Sieraari

Hello , need help with Motronic ecu wiring.Im trying to finish my AAN engine swap and im stuck with the wiring that feeds the ecu.At the moment the biggest problem is that when i crack the engine , 12V feed to injectors goes to zero, when i stop cranking the 12V comes back. The fuel pump relay J17 is connected directly and it has 12V connected directly to the nut that is under the J17 relay.This is temporary solution for testing puropuse.Everything else seems to work ,even the coils make spark. I have looked diffrent threads about the wiring and schematics but no clue.

The motronic ecu is from 93. urs4 automatic and is used with manual setup but the engine is used on Ford. Maybe im missing something on my wiring so ...

All kind of suggestions are welcome.

Sieraari

For some more info the car where the engine sits is Ford Sierra and i use a separate relay for fuel pump. And the AAN stock j17 relay makes click all the time when i crank the engine and also hear the click inside the ecu.So the ecu seems to get all the nessecery info from cam hall sensor and the (G4)flywheel position pin.But after the click inside the ecu and inside the j17 relay the power feed to maf and injector goes to zero.When im not cranking the engine all 5 injectors and maf have power.

I just dont get it.

UrS4boy

Are you sure the AAN ECU is a good one? Sounds like a holding relay problem.

1. Holding relay info

2. J17 Fuel Pump relay info

Check on *other* forums that you have posted on recently.

Sieraari

Yes, i have red those posts.I think problem has to be somewhere else, i tested my ecu on a frends urs4 what is with manual trans from factory.And the engine started without any problems.Even better with my ecu
So the holding relay should be ok.
Also got email today , so i have some ides what to check.

Sieraari

The problem was in J17 relay. I had a the old 208 nr relay and i mesured the current flow through the terminals inside the relay.And find out that ,terminal what should lead the current to 87a wich is needed for maf and injectors and that was my main problem didnt lead the current.Terminal contacts had a very little gap so thats why no current flow.And then i thoguht il buy newer 372 relay for replacement maybe it solves my problem and it did For a 5€ it was worth it to try.
Puted newer 372 relay in place cranked the engine and it started up like it should.

UrS4boy

Congrats. I hope the J17 info that I pointed you to helped you figure that out. Onwards and upwards now. Some photos of the car and the AAN install would be welcomed here.

Sieraari

So took some pictures of the car.Needs some work to get it on the road.

Sieraari

UrS4boy

Great job. Only one small comment: The Mushroom air cleaner is a) quite small and the flow through the MAF might be more turbulent than it should be and b) it's going to suck hot air from the engine bay which will drop the power. What did you do for an intercooler (you need to have one).

Sieraari

Thanks. It was a tough job ,but worth every spended work hour.
Yes , that mushroom filter isnt the best solution, but is all about the lack of space , i tried to use bigger cone filter but didnt have enough room for it .And about the hot air i have 2 solutions for that 1)lift the up the bonnet´s back end from hinges to allow better air flow through the engine bay.2)Next to filter there is a big hole where i plan to bring aluminum flex pipe back of the bumper up to that hole.But anyway i have 550X230X65 intecooler mounted behind the bumper that shoud do quite good job.