Twin Plug-no spark

[Germanblood]

Too true...

Checked resistance at the DME connector. Both speed and reference sensors at the connector read 970 ohms, so I've got continuity all the back to the DMe connector.
The cylinder head temp sensor also reads 2.54 kohms at the DME connector, so I've got continuity all the way back on that as well.

Going to pull the dizzy caps and recheck that as well. It's a new/rebuilt 964 dizzy so unless they are not tightened down or out of spec that should be good.

Can't try a start again until I get the ECM back sometime in the next couple of days.

I think there's a little man in that engine compartment somewhere laughing his little rear end off!

Thanks again cgarr for the input.

[fastfredracing]

Originally Posted by Germanblood

It's got to be a connector somewhere. Pushed pin or something. I should get a chance this afternoon to look at it again.

Thanks cgarr for your input.

Yep, look at the ref and speed sensors connectors carefully, I had a carrera stump me for a little bit yesterday. Car came in dead, with no spark, no injector pulse, and no signal from the ref sensor. Replaced both sensors, started right up, but after puttting the air ducts back on, car did not start again. I checked, and again had no signal from the ref sensor. I unplugged it and the dme, and was going to check for continuity, when I noticed a pin pushed out of the ref sensor connector on the harness side. Would be nice if this is your issue

[Germanblood]

All connector pins look good...darn, wish there was something wrong with one. Never thought I'd say that.

Awaiting return of ECM, then more testing and measuring.

[Germanblood]

ECM is back from S.W...Thanks for getting it here quick Steve

I was 99% sure I had plenty of fuel going to the injectors, but I got a glycerin filled gauge and made an adapter to get it on the system.



Tricky to get my handheld camera to focus in the odd lighting in the engine compartment, but it says 26 psi. This is the residual pressure as the ignition was off when I took this picture.

Going to put a noid light on next and see what happens.
Then going to try defeating the splitter and run on one coil.
Then going to try same with my old coil and old plug wires.

If none of this produces an answer, I guess I'll just have to get it back up in the air and check the speed/ref sensors air gap yet again and delve deeper and deeper into the electrical system with scopes and prayers.

[Germanblood]

Check that...actually it reads 32 psi. Seems like plenty of go juice going in.

[Germanblood]

I took all the wires out of the splitter and took some measurements.

No coils connected at all, nothing attached to the splitter. +12V wire (one that was stock going to the #15 pin of the original coil) to ground and I got 5.2 ohms with ignition off. 1.2 ohms with it on. Is this normal? The battery was disconnected on the neg side. Why would this lead test with such a low resistance to ground? Odd... Wires I ran for the second coil all show infinite resistance to ground so they aren't pitched or cut anywhere.

Tried connecting just one coil without the splitter in the circuit at all. Crank and crank and crank....no life.

Still have fuel pressure and plenty of it. 38+ psi residual.

So now I went to checking silly stuff, again! Both dizzies have rotors and they turn with the crank. Check dimensions from rotor to cap, all make contact with each other.

Also tried (for kicks) swapping the connectors for the speed and reference sensors with the splitter defeated. Crank and crank and crank....nothing. Moved them back.

Now to obtain a friend's scope and check the speed and reference sensor signals while cranking. Also going to get my hands on a noid light to see if the injectors are firing.

Nothing is showing it's ugly head yet.

[Germanblood]

Nothing is a substitute for perserverance and hard work kids!

I got it running!

Check your sensor gaps and check them again and again and again and again.

Put the car back up in the air, contorted myself around the headers and loosened the sensor bracket. Move the sensors to as close to the right gap as I could again, retightened the bracket. Then I stared at it for quite a while. Shoved a small mirror up there and eyeballed it as best I could (no room for getting a gauge in there).

Put the car back on the ground and presto chango alla kazam, she turned over a couple of times and announced life with a loud burst of straight head rumble!!!

Haven't had a chance to run it on the road yet, but I'm really jazzed now.

[Germanblood]

I found a willing soul to watch for leaks and noises and ran it for 15 minutes.

No problems...idle stability was iffy, but it's way out of its element so I'm sure it needs some adjustment on the valve to get it stable.

A couple of minor oil leaks. One at the return tube from the engine mount oil cooler. Probably will replace with new rubber because I'm sure there is a small crack in it somewhere. The other was at the driver side tensioner line where it attaches to the case. The compression fitting probably isn't seated great. Both easy fixes.

No case parting line leaks or cam tower leaks. Amen!

Now I need to find a spotter as I take it out on the road. Tranny was rebuilt as well so it should be interesting.

I will sleep well tonight.