Timmie

well after a top end rebuild of my engine,
and after more then a year of disastrous ( other ) car troubles.
think of a transmission that went south and needed a rebuild.
a body that needed to be rewelded.
floorpans that arrived after 7 months of waiting ( ordered september arrived in april )

I finally got a new problem.

first
engine is a 3.4 v6 engineblok. build up like a 3.1 engine.
it has a comp cam 260H cam, new lifters ( came with the kit ) new valves, new valvesprings ( came with the kit ) new timingchain.
intake and exhaust are polished.
pacesetter headers. 3,4 injectors.

second, I noticed that I had a valve ticking, and I was going to do an engine flush. ( just needed to get underneath the car )

anyway, while driving to the garage 10km further, ( and after fueling up again ) the car started to run strange when I ran it up to 55mph and brought it back to a stop.
the car stalled out on me. I restarted the car and drove another km or so and it shutted of again.
after the last time it shutted I couldn't get it started again.
fuel pressure was good. and I got ignition on the coil. but it wouldnt start.

I pulled the spark plugs and they ALL smelled like fuel.
so I cleaned the spark plugs, reinstalled them and tried to run it again. ( it didnt work )

after a while I disconnected the injectors and started the car full throttle.
( cleaning out the cilinders)

after that I got my car started on propane( since I also have a propane tank in the car ) dropped a lot of black smoke out of the exhaust and the car drove on propane.....


does anyone have an idea why my car is fueling the spark plugs.....

btw, if I look at my air fuel gague, I can see that my car runs a little bit rich ( and this is really a little bit ) on startup, but when its in closed loop the car does the normal running between lean and slighty rich. ( nicely going up and down without a problem)

Timmie

No one ????

Base91

iTrader: (1)

Are the injectors new? Have you checked them?

Timmie

injectors are fine, starting to suspect the ignition coil getting weak.
would also explain some backfiring ( sometimes ) in the exhaust.

Timmie

guess I made a mistake, injectors arent firing. since it runs on propane just fine....
starting to think its a short in there somehwere.....

Schrade

Fuel pressure leakdown time?

Any loping idle / vacuum leaks in Closed Loop?

Any DTC codes?

Timmie

no codes since car wont even run on gas....
no lope on propane...

fuel pressure is good...

Base91

iTrader: (1)

At a minimum you need to check the resistance of each injector. If they're original or older then they almost certainly need replacing. Southbay on this forum does a good set for not much and with a discount. As you need to take the upper plenum off it's a good idea to also replace the fuel pressure regulator diaphragm if it hasn't been done any time recently.

Timmie

tested all injectors and they tested fine, around 12.x ohms each.
my old injectors also tsted around 12 ohms.
starting to suspect a bad ground on the back of the drivers cilinderhead, since I had to remove the valvecovers and 1 of the ground wires tried to crawl under the cover during reinstall. so took it and put it out of the way a bit.
maybe the bolt came loose....

Base91

iTrader: (1)

Have you checked the injector fuses. I think there's one for each bank.

Timmie

checked them, they are fine...

Base91

iTrader: (1)

Maybe try a noid light? Pity the injectors are such a pain to get to.

Timmie

like I said, tomorrow I first gonna check the mass on the rear of the heads.

Timmie

checked mass, didnt fix it.
change ICM module, no change.
gonna try changing the computerbox here with the one from a 91 bird v6.

Schrade

Won't run? Start with basics...

Air, fuel, fire.

Air - air filter clear?
Fuel - what is the fuel pressure? What is the pressure leakdown time?
Fire - are the plugs gapped properly, and clean? Impedance of the wires? Static timing correct?

Timmie

after tearing up the engine and changing the ICM module + changing the compuiter

and checking the injectors, I can now say certain that the injectors are fine. I also tested my old injectors, but 1 of them leaked and another didnt even make a clean spray.

anyway, I got some errors.
code 22
code 42
code 54

code 54 could be related to a bad relay, thank god I had a brand new one in the box in the back of the car.

42 the ICM module had low voltage... I reinstalled the old one and the error was gone again. (so my spare part was actually bad )

code 22 low voltage at TPS.
looks like if I disconnect this sensor the car would start.
I can reconnect the sensor bt it wont run right. I think I can say that my TPS sensor is the culprit. so I'm goning to change this sensor and offer the old one to "the fire of destruction" to please the camaro gods.....

Schrade

DO YOU HAVE FSM FACTORY SHOP MANUAL???

ANY one of your DTC's, in FSM diagnostic procedure, I guarantee, will defer to another DTC, and once you get the first one solved, at LEAST one other DTC will be FIXED, if not more.

Timmie

@schrade, its not that I dont appreciate your help. but your answers are a bit weird.
ATM I finally found the culprit of my problem and its probably my throttle sensor.
since when I disconnect it the car stays running, else it shuts down on me.

Schrade

You can test TPS voltage without the car running:

https://www.thirdgen.org/forums/tech...ackfiring.html

Timmie

aargh, this car is giving me a headache....
wel, it seems I got some new weird symptoms.
today when I tried to start the car it wouldn't run.
so I checked on my tunerpro RT and I see that the voltage at the fuelpump is 0.00V
yet, the relay works ( brand new )
and the orange wire has 12V on it. the black one is grounded.

so for testing purposes , I bridged the red relay wire ( going to the fuel pump with +12V of the battery, making the pump run.
so I started to crank it and something weird happened. to moment the car ran, the fuel pump voltage went back to 0 again.
its like something is shorting it out....

Schrade

Fuel pump shuts off after priming the fuel lines, until some signals get sent to ECM. You can test voltage at the fuel pump relay, and test for continuity FROM the relay TO the pump.

See third page, post 1, column 2, here

The relay will have 4 leads - relay in, relay out, fuel pump in, and fuel pump out. Pinout ID I do not know. Someone can post that I'm sure.

Sorry if this is just another 'weird' answer........................

Timmie

its not a bad answer.
its just that I already checked that part.

I know that the fuel punp shuts of after priming the fuel lines.
there is even a connector on the red wire coming from the relay. that if you put 12V on it. the pump will run and continue to run.
so I put 12V on this wire.
this way my fuel pump keeps priming and I get 12V on my fuel pump whatever I do.
my tunerpro sees the 12V to, so this is good.
but for some reason the moment I start, and the engine is running I dont have 12V on my fuel pump anymore. Yet, it should have 12V on it whatever I do since it got hotwired straight from the battery on the red wire.....

Timmie

I HAVE FOUND THE PROBLEM.

and you where actually really close.

when I put my contact on , I was getting 12V. put when I started the car, or when it was running. little shaking of the engine made sure the negative injector cables where hitting the engine block ( near the aircopump). this way the injectors opened, but because the ecm didnt get any pulses anymore because the signal was already at the mas without going through the ecm.
it shutted of the fuel pump.
I re isolated the injector wires and the car fired right up