not another no-start thread...

agilchrist · 11-25-2010, 09:34 AM

This is kicking my butt.
Good fuel pressure, swapped out distributer cap, coil, and computer. Checked and re-checked cam belt timing. The speed and reference sensor signals look good on my scope, but I've swapped them around with a 3rd one anyway. It sputters like it wants to start. Starting fluid does not help.

The weird part - I have spark on cylinders 1 and 4, no spark on 2 and 3.
Plug wires 2 and 3 do spark if connected to terminals 1 or 4 at the dist cap.

Has anybody else seen this? Any other tests I can run? I can't imagine what would affect spark on only 2 of the cylinders.

Early 85 NA

Roman944 · 11-25-2010, 10:23 AM

ah damn, that is weird

maybe its your wires - for the no spark portion at least

have you checked if your injectors are squirting fuel?

agilchrist · 11-25-2010, 10:38 AM

Thanks for the reply, Roman. I haven't watched the injectors squirt, but I can smell some raw gas after cranking, and starting fluid doesn't help.
I don't think it's the plug wires, since I've tried swapping them around.

All I can think to do is pull the starter and watch the gear teeth while someone manually turns over the engine. Maybe a broken tooth throwing off the speed sensor's count? Although I would think a broken tooth would cause the starter motor to make some kind of weird noise.

Roman944 · 11-25-2010, 11:09 AM

my starter is new

and I too have a weird no-start

maybe the starter is all messed up ... form Autozone ...

agilchrist · 11-25-2010, 12:35 PM

Woo-hoo! I've got spark on all 4 cylinders.
I'm posting this in case anyone else runs into a similar issue.
The previous owner had fixed the speed and reference sensor connectors by globbing hot glue all over them. I cut that mess out and soldered the wires together. Apparently connecting yellow to yellow and black to black isn't necessarily correct. If the reference sensor is backwards, the sparks occur at seemingly random intervals. Very hard to troubleshoot. I swapped the two wires, and the spark is happy again. (I swapped the wires in the DME connector rather than re-do my solder connections.)