Cranking but won't spark

[hoodedreeper]

Hello,

I've got a '92 1.6 running a MP45 Supercharger. It recently stopped running,after changing the spark plugs,ignition leads,ignition coil,cam angle sensor and ignitor pack it still wouldn't run on all cylinders. Checked the injector pulse and found that injectors 2 and 4 were open. Opened up the ECU and found what looked like a driver had burnt out. So i changed the jumpers so it worked on Sequential firing and also moved the wire on the ECU harness.

It now won't run at all. I've done a spark test and each plug/lead sparks. I've also swapped back the CAS,aswell as moving the CAS to see if it changes. I've swapped the Fuel Inj relay too from my daily and still no change.

All the wires on the ECU and on the Coil/CAS look good,i've also cleaned up the earth next to the CAS. I could get it running before but now it cranks but it wont fire up.
Many Thanks
​​​​​
​​Chris

[NCGreasemonkey]

We are on two different sides of the pond. But I'm guessing that parts over there are like parts here. If you go for the cheaper stuff that is what you get.

My first thought would be to reinstall the OEM stuff one item at a time. When you have it running then you can return the failed 'new' part and restart your diag.. When you do a lot of parts at one time there are just too many variables that could be the culprit.

HTH and update with a fix or closing in on one for us.

[hoodedreeper]

Hello,

With the replacement parts fitted (but before we diagnozed the ECU fault) the car would run but very lumpy. We couldnt have it running for long due to the amount of fuel going through.

Since then all i've done is sort the ECU injector driver and tried to start it.

I did a compression test early on in the fault finding and it was 140/120/135/120 but again,it still ran

[hoodedreeper]

Multimetre probe in the blue wire on coilpack,turning over its showing 9.6v

​Also did the ignitor pack...
White is 11.8 engine off and 9.7 cranking
Blue is 11.9 engine off and 9.7 cranking
Red is 11.8 engine off and 9.7 cranking

[NCGreasemonkey]

I know you are not a newby to this. Sometimes you have to step back and rethink.

Compression will be down on a cylinder that is fuel washed. ATF (one ounce of automatic trans fluid shot in the cylinder. Less for hgh compression engines) will help seal fuel washed cylinders. Retest the compression.

Are you getting blue-white spark across a 30K tester?

OHM the injectors? Some of our cars are up there in age. Noir is one.

Update and ask. I want you running!

[hoodedreeper]

Today's update...

New Spark Plugs fitted
Intercooler Pipes refitted

Tried jump starting it with a power pack and off another car and still nothing.

Also tried a stock ECU and still nothing

[— kung fu jesus —]

Q1: when you say you replaced the fuel inj relay, you are referring to the the big one up under the dashboard, yes?

Q2: have you tried swapping the igniter from your daily?

Q3: why mess with the injection wiring to go sequential?

Q4: are you having fuel or spark issues? both? both would point to the aformentioned relay up under the dash. looks like this:



Q5: could you have a massive vacuum leak? i know you may not want to hear this, but removing the S/C to get the car running again may be worth the labor.

Q6: did you check the timing belt alignment? if it jumped a tooth or two, it gets all funky.

[Hyper]

Q1: when you say you replaced the fuel inj relay, you are referring to the the big one up under the dashboard, yes?

Q2: have you tried swapping the igniter from your daily?

Q3: why mess with the injection wiring to go sequential?

Q4: are you having fuel or spark issues? both? both would point to the aformentioned relay up under the dash. looks like this:



Q5: could you have a massive vacuum leak? i know you may not want to hear this, but removing the S/C to get the car running again may be worth the labor.

Q6: did you check the timing belt alignment? if it jumped a tooth or two, it gets all funky.

remove the spark plugs to see if they are flooded, that should be the first step. Work backwards. next remove each spark plug cable check to see if you have spark on each cylinder. put a screwdriver where the spark plugs should hook up and ground it to see if you have spark on each cylinder.
next check for fuel delivery. That should be easy to do.

The last step is to check your timing is correct, if by any chance the crank pulley belt slipped you will never start the car until timing is correct. FYI, all early 89-94 crankshaft pulleys are defective. The solution is to remove the timing belt covers to make sure all the timing marks align at TDC. Don't go by the lines in the crank pulley.

last resource call your friends and pay a mechanic to help you. You have Miata friends do you?

[— kung fu jesus —]

Reading is fundamental.

[hoodedreeper]

Q1: when you say you replaced the fuel inj relay, you are referring to the the big one up under the dashboard, yes?

I've swapped the relay in the fuse box in the engine bay with the one off my daily. I haven't tried the one under the dash yet

Q2: have you tried swapping the igniter from your daily?

Yes,made no difference

Q3: why mess with the injection wiring to go sequential?

I followed instructions from the ECU builder as that is what he told me to do

Q4: are you having fuel or spark issues? both? both would point to the aformentioned relay up under the dash. looks like this:

I've got fuel and spark. While cranking i can smell fuel,injectors are pulsing as they should. We ran a spark test via Tuner Studio and all work as they should.

Q5: could you have a massive vacuum leak? i know you may not want to hear this, but removing the S/C to get the car running again may be worth the labor.

I haven't checked vacuum lines,the main one being the one from the inlet manifold to the ECU. Will be giving this a look at the weekend

Q6: did you check the timing belt alignment? if it jumped a tooth or two, it gets all funky.

We've checked the belt and it hasn't slipped a tooth. I need to borrow a timing light to check it

[hoodedreeper]

remove the spark plugs to see if they are flooded, that should be the first step. Work backwards. next remove each spark plug cable check to see if you have spark on each cylinder. put a screwdriver where the spark plugs should hook up and ground it to see if you have spark on each cylinder.
next check for fuel delivery. That should be easy to do.

The last step is to check your timing is correct, if by any chance the crank pulley belt slipped you will never start the car until timing is correct. FYI, all early 89-94 crankshaft pulleys are defective. The solution is to remove the timing belt covers to make sure all the timing marks align at TDC. Don't go by the lines in the crank pulley.

last resource call your friends and pay a mechanic to help you. You have Miata friends do you?

With the plugs removed they are wet with fuel. We ran a spark test via Tuner Studio,having each spark plug in a lead and held against the block. It sparks and it also clicks when its all back together. As mentioned above,the belt hasn't slipped a tooth but i'm yet to check it with a timing light.

[—RuckkehrMiata—]

This sounds very similar to the issues I'm having with my MS3 basic

[—RuckkehrMiata—]

Except one of my biggest problems is random power loss during cranking, ECU remains powered but something causes everything in the car to shut off. All grounds are almost factory

[— kung fu jesus —]

I would try putting the stock ECU in to see if it solves the issue.

That big relay I mentioned above, under the dash, is related directly to the injectors, CAS, fuel pump, and ignition. It's a bitch to diagnose and the replacement cost is $80+ USD. This would be one of those instances where I would take the suspect relay and try it in your DD rather than the other way around.

[hoodedreeper]

Small update...the ECU is now on its way to Reverant for him to have a look at it