewise have been replaced, but it would not be the first time a new part failed. That is my best guess.