KCGTA

My number 8 injector ohms at 8.3, so I know it's bad. The other 7 are above 16.5 ohms. Fuel pressure at the rail is 47 psi primed/37-39 while at idle. After shutdown, the pressure will hold above 40 psi for at least 15 minutes. Car always starts when sitting 3 hours or longer, but will not start after it's been running for any length of time (when warm). In the no-start condition, pressure remains the same as stated and spark is confirmed present. My question is, can one bad injector cause this no-start condition when warm? The idle is slightly rough also when warm, but from what I've been reading on this site, it is probably related to the bad injector. Does this seem the likely culprit of my dilemma? If there could be any other contributor, I'd gladly replace it while I have the plenum/runners on the garage floor. I run a stock 1989 L98. Thank you in advance for any insight you could lend me in getting my baby of 18 years (1st and only owner for life) back on her feet again!

3.8TransAM

One injector like that prolly wont do it by itself. If it was completely gone ir more than one I would say yes.

It could be possible.

But no hot restarts and only one injector with an issue, u might want to look at ignition module, ignition switch, pick up coil route first.

later
Jeremy

KCGTA

Hey Jeremy,
Thanks for the input. I'll look into the ignition switch as well. I have recently replaced the ignition module and pick-up coil during the "throwing parts at it" phase, but completely overlooked the switch.

3.8TransAM

Had that ignition switch happen to me and drive me nuts.

Car would shut down, when I checked it with a meter everything would have power, drive car and it would shutdown again.

The injector does need to go as well, it is bad.

Also ground issues show up way more with heat than without if they are borderline.

Could also see what happens with one dead cylinder as well by unplugging the one injector.

KCGTA

Hey Jeremy,
Thanks again for all your help. I did unplug the 8th injector, fired the TPI up cold start, ran fine on 7 injectors. After the engine warmed up and shut down, it would not restart. Checked the number 8 and number 1 spark plugs, dry and normal. I then began looking at connections. I pulled the CTS connector and plugged it back in. Car started 4 straight times hot. Took it out drove it a good 30 miles, put it back in the garage and no start again. Unplugged the CTS, plugged it back in, started right up. I think I'm on to something here. Gotta love it!

rv1890

iTrader: (3)

Sorry man....but whats the CTS again??

KCGTA

Coolant Temp Sensor. It turns out that isn't the case, however, cause I had another fail to start after the engine had cooled a good 2 to 3 hours. Played with the connection again, no start. It reeked of fuel this time, which is the first time I noticed this. I did get it to start eventually. It always does, which is why this is such a perplexing problem. I am planning on relpacing the FPR along with the new injectors (just because 133K miles, I don't want to do this again anytime soon) and I really hope this will cure the problem. I am all out of ideas.

umland03

I am having the same issue. I placed a TPI system in my old 72 chevy blazer. When it is warmed up it will not start after being shut down. It doesn't even get very hot. If I wait 10 or 15 minutes it will start and run fine. I have a Idle air motor sensor, TPS, coolant, detonation, oxygen, and air temp sensor. I had the system placed on a computer and found that the Idle Air motor (IAC) was not reading. I replaced that and still will not work properly. All of the other sensors showed that they were working just fine. I checked spark, fuel pressure (40psi) and put in a different coil (used). I read that if the 02 sensor was dirty it may cause a problem. Could this be what is giving me problems? I don't know what else to try. I even checked the injectors.

3.8TransAM

Pass side rear of cylinder head engine grds?

Check those if u havent

KCGTA

Hey Jeremy,
I am a middle-of-the road TPI knowing guy. What is grds? I'll check it!

KCGTA

umland03,

One thing I do know of TPI systems is that anything is possible. I know that doesn't help you much. I replaced my O 2 sensor and it didn't change things one way or the other. From what I have seen on this site, the ECM quits regarding the 0 2 sensor once it gets out of limits. It may be worth the shot. If you've eliminated everything else. TPI can't beat when it works right, but diagnosing these things can be a nightmare! Let me know if you have success!

rhomanski

GRDS means grounds as in electrical type.He means for you to take them apart and clean them up ensuring good contact.Bad grounds cause a lot of problems on old cars.

KCGTA

I see, and thanks, you know it makes perfect sense now! I'll check those out as well.

KCGTA

I have a bit of an update. I hooked up the fuel pressure guage again. I cycled the fuel pump to prime several times. Each time, it would get to 45-47 psi, then fall rapidly to under 20 psi (within 2 minutes). The catch is that each time I did it, it took longer for it to drop. This car throws a curve at me every time I think I have it figured out. I unplugged the 1 bad injector and it ran like a champ, so maybe the FPR? I just don't see what would cause a no-start in this case. Especially when warm. Can the F/P check valve cause such a condition and drop pressure that quickly? I was reluctant to do the crimping thing on my fuel lines, as I don't want to damage them, but may try it just to narrow down the possibilities.

KCGTA

It was a bad ground! Jeremy you rock! Thanks to all for lending me your knowledge!

umland03

Well I started having new issues and was unable to start at all. I found that the rotor was actually broken in the cap. I have never seen this before. I also had a bad ingnition module and a bad distributor cap. With all of these things replaced I thought I found the problem. But now I am back to the motor starting and then when you shut it off it will not start. I am going to check th grounds and see if this makes a difference. I found some good info on this thread. Thanks to all. I will let you know what I find.

KCGTA

Hey umland,

It wasn't just a bad ground in my case either. I also had a bad battery of all things. When my GTA wouldn't start, same as yours, I tried jump starting it with another car even though the motor would seem to turn over fine without the other car. Sure enough, every time I hooked up the jumper cables, it started. If I unhooked them, it would turn over but not start. Hooked them back up, it would start. The battery was only supplying about 10.5-11 volts, apparently good enough to fire up a dead cold engine, but not enough when it was running for any length of time. Sometimes the problem is a lot easier than you may think, just look at all the crap I did to find this out, LOL!