00' sport so 5-sp lost relay today...replaced relay and was running good....then lost relay again(fuel pump relay) replaced...no juice to the lp. when we hot wire the lp it builds pressure and runs good...when attempting to run as per the harness...no go? the truck throws a 1693 code my superchips pulls a 1689 need some expierenced help on this one. BTW superchips manual says 1689 is no comm between the ecm and ip

 

I removed the battery terminals and cleaned them....the grounds were pretty grose! the truck then would start and we ran it in the driveway up to 190* and it never did anytthing wierd? hmm? can the ground feedback or lack thereof cause the lack of communication between lp and ecm? also just before the truck died he climbed a 10% hill for a half mile or so on 1/4 tank or so methinks it lost prime and was just running on the fuel filter reserve? who knows? I know this it would not trigger the lp until after I r&r the bat cables. any help as to the trucks future will be appreciated. BTW he is gettin gauges in the morning

 

It's amazing how many problems can be caused by dirty battery terminals.

With more and more of the truck being controlled electronically, good electrical flow is a must.


phox

 

If it turns out to be the PCM on either ground or hot, just ground the pump at the frame and power it from the ASD relay. It is fused at 30 amp and has the turn on sequence of the stock wiring. That is where the PCM gets the power for the pump circuit. You will only lose the half power starting. My truck runs 20 pounds pressure on full power and I have no problems starting. Just wait till the wait to start light goes out and it will start fine. That would be a perminate fix for it.

The way the PCM circuit works is that the 12 volt is switched by the PCM and the ground is modulated by the PCM for the lower power to start. The PCM relay is in the relay box and the main output can be found on either side of the engine compartment. On the drivers side at the realy box and on the passenger side where it feeds the PCM.

If you run into it and lose the alternator feed the regulator can be feed from the same wire as is mine.

 

do you by chance remember the color or location of the wire? I can find it but if you know it will save me some legwork.

Thanks,
GREG


PS if anyone has had the misfortune of telling you close friend that he is now $1000 lighter it is a crummy feeling....I sure hop it was just dirty cables makes me wonder howmany folks get swindled at the dealer

 

I did not add the color on purpose because I have a '99. I know the later years are the same setup but do not know the colors are the same. On the '99 it is a #10 wire and is dark green with an orange stripe. You can find it coming out of the power distribution and also as it goes into one of the plugs of the PCM. Hope this helps.

Of course the test is to stick a test light in it and key it. It should come on for a few seconds and go off, same as the fuel pump.

 

THE SAGA CONTINUES.....it works great in the driveway.....buddy leaves to go to work this morning and wammo! again! I wonder does the ecm shut everything down if it loses fuel....I mean he lives up a very steep hill and I think he might be losing prime to the pumps due to the low fuel level in the tank, he said the relay was pretty warm so it must have been working overtime or shorted...hmmm? I hate computers!