Need help. Car won't start

[Damarr30]

Hi everyone. I just recently bought an 84 Fiero 2m4 se 4 cyl 4 speed. The person I bought the car off of was going to take it to the crusher. So I bought it, not wanting that to happen. Plus it looked better than my other Fiero inside and out. He said the car had been sitting for about 2 years, and that was all he knew, someone gave it to him. When I got the car towed home (tires were dry-rotted, radiator had a hole in it, no battery), we drained the old gas out. Put about 2 gallons of premium in it, went to change spark plugs, and one broke off in head. So, took head off (pistons are bored .040), had shop take what was left out, put new head gasket on, changed radiator, new plugs, wouldn't start. Car would try but wouldn't do it. Changed O2 sensor, fuel filter, checked vacuum lines, changed injector, still no go. Had it at one point to start for about 2-5 seconds, then die. Now if we put gas straight into TBI, car will run til that is gone. I am stuck. Please help.

[Damarr30]

Anybody have ANY ideas???

[fIEROWISEGUY]

The fact that it runs when you put gas in, means you have air, spark, and compression. So, you've already done a good job of diagnostics.

When you turn on the key, you should hear the electric fuel pump in the tank run for about 3 seconds. If not, do the following.

I assume the "check engine" light goes on when you turn on the key. This is good, and indicates the computer is getting power.

First, check the obvious. Make sure the fuse for the electric fuel pump is good. Also, with the ignition on, make sure there is 12 volts on the fuse.

Remove the black plastic cover (2 torx screws) under the cigarette lighter to get to your diagnostic plug. With a digital voltmeter, measure the voltage from pin (1) to ground, when you turn the key on. You should have 12 volts for 3 seconds.

If you HAVE voltage, but DO NOT hear the pump, you probably have a bad fuel pump in the tank.

If you do hear the pump, borrow or buy a pressure tester, and make sure you have of at least 10 psi.

If you have pressure but still no fuel is getting into the engine, get a "noid" light from your auto store Usually a couple bucks) to check the electical signal to the fuel injector. removal the electrical plug off of the injector and connect the light to the plug. While someone cranks the motor, make sure the light pulses. If no lite, it may be a broken ground wire (quite common), ignition related (bad module or harness on the module), or a defective computer. (rare.)

If the lite pulses, and you have good fuel pressure, then the injector is defective.

The bottom line is; it's either electrical, the fuel pump, or the injector.

For what it's worth,

fIEROWISEGUY

[Damarr30]

I hear the fuel pump kick on, and it shoots some gas from the injector. I checked all fuses and they are all good and all right amps. I haven't had a chance to get a hold of a pressure tester yet. When I did the light test, I got light, but constant light, not pulsing light.

[Ragtop_Renegade]

Are you using a standard test light or a noid light? only noid lights work on fuel injectors. If you get a constant light using a noid light, the problem could lie within the ECM.

[Damarr30]

Went and bought a brand new noid light from Autozone. I don't get any light or anything now.

[Ragtop_Renegade]

The fault is in
a. the ecm
b. the wiring to the fuel injector
c. another component connected to the ecm that is faulty, confusing the ecm and preventing it from injecting gas.

Check the fuse for the TBI if you haven't already. The next step from there requires removing the center console and glove box from the car. (if you're willing to do so)

[Damarr30]

Well, we checked the wiring to the injector all the way to the computer.Already pulled the console out.( Seems the computer is remanufactured). All wiring is good there. When I check codes, all that flashes is 12,12,12,12,etc. Now, if the injector is pulled out, gas comes all the way to through tb, but it's just not going through injector. Could that be weak fuel pump? I even pulled the injector out of my good running 84 and no change.

[fIEROWISEGUY]

Okay,the next step is to connect the noid light from the injector connector to ground, one pin at a time (with ignition on.).

If neither wire is hot, check the DSL/ecm fuse. (10 amp).

DO this, and post.



fIEROWISEGUY

[Damarr30]

Raining a lot today. Will do tomorrow if not raining.

[Ragtop_Renegade]

With the injector being grounded internally by the ecm, and the wires being good, I'm starting to think your ecm is acting up. The fact you mentioned it's remanufactured makes me think you're doubting it a little. I agree, as I trust remanufactured electronics about as much as I trust poison ivy as toilet paper. Since you have a running 84, you might want to try a ecm swap. (assuming the ecms are the same, CHECK THE NUMBERS before you plug it in, sometimes subtle mid year changes will make ecms from the same model year incompatible) Disconnect the battery before you touch the ecm. In theroy, there shouldn't be any problem as long as the keys off, but I've wrecked an ecm already by not disconnecting the battery.

[Damarr30]

I went and bought a fuel pump today at advance auto. Going to put it in today and hopefully that helps. Any suggestions to make it a little easier than Haynes manual shows?

[Damarr30]

Finally got the fuel pump changed. That was it. It started right up. Now to get any little bugs worked out, including a slave cylinder. Thanks for everyones help on this.