no start 94 turbo slope nose

[SCTA99]

hello to everyone iam new to this site,
iam looking for a bit of help we have a no start condition with no fuel and no spark. we can ground pin # 8 & pin # 12 on the turbo control unit to make the vehicle run. the turbo control unit is under the passenger seat and this vehicle does not have a dme relay system any help would be greatly appreciated.

thank you,
brian v.

[John McMillan]

I don't usually check this site as the Rennlist site has a seemingly bigger concentration of Turbo 3.6 owners, but I stumbled across your post this morning and may be able to help.

Firstly, if you didn't know, these are the pin functions on the TCU


There is some discussion about the TCU in a thread I started a few years ago

Turbo Control Unit - Rennlist Discussion Forums

Your problem sounds different to mine, but a reply in the thread could be useful, it reads, "I was not getting a grd. to pump relays, to igniton relay, or the xz69. and in turn the ing. coil. I took and soldered a wire from the turbo control unit on the back side from Ter.#8 to Ter.#10 to Ter.#12 and it starts and runs fine. They each now have a ground".

Good luck

[lucittm]

Pin 8 of the Turbo Control unit sends a ground to the ignition relay which powers the coil and the EZ69 Control unit. Pin 12 sends a ground to the fuel pump relay. I believe these ground signals come from a chassis ground that is routed via a brown wire from the chassis to pin 13 of the T31 terminal connector on the rear fuse panel, then to pin 13 of the Accelerator Enrichment Control Unit, see the diagram above (also under the Driver's seat), and then to pin 7 of the Turbo Control Unit, see the diagram below. The other possibility is that the ground comes in from pin 3 of the T31 terminal connector on the rear fuse panel and straight into pin 10 of the Turbo Control Unit, see the diagram below again.

I would try grounding those last pins on the Turbo Control Unit (pin 7 and pin 10) and see it it starts. If it does not start, you have a bad Turbo Control Unit because it is not routing the ground signal properly. If it does start, you have a broken wire/bad connection leading to the Turbo Control Unit because there is no ground to route.

If you solder hard grounds onto the Turbo Control Unit you will bypass the circuit that shuts off the fuel pumps in an overboost or airbag deployment situation. You will inadvertently overboost, spin the tires, loose control, crash, burn and die.

Good Luck,
Mark

[John McMillan]

Firstly, if you didn't know, these are the pin functions on the TCU...right image this time

[John McMillan]

Originally Posted by lucittm

If you solder hard grounds onto the Turbo Control Unit you will bypass the circuit that shuts off the fuel pumps in an overboost or airbag deployment situation. You will inadvertently overboost, spin the tires, loose control, crash, burn and die.

Good advice, the person that posted on my thread was not an expert. The important point is look for an interrupted ground.