Weird Electrical Prob.....

[Mogobs30th]

I got the Firebird fixed with the problems it had before, now I have developed a new problem. Im not sure if it is a dead short, or a PCM problem, but something is doing something else to make the car act like its starting over and over and over again.

When the car is RUNNING, there seems to be a short somewhere that activates the fuel pump primer, and at the same time, the SES light flashes in conjunction with the check gauges light. While this is happening the car wants to surge, probably because the PCM is ignoring the O2's and going thru a starting cycle, dumping more and more fuel in the engine. Whether or not I give it gas doesn't matter, it still wants to surge. Imagine the car running, but the key is in the ON position, and its getting switched to the START position probably 20 times a minute. I hear the fuel pump relay under my foot constantly clicking on and off, on and off, on and off, probably AT LEAST 20 times a minute. With the primer wanting to dump more fuel in there, disregarding the sensors because of it thinking its going thru a startup cycle, its surging badly.

My guess is a bad PCM. But maybe someone else has some other insight?

[97rs4life]

Re: Weird Electrical Prob.....

any idea what codes are flashing?

[Mogobs30th]

Re: Weird Electrical Prob.....

Only code I have is a EVAP code, always on, but I did have it checked today. Still the only code. I really think something is fried. Because of that relay clicking, the only power to that relay comes directly from the PCM. Without the power from the PCM, the relay wouldn't activate. But because it is clicking constantly and messes up the car, I have a belief that it is the PCM that is faulty.

[CDNFB]

Re: Weird Electrical Prob.....

First check the relay, wiring and all connections from PCM to relay. Any one, or combination of all could be the problem. Check those before blaming the PCM.

[Mogobs30th]

Re: Weird Electrical Prob.....

First check the relay, wiring and all connections from PCM to relay. Any one, or combination of all could be the problem. Check those before blaming the PCM.

They were checked, I have conductivity thru all the conductors to the fuel relay, and the relay itself is fine. Its something more than the relay, as I said, this problem is making the relay and several other things not act right when running.

Its either the PCM, the key cylinder, or some other part that tells the car to START. What makes it bad is that it wants to start, or act like it is starting, is that it keeps dumping fuel into the car, similar to being in open loop (I think) before startup. The pump dumps more fuel into the engine, disregarding the sensor relay, and ALL the dash lights that light up BEFORE starting the car, flash in conjunction with the relay clicking. And remember, it is doing all of this while it is already running and up to temp. Its what leads me to believe its a startup system problem, but something far more serious than just a faulty relay.

[CDNFB]

Re: Weird Electrical Prob.....

Conductivity tests are fine, but what is the voltage actually doing at the relay. If the relay is clicking on and off like that, then you should see the voltage jumping up and down (0V-14.4 or there abouts) on your volt-ohm meter when measuring at the relays control inputs. You have to chase that intermitent voltage to find the faulty component. For example, you should also see the voltage jumping from high to low at the PCM output, and if the PCM is not faulty, then you should see the same voltage jumping on the PCM inputs, and back to the ignition switch, etc...

I'd bet the Ignition switch is the major culprit here.

Also, the fuel pump does not control the fuel metered to the engine. The PCM does this. And there is no such thing as "Priming". During engine start, the PCM gathers all the parameters and based on that schedules the proper fuel mixture. There is no generic fuel quantitiy or "prime" that is just thown into the engine at start up.

Yes, just after engine start the engine will be in open loop for a bit, but the difference between a hot engine running in open loop just after an engine start vs hot engine running in closed loop would not be so significant as to cause running problems because of overly rich mixture.

[Mogobs30th]

Re: Weird Electrical Prob.....

So im guessing, from what you said, that possibly its something giving power to this relay that is making it tick. But just to let you know, the relay clicking on and off is an EFFECT of a cause of a problem. There is something else that is f'ed up making this relay go off like that. The only thing that doesn't make sense with blaming the ignition switch is that when the ignition switch is turned to the START position, power is diverted to the starter, and in my case, the starter never gets power again once the car is running, that would be the first thing I would have noticed. The starter not energizing again makes me want to believe that it is not the ignition switch at all.

I can start checking individual wires, but as for the voltage reading on the relay, I can't check that with the DMM I have now, I need a VOM with an analog meter on it to see the voltage rates that fast. This relay is clicking fast enough that my DMM wouldn't read the voltage drops efficiently. It sounds like a stenographer on crack.

I can agree with you about the hot engine open loop vs. closed loop, but if the PCM is screwed, and it is disregarding ALL info being brought to it, its going to dump more and more fuel into the engine as if it were a cold engine at Startup, which is what the symptoms are telling me as of now. There are only three things that I can go off of to trace the problem....

Fuel Pump Relay going ape****
The SAME instrument lights flashing intermittently as there are when your car is in the START position before the car fires.
Excessive fuel being dumped into the engine.

And one more thing.
The fuel pump relay, the cars hesitation, and the instrument lights flashing all happen at the same time. The car sputters, the dash lights(CHECK GAGES, SES, and AIRBAG lights) flash, the relay clicks, all at the same time. After about 20 sputters or so, there is enough fuel in the engine to get the RPM's over 3500, and I have the car in Neutral and my foot is off the gas. Thats pretty much the best I can explain it without getting vids.

[CDNFB]

Re: Weird Electrical Prob.....

Regarding the starter thing, The ignition switch has a multitude of contacts in it. Each contact will provide a power feed to its assigned system(s) and/or component(s). In other words, with the ignition switch in the "START" position, the contactor in the switch that provides power to the PCM is not the same contactor in the switch that provides power to the starter circuit. It could be that contactor in the switch that provides the PCM with power that could be damaged or worn, allowing arching or power drops that confuse the PCM. To confirm this, find that wire that leaves the ignition switch, and powers the PCM, and meter it. If you can't meter it, use a jumper and provide a known constant 12VDC to the wire and see what happens.

[Mogobs30th]

Re: Weird Electrical Prob.....

I haven't had the time to go back to Indianapolis to check on the car, but I am still trying to figure out what I can from here.

It is possible that it is the ignition switch, so that would mean there is a short somewhere inbetween the RUN and START contacts?

[CDNFB]

Re: Weird Electrical Prob.....

It could be, but not necessarily a short. Could also be dirt or corrosion that is causing intermittant connection of the contactor. Could be a loose contactor that constantaly makes and breaks contact.

Could be.......could be.....could be........

The possibilities are endless.