V6 Ignition - Am I sitting on a bomb? - Alfa Romeo Forum
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155 V6 33 1.7GCL

Help V6 Ignition - Am I sitting on a bomb?

A quick trip to the shops on a bumpy road with a sharp bend, and my V6 engine stopped, and despite all my efforts has not fired for the last four days. A tow got me home after a few hours - of course it was the coldest day of the year!

I suspected a fuel pump problem, and remembering the bumps, checked the inertia cutoff switch - seems OK. Every now and then after I've fiddled with something, I turn it over for a quite a long period every time I think I might have fixed something, but to no avail. Only just found out about the flashing diagnostics do you really have to go into the ECU connector pin 8 (horrors) or does it come up on the panel somewhere??As I think I read in one posting...

All the lights on the panel look right (code, injectors etc behaving as normal). I checked a spark lead with a scope and got activity, but not very convincing.

Then I was playing with the braid earth strap from the rocker cover to somewhere under the water inlet, and lo! it came away in my hand. I had to take the coil block off to find where it had been attached, which led to the discovery that the coil block is mounted on insulating bushes, and the braid appeared (tested with a meter) to have been the only electrical connection from the block(s) to the earthy side of the coil, presumably the metal body?? Could this be the reason for my sudden catastrophic failure? Looks possible. Reinstating the braid with a croc-clip lead produced a really good spark on the one (wet!) plug I have tested so far.

Trouble is, while obsessing about lack of fuel which was there a-plenty, I have probably been filling up the cylinders from the injectors if they are functioning normally, but not burning it and blowing the gas out the back....So flooded is probably an understatement, and the repeated starter action will have pushed a lot of unburned fuel vapour into the exhaust, where in this cold weather it will have condensed and be sitting there in a pool, ready to blow the exhaust system and maybe me to bits when I eventually get the cylinders dry again.

Does this all sound reasonable, and should I try to blow the pipes through before any further attempt to start?? HELP.....

This is getting me down, but I really want to find it - so do my neighbours!!

Thanks in anticipation - Marconi

Last edited by Marconi; 11-01-09 at 19:45.
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Re: V6 Ignition - Am I sitting on a bomb?

Well at least you have found the problem!! From past experiance with individual coil packs an earth failure can very easily burn them out so fingers crossed with that one, if you have a cat fitted in the exhaust system then that may well be u/s now too!If it were mine I would just fire it up and let the vapour escape through the exhaust as normal it would be very unlikely to cause any more damage than has already been done, fingers crossed for you!!
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Re: V6 Ignition - Am I sitting on a bomb?

Nah! It'll be okay. "Flooded" doesn't mean there's half a gallon of fuel in there.. just a few cc's..

I thought the metal strap was to earth the fuel rails rather than the coils. My old bus has one from the foot of the injector rail to the rocker cover.

The coil should be earthed through the connector plug to it.. but if yours runs better with an artificial (?) earth, it may suggest the connector plug (wiring) maybe needs testing.

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