bil_s2

Hi, hope someone can help...
my 1990 s2 has no spark leaving the coil. When I put a voltmeter across the coil terminals i get 5v. When i put a bulb across the coil and turn the key, it flashes rapidly so it looks like the wiring and ECU are beghaving correctly? When I take the HT lead out of the dizzy and hold it close to the block it doesn't spark at all. I have replaced the coil with one from a breakers yard and still the same. Any thoughts as to the next step, other than to try a new coil from a more reputable source? The bit i'm unsure of is that if the test bulb across the coil flashes, but the ht lead doesnt spark, is there anything else it could be other than the coil? Also, is the 5v across the coil correct?
Thanks for your help
cheers
Billy

bil_s2

Update -

Changed the coil for one that's known to work and still have the same problem....
Please could someone suggest the next step in the process? i.e. if my test bulb across the coil flashes regularly on turn over but there is no spark at all, where do i look next?
Any suggestions greatly appreciated.
Thanks
Billy

coswurv

iTrader: (8)

With ignition on you should get the same reading at the coil as what you get on the battery 12+, try a lengh of wire from the battery pos side to the pos side of the coil remembering to push the black rubber terminal back on also and try that, if it runs then you have a break down in your wiring so trace it back, i have found that the little green wires that are taped to the ouside of the main loom where broken just where the loom runs under the rad so worth a check, i would also try a different dizzy as ive had a few of them go down causing no spark, worth just going over the engine and making sure that any changes that you may have done recently havnt knocked any plugs off or are on the right sensor etc.

xrs_man

iTrader: (1)

hi, have you tried it with different ht leads? It could be that they have gone, so you wont get a spark no matter how much you change the coil.

bil_s2

Thanks for both replies.

I've also changed the HT leads for brand new ones.

Today I tried the suggestion of connecting the positve end of the coil to the positive end of the battery. When I connected the cable, the battery and oil lights lit up on the dash board (as if the key was in position 2)

I tried turning it over but still no spark. I swapped the distributor / arm / cap over with one known to work and still no joy.

With the test bulb across the coil, it flashes rapidly when I turn the engine over but there is still no spark coming out of the coil. I swapped the ECU, the blue relay under the dash, and the relay in position "V" in the fuse box, still the same....

My immobiliser appears to be disarmed. i.e. the red light goes off and it also allows the starter to turn (which it doesn't when immobilised)

Any help / suggestions / thoughts appreciated...
Thanks again
Billy

cossiedan1983

could be the pick up sensor in the dizzy try volt meter on multi plug on dizzy

coswurv

iTrader: (8)

Did you try it with the new dizzy in with the lead connected to the coil and batt, also are you getting fuel does the pump prime etc ?, make sure you have a good earth to the engine also,

bil_s2

Thanks again.

Today I untaped the green wires that run from the negative end of the coil around the front of the car. Both wires are good. With my continuity tester I get a beep from the coil plug to pin 1 on the ecu. I read somehere on this site that the ecu runs at 5v. Is this correct?
When I connect a wire from the postive end of the coil to the battery positive, i still only get 5.6v across the coil. is this correct?

The fuel system primes and there is definitely fuel getting there. The lack of spark from the ht lead at the coil seems to be the main issue.

As my test bulb across the coil flashes rapidly when i turn the engine over, im guesing that the distributor is asking the ecu for a spark, the ecu is providing one to the coil, but the 5.6v isn't enough to generate a spark on the ht lead?

A silly question - should i get a continuity beep from one end of the coil ht lead to the other? I had assumed so, but i've tried 2 and it doesn't. Is it beacause of the graphite core? I'm now very confused by this.

Any further thoughts appreciated.
Thanks
Billy

HOL

How good us the engine earth? A bad earth gives a weak spark.

Hotwiring the coil straight to the battery bypasses everything, so your problem is between the coil and the engine.

bil_s2

The engine earth runs from one of the starter motor bolts to the battery negative terminal and seems solid. I disconnected it, put the continuity tester on it and it is good, both ends seem ok and feeling the cable itself, it doesn't seem damaged. The battery earth to the inner wing is solid also.

Thanks for the help. Gonna see how much ford want for a new coil altho i suspect that my original and the 2 second hand ones i've tried can't all be faulty?

HOL

You sussed it yet??

bil_s2

My brand new coil arrived in the post today, i swapped it over and it started first turn of the key!!!!!! I appreciate these things are getting on a bit, but for my original coil to fail, then the one from the breakers yard to be faulty, then the one from ebay to be faulty... Thanks to all for your help and patience on this; much appreciated
cheers
Billy

clyde 1800

I have the same problem in my 2litre dohc. Although I'm getting 12v at the coil. I swapped the coil with another car that's running 100%
I changed the crankshaft sensor.
Wired coil direct.
Wired fuel pump direct.
Put extra earths on engine.
Any ideas? Help much appreciated.
Adam

martysmartie

iTrader: (1)

Does the fuel pump prime when the ignition is switched on? If not I would suspect the CPS although you have changed it check the wiring, this will also result with no spark.

Martin