1.8 l-jet fires, but dies within seconds, tried searching :-/ Options

[Valy]

I bet it dies because the fuel is cut at the injectors. The spark should be working.
The FI cuts the fuel during deceleration so it thinks you have high RPM and the throttle is closed.
Something fools the FI to think that way so it's probably the AFM, throttle switch or cabling. The computer is very rarely at fault.

[timothy_nd28]

Okay, so some further tests you can do. On the (+) side of the ignition coil, you can jump straight to the positive side of the battery. Start the car and observe if the engine drops out. This tests your hypothesis with the ignition switch dropping out. I think this is unlikely, but its worth a shot. (if this test failed, remove the jumper wire)

Do you have a fuel pressure gauge installed, what is the fuel pressure right when the engine begins to quit?


Another test, for the throttle valve switch. Probe pins 18 and 3 on the ECU plug, what is the initial resistance. Now manually open the throttle plate all the way, what is the resistance between pins 18 and 3 now?

How did you remedy the AFM? What is your new numbers when rechecking? I'm still betting on the AFM being the issue here. The ECU could be faulty, however very unlikely. My money is on the AFM! (IMG:style_emoticons/default/biggrin.gif)

Do you happen to have the altitude compensator module installed on this car?

[timothy_nd28]

One last test, in addition to pin 88d being jumped to +12v on the battery, you can also jump pins 88a and 88b to +12volts on the battery. One half of this relay contrls the fuel pump, where the other half turns on the ECU. All these jumpers will essential bypass the dual relay, just another test we can do to rule things out.

[malcolm2]

so what ever happened here? Did you buy a new AFM? Is it running?

(IMG:style_emoticons/default/poke.gif)

[thatguywiththedatsun]

Once again, other stuff got in the way. I'm poking around as I'm able. Bought a $2 noid light from work. Really looks to me like an unreliable injector pulse. Maybe a bad coil? The light comes on and stays on *brightly* in conjunction with the buzzing that sometimes happens (and sometimes doesn't) with key on. When there's no buzz, there's no light. If I try to start it, it blinks a few times as it should, then turns off shortly before the car dies.

TL:DR; Haven't found a test afm yet, though I'm still trying.

Aside from a new afm, and the tests that I haven't got to yet... anyone have any other ideas?

[thatguywiththedatsun]

Bought a rebuilt afm from fuel injection corp. Same results. Getting back to basics here....... The injectors are essentially just simple solenoids, which would buzz in a situation where they aren't getting adequate voltage. The starting has to be on the cold start injector alone. I have noticed that the buzzing goes away if the air flow meter is unplugged, and comes back if it's plugged back in.

[thatguywiththedatsun]

Bringing a thread back from the dead here I know, but maybe someone else will benefit from my time spent troubleshooting this problem. I ended up reading a post somewhere that dealt with fiats I think... maybe volvos? Don't think volvos ever used l jet. My main source of confusion was the buzzing injectors, and this one was the only l jetronoc thread that I could find where a similar symptom presented. I eventually popped the ecu out, and open, and sure enough found burnt traces on the boards. I bought a reman unit from fuel injection Corp in Tracy, Ca and that was that. I never suspected the ecu because everything I read stated that they were pretty robust, but you really can't rule it out without testing it with one of those nifty Bosch testers, or an o-scope.

[Tjmrfe]

Bringing a thread back from the dead here I know, but maybe someone else will benefit from my time spent troubleshooting this problem. I ended up reading a post somewhere that dealt with fiats I think... maybe volvos? Don't think volvos ever used l jet. My main source of confusion was the buzzing injectors, and this one was the only l jetronoc thread that I could find where a similar symptom presented. I eventually popped the ecu out, and open, and sure enough found burnt traces on the boards. I bought a reman unit from fuel injection Corp in Tracy, Ca and that was that. I never suspected the ecu because everything I read stated that they were pretty robust, but you really can't rule it out without testing it with one of those nifty Bosch testers, or an o-scope.

Your guess was right, I'm having similar problems and this will definitely help me out...thanks!

[Root_Werks]

ECU failure is uncommon....used to be. Maybe as they continue to age, it will become more common. I had one years back that was causing one injector to stay open. Fiddled with a number of things for too many days. One day a buddy showed up with an ECU just for giggles. Swapped it and ran perfect.

I'm not a supporter of blindly swapping parts to fix something. But if done one at a time, then swapped back if it didn't fix the issue is sometimes a quick path to correcting the issue.

Thanks for following up, this thread could save someone a lot of time.