Lost my Spark

My 1989 2.5 GTA Turbo has given some warnings over last months that all was not well on starting, sometimes (usually away from home) she would spin over well but not start... Waiting an hour and praying seemed to cure the problem.
Anyway two weeks ago at work that was it, it was no go.... two days later I hired a car trailer and towed the girl home.....
So far I have ....
I stripped out imobilisor, which wasn't working and could have been problem...+ Gamma alarm, also not working, making sure all std wiring was not affected or made good......

I still don't appear to have a spark from the coil... which is a a 7700 732 263 bendix AEI Module which as much as I can tell includes coil and an ignition advance curve control.... This has 12 volt supply feed to it (working) and earth which seems OK also + third lead to Tacho? a second plug with two orange leads appears to be he control feed (5 volt) one lead (earth) is cut at about 4" but doesn't look like its been disconected from anything? I am usure about this 5 volt control plug..
the Wiring diag doesn't show the control earth lead but in the Ignition section Z7U (C-11) in the manual the two way connector states control earth and control feed???

With ignition on or off I can't get a 5 volt control feed to the AEI?? Is this pulsed and only registers when running or does this indicated a problem with my power feed?? The AEI seems also to have a seperate earth feed which is a spade fit and looks original - this might have been a mod to the control earth??? but why leave 4" of orange lead dangling???

Can an expert out there advise if symptoms point to a failing coil and would simple course of action be to take AEI unit to auto electrician to check out? or is something else here wrong?

If the AEI is OK I suspect the computer as the 5v control signal comes from here I think?, I don't even want to think about going there...

Also tried the manuals preliminary check of removing distrib cap, earthing HT, ign on and with other HT close to coil socket wiping a magnet over the distrib winding..... no spark at coil ?...C-5 in maual...

Losing will to live! Please help if you can............

Peter

The flywheel sensor seems to be the first culprit to suspect on GTAs if they wont start intermittently. Search the forum and you'll find some previous examples of problems. They seem to deteriorate over time starting to cause problems with starting when hot, eventually leading to complete non-starting.

On the ignition module, as you stated, the 3 pin plug is 12v, earth and tach output, and the other 2 pin plug is the 5v pulse from the ecu, to trigger the spark from the coil. There should be no wires dangling.

But.., it will only pulse 5v if it is getting its signal from the TDC sensor, so as Michella said, investgate the sensor, plug and wiring too..

Mine also has an orange wire 4" long just dangling from one of the coil plugs, but now tucked into the corrugated conduit. My GTA is the 1989 update model with twin fuel regs.

Are you getting power to the coil on turning the key? and as mentioned above the trigger voltage on turning the engine over? If so, check to see if you are getting a spark from the coil, use the king lead this is the HT lead from the coil. Place a phillips screwdriver in the end that attaches to the distributor cap and hold next to engine block turn car over again. You should get a spark (Top tip do not electrocute yourself while doing this). If you don't get a spark but you are getting power at the coil replace coil.
If you do check to see if you are getting a spark past distributor use same technique but place Phillips screwdriver in end that attaches to a spark plug. You should get a spark on turning the engine over if you don't the fault lies in the distributor cap or rotor arm. (note also when you felt your car was running badly a good test to ensure integrity of your HT leads is to open the bonnet at night while the engine is running, if the insulation is faulty you will see black pool illuminations)

As always a fantastic response... I think I have eliminated the points Miles has raised and glad to here Alan has stuff dangling - Why the hell do they do that? I'm off with renewed vigor to check out the TDC sensor... The desciption of slowly getting worse as Mitchella says rings true....

Let you know how things go..... French electrics don't you just love em!

Another thing why is the damn workshop manual colour coding up the swanny or is just me gooing colour blind? OR/JA I don't think so chum not on mine anyway...

I owe you all pint if its the TDC Sensor!

Peter

Peter having just read the manual too,
From your first post you should have had a spark when you moved the magnet up and down if the book is correct, regardless of where the TDC sensor is as the test is done with the engine static.
If I had a magnet at hand I would give it a go on my car. ( Might be able to get hold of one for the weekend, so will keep you informed, if I can produce a spark) Basically what I am saying is, if the procedure in the book is correct and you have followed it to the T it would point to a U/S coil or faulty TDC sensor on Distributor.

Peter for me to prove the above would be difficult, as this is not the system on my car. It appears there are two completely separate systems

Update on situation ref Lost my Spark -

TDC Sensor now out of car - outer sleve melted in three places revealing one patch where bare wires are meeting........ By the way my TDC Sensor was held in place by an intergral (wishbone) metal bar affair which is part of the Sensor unit..held by two 11mm bolts . This looks nothing like the manual picture and is not adjustable as far as I can see? Are there different TDC Sensors fitted to the GTA's? Also, I didn't realise until I tried to remove the TDC Sensor that being double jointed was a pre requisite to owning a GTA. God knows how you guys get to it from above, I had to go over the offside rear suspension wishbone and up, nearly cut my damn arm in half just to get a 1/4tr turn on the 11mm nuts holding the unit on... What a botch.... Just hope I can get a new one back on.........

Secondly the Coil/AEI unit is also US according to local (Ex Renault) mechanic.

So I am in the market for new or replacements for both.........

Any suggestions on best (thats cheapest to you) place to get these...

The AEI unit has following part Nos: HOM 7700 732 263 & Smaller No 7700 722 070 Bendix.........S10062001 E

I think Stephen Hendell might have one for sale so I'll email him in case he doesn't read this....

Hopefully I can have the car back on the road soon!

Thanks for any leads

Peter

If you don't get a spark but you are getting power at the coil replace coil.

This isnt quite right on a GTA turbo (correct on a non turbo)

The TDC sensor sends a pulse to the ecu. The ecu then sends a trigger pulse via 5v to the ignition unit, which tells it when to fire. This is fully computerised via the ecu so it can tell the ignition unit how much advance and retard to run. So cranking the engine and not getting a spark, even though there is 12v to the coil doesn't always mean the coil is dead. It could be ecu or trigger wiring related.

A TCD sensor should be around £30 (was a year ago when I replaced mine) dont be tempted to buy the version for the R25 as although it's the same unit it doesnt have the heat shielding required to prevent melt down from the heat around the area. Any Renault dealership should be able to source it , Bmth branch had no problems - or go to Simon Autos.

I assume this coil/AEI unit your refering to is the RENIX unit ? If so I have a spare working unit you can borrow - I initially thought mine was faulty and replaced it first before doing the TCD sensor.

There is a Tech Note on the TCD fault, PM your email address and I'll send you a copy.

[Alpineandy]

Also, I didn't realise until I tried to remove the TDC Sensor that being double jointed was a pre requisite to owning a GTA.
Peter

That's an Alpine thing, not just GTAs.
It also helps if you have exceptionally small but amazingly strong hands (like a Thai massage girl...... i guess)

Okay, so the Alpine Babes idea died a death, due to lack of support for the idea and shortage of web space. What about a series of technical help pics with “exceptionally small but amazingly strong hands” (as suggested by Andy) bending over the engine compartment to point to the various not easily identifiable parts? It may even help Peter regain his pulse!

[Alpineandy]

You've got to admire his persistance

OK so I have a new TDC Sensor, (old one fried)... New Coil...all quite good price from Renault dealer - < £70 for both + air filter -
Have been contemplating getting the old girl back on the road again...... Problem is I don't fancy my chances of getting the TDC back in place without a lot of blood spilled and have considered access through the body cutting an access hole behind the rear offside seat... Problem is the heat shield looks like it is in the way and it doesn't appear to easily come out either! Has anyone else contemplated this or am I just barking mad? Obviously the hole will need suitable cover and sealing after job done!

Any other crazies out there?

Peter