Check for spark. If you don't have spark, you could have a bad ignition control module in the distributor. Spray some starting fluid into the throttle body. If it fires off and quits, then it's a fuel problem. I can't hear the pump run on either of my cars.
Originally posted by fierofool: Check for spark. If you don't have spark, you could have a bad ignition control module in the distributor. Spray some starting fluid into the throttle body. If it fires off and quits, then it's a fuel problem. I can't hear the pump run on either of my cars.
if FP is not running then this doesn't help. But if have Ignition problems or ECM dying and thinks so then ECM won't turn on Injector(s).
FB not running then Fuse, relay, pump, or ECM have problems... put 12c on ALDL G plug should run FP even if fuse etc are bad. Many jump lighter plug to G but FP needs 7-10a so don't phone wire (<18awg) to jump. If FP is bad can blow lighter fuse but not always so don't jump and leave it w/o pump running.
Warning: Gas is coolant and lube to FP. Do Not allow FP to run dry.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
[QUOTE]Originally posted by fierofool: Check for spark. If you don't have spark, you could have a bad ignition control module in the distributor. Spray some starting fluid into the throttle body. If it fires off and quits, then it's a fuel problem. I can't hear the pump run on either of my cars.
if FP is not running then this doesn't help. But if have Ignition problems or ECM dying and thinks so then ECM won't turn on Injector(s).
FB not running then Fuse, relay, pump, or ECM have problems... put 12c on ALDL G plug should run FP even if fuse etc are bad. Many jump lighter plug to G but FP needs 7-10a so don't phone wire (<18awg) to jump. If FP is bad can blow lighter fuse but not always so don't jump and leave it w/o pump running.
Warning: Gas is coolant and lube to FP. Do Not allow FP to run dry.
[/QUOTE]
Please correct me if I'm wrong in my assumption/theory.
If the ignition control module is bad, you will have no spark. No spark signal from the ICM I don't believe the fuel pump will run. If you have spark and no start, then you have a fuel delivery problem. Pump, injector fuse, relay.
Regardless it should run for a few seconds after turning key on before attempting to start. Also in a V6 with a good oil pressure switch it should run with engine cranking once oil pressure builds right?
If good, the OP switch should turn on but many Fiero V6 have oil pressure problems and can take along time to crank and build up 4+ PSI. That can damage the starter etc from heat generated in starter and cables. Safe stater run in many GM books... 30sec on and 2-3 minutes min to cool before trying again.
jump ALDL G w/ 12v is easy and more safe. If you use a extra/jump battery then make sure they have very good ground to "frame." Iffy grounds can fry any motor/pump. See my Cave, Electric Motors
Some pumps just don't make a lot of noise and 12v to G doesn't make noise trying to hear them when on. If need to test F Pressure w/ engine off then need G jumping too.
[This message has been edited by theogre (edited 10-31-2017).]
Originally posted by fierofool: Please correct me if I'm wrong in my assumption/theory.
If the ignition control module is bad, you will have no spark. No spark signal from the ICM I don't believe the fuel pump will run. If you have spark and no start, then you have a fuel delivery problem. Pump, injector fuse, relay.
I think that's what I said above.
I've check in Fiero SM and yes Iffy Ignition can turn off FP while cranking. More common is Iffy Ignition or Iffy ECM Very Often Won't allow Fuel Injection to run. Example: ECM doesn't see good Ignition Ref for any reason. IOW The Ignition can be 100% but wires to or ECM itself have problems result in things like ECM try to run injector(s) but have "blown" drivers etc and final "Transistor(s)" won't turn on. ECM uses relay for FP but have direct control of injection thru MOSFET drivers. These MOSFETs are biggest heat generator in the ECM and ECM case is the heatsink for them.
[This message has been edited by theogre (edited 10-31-2017).]
It's true that if there's no EST signal, then the ECM won't activate the fuel pump relay. However, that does not affect the initial fuel pump prime when you turn the key. Unfortunately, the OP didn't specify if the fuel pump primes when he turns the key. But if the pump isn't priming, then I doubt it's an ignition problem.
Like Ogre said, jump 12VDC to pin G in the ALDL. If the pump runs when you jump it, then the fuel pump relay is bad (and if the pump doesn't run after cranking the engine for a few seconds, then the oil pressure switch is probably bad too). If the pump still doesn't run, then either it's dead or there's an electrical fault.
Best of luck!
[This message has been edited by Blacktree (edited 10-31-2017).]
Yes, Noid light will show bad ECM won't turn on Injector(s) for iffy ignition etc. But...
87 Fiero SM 6C·2 FUEL SYSTEM (and just about any GM Factory SM w/ OBD1 systems.) Electric Fuel Pump When the ignition switch is turned to the "ON" position, the fuel pump relay activates the electric fuel pump for 1.5 to 2.0 seconds to prime the injector(s). If the ECM does not receive reference pulses from the distributor after this time, the ECM signals (turns off) the relay to turn the fuel pump off. The relay will once again activate the fuel pump when the ECM receives distributor reference pulses.
Is because FP will pull down the battery w/o engine running. FP draws 7-10a @ 12v and more if battery is low. See my Cave, Electric Motors
When we hear the relay click, that's actually a disconnect from the cold start circuit. Does the ECM re-energize the relay once it sees a spark signal?
What I was referring to under 'no spark condition' is that if the ECM doesn't see a spark signal, it won't turn on the fuel pump and injector circuit. That loss of spark could be from the ignition control module, pickup coil, ignition coil, or as you indicated, the relay or oil pressure sensor.
When the ignition switch is turned to the "ON" position, the fuel pump relay activates the electric fuel pump for 1.5 to 2.0 seconds to prime the injector(s). If the ECM does not receive reference pulses from the distributor after this time, the ECM signals (turns off) the relay to turn the fuel pump off. The relay will once again activate the fuel pump when the ECM receives distributor reference pulses.
OK, this is correct. I'll edit my previous post to correct it.
