Red Van Man

Can anyone tell me the best one person method for testing to see if I have a good spark. I've changed my leads, plugs, coil, cap rotor arm and distributor and now I think its the ecu.
Cheers in advance for any help

phill295

you should be able to remover the lead from the spark plug then place a another plug in the end off the lead an now turn the engine over with the plug earthed on somthing metal and should see it spark
ps dont hold the lead at the point ( mite hurt ) hope it helps

BlueFiesta85

start the engine up, and remove the lead from cylinder ONLY a few mm away from spark plug (DO NOT REMOVE COMPLETLEY while engine is running), you should hear a 'clicking' sound constantly (indicating a good spark)
hope this helps

rstubby

is your car able to start in the first place, if not then check the brown wire which runs from the ignition coil all the way round the front of the car, i had a simalar problem and found this wire to be earthing out on the bodywork.

SafeChav

Have you got a spark at all?

Tell me a little more about your problem and what you have done/checked so far and i'll do my best to help you out.

brown????????/ try green

Red Van Man

I've changed my plugs, leads, dizzy, dizzy cap, rotor arm, coil and tried a second hand ecu and I don't seem to be getting any spark.
Cheers

rs will

EASY FELLA, THIS MIGHT SOUND STUPID BUT HAVE YOU CHECKED TO SEE IF THE COIL IS GETTING ANY POWER? THE BEST WAY TO TEST IT IS TURN THE IGNITION ON THEN CONNECT A BULB BETWEEN THE + ON THE COIL AND THE EARTH ON THE BATTERY.

SafeChav

That will only tell you if the coil is getting a 12v feed, doesn't tell you whether or not the coil is being trigered

Red Van Man

Checked the GREEN wire from the coil that goes round the front of the car and it seems to be ok.

SafeChav

pull the 2 small plugs off the coil and connect a bulb across them, turn the key and see if the bulb flashes while the engine cranks over.

Red Van Man

Tried a bulb on the coil conections and nothing

SafeChav

hmmmmmm, and you've actually changed the dizzy itself?

Red Van Man

Got a second hand dizzy first and no better.
Then I got a brand new one.

SafeChav

crank the car over and tell me if the fuel pump is working when you crank the engine over.

Im not interested in priming, its whether it runs when you crank thats important.

Red Van Man

Nothing at all when trying to crank the car

SafeChav

right well assuming the relay is ok (they are pretty shit) you either have a wiring fault or an ECU fault.

The relay is triggered by the dizzy, the dizzy derives its power supply from the ignition ECU as its 5v.

If say the fuel pump relay is knackered it wont stop it sparking, but obviously you wont get it running either.

Red Van Man

I did buy a second hand ecu but I did think it was suspect. I'll try to get another from a more reliable source,
Cheers for the help Safechav

Tombra

I am having the same problem as you Red Van Man!
After rebuilding the engine, I have no spark.

Changed/new coil, leads, plugs, dizzy, dizzy cap, and rotor.

I have 12V @ the coil + connector, but are looking for a way to check if the coil's earth-signal is OK.

It should only be earthed in short periods at the time, while cranking the engine. How do I check this? Have you Red Van Man tested this?

If it does not trigger right its probably the ECU.


Hope you understant what I am trying to say..:P

SafeChav

Tombra

And you are sure that a normal 12V bulb will have time to start flashing?

SafeChav

100% sure

Use a sidelight bulb

Tombra

OK, thanks mate, I'll try it and see if my ECU are playing up.

SafeChav

If the bulb doesn't flash its not necessarily saying the ECU is at fault though.

Re-read what ive posted above it'll give you a good idea of what to look for

johnnysash

just read the above thread, I had a similar fault a while back on my s1 turbo. I did a continuity test between the trigger wires on dizzy (the 3 that plug into the little module on the top) and the ecu. turns out i had a break on the black and red wire.

Tombra

Sorry for hijacking the thread, but I hope this can help Red Van Man too.

The bulb did not flash.
I have checked the wiring to the ECU, so it's OK. So I think its the ECU, if not the ECU uses another sensor to trigger the - pulse to the coil.

Iam not sure if I understand what you mean SafeChav, do you think it might be the fuel pump relay?
It seems ok, and I also tryed to bridge the two big wires, so it runs non-stop, but still no spark/ -pulse to the coil.

Thanks for all the help so far

SafeChav

Well does the fuel pump run when you crank the engine over?

Tombra

It primes like normal, and I think it runs while cranking (hard to hear in a garage). Sounds just like it did when the car was running fine anyway.

Just tested another ECU, but still the same.

johnnysash: Do all the 3 wires from the dizzy run straith to the ecu? I'll test them tomorrow.

Not sure what else to try now really

Thanks again!

SafeChav

Have someone help you and listen to see if the pump runs.

Finding this out will greatly help pin point what is at fault.

Tombra

And if it does/does not?

SafeChav

do the test first and then we will go down that road.

Tombra

I did not hear the pump running while cranking the engine.
I have done all I can think of now, so I am all yours SafeChav

Bit of info:
S1 engine in S2 car, been running fine before, never had problems with spark.
Engine rebuild, only engine have been out of car this time (gbox, metering unit etc have not been out.).

No I dont have a - pulse on the coil.

Tryed new coil, dizzy, rotor, ECU

Tombra

SafeChav

must be a wiring fault then

Tombra

I can't figure this one out

Does anyone know if the ECU triggers the - to the coil on its own, or is there another sensor (the one on the dizzy?) that triggers it?

I think it has to be that sensor or a broken/bad connected wire.

SafeChav

the dizzy sends signals to the ECU, ECU triggers the coil