patgizz Posted May 5, 2008 Report Share Posted May 5, 2008 this developed yesterday morning - on my way home after the car sat all night it was down on power. i installed new plugs/wires(r42ts delco plugs @.045"/accel 8mm spiral core wires) and took it for a test ride .then as i went around the block it developed into trying to cut out when i hit a certain throttle position or rpm. when i got home it stalled. when warm it will not or barely restart. when cold it will start and idle fine, but when i hit the gas at all it will cut out immediately. even a slight tap on the pedal. i tested fuel pressure last night and thought i found the culprit and put in a new walbro pump, and tested again to no pressure only to find my tester bad. new tester shows 50psi @ cranking and when the pump turns off it stays at a steady 41psi without draining down so it appears the regulator is good. while warmed up and not restarting, the car restarted immediately on starting fluid. the car has run great since wednesday and i've put about 500 miles on it so far. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 5, 2008 Report Share Posted May 5, 2008 seafoam!!! I love that shit. Quote Link to comment Share on other sites More sharing options...
ManicMechanic Posted May 5, 2008 Report Share Posted May 5, 2008 SES light? ICM? CPS? TPS? Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted May 5, 2008 Report Share Posted May 5, 2008 Welcome to the world of TGPs. Seriously, I think we're all had these symptoms at some point. It's cranking right? Just not starting? Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 5, 2008 Author Report Share Posted May 5, 2008 SES light? ICM? CPS? TPS? no SES. i have a known working low mile ICM. i am suspecting TPS and i'm going out to the garage to dig one out... might just go get a CPS and some other stuff and throw them at it since all the sensors are original. it cranks no problem. Quote Link to comment Share on other sites More sharing options...
R Dubya Posted May 5, 2008 Report Share Posted May 5, 2008 this is possibly injector related, but have you replaced the fuel filter? I would say if you are getting 41 psi at idle it should be fine but never hurts to ask. This sounds like a strange one. What chip are you using? Done anything to the intake? How about throttle body? possibly a folded gasket or something? Quote Link to comment Share on other sites More sharing options...
Bake82 Posted May 5, 2008 Report Share Posted May 5, 2008 I know alot of people run a much smaller gap than .045. Most will run .030 or .028 even. I don't know if the plug gap would make a big enough deal to make it not start, but it's food for thought! Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 5, 2008 Author Report Share Posted May 5, 2008 the plugs i took out were almost new and .045 and it was running awesome up until yesterday morning. the chip - not sure who made it. it's been modified for 5 speed and 180* and other than that i'm not sure. it came with my donor car which was run with it for a while. replaced the TPS and CPS and nothing new. it almost started but keeps cranking. i do have good spark through a test plug. fuel filter is brand new as of this morning. it's cooled off now and will not start. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted May 5, 2008 Report Share Posted May 5, 2008 check the injector connectors with a test lamp while trying to crank it. Did you check the injector fuses? Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 5, 2008 Author Report Share Posted May 5, 2008 i just did that. no pulse @ injectors. i'll check the injector fuses otherwise if injector fuses not blown? ECM dead? Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted May 5, 2008 Report Share Posted May 5, 2008 ECM or bad harness? Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 5, 2008 Author Report Share Posted May 5, 2008 ECM or bad harness? fuses are good. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted May 5, 2008 Report Share Posted May 5, 2008 Try swapping a known good ECM? or use your test light to confirm no signal at the ECM side of the harness? Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 5, 2008 Author Report Share Posted May 5, 2008 heh. i had my test light hooked up to injector plug again and the car started. plugged injector back in, then it kept wanting to die with any accelerator pressure, stalled again, no more pulse. dying ecm or wire rubbing somewhere i guess? no known good ecm's around here. i'm going to try to get signal or no signal at the ecm side of the harness. since i have no signal right now hopefully i can prove the injector harness faulty or ecm faulty. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted May 5, 2008 Report Share Posted May 5, 2008 sounds like a good plan Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 5, 2008 Author Report Share Posted May 5, 2008 i remembered i bought the TGP FSM supplement. ran down the flow chart while it was in a no start condition with no signal at the injector. ruled out the injector harness and the harness in between ECM and that, and the FSM concludes bad ECM. which other ECM's can be used if i were to junkyard one up? i have so litthe $ into the car at this point that i might just go buy a new one. Quote Link to comment Share on other sites More sharing options...
ManicMechanic Posted May 5, 2008 Report Share Posted May 5, 2008 CORVETTE 90-91 Elec Cont Module (ECM); base CUTLASS 88-89 Elec Cont Module (ECM); 6-173 (2.8L) CUTLASS 89-92 Elec Cont Module (ECM); 6-191 (3.1L) CUTLASS 93 Elec Cont Module (ECM); 6-191 (3.1L), VIN (8th digit) "T", TH125 GRAND PRIX 88-89 Elec Cont Module (ECM) GRAND PRIX 90-92 Elec Cont Module (ECM); 6-191 (3.1L) GRAND PRIX 93 Elec Cont Module (ECM); 6-191 (3.1L), TH125 LUMINA CAR 90 Elec Cont Module (ECM) LUMINA CAR 91-92 Elec Cont Module (ECM); 4-151 (2.5L) LUMINA CAR 91-92 Elec Cont Module (ECM); 6-191 (3.1L), gasoline LUMINA CAR 93 Elec Cont Module (ECM); 6-191 (3.1L), gasoline, TH125 REGAL 88-89 Elec Cont Module (ECM) REGAL 90-92 Elec Cont Module (ECM); 6-191 (3.1L) Doesn't seem to be a difference between turbo and non turbo. Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 5, 2008 Author Report Share Posted May 5, 2008 meh. advance has one for $70 so i ordered one for tomorrow morning. don't want to pull the one off the vette to use to test it Quote Link to comment Share on other sites More sharing options...
krenzy Posted May 6, 2008 Report Share Posted May 6, 2008 Otherwise I have an ECM from a TGP I'll sell you for $25 plus shipping. Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 6, 2008 Author Report Share Posted May 6, 2008 lo and behold the factory manual is retarded. i've also thrown in a known good coolant temp sensor which helped not and i'm going to toss in a known good ICM which could certainly be a culprit by not relaying crank sensor info to the ECM. Quote Link to comment Share on other sites More sharing options...
BXX Posted May 6, 2008 Report Share Posted May 6, 2008 Remember, on the MPFI engines, if 1 injector dies (resistance too high or too low) the entire bank is forced to shut down. Sometimes causing no pulse whatsoever since the ECM cant drive the injectors. It could also fry the ECM also.. And of course, remember this, the early ECM's are quite known for failing or just having issues. Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 6, 2008 Author Report Share Posted May 6, 2008 for the hell of it i tossed in a known good ign module with no change and bumped plug gap to .035" with no change. with ignition on, test light connected to ground and probing injector connector on both banks i get steady light off each wire and pulsing off each wire when cranking - is that right or wrong? shouldnt there be no power to the injectors when the key is on and car is off, only when cranking and running? Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 6, 2008 Author Report Share Posted May 6, 2008 pulled plenum tested injectors with ohm meter: 1: 8.4 2: 10.5 3: 12.5 4: 12.6 5: 12.5 6: 2.6 (holy crap that one is way out) so it looks as if 3 injectors are bad how big are our injectors? 21#? i have 2 sets of LT1 injectors which are rated 22# and i should be able to get 6 good ones out of them if not 16(testing them right now) - will they work? Quote Link to comment Share on other sites More sharing options...
R Dubya Posted May 6, 2008 Report Share Posted May 6, 2008 22 lbs/hr. you will be fine as long as they ohm out properly and also have the correct adapter. I know you probably know this but replace the o-rings on the rail and the injectors when you re-assemble. Quote Link to comment Share on other sites More sharing options...
patgizz Posted May 6, 2008 Author Report Share Posted May 6, 2008 yep i'll be putting on new o-rings. need to go get a set. hooray for all 8 injectors i just tested being in the 12.2-12.5 range. they're physically identical in size, appearance, and plug. GM/ASC probably just took corvette injectors off the shelf and called it a day since the 22# LT1 units are a 350 TPI carryover. if this doesnt fix it then gasoline and matches might. Quote Link to comment Share on other sites More sharing options...
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