jeffro951

First year of turbo is 86 so that rules out the crappy early ignition switch but leaves factory alarm in question. also did you check the other ground on the bell housing that could cause some intermittent problems if its dirty.

divil

Do you get the same results testing for spark with the new coil?

zogster

I haven't tested for spark since fitting the new coil... will report back.

I've just been looking at sensors, and I can't quite make out whether the speed and reference sensors are actually two examples of the same unit (FAE seems to make 'em)

divil

Yes they're identical.

zogster

When it's not starting, there's no spark, with new coil fitted.

divil

Have you managed to get a positive result at all? Where are you grounding the coil (and plug) to for this test?

zogster

Before I just go ahead and replace speed and ref sensors and/or wiring... what are there other likely electrical gremlins here?

jeffro951

grounds and faulty connectors.
the sensors are not expensive unless you go for OEM. here is a link for them at 32 dollars each the brand is FAE I have run many of these without any issues.
http://www.pelicanparts.com/cgi-bin/...606-115-00-OEM

zogster

Speed and ref sensors ordered, along with new female connectors...

So I'll replace those, clean the grounds that I can find, and see where that gets me.

zogster

Well, it's not the speed and reference sensors. Just changed them, and the engine is still cranking without catching.

This is really starting to get quite aggravating…

Divil: to answer your earlier question, I've only observed a positive result (ie. spark indication), when the engine is running, or starts up properly. The coil was grounded to its usual grounding point, via the green cable., which I think is where I was grounding the extra spark plug when I was doing that test.

As the sensor replacement hasn't achieved anything, I'll do spark testing again, not sure what's next…

divil

The test should involve you manually grounding the coil (to charge it), then taking the ground away (to fire it). What I was asking was what ground point are you using for that? You should be attaching a wire to the negative terminal of the coil, and then tapping the other end of that wire to something grounded - ideally the battery negative terminal. If you still can't get a spark, the next thing I'd try is using a jumper wire to take power directly from the battery + to the coil +. That cuts everything else out of the equation. You are just testing the battery/coil/HT lead/plug.

If you've never succeeded in generating a spark with this test, then you have to consider the possibility that you're not testing it correctly. Either way, I think you should get to the bottom of this no spark issue before going any further.

zogster

I've just repeated the test, grounding the coil negative terminal to the ground point at the rear of the engine bay (with the green lead removed, of course). No spark.

I do see 12V-stylee sparks at the ground-to-coil point when I make and break that, but nothing at the spark plug.

I'm definitely open to the idea that I'm not doing the test properly, however! I'll look at the HT lead from the coil also... it just struck me that it's a link in the chain that hasn't been tested, and given that I have a new coil there's not much else there to create a problem.

divil

Yeah I think you're on the right track there. It does sound like you're doing the test correctly. Where is the battery located in the RHD model? If possible I'd try using the battery negative as the ground point, just to rule out a bad battery->chassis connection. But you obviously have some connection there at least.

I wonder if the HT lead can be substituted for a plain test lead to the spark plug, just for the purpose of the test...I don't see any reason why not. Or maybe one of the distributor to plug leads will fit for a quick test?

zogster

Battery's all the way at the back, behind the left rear wheel arch.

I had the same thought about swapping for distributor-to-plug leads, but the connectors are wrong - as in, the coil end of the short HT lead has a very different connector to the plug leads, so they can't be plugged straight into the coil.

I checked the short HT lead, and it shows quite low resistance, under 1 Ohm - which I think indicates that it's OK.

divil

If the HT lead is ok, that still leaves the power wire to the coil. I know it shows 12v, but if there's excessive resistance anywhere in that part of the circuit, it will drop when loaded and could be the cause of the no-spark issue. Although I wouldn't rule the HT lead out completely tbh...measuring resistance is not always a reliable test.

Do you still have the coil you replaced? Since there was no change with the new one, the old coil was probably fine. So you could bring it around to the back of the car with 2 test leads, and the HT lead/plug attached - then do the test there directly off the battery.