John McM

Just took my car out of storage and found starting idle non existent. Suspected the AAV, but mechanic has diagnosed the Turbo control Unit as faulty [OEM-96561813001], as no voltage is getting to the AAV in the first place.

Doubting Thomas that I am, I asked him to double check. Swapped a unit out of a '91 3.3 and my baby's idle was rock solid. Point made.

The damage for a new unit is going to be USD 720 + costs to get it to NZ. Before I cough up for a new unit, I thought I'd check if any EFI converts out there have a spare that works and are looking to sell it.

fritz k.

main function of 96561813001 is voltage supply for ignition, fuel pumps and lambda controller, that does not cause high complexity.

often occurs, that just soldered junctions are faulty.

i would try to give the board for resoldering before buying a new one.

fritz

John McM

Thanks for the reply Fritz. During my training in the Air Force we spent a whole week learning how to solder to NASA standards, as bad solder joints were considered the main cause of component malfunction, so your point makes sense. What is inside the box? Is it set in resin?

For others who may search for a fault. The car took four or five turns of the key to idle after start. Very low idle, then up to 1,400 rpm, which took ages to come down to the norm of 950 rpm. When the car warms up, then the idle is rock solid, but the car stumbles pre boost. The mechanic diagnosed it by measuring voltage at the AAV connection. As there was none on start-up, he concluded that the control unit was faulty as not supplying power. They cleaned the contacts and got it working normally, but at the next start in my hands it went faulty. I can easily believe Fritz's theory, as this part is directly mounted to the body, so would have a lot of jolts and vibration after 15 years in operation.

Benengo

If you do dare to break out the soldering iron take a few photos like the chap from this thread.

https://rennlist.com/forums/showthre...ccu+transistor


Saved me a fortune... and even with my basic techie skills (Also taught by the RAF (UK) by the way!) I was able to rectify no problems!

John McM

I've got nothing to lose in trying. It's 20-years since I did my "high performance soldering" course, but I'm sure I can do it. I'll post the result.

mjims

If you fail to fix it, drop me a PM, I think I have a spare in a box somewhere.

Colorado964turbo

The box is very simple to take apart. Take a look at it and see if anything looks out of place. Mine was clicking, and I was having boost problems as well. The actual box would click at certain RPM's. I replaced it to the tune of 720 like you said....

Bill

John McM

Opened the box. It is definitely early '90s technology. Everything looked correct, including the solder joints. Put it back in the car and it worked perfectly. I think I have a bad connection in the plug, as the cable has a very tight curve into the unit i.e. I don't think the unit is at fault. More work to do. NB: Does anyone know how to track down replacement chips? I figure the chip availability is the only thing holding back repair if the unit is the problem.

Turbohead

I have what you need from my 3.6T and other parts of the 3.6T CIS
Pm me Elliot

John McM

The reason I haven't PM'd anyone is that I've been away in Indonesia and it was all too messy to arrange shipping etc. Now I'm back in NZ for a couple of weeks I thought I'd do some investigative work before replacing the unit. So far it looks like the main relay on the board is unserviceable, and that's the means of supplying power [through pin 9] to the AAV, and Acceleration Enrichment units, which is a likely cause of the problems. Anyone got any ideas on where to source relays? I think I might jury rig a Porsche relay in the meantime. Any idea what OEM relay might do the job? I was thinking of getting one of the common relays in the front trunk and wiring that in the circuit.

John McM

Ok, feeling very satisifed now. I have an interim fix until I can find an original relay for the board. Sourced an auto horn relay [30 Amps] and carefully soldered it into the existing circuit for the defunct relay. Personally I hate doing this type of thing to a quality car, but the reality is do this or junk a USD 720 part all because of a USD 10 relay. Hope this helps someone else out there who may have the same problem. BTW: Not proud of the soldering, but I didn't want to put too much heat on the board. Also, due to the internal guide to hold the circuit board in place it is impossible to completely lock it in the way I have routed the wires. I can live with that as it's very solidly held.

John McM

Courtesy of Adrian Streather's previous publicly posted article,

"The turbo control unit, located under the left seat, controls; 2 fuel pumps, Safety cut out circuits of the fuel pumps, Boost pressure safety circuit Ignition delay relay & Power supply for
1. oxygen sensor control unit
2. acceleration enrichment control unit
3. ignition system
4. control pressure regulator
5. auxiliary air regulator
6. frequency valve at the fuel distributor
7. oxygen sensor heater"

There are two relays. One controls the oxygen sensor heater and the other one controls most of the rest [not the ignition]. In my car it was the latter that broke. It appears that the solenoid coil in the relay went open circuit.

fritz k.

feasible solution so far......

John McM

There are now solid state relays available that would fit in the case, but they're only rated to 3 Amps. One of these days I'll check the current draw on the unit and see if I can fit those.

al 965

John, I did what you did and it started and ran fine for about 4 min. so I cut it off as to unplug each ter. on the relay to install the little sheild that covers the ter. and hooked it back up and it would do nothing. I found out I was not getting a grd. to pump ralays, 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 . Don't Fig. AL