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Discussion Starter · #1 ·
Had it all running, after lots of great help from the forum. Lined up for CHP VIN# Jan 12th. Had some unused wiring, loose running to unused connectors. Clean it up, right? Well, I did, being very careful to note if splices were involved. Apparently I blew it and should have just "buried" the spare wiring behind the dash.

Here's the issues:

1)When key is turned to "ON", the fuel pump goes on, and stays on, forever.

2)When key turns to start, it does not start; turns over great, though.

Had it for today. Please, a simple solution?.
 

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Discussion Starter · #3 ·
NAGA, How strange...I did change the location of the 'puter ground; I did change it back though - after the trouble - to no avail. Didn't really mess w/ the plug, but I'll double check in the AM. Thanks
 

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I have spent a lot of time in this area of my wiring harness. but that does not make me the expert. Far from it.

At first my pump ran all the time. That was because the donor owner had by passed the fuel pump relay and for some reason installed a 1992 wiring harness in the 1989 donor.

Now my pump does not run at all. But it will run if I ground the appropriate wire in the self test connector (the one to pin 22 of the ECC). If your car was running and now you have the problem you might want to check to see if pin 22 is shorted to ground.
 

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Actually it's not quite that simple. Fuel pump runs all the time doesn't mean the processor will pulse the injectors. Fuel question alone is not that simple. Pump runs doesn't mean fuel pressure. Combination of pump output and known good pressure regulator create fuel pressure....providing there is fuel in the tank....good fuel....sock not plugged etc. The processor pulses injectors and puts fuel where you need it. Then there is the question of ignition...........
Really need to step back and look at the situation. When there is good history such a this case it needs to be looked at first.
Engine ran ok until what?? Wire chop and mod. Most likely the problem is in that area. This concern seems to come up a lot in this forum.
You can have a missing ground and have a fuel pump run and no start. You need to go back and look at what you've done to the harness. Get a schematic. There really are not that many wires that run the EEC. The donor harnesses do contain about 20 lbs. of excess wire for all the other systems in the donor car. These EEC systems will not tolerate power input or ground problems. They simply will not run. I hope all that helps.
 

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if you have access to a set of "noid" lights(available at most local parts stores) these plug into the injector harness clip and you turn the engine over, if the computer is pulsing the injector, your fine, if not, at least you know the ECM isn't working. Hope this helps.
Ben
 

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Forgot to mention that the Noid light should light up if the injector is being pulsed, sorry
 

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I would not try to make the injector works until you figure out the fuel pump running.

There is a power relay controlled by the EEC as well as the Fuel pump relay. The power relay is power on when the car is on. Trace to it and the fuel pump controls. see if the the control is hot all the time - OR - you have patched in a Hot down stream of the relay to the fuel pump.

As I recall, there are about 5 or 6 hot lines just into the engine compartment from the computer. They drive a lot of the engine sensors the eec takes them to ground to power them. That is also the source of the power for the fuel pump.

I cleaned out the air pump controls and ended up trimming a little to much, I caught it and put back the red ones I did need. That is where I would start.

Anyway I am sure I did not say this very well, but check the engine solenoid power relay output and the fuel pump relay control ckt. :D

 

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Discussion Starter · #10 ·
Started out this morning reinstalling the connectors I dieted the other day; still did not make sense to me, because all wires ended in single, unused connectors. Checked all around and found that one of the wires soldered to the red battery charge light 510 resistor had broken free from too much activity behind the dash. Resoldered the connection and 1) the fuel pump went on briefly when I turned the key to ON, and 2) the engine started. I'm wondering if this did the trick (does it make sense) or is it unrelated and I just happened to move some wires and "undo" a short? Thoughts?
 

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Hey Dale,
Fixing the Alternator Sensing circuit's resistor shouldn't have made a bit of difference. It's not involved in anything unless the Charge Light burns out and then the current flows thru it to get to the alternator.
I'm still going with my original guess. The plug going to the computer was not seated completely. You got it back to doing it's thing.
Anyway! You're back in business!! Yay!!

d



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Like I said in my last post, the most important thing all of us working with EEC systems is to consider history before jumping to any contusions..... If the engine was running okay then has a problem, what was done since the last time it ran okay???? Sit down and back up and look at the last things you did, chances are you screwed something up. Check connections, power, grounds, previous work.....very carefully before getting too carried away.
Just a suggestion.
 

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Discussion Starter · #13 ·
Thanks! Just glad it's working, so I can get the body on. Does seem like there must be something "loose" and maybe ready to short again.
 

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Brain...
Hurt...
that's why I'm going carbureted.
I spend way too much time thinking way too hard at work. It would drive me mad to think about this kinda stuff during my 'down' time.
 

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Mine also ran fine when I first (roughly) wired it all together. After I'd put the wiring in its final place, the fuel pump ran continuously. I tried to remember what had changed since it was OK and narrowed it down to the EEC wiring through the footbox. Took it back out, used a magnifying glass and discovered several wires had chafed through the insulation, thus were probably grounding on the aluminum. Anyway, I insulated the chafed wires and wrapped electrical tape around the bundle, and put some of the edge protector from the F-panel around the hole. Works OK now.
 

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If you are using the original donor fuel pump relay , replace it...They are notorious for being the culprits in this situation....Will work sometimes , and sometimes will not....It is a $12 part....They will frequently cause the pump to run on , or not at all.
 

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Discussion Starter · #17 ·
John, thats my thought now, too. I do recall jostling the EEC wiring around through the footbox during the diet (putting looms on and customizing the gromit fit. Will look at it closely now, even though it currently works.
 
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