94 rs tt to st 1s conversion problems

[ray at onshow]

hi all need some help on this

car is 94 rs tt manual and i hav done the usual mechanical side for single turbo conversion using same motor to run 1s yellows and orange afm.

for wiring side we have done the 4 plug to 3 plug following gazzy's thread. we have also done all the earthing mods to it and the 1s ecu is not giving codes when on. however when we go to start it,only only number 3 cyclinder is firing.strange as 1s runs wasted spark so ideally should run cyclinder number 4 on other side? at first we were using tt ignitor and coil on plug setup.then we tried to bypass ignitor and run the newer 3 pin coil on plug with individual ignitors.

on gazzys thread there wasnt much mentioned about using stock ignition?do i hav to run wrx/sti ignitor and coilpack with leads for it to run?

we traced the two ignition pins from the ecu through to the plugs and doesnt seem to be pulsing?problem with ecu?

another wire we were thinking to check was the ignition power for the ecu?mentioned on the thread about it going to drivers floor by the fuse box? DOES THIS WIRE MEANT TO BE HOOKED UP?

any help please?

[Rosssub]

Does the check engine light come on with ignition on/engine off?

[Joker]

any chance you read Ruben's one?

that mentions you picked the worst/hardest project known to mankind, guts

[ray at onshow]

yes check engine light comes on and off...everything seems to be doing what it should but wont run...

hav done plenty of single turbo conversions on gtbs and bh5s

yes its a hard project and its a customers project!!

any help?????

[Joker]

oh bum no pressure then, not impossible either, but hard to see from here aye (also I have never done it so I cant really help

[boon]

Not pulsing spark = I would be looking at cam and crank position sensors.

[ray at onshow]

cam sensor did come up when we were doing the earthing wires. stayed on until we changed to another cam sensor...but now no spark pulse...so mayb hav to change back to old one and try again

[Rosssub]

Reading through the conversion thread, it looks like a lot of different earthing changes going on.

Pull the cam sensor plug off and crank over, then check for Cam CEL. Then do the same with crank sensor.

With no crank/cam CEL/faults, I would pull both ECU ignition control pins out(B137 9/10). Then check for 3.4v ignition pulses at the ECU plugs while cranking. Eliminating the possibility of ignition pulses being lost through earth somewhere.

[Koom]

Check the polarity of the cam and crank sensor and then chase the wires all the way back to the ecu. Some models swap the wire color on one of them at the midway plugs i.e. white becomes black and black becomes white.

From memory the 3 plug ecu ties the two sensor negatives together where the 4 plug leaves them separate where they go into ecu.

It will be able to run on the 3 wire, internal ignitor coils. Just make sure they're paired correctly (cylinders 1,2 and 3,4).

Can you hear the fuel pump prime? And then does it start when you're starting the engine? As when the ecu doesn't get the correct cam/crank signals, I don't think it starts the pump either. (But incorrectly polarity on one or both may be enough for the ecu to think it's getting a signal).

[ray at onshow]

Earthing changes done...I happened to use a cam angle sensor from a v8 wrx....are they the same? Mayb y we have no spark? I know the cam gears are different. ..

As for 3 plug coil....I can bypass the ignitor all together?

Fuel pump is priming n we hav injector pulse..

[Koom]

Yeah for the 3 plug coils, you need to completely bypass the ignitor. So channel 1 from the ecu is directly connected to coils 1 and 2. And channel 2 direct to 3,4. Plus the common 12v switched supply and the additional earth's. Run them to terminate with the other earth's at the back of the manifold above the starter motor.

The fuel pump will prime every time, but the test is if it comes on when cranking.

Not sure about the newer cam sensors and if they're the same type? But I know you can check the polarity of the early ones by putting a volt meter across the two wires then watching voltage as you bring a steel ruler towards sensor. It should read positive, then negative as you move the ruler away.