what is battery voltage when this clicking happens?


wondering if maybe the GP are pulling the batteries down or not

 

Haven't check voltage, yet how could I forget to check that. I'll take a look today.

 

I know this is quite old, but did you ever find any type of adjustment screw on the gauge?

 

I was using the wrong boost gauge, I had a a vaccum/boost gauge, I bought just a boost gauge from Autometer and worked great.

 

Oh ok, glade that worked out. Sorry to hear about ur electrical gremlins. When I have those issues I sell the vehicle. Haha I'm horrible with electrical issues. I don't know whether to use a voltage meter or contact a wizard.

 

By the way, what are the two small wires on the GPR? I thought one was a ground but someone said it wasn't. Any idea ?

 

The two small wires on the GPR are a constant 12v, and a ground supplied by the PCM. If you hook those wires together, you are putting 12v back through a ground coming from the PCM.......that's not good.

 

That's how I have mine right know, and it's the only way the truck will start.

 

Do you have 12v on one of them?

 

Ok checked voltage 12.8v with key on, 12.6v both batteries have the same voltage (not connected to each other) cranked engine and spins fast and voltage drops to 11.5 while cranking, so for a fact glow plugs ain't coming on. The only time the clicking sound goes away is when I unplug the 42 pin connector relay #2 or remove MAXI fuse #22.

Bill yes I have 12v going to one of them, if I don't connect them together I get no WTS light and truck won't start.
Man this is frustrating ahhhhhh!!!!!!!! I'm removing the engine wiring harness and go from there.

 

Adam, I am confused. You disconnect both of the small wires from the GPR and bypass the GPR and connect those two small wires together and it's the only way your truck will get a WTS light and start?

Something isn't right with your GPR wiring. If it were mine I'd try to trace the individual wires before I went and pulled the whole engine wiring harness. Figures that with all the real work to be done with your new motor you have to deal with this cr*p instead.

 

Yes that's the only way it will start and get the WTS light. I haven't had a chance to look over the harness but it's easy enough to remove, that way I can check wire by wire to see if there's anything out of whack. I've unplugged each of the VCH connectors to see if the clicking #2 relay would stop but no luck unplugged all of them at the same time still clicked. The only way to stop the clicking was by removing the 42 pin connector, unplugging the PCM, or connecting the two small wires going to the GPR. Also unplugged the IDM and clicking was still present. So the problem lays between the PCM harness to engine harness. I'll try to do something tomorrow.

 

The fact that jumping the two wires for the GPR together is what gets the truck to start, tells me that you have either a power circuit or ground path open somewhere in the PCM wiring. What you're doing jumping those two wires together is feeding 12 volts DC back to the PCM on the ground path. The way the PCM switches the GPR on is to feed it a constant 12 volts on one wire, and then it pulls the other wire to ground to close the circuit and energize the relay. You're feeding the 12V back to the PCM on that ground path.

Here's what I would do if it were me. Leave the GPR disconnected, unplug ALL the sensors you can that wire into the PCM (ICP, IPR, TPS, IVS, CPS, EBPS, VSS, the sensors on the fuel bowl, anything you can think of). Then unplug the connector to the IDM as well. What you're trying to do is to isolate the PCM completely from anything else. Then turn the key on, and see if you get the same trouble. I know the truck won't start this way, but see if you get the same chattering of the IDM relay. If you don't get that clicking, then add one thing at a time back into the PCM wiring (plug one sensor at a time back in) and look for the one that causes the issue to return.

When a relay chatters like that, it is doing so because it doesn't have sufficient power to hold the relay coil in. That means that you're either seeing a low voltage condition on the 12 positive side of the circuit (which could be caused by a short in the wiring or a bad sensor somewhere on the same circuit) or that the ground path is showing a high enough resistance to keep the relay from getting a good ground (this, you could check by testing the resistance between the ground pin of the relay socket (terminal labeled 85)and a negative terminal on the battery). For that matter, you can test the voltage at the positive coil side of the relay (terminal 86) and see what the voltage is there.

I hope this helps.

 

Exactly what I was thinking. Not that I am an expert. You could also check what voltage you have at the idm relay and go back to the source from there.

 

Bill suggested I tape mine apart because of the possibility of a ground going back thru my PCM and IDM from a bad GPR stopping me in my tracks on the freeway. They remain taped that way until I get home mid Oct to start experimenting to see what might of happened.