Hey All,
I have been having a hard start (takes three tries) and after it runs for awhile, I shut it down and try to restart but it justs cranks and never fires. Wait just a few minutes and it will start again. Problem is getting worse and idle has become erratic.
Car is 89 IROC L98, 57k miles. Fuel pump is maybe two years old and the pressure at the rail is o.k. (adjusted from 39-50 w/AFPR w/no change in condition). While running, clamped off return line, press. shoots to 80psi and engine stalls. If I shoot TB cleaner in intake, it will start alittle easier, Idle revs up and smooths out while spraying TB cleaner at throttle blades. With the MAF boot off, very loud sucking sound from IAC (which I removed and cleaned). Reset TPS, new CTS, Cap&Rotor, plugs. Could it be injectors or ECM ? ECM is holding codes when I remove the MAF so the ECM SEEMS to be working. Also, when I shut it down, I can hear the fuel pump run for a few seconds after the key is off. Is this normal? Any help is appreciated as my tag renewal is due by 5/31.

 

update...
Switched to another O2 sesnor and the condition persists. Car did start on the first try last night with the key in run for a few seconds before cranking it. Runs very rough (engine shaking) and doesn't really smooth out as throttle is applied.

 

update 2...
Car won't start unless starting fluid is sprayed into the TB. Once started, it runs with the surging/hunting idle. Tried to reset the IAC (minimum idle) w/no luck. When trying to start, after it cranks and the key is released, there is a strange sound at the fuel rail like there is air in it gurgling, or it is filling up. Fuel pump is running and the pressure at the schrader valve is set at 42PSI. Obviously it is a fuel related issue but I cannot seem to pinpoint the source. Also, I have already replaced the fuel filter. How do you check the injectors?
Thanks.

 

update C...

How do you test the injectors and what should you look for on a scan tool for the injectors? I may be purchasing an Auto X-ray to help diagnose this. (I should have one anyway). How do you check the MAF to see if it is functioning properly?
Thanks

 

This is just IMO, but I would check the plugs. When my engine starts to run rough, or has starting problems, I always check the ignition system first, and 9/10 times, my plugs or wires or dist. have been the cause. But then again, you probably have done that already...

 

Thanks,
I replaced the plugs, wires, cap, rotor, ignition module and tried my stock coil and my jacobs coil. I removed every wire and got spark at each one while the engine is running. Maybe I should mess with the timing. Could the ECM be bad but still store codes (like when I disconnect the MAF while the engine is running)?

 

If you disconnnect the MAF while the engine is running you will get a code. If not there is another problem. Does your SES light work?

 

update IV...
DannyT,
Yes the check engine light is comming on when I disconnect the MAF (engine running) and the code is set. The ECM diagnostic function (one flash, two flashes) is operating normally.


I did check the resistance of the injectors and came up with this...

Driver side
7.2
16.5
16.6
16.7
Passenger side
7.1
6.5
16.7
14.6

Are the injectors that aren't reading in the 16's bad? I disconnected the driver side bank of injectors and it didn't make a very big difference.
Vader, What are your thoughts??

 

You have three bad injectors.

 

From your resistance readings, it seems that you have three injectors that are on the way out, and possibly a fourth. Are these Multecs? (Rounded bottom?)

Bosch and Rochester injectors should read about 15.95-16.35 ohms new, and have a lower service limit of 12.7 ohms. Multecs should read from 15.8-16.6 new, and have a service limit of 13 ohms. Either way, you have issues if your meter is correct. Did you try measuring each injectors' resistance to ground on a high (megohms) scale? That's another way to spot a failed solenoid coil.

 

Thanks for the feedback.
I think I will be looking more closely at the injectors.

 

tpi injectors should read 14-16 ohms if i remember right. if they falll below 10 ohms replace them

 

I have another question concerning the fuel injectors. With the engine running, if I disconnect an injector plug and test to see what the voltage is at the contacts in the injector plug (harness), what should the voltage be reading? In other words, how do I check the signal going to the injector and what should it be reading? Can the injector function fail in the ECM (maybe from pushing failed/failing injectors?) and still not set a code?
Thanks again for any input.