Hello all. I have an ex David Sutton 1990 Sapphire rally car here in the US that I have been putting back together. The engine is a 200 block 4x4 head, L6 ecu, chipped with 803's and a 3bar map. After assembly, upon fist firing, it would crank over for a few seconds and fire like the timing was very advanced. I checked the cam, crank, and distributor timing multiple times and couldn't find anything off. I unplugged the phase sensor to test the circuit, forgot to plug it back in, and it fired right up, will stay running, and accelerate with no issue. So I changed the phase sensor. Same result. I opened the gap a bit on the phase sensor, and it will start, but as soon as you rev it, it will backfire and die, sometimes run backwards. The more I open the gap on the phase sensor, the higher the rpm untill it pops and dies.

I have tried another ECU, another chip, and combinations of ECU's and chip's with the same result. I have pin tested the harness, and every sensor. I set the gaps on the crank sensor and phase sensor to the manual. Kind of at a loss here. Any suggestions?

 

An L6 ecu shouldn't be capable of firing up the engine, never mind running, without a Phase sensor, because the ecu doesn't know what cylinder 1 is.
As it is running without the phase sensor, I think there's a second phase sensor.
Group A car's can have a phase sensor mounted in the camshaft cover.

 

This might help you.

www.bigturbo.co.uk

As said the phase needs to be connected to tell ecu the TDC. So you must have a cam sensor ?

Pictures may help us to understand what is going on.

Paul

 

This is not the original Grour A engine, there is definitely not a second cam or phase sensor. From my understanding, ignition will occur with out a cylinder reference due to the distributor, the ignition doesnt need to know what cylinder is firing as the rotor points to the appropriate one. Phasing is only for sequential injection, so it must be running in a batch fired injector sequence.

Sorry for the terrible quality pictures.

 

Phase sensor has nothing to do with ignition (that's the CPS).

Correct, it's job is to provide phasing information to the ECU, as said on early ECU's it will result in a non starter.

Are you sure it's not an L8?

Martin

 

I will add one more thing, after reading the big turbo site, I have L8 ecu and a L8 4x4 wiring harness, as it has knock sensor, and wiring for canister purge

 

That's what I suspected. L8 can run without the phase sensor by using a calculation based on battery voltage.

I guess you could test what output the phase sensor is giving?

Martin

 

I can bring my lab scope home tomorrow and grab a pattern. I did just check position again, with the crank turned 90 degrees past cylinder 1 tdc, the first point of the phase sensor rotor ligns up with the sensor.

 

Check what tps you have. You should have a pf09

 

Check the connector you are plugging into the phase sensor is for the phase sensor and not the knock sensor.

 

That was one of the first things I checked. I think I have it solved, the phase sensor polatiry was reversed. I installed the new sensor and matched the polarity of the old sensor, but since I have never had the car running, and it has been apart for 18 years, it may have been backwards. it now fires up with the phase sensor plugged in, revs through the range normally, idle is normal etc.

Thanks for all the help guys! It is a bit difficult here in the US as there is no support base.

 

Good you have it sorted, very rare engine over there ehh

 

For sure, there are not many stateside. The Pacific North West of the US has a good representation of Cosworth cars. I take cars of 2 Ecos, have a friend with a stunning original 3dr, there are 2 Sapphire's in Portland, and 3 RS200's that I know of, including an EVO. My car will be the only Cossie actively rallying in the US.