[majakarot]

I thought I did all the research, tried following the l67 walkthrough, but heres the rub: 97 monte carly ls, 01 impala 3800. thought that by getting all the wiring and pcm from the impy we would be able to wire the c100 into the harness and get it going but no luck. First, noone has been able to find the pinout for the plug that passes through the firewall in the 01 impala from the fuse junction blocks. I got the one for the strut tower only. I hooked it up to what we thought might get us started but nothing, no fuel pump, wont even roll over (assuming the three wires from the monte that are 2 tranny position and 1 theft deterrent that I can't find on the impy harness)

I now have a week and hundreds wrapped up into this and a lawn ornament.
would a 98-99 z34 wiring harness work with this 01 impala motor? if so, do i use the pcm from the z34 or the impy? Or better yet, does anyone have a clue how to wire this? at this point I would love just to get it started and work on details later... anyone know what wires are required to start this motor... as in bare minimum to start?
any thoughts would be appreciated

[nitehawkjcb]

A '98-'99 Z34 / LTZ harness should be fine. You need the harness hooked up in its entirety for the engine to start and run correctly. The Z34 PCM should work, depending if the Impala tranny has the same gear ratio as the Z34.

[DigitallyPhoenix]

ok, like said you will need a 98/99 z34/ ltz/ or 9c3 police harness. and you will still need to change a few things to be good. some said you dont, but i made the changes and my swap runs great.

i have a zip with all the research i did to do the harness and i can email it to you. mine was a 96 DOHC to a 98 L36 but i think there is enough info to do your swap.

[majakarot]

I finally found a harness and pcm, they are from a 98 monte carlo z34, i have the c100 pinout for a 99 z34, but don't know if they are the same for the 98 as the 99. Any help would be appreciated.

[Dave96Z34]

majakarot, on 09 January 2012 - 06:27 PM, said:

I finally found a harness and pcm, they are from a 98 monte carlo z34, i have the c100 pinout for a 99 z34, but don't know if they are the same for the 98 as the 99. Any help would be appreciated.

you will need this

Attached File(s)

•  95 to 99 all engines c100.zip (988.38K)
  Number of downloads: 4

[majakarot]

OK, heres where I am at. Got a 98 z34 harness and pcm. C100 plug was identical wire for wire. Couple of issues:
The temp sensor has three wires on the engine and two on the harness, hooked up the black and yellow left the green unhooked.
Alternator has 2 wires on the alternator and 1 on the harness, hooked up the red and left the orange unhooked.
Have 2 O2 sensors hooked up but have a plug for a third on the wiring harness ?? left it unhooked.
Tranny linkage reads a gear off (park is reverse), gonna try to swap the arms from the old tranny to see if it brings it back.
tranny kickdown cable needs to be reworked to fit the new throttle linkage and the throttle only pulls about 90% wot.

heres the biggie: ran it multiple times, smooth idle, quick start, all good.I drove it up to the lift to put some exhaust on. At this point I left. Some friends/family welded the stock 3.1 exhaust to the 3.8 downpipe. Now I get a call saying it won't start, it just backfires. I'm thinking it is basically one of three things: They may have tacked it on the car, could possibly have fried my one-day-old (to me) PCM, or maybe the tiny 3.1 exhaust is just way to restricted or plugged for the 3.8 to run (??) or maybe some fluke s thing like a bad wire connection or something. Anyone have any insight on the exhaust restriction/collapsed thought?

Anyone have any solutions to any of these conundrums?
Thanks again

[Buck531]

You could put a 1" exhaust on the car and it would run fine. Not efficient, but it would be fine. They must have f'd something up when putting on the exhaust. Maybe fried a wire or two. I believe the exhaust from the 3.1 and the 3.8 are the same diameter so that won't matter. If it just backfires it could be the plugs, wires, ICM or even the PCM. Not sure what to say on that one.

[nitehawkjcb]

Might be the crank sensor too...

[majakarot]

OK, so i first I checked it all over for loose or melted wires, then I loosened up the exhaust and pulled it back a little to see if it was clogged, nothing. Got out the haynes and started doing some checks. Crankshaft position and Camshaft position sensors check out like the manual says they should. voltage to ICM was good so next it says to pull a coil pack and check for signal voltage, nothing until I let off the key, then one blink (the random backfire) checked another coil pack terminal set and the same thing, haynes says is probably the ICM so I head to a junkyard and pick another one up. Same thing. no spark while rolling over, one when I release the key. Do I have 2 bad ICMs or could this be the PCM?
Also I noticed the ignition relay makes a buzzing should when the car is rolling over, or just finished rolling over, i tried swapping a couple different ones in there and they responded the same.

I did try the impala pcm with no luck, but the wires werent colored the same on the connectors, so I don't think it was a fair test of the pcm.

In my head I am thinking that either the PCM or ICM got fried from the welding (battery was still hooked up) but think it unlikely (but possible) the junkyard ICM and mine are both bad.
Is replacing the pcm the only way to test it?

Ideas?

[majakarot]

So it turned out it was two things, we had a loose ground to the ignition relay and the PCM was bad, probably actually from us swapping them back and forth and whatnot.
Here's the kicker, ran it for a while then started putting it all back together, went to swap out the tranny linkage when the dang thing snapped inside the tranny case. 7 hours later, we hope we have it back together right and the car is waiting to be reassembled.

[Dave96Z34]

majakarot, on 14 January 2012 - 11:24 AM, said:

went to swap out the tranny linkage when the dang thing snapped inside the tranny case.

How in the f*ck you pull that off? its like a 15mm nut that's not really on that tight to begin with?

[majakarot]

LOL!! thats about what I said!! The one came off the monte with NO problems, then I try the impy nut and this thing was STUCK, I kept telling everyone I was gonna break something but everyone thought I was crazy until the damn thing snapped off. And I was only using 3/8 socket tools. Looking at the linkages later I saw they were the same, but my gears were off so I think maybe it got bent when the engine was pulled which would explain why it was off and why it broke.

Here's where we're at now. Tranny seems to be good, temp gauge not working with the yellow and black wires, tried the green and black and that didn't work either, going to look for a 3 wire sensor.

Power steering lines blew off twice (I told them we needed the high pressure lines) finally we drove it home with no power steering, maybe 9 miles. He said it drove great, but scary with no temp gauge, he monitored the temp of the air coming out of heater for any fluctuation, seemed good.

We are going to try putting a small flare on the line and using high-pressure clamps for now, was wondering if we could either use the low-pressure pump from the 3.1 or if we could just loop the out and in lines to the pump to protect the pump and drive it without p.s. for now? If the low pressure pump would work it would be best for us. I know that changing the lines would be the best option, but we are just out of money and time for this week.
If we need the new lines, do I need lines for an 01 impala for the pump or a 98z34 for the car?
thanks again

[majakarot]

Weirder and weirder... Pulled the temp sensor from the 3.1 because it had the 3 wires, the black plastic around the plug was broken but I didn't think it would hurt anything. At the same time I cut the downstream O2 sensor from the body harness and hooked it to the engine wiring harness.

Started the car and one of the fans came on immediately. The temp gauge also never moved.
After running it for a while the brake light came on. ?? the power steering pump still isn't hooked up, I dont know if that could have anything to do with it. ??
We are going to try a 98z34 line on the ps pump output side.
Guess we will try a new temp sensor for a 98 z34 also unless someone has another idea.
Another odd thing, he just tried the wipers and they don't work, but the dash fuse is good. Maybe pulled a wire during the swap?

[majakarot]

New sensor fixed the fan and temp gauge problem, however we can now see that the temp is running too low, guessing the thermostat. Is that right at the top of the engine where the top radiator hose goes in?
The new high pressure line for the ps got that together but it sounds like we may have hurt it driving it home with no fluid (when the line blew off) it whines now.
brake warning light is on along with anitlock, not sure what the problem is, fluid seems good and the e brake is off, put it on and off a couple times, didn't change.
Wipers are completely dead. fuse is good... is there a relay? they were fine before the swap so I am pretty sure it is something we did.

After about 15 miles the SES light went off. Possibly from getting the 02 sensor switched right?
thanks again