iroc no start sometimes

Unfortunately im back, was here in feb and gave up so I did stuff like paint and rebuilt trans, convertor,but the first prob of sometimes the car fires right up and others you must give a spray of carb cleaner then it starts right up is stiil with me, fuel pressure okay, spark okay, injectors blink both sides Ive tested every thing but one,CAN THE EGR STICK OPEN DURING CRANKING SOMETIMES AND NOT OTHERS CAUSING A LEAN CONDITION ON START??? I remeber most of ya were helpful and just want your opinion. Thanks

An EGR sticking open wouldn't be enough to keep it from starting. You say you have good fuel pressure...but if you have a partially blocked line you won't have enough volume. You can try running the fuel supply line into a bucket and have some one turn the key on as you watch the fuel spray into the bucket. It should be good strong steady stream. Next have them crank the engine for a couple seconds and see if you still have a good strong stream. If that checks out good I would try replacing the pressure regulator (about $25). The next thing after that would be to take the injectors out and send them to Rich at cruzinperformance.com to be cleaned and flow checked, unless they are multec injectors. In that case I'd throw them in the trash and get a set from five-o motorsports.

If it starts after you spray the injectors then....fuel pump?

If your fuel pump is putting out good pressure and volume, this intermittent problem could be wiring. Check grounds, you might have a loose wire somewhere. Prob not but would not hurt to check...

Good luck find this problem...

If the fuel system checks okay, pull the MAF connecotr and make sure the center pin (c I think) is not corroded. Unlikely to need because it sounds like your problem exists in the fuel system.

For clarification, standing fuel pressure should be 44 PSIG, ± 3 PSIG with no vacuum on the FPR. Free-flow volume output of the fuel pump should be at least one pint in 15 seconds. Most will do a lot more than that.

sorry boys thats all i got,Put my pressure gage on the fuel rail today, got 42psi then hit the relieve button while runnin and there plenty of volume. If the injectors were clogged would it still run fine its got plenty of tourqe and doesent hesitate or anything. I got the gm shop manual and ive done every test except verifing the egr is staying closed just cause you have to remove the runners and stuff Its a shame Ive brought this car a long way since feb and just cant lick this prob oh yeah wright the maf and its connector is new, I did get a snapon scanner this summer and all the ecm data checks out. It just seems like something is leaning it out sometimes, cause carb cleaner will get it goin

Have you checked the injector signal while the engine is cranking during a time it will not start? Sounds like your losing the injector signal for some reason, and after it starts off the starter fluid, you let off the key and the injectors get signal again.

Next time it screws up and will not start, turn the key over to acc. position (normal run position) and jump the solenoid to try and start it up. If that starts it up, the problem could be computer or ignition related.

scan tool reads rpm and the noid blinks while cranking so I have reference and the ecm is controling injectors,Ive checked all that stuff this isnt a typ prob, No body thinks the egr stuck open could lean it out enough for a no or hard start. What else could lean it out

Have you put the fuel pressure guage on at first start up?Might be the check valve in the fuel pump.Seen it before,not saying thats it but just a thought.

nah when you turn the key on it jumps to 45psi and will hold, when you crank it it drops to 39 40. Im thinkin about trowin an egr valve at it but Im real tired of throwin parts at it Thanks every one any more thoughts. Trust me I bought the gm shop man for 89 camaros and have followed the cranks but will not run flow chart to a tee the only thing left is in the diagnostic aids it says an egr valve stickin open will cause this but damn It dont seem right to me either

You dont have some dumb azz problem like a hole in the rotor or an arching coil?I had a Lumina APV in the shop once that would not start every now and again,turned out to be the coil.Once it fired it was ok but the cranking revolutions were not enough to make the coil work.It just shorted to its own ground.To check the rotor just turn it upside down and pour some brake cleans in it,if it leaks through you gots a hole.

no no remember the key here is when it wont start you spray a little carb cleaner in the air intake and it will suck it in and start, but i have good fuel pressure and volume, ecm is controlling injectors,lots of spark hell all that stuff is new,something is leaning it out intermitently, all i can think is egr cause the iac is new and set the tps is in range,this 89 was the last of the maf and the first without a cold start injector its an odd year,Does anyone know what my prom id should be it reads 541 on a scan tool Ill post this ? by its self too thanks

no no remember the key here is when it wont start you spray a little carb cleaner in the air intake and it will suck it in and start, but i have good fuel pressure and volume, ecm is controlling injectors,lots of spark hell all that stuff is new,something is leaning it out intermitently, all i can think is egr cause the iac is new and set the tps is in range,this 89 was the last of the maf and the first without a cold start injector its an odd year,Does anyone know what my prom id should be it reads 541 on a scan tool Ill post this ? by its self too thanks Had a pontiac do the same thing. I put a new ecm,crank sensor and several other parts on it. After a wif of starting fluid it started and ran great. So I traded it in to a dealership. They put it in the dead row after a few weeks. But now I've got a 95 camaro, The same problem, I'm almost bald now.People think I'm nuts. I tried an egr off another camaro and no difference. Hope someone can help.

Complete shot in the dark, but are you buying gas from the same place all the time?

Complete shot in the dark, but are you buying gas from the same place all the time? No I use about 3 different places. I've added octain booster &inj cleaner.When it cranks it might try to start on first turn then I can crank till the battery runs down. But I've noticed when I let go of the key it kinda spits a little back fire and engine turns backward a 1/4 turn.

Okay, thought I'd jsut throw it out there.

Looking at the basic problem here is that it is too lean at startup or the ignitio system is not throwing enought spark to fire it off. So, we could be looking at low fuel pressure/volume, worn secondary ign. system, or improper valve timing (jumped timing chain).