Car Completely Cutting Out At Speed.

[Bobbafett 49 2 Cars]

I had new engine mounts fitted on Thursday (full set BBM Grp.N). Since then, now 3 times, when going down a dual carriageway and giving it some, the car cuts out. I lose all instruments (inc speedo, rev counter, oil pressure etc) and the STOP light comes on. The power remains to the car though (lights on, dash lights). Then after a random amount of time (an hour the first time, only about 2 mins today when it happened) the car will start and I can drive away normally.

 

I have checked all the earths and renewed the battery connections (I did notice the live one was split).

 

Any ideas? The annoying thing is It only happens on when I boot it on dual carriagways, and i'm sick of breaking down on them already. Tried booting it around other places to re-create it but it won't happen.

 

Rang the mechanic who put the mounts in and he said check the crank sensor, but I can't find it? (1993 motronic+cat)

Edited October 11, 2014 by Bobbafett

[hoodygoodwood 70 3 Cars]

Could the wiring to the fuse/distribution block behind the passenger headlamp have been disturbed , the connections often get corroded and may have worked loose .

Is your speedo not cable drive like all the 205/309 I have worked on ? Have never worked on a catalysed car but maybe its a problem specific to that model .

[Bobbafett 49 2 Cars]

Do you mean the connection box on the slam panel? May well have been. Will def check that.

 

Got the AFM and bracket out tonight and checked the crank sensor connections, all look good. Could a failing crank sensor cause this?

 

The car does vibrate pretty badly atm from the new mounts, was wondering if the vibrations have uncovered something.

[dobboy 231 2 Cars]

I can't remember exactly what the 8v loom is like, but if its like the 16v loom the engine/ecu side of things gets its feed from being doubled up on the starter motor mains. (There is a heavy wire that runs from alternator to starter to battery.)

 

Have a look at the engine loom feed connection at the starter, because as you still have headlights, indication/dash, it suggests it could be the feed to the ECU is where the problem is. The connection maybe have even stressed when they've been lifting engine etc to fit the mounts.

[jackherer 543]

I can't remember exactly what the 8v loom is like, but if its like the 16v loom the engine/ecu side of things gets its feed from being doubled up on the starter motor mains. (There is a heavy wire that runs from alternator to starter to battery.)

 

Only the GTI6 loom is wired like that, 8v and Mi16 looms get their permanent live straight from the shunt box.

[Bobbafett 49 2 Cars]

Shunt box is the black box at the front by the slam panel? Checked all that this morning, all the connections were nice and tight. The bracket for it is broken so I did notice that the vibration from the new mounts shakes it pretty bad so I damped that with a big lump of blutack (new bracket in the post). Don't see how that could cause this though.

 

Could anyone give me a comprehensive list of the only things that could cause this behaviour? Then if the worst comes to worst i'll just change everything for new.

Edited October 12, 2014 by Bobbafett

[Bobbafett 49 2 Cars]

Right, just went out and got it to do it twice in a long stretch of quiet road. Up to 6000rpm in 2nd, into 3rd, foot down, then cut out. Both times.

 

I'm thinking fuel pump now/pressure regulator/relay? Does the motronic phase 2 have a fuel pump relay?

[hoodygoodwood 70 3 Cars]

Straight after the car conks out do some checks to try to narrow down the problem . Get one of those lights that connects into the spark plug lead and see if you have a spark when you turn the engine over . You could also check for voltage at the fuel pump under the rear seat and then crack open the fuel pipe connection at the fuel rail to see if you have pressure there - although this is dangerous of course .

Have a feel of all the electrical components to see if any are overheating - coil , ignition amp , tachy relay etc .

[Bobbafett 49 2 Cars]

Got it to do it a few more times tonight, same method; changing into 3rd and booting it after getting up high RPM in 2nd.

 

On restart the engine turned over and chugged like there was no fuel, then finally jumped into life. I had the back seat out and looked at the fuel pump and noticed it doesn't prime when I power on the key, then runs when I start the car. I had a look under the dash, is the yellow relay next to the ECU the fuel pump relay? Any idea where I could source one for a PH2 cat 1993 car?

[hanpug25 2]

Try swapping the dizzy. Mine had this -ran fine when cold and at low revs when warmed up, but as soon as it was thrashed, would cutout at speed and not restart for 10-20mins. Changed everything electrical until the dizzy sorted it. Coil in the dizzy is breaking down when warm...good luck, mine frustrated me for weeks!

[Bobbafett 49 2 Cars]

Funnily enough I solved this by changing the ignition amp and coil so not sure which one it was.

[hanpug25 2]

Funnily enough I solved this by changing the ignition amp and coil so not sure which one it was.

I literally changed everything. Dizzy was the last thing - I was ready to burn it...