Connector or wiring harness to ECU

[dadofanna]

Does anyone have a source for a new connector for the ECU or the entire wiring harness to the ECU on a 92 with TBI. I know I could junkyard one and splice it in but I prefer a new one if possible. They are no longer available from GM or the usual parts stores. Or if you know who the OEM for the connector was I could get a pin extractor and insert new pins.

[astroturf]

That is a tough first question.

Are you having problems with yours?

Thanks,and Welcome Aboard.

Jim

[RECox286]

This is a toughie. What I would do is check out the racks of electrical stuff at the LAP store, Napa, Pep boys, Advance Auto, Auto Zone and the like. Seems I have found replacement pins at those locations.

Last chance would be a JY for sure. That way you could get the PCM as well as the connector.

Good luck with this one.

Bob


Jim: how about the online GM parts link?

[Big_kid]

What's the problem with what you have now? I have a feeling you'll end up with a junkyard connector on this one.

Sorry to be negative on your first post, but I've only heard of one problem with this connector. A neighbor had a melted pin on his (Camaro) and it would not idle down. He went the junkyard route, IIRC. If someone knows where to find one, they'll post.

Welcome aboard!

[Phantom]

Since GM no longer offers this part it will either be a custom harness maker which will charge a lot if you can find one , It also depends on which engine it is a "W" or a " Z"TB , the harness or connector can be from a Astro/Safari , S-10, S-15 , Bravada , Chevy/GMC pickup maybe camaro/firebird with the 4.3L motor , If you look at a few junkyard vehicles you will likely find one that is in decent condition , I often cut of a pigtail for hard to find wiring items where I browse the salvage yards . You will find a decent one and then use Electrical Contact cleaner to clean the pins up , a spray cleaner also known as TV Tuner cleaner

[dadofanna]

The problem is rough idle and missing surging, loss of power on accelaration and up hills with what feels like backfires but is a caused by inaccurate ignition timing advance also ocassional stalling at idle. I have gotten intermittent codes 42 and 43. Replaced the distributer ignition module, new quality cap and rotor (brass posts), new plugs and wires, knock sensor, rebuit the fuel pressure regulator. I have traced every connection back to the ecu. Have thoroughly tested the throttle position sensor ,map sensor, temp sensors, and used an dual trace oscilloscope to measure the frequency and voltage and analyze the waveforms during acceleration between the ecu and ignition module and also from the pickup coil on the distributer. I have used a timing light to check base timing. Checked fuel pressure with a gauge, watched the spray pattern on both injectors (its the Z engine w/ tbi). Everything was in spec. but still after all that and no joy I was driving it with the ecu sitting in the passenger side floor and it ran much better, then at a stoplight my passenger was moving the ecu slightly and the van stalled, he put the ecu done and I was able to restart. So back at home we sat with it idling and with needle nose pliers selectively jiggled each wire. When we moved the purple one it stalled. Also noticed a black wire with a white trace next to it was lose. According to the wiring diagram in the chilton manual the purple is ground for the map sensor and the black/white trace is a ground for ecu. Intermittent grounding and intermittent loss of map sensor data explains everything. The map sensor is probably not cutting out long enough to trip a code or to make the ecu ignore it and use tps data only but is enough to cause inaccurate data.

[RECox286]

Wow, you've really done your homework. I think I would get thee to the JY.

Bob

[webcat]

What ECU do you have?

[dadofanna]

Got the harness off a '90 astro at the junk yard. There were a few wire color mismatchs but just matched to the correct pins ignoring the colors and it worked. This fixed the stalling but nothing else. I then changed the plug wires and rerouted them a little better (further from hot things and less crossing over each other. I thought I had changed them a few months ago but I must have been remebering a different vehicle because the old wires were pretty stiff. Now no more misfires or knocks and much better power. Only problem left is rough idle so next I need to look at the idle air control valve. When I'm done I should have a new van built piece by piece.

[astroturf]

Kewl

Glad you are getting it together.

Jim

[Big_kid]

Glad it's coming together for you!

[RECox286]

Piece by piece ? Sounds like a car I had once. It was a 69, 70, 71, 72, 73, 74, 75, 76, 77, 77-1/2, 80. It looked odd, but drove great.

Bob

[Big_kid]

That's several of the cars I've owned. They're usually the best ones!

[dadofanna]

Replaced the idle air control valve today, along with the pcv, put in new air filter and changed oil. Also installed a tach. Idle is alot smoother now although not perfect. Maybe I'm expecting to much from 18 year old van. It idles at 750 when not in gear but drops and stays at 500 when in gear with brake applied. My previous experience with vehicles with Bosch fuel injection is the idle is between 700-900 then drops briefly when load is applied, such as put in gear or turn on AC, but then quickly recovers to previous value when the computer compensates. Is this not how GM TBI systems work. I don't have the stickers on my van that tell idle and timing values and when I tried to order from GM parts online the said they were no longer available. Any ideas?

[Leeann_93]

I don't have a TBI to look at, but:

http://www.trademotion.com/partlocator/ ... atalogid=0

[dadofanna]

That's who I placed the order with, then they emailed me and told me they canceled the order and its no longer available. I don't know why they don't take it off their site.

[Leeann_93]

Well, heck. Sorry