GSI is no longer dead..... new ecu

[3000gsijim]

Hi people, as you may of read my 24v gsi died on me last week. i have a VERY weak spark from the coil. Bernard from this site came over today as he lives about 1 mile from me and put his multi-meter on virtually everything with a plug on it bless him but we have come to no solid conclusion.
 i have paper-clipped the ecu and the only fault code it reads is 31, crank sensor, but as we know this is a hit and hope as the car is not running when paper-clipped. everything else on the car was also paper clipped and the only other fault was the alarm ultrasonics.
auto box no faults

 if anyone wants the alarm codes i`ll gladly email them
 
the coil was put on another car and gave a very strong spark so basically, we dont have a clue. any ideas from all the people in the know? help and ideas would be much appreciated as 200 hp sitting idle at the side of the road is just not on
 maybe it is the crank sensor or ecu??
very weak spark at cranking is the major concern and symptom

 thanks guys and girls

 special thankyou to  Bernard .........
and to Scatmancraig for supplying the ece which sorted it

[defold-git]

if you are getting a weak spark on your car, and a strong spark for another car fitted with the same coil, it must be a bad earth or poor low voltage wiring fault.

[3000gsijim]

where is the problem, been all over it. may start again from scratch, if all else fails then it will be up for sale as dead. but thats a last resort as i love it.
 may try some new earths i think

[von-opel]

My money's on a faulty crank sensor, (or possibly the wiring associated with it...it tends to become a bit brittle with engine heat - check this first). Code 31 is always present when ignition is turned to on, it iis only cleared when the ECU receives a stream of pulses from the crank sensor. (Output from a working crank sensor should be around 12v A.C. at idle...Approx 30v A.C. @ 4000RPM.)

[A3LTR]

if you've got some jump leads, connect only one lead to the neg on the batt and to a good point on the engine then double check the quality of the spark.. 
It's a quick way to confirm if you have an earth problem

[defold-git]

where is the problem, been all over it. may start again from scratch, if all else fails then it will be up for sale as dead. but thats a last resort as i love it.
 may try some new earths i think

check the coil holder (rub a bit of emery cloth around the inside) check the bolt holding the coil holder onto the body, wouldnt hurt to remove and clean around the metal to metal contact area, clean around the coil body contact area and reinstall. Lastly the problem may lay in the coil ampifier circuit in the control unit, but there I cant help you. Haynes book has some info on this subject.

[3000gsijim]

thanks lads, i will be doing all of the above and more to get the animal going again, keep the thoughts coming........

[von-opel]

I forgot... a good way to check the crank sensor is to crank the engine over on the starter motor; if its ok the ecu will earth pin 3, causing the fpr/coil B to operate thus providing batt+ to the fuel pump (and the lambda sensor heater). You could test this by putting a test lamp on the lambda sensor...its the red/blue wire on the lambda sensor plug ( Just unplug it and connect the test lead: one wire to earth the other shove in the socket where the blue/red wire goes - you can unplug thr lambda sensor for this ; it doesn't make any difference on starting.)

So using the above method, crank the engine over, if the lamp lights, the crank sensor is OK,

If you want to check the coil,  connect batt+ to coil plug 15 (with the black wire) and pulse earth to coil plug 1 (with the green wire). You should then be able to see what the sparks like under running conditions.

[3000gsijim]

I forgot... a good way to check the crank sensor is to crank the engine over on the starter motor; if its ok the ecu will earth pin 3, causing the fpr/coil B to operate thus providing batt+ to the fuel pump (and the lambda sensor heater). You could test this by putting a test lamp on the lambda sensor...its the red/blue wire on the lambda sensor plug ( Just unplug it and connect the test lead: one wire to earth the other shove in the socket where the blue/red wire goes - you can unplug thr lambda sensor for this ; it doesn't make any difference on starting.)

So using the above method, crank the engine over, if the lamp lights, the crank sensor is OK,

If you want to check the coil,  connect batt+ to coil plug 15 (with the black wire) and pulse earth to coil plug 1 (with the green wire). You should then be able to see what the sparks like under running conditions.

where should i pick up the pulse earth from?

[HMK]

I wouldn't be surprised if it isn't the crank sensor

[von-opel]

I forgot... a good way to check the crank sensor is to crank the engine over on the starter motor; if its ok the ecu will earth pin 3, causing the fpr/coil B to operate thus providing batt+ to the fuel pump (and the lambda sensor heater). You could test this by putting a test lamp on the lambda sensor...its the red/blue wire on the lambda sensor plug ( Just unplug it and connect the test lead: one wire to earth the other shove in the socket where the blue/red wire goes - you can unplug thr lambda sensor for this ; it doesn't make any difference on starting.)

So using the above method, crank the engine over, if the lamp lights, the crank sensor is OK,

If you want to check the coil,  connect batt+ to coil plug 15 (with the black wire) and pulse earth to coil plug 1 (with the green wire). You should then be able to see what the sparks like under running conditions.

where should i pick up the pulse earth from?

When I said pulse earth, I meant just attatch a piece of wire to an earth point & keep touching it on & off to the coil plug 1. Each time you do this it should produce a spark at the end of the coil HT lead held close to an earth point, probably best to attatch it to an old spark plug, rather than hold it (Voltage is very high i.e 25,000 volts)

Sorry if I got a bit technical, but I'm an ex Vauxhall dealer sparks (many years ago!) & I tend to lapse into the vernacular when trying to explain something.

[ian]

i know this may sound daft,but have you cleaned up ALL the connections going into the coil,
cleaned the last 15 years of crud off them,

[Pedro]

i know this may sound daft,but have you cleaned up ALL the connections going into the coil,
cleaned the last 15 years of crud off them,

Doesn't sound daft at all Ian!

I bet there's millions of cars on the roads that never get lecky connections cleaned in their life.

[A3LTR]

had any luck yet

[3000gsijim]

had any luck yet

nah, shes still dead. i have replaced the cranks sensor, still no joy. i`m thinkink dizzy assembly or ecu  

[carltonman]

If you squirt some petrol down the bobres, turn over after replacing spark plugs what happens???

[3000gsijim]

If you squirt some petrol down the bobres, turn over after replacing spark plugs what happens???

I`M NOT EVEN GOING TO ATTEMPT THIS AS THE SPARK IS THAT WEAK FROM THE COIL THAT IT DOESN`T CARRY DOWN THE LEADS. FUEL PUMP IS WORKING IF THIS IS WHAT YOU ARE GETTING AT. excuse caps lock......left `em on

[Scatmancraig]

I still have the spare dizzy!!  I even gave it a clean as it was covered in grime!!

[carltonman]

If you squirt some petrol down the bobres, turn over after replacing spark plugs what happens???

I`M NOT EVEN GOING TO ATTEMPT THIS AS THE SPARK IS THAT WEAK FROM THE COIL THAT IT DOESN`T CARRY DOWN THE LEADS. FUEL PUMP IS WORKING IF THIS IS WHAT YOU ARE GETTING AT. excuse caps lock......left `em on

My car did same a while back, had to squirt petrol on a red-ex mix in to bores. Turned out fuel pump relay was on the blink. Got real hot on the relay and was cutting out.

[3000gsijim]

If you squirt some petrol down the bobres, turn over after replacing spark plugs what happens???

I`M NOT EVEN GOING TO ATTEMPT THIS AS THE SPARK IS THAT WEAK FROM THE COIL THAT IT DOESN`T CARRY DOWN THE LEADS. FUEL PUMP IS WORKING IF THIS IS WHAT YOU ARE GETTING AT. excuse caps lock......left `em on

My car did same a while back, had to squirt petrol on a red-ex mix in to bores. Turned out fuel pump relay was on the blink. Got real hot on the relay and was cutting out.

did you have a really weak spark at the coil then? hope fully this may be the problem. only thing is my fuel delivery is great, just a piss poor spark at the coil and it is that weak it will not carry down the leads. 

[GMC]

Is the coil itself knackered?

[3000gsijim]

Is the coil itself knackered?

NO, i put it on another car and there was no problem. i also put the other cars coil on the gsi and still had a weak spark, so i know its not coil.
   

[Whippit]

I assume you have changed the HT lead?

Don't kick me if its obvious I have read the thread and its not been mentioned.

[3000gsijim]

I assume you have changed the HT lead?

Don't kick me if its obvious I have read the thread and its not been mentioned.

its been done......no kicks deserved

[Bernard]

PM sent