69MyWay

iTrader: (2)

I'm confused. I'm working on a car for a friend (69 Vette) That has a GM LSx block, LS3 heads, hot cam...102 Fast intake and DBW TB. It has a 4L60E and is all connected by a 802 (12602802) ECM. It has a 24 tooth reluctor.

I'm rewiring the chassis harness and finding all sorts of strange things. I can't ID the manufacturer of the harness. I know that it isn't a painless brand - but would be most like their #60221 BUT - it is a long harness so that the PCM can go in the back. Painless does not make a LONG harness version that will use the 802 PCM.

The prior intaller has the brake switch wires NOT connected and a note on there saying "NOT USED." Also, there is no shift indicator sensor/swtich on the side of the transmission and the park/neutral was NOT hooked up to the ECM.

The car has some problems - it idles high most the time and won't drop under 1,200 RPM for very long if at all. Shifts way early. It has an off idle hesitation.

Several shops have attempted to "tune" it. None of them ever getting full success. It has driven about 8,000 miles with this set up, but it just isn't right.

So, I'm committed to hooking it all up right. I believe however it has a C5 corvette pedal - which I didn't think was even possible with an 802 ECM.

So tell me - why would anybody NOT hook up the brake switch with an Automatic transmission?????

I'd prefer to yank it all out - but then I'd be on the hunt for not only probably a 411 (right?) - but all the (MAF, O2...etc. et) that would be compatible with that.

oldgoat69

So it is a green/blue PCM? It will need a brake switch for the converter lockup. The switch on the shifter side of the trans won't matter. Have you verified the harness pinouts yet? I am led to believe that with the correct TAC the C5 pedal will work. You do have an 8 pin TB?

69MyWay

iTrader: (2)

Sorry, I missed your reply.

The plot thickens. The computer is green/blue, but the harness has the RED connector.

Six pin on the TB.


It would appear somebody took the 411 computer harness and put the wrong computer. I don't know what they did or didn't do, but there are a few wires that have been "re-pinned"

So, I went to PSI and ordered a complete new harness for a 411 computer what would match the pedal and tac module - 24 tooth reluctor and SIX pin TB harness.

Waiting on those parts now - have the other harness out of the car.

69 Ghost

The 802 pcm is a better faster pcm and the pinouts are basically the same as the 411 wiring configuration except for a few things like the O2 grounds. I think you are better off cancelling your current order and trying to figure out what is going on with your wiring first or at least cancelling the 411. If you PM me I may be able to help you out with some of the wiring.

69MyWay

iTrader: (2)

Excellent info. The owner of the car does not want to have anything that has been "modified" outside of a "known" product parameter. In other words, he wants to have all the components matching up so that virtually any tuner can assess what is there and deal with it.

Now...with that said, it looks like the old harness will be left over and something that I could use on one of my future projects. I have another 69 Vette now and may go LS power. So...I hate to see this old stuff go to waste. I'd love to carry on a dialogue about how we can make this harness work for a future application. In so much as the current car though - that shop has sailed and the order is coming in to replace. Also, the trunk mount was a huge problem as the bulk of wire along with other equipment in the car was causing some problems. The new harness will be a standard length and the PCM will tuck away in the left front fender out of the way.

Now...back to the 802 set up.

You mentioned grounding of the O2s. This car was having some issues breaking up on high RPM and they were chasing that. Funny you mentioned this because there was talk about an ignition problem. The coils are mounted on an extension on the fiberglass firewall with no extra ground that I can see and I don't see a ground to the O2s

Let's start there - what needs to be done?

69 Ghost

The newer 1mb pcms ground the O2 heaters to the pcm itself and is included as part of the diagnostic. Basically you can take an older harness and plug in a new pcm turn of those diagnostics and the car will run fine. The 411 harnesses will ground the pcm, O2's, etc to the motor in the rear of the head on a factory harness. That is what I was talking about. The problem that a lot of guys experience is that tuners will turn off all the diagnostic codes when doing a conversion to avoid the check engine light. What happens is that when you start having problems you don't get any codes so you don't know what the problem is. It sounds like you need to hook the motor up to a scanner to see what is happening. Without further info there is not much more you can do other than chase wiring diagrams.