Mk2 T3 Engine Harness
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Author:  Rustyoid [ Thu May 18, 2017 11:14 am ]
Post subject:  Mk2 T3 Engine Harness

I'm trying to repair my Mk2 T3 engine harness. I am getting code 33. Car runs ok but hits fuel cut at about 2-3 psi of boost. Verified by wideband and boost gauge. I have replaced the VAF sensor, did not fix the problem. I repaired frayed wires near the timing belt (I do not use the timing cover).

It started out late last fall, the car would hit the fuel cut on the first one or two pulls after starting, then ran normal. Progressed to the point where I cannot get above 2-3 psi of boost, and I parked it for the winter.

I replaced the fuel filter first thing this spring. It made a good difference with starting, idling and initial pickup, but didn't make a difference with the main problem. I also noticed the injector seals are leaking a small amount. I plan on replacing the injectors all together, I know that a fuel pressure leak can stop you from getting any fuel if manifold pressure is higher than fuel pressure, but I do not think this is the main issue, as it is showing code 33 for the VAF sensor circuit.

I am wondering, is there any other common spots for the wiring harness to break, besides around the timing cover.

Also, does anyone have a spare wiring harness for sale? Yes I have posted in the market place...

Any other help is always appreciated

Author:  CMA [ Thu May 18, 2017 8:44 pm ]
Post subject:  Re: Mk2 T3 Engine Harness

Okay according to T3 diagram map.

First 2 things I would double check for opening circuit... pull out ECU harness after disconnect the battery.

use DVOM
- Check TPS power supply as Gr/W (grey/white)
- TPS, MAF and WTS share the ground.... check each wires of Lg/B (light green/ black)

If you already do that.. let us know.

PS, ECU has two grounds (b/bl and b/g) but don't need to test it... since it's not possible but assume ECU has good ground.

Author:  Rustyoid [ Sat May 20, 2017 4:17 pm ]
Post subject:  Re: Mk2 T3 Engine Harness

Made some progress. Fuse block ground was loose. Tightened and runs up to 7.5 psi again. However code 33 still persists, and it occasionally hits fuel cut while boosting

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