DaleClark

iTrader: (55)

So I've been helping @Snipe G with getting his FD running again after a +20 year dormancy. Yes, really that long .

Got the long block assembled, got the engine in the car and happy, went to start - engine would crank over but it would not try to fire at all.

First part of troubleshooting was verifying we had fuel. I could smell fuel on the spark plugs and at the tail pipe so fuel was getting in there. We also had pressure tested the fuel system and I knew the pump was running. Possible an injector was having problems but not likely. If the car is just cranking and there's evidence of fuel but NO "pops" and trying to start that's going to mean no spark.

So, yesterday I came over with my shop manual and a multimeter and set out to figure out what was going on.

First, coil packs - pulled them, tested per the shop manual, all right down the middle for resistance. I have found the shop manual test is very good at sorting out bad and good coils. So, rule that out.

Next, crank angle sensors. I foolishly decided to get down to them in the car which is a pain - you have to remove the vacuum reservoir, which means you have to pull the oil neck, and the UIM, and the alternator bracket, and the alternator....it's a string of crap that keeps having to come off. Once we got down to them, the wiring looked good, connectors looked good, and I pulled them and did a resistance test - I believe 1.12 kilo ohms, in that neighborhood. White connector goes towards the left if you are looking at the front of the car, grey connector on the right. I also pulled the trigger wheel, spec is 1-2mm gap between it and the CAS, but big thing is making sure it's close, not hitting, and not damaged or bent. It looked fine.

To double-check I tested resistance at the ECU terminals. Pins 4E, 4G, and 4H go to the crank angle sensors, one is a common wire and the others go to each unique sensor. Got the same resistance at the ECU, that means the sensors are good and wiring going to them is good. In hindsight I should have done this test first instead of tearing off half of the front of the engine.

So, we've got good CAS, we have good coils. Coil pack harness is plugged in properly and it's plugged into the main harness behind the power steering pump. Last part of the equation is the ignitor, it's bolted just left of the firewall under the US cruise control. Physically it looks good, plugged in, etc. Unfortunately there is no good test for it in the shop manual - they say to plug in a special Mazda checker, no further resistance or voltage tests or anything.

Needing to get lunch and running out of ideas, we stopped at my house for a spare ignitor (which I have NO idea where it came from) and got some lunch. After lunch buttoned things up and plugged in the new ignitor. SHE STARTED UP. We were both VERY startled to say the least.

He took the ignitor apart years ago to clean/paint it, and I think the paint was on some part of it that needed to ground to the chassis. Best bet on the ignitor is to not paint it at all, just clean it up and leave it be. There's also a ground resistor (single black wire) over there that goes to one of the bolts that holds the ignitor to the car, that was clean and in place.

Didn't get a lot of run time on the car, the gasket around the thermo wax was leaking so we shut it down. Also have to permanently figure out the mounting for the intercooler and radiator, that's a whole 'nuther thing.

Wanted to document this, hopefully it helps someone else down the road!

Dale