Ref/Sync signal for EFI using distributor?
 

It looks like I've had another sync sensor go bad and this was a good one from Motec. So I'm thinking about getting the Ref and Sync signals from a modified distributor rather than with a sensor on the crank pulley and on the cam.

I have a good 5" clearance between the distributor hole and my BOV. Any of you guys running this set up: can you tell me if that's enough room and have you had any trouble?

If you go off even a locked down dizzy you have slop in there from gear lash, bearing play, etc. I would find out why your sensors are failing. Is it a 5 volt sensor and you are applying 12 volts to it?

It didn't completely fail, but when I was driving around with my tuner, he noticed some Sync failure errors right when I was having a stumble. Of course the error could be from the engine almost coming to a stop.

I pulled the scavenge pump off and noticed a drop of oil on the end of the sensor and on the magnet. I don't know if that would have any effect.

The pump leaked before and I replaced the little seal, but oil's still coming out from somewhere. It looks clean under the pump, but I guess it could be coming from the cam seal. Damn I hate looking for oil leaks!

David,

Drop Geoffrey Ring a PM, I remember years ago he said he preferred using the distributor as the cam trigger, rather than some type of off-the-cam sensor. I thought he still used the crank sensor in conjunction with it.

I would think it would be the other way around. The Dist in place of the cam but with a crank wheel.

Well that's what I meant, but after I read it again, it sounded wrong.

Yes, distributor setup for the cam pulse, used in conjunction with a crank wheel and trigger on the crank.:D

I wouldn't take the home (ref) and sync signal from the same device.

You can use a distributor for the sync signal easily..

Most EFI software has rather large window in degrees of crank rotation that the sync signal needs to occur in.. a little slop in the distributor drive doesn't matter.

You really shouldn't get the crank signal from the distributor as it won't give a high enough resolution. Its a great option for the cam signal. For more advise, you can call Mike at JB Racing or Neil at Performance Developments. They live for this kind of problem.

OK, so I'd only use the distributer only for the sync signal. My tuner can provide the parts, I'm just wondering if anyone here has done it.

Motec sells a narrow tooth chopper wheel for the distributor, but I need to figure out how to rig a sensor. My tuner suggested a '94 turbo distributor due to the bullet proof sensor. I'm pretty sure those don't grow on trees so I'm looking for other ideas. Anyone?

David- Your not talking about the 3/8 threaded body Motec sensor are you? If so the only thing I can say is that particular unit runs off of 7 volts. I also have an accel dfi dual sync distrubtor that would work good for what you are doing.

I have a 3/8 threaded Motec sensor reading a magnet on my cam now. When it gets hot, it gives an intermittent sync error and then it won't start til the sensor cools.

What's the dual sync distributor? 2 sync signals?

yes it has twin hal sensors built in to the distributor- Can be used as distributor or simply a something to produce signals. If you only need one signal you could leave the other sensor dead.

Do you know if they make a flat cap if you don't need the distributor cap?

no they dont make a cap, but I am sure it wouldnt take much to have one turned out on a lathe- it will work without the cap.

I emailed Simon at Motec and he doesn't think it's the sync sensor and thinks it may be the ref sensor. I'll put it all back together and do some driving with my laptop ready to do trouble shooting.