Lux wont start

[barks944]

Right, shortly after filling up the other day my LUX started to experience issues. I drove about 3 miles and parked up with no issues. Came to start the car later on that day and it took longer than usual to start, about 5 spins. Got down the road and it stalled at a traffic lights, got it going after LOADs of cranking and drove a bit further to try and turn round, it stalled againd and I had to push it into a parking space. Left the car and manage to come back and start it again later than night. I then drove it about 15 miles home, it would cruise ok but it would backfire if you tried to put your foot down. It wouldn't idle and stalled a couple more times after that. The car will not start at all now. I have tried pretty much everything I can think of to get the car going. It doesn't even try to go on any cylinders, its completely dead. I have done the following.

Changed DME and AFM
Changed Fuel Pump relay (Pump is running and ive got fuel rail pressure and fuel coming out the injectors)
Fuel rail pressure is 2.5 bar.
Changed both reference sensors (RPM counter bounces)
Changed ignition coil
Checked for a spark at the plug (Leads Cap and plugs at <1yr old)
Checked DME coolant temp sensor (4500ohms at 10deg)
Checked for vacuum leaks
Injectors fire
>120psi on 3 cylinders (cant get the meter on the 4th) the other cylinders blow the compression tester out of the spark plug hole.
Camshaft timing is correct.
Its not got diesel in the tank.I filled up at a shall garage and I'm pretty sure it was optimax. The only other option would be super unleaded or diesel wouldn't it, and its deffo not diesel in the tank.

I can only think that theres an issue with the fuel or that the ignition is totally out of whack. But surely the dizzy prevents the timing from being too far out and its not shorting across the cap. Maybe the spark is too weak but it looks ok and I swapped the coil (albeit for one of unknown quality).

The plugs are a light brown colour which I'm sure is spot on. The car showed absolutely no issues until I filled up the other day. It could just be a coincidence I guess. How long would it take to see the new fuel on the rail?

Any ideas appreciated, I'm totally stumped atm.

 

[craig2105]

Is it worth phoning the garage/Shell customer services to see if anyone else has reported running issues since filling up at that garage?

Otherwise, I'd be stumped too....

 

[barks944]

Yeah, I will drop by on the way home.

 

[AndrewS]

ORIGINAL: barks944

Right, shortly after filling up the other day my LUX started to experience issues. I drove about 3 miles and parked up with no issues. Came to start the car later on that day and it took longer than usual to start, about 5 spins. Got down the road and it stalled at a traffic lights, got it going after LOADs of cranking and drove a bit further to try and turn round, it stalled againd and I had to push it into a parking space. Left the car and manage to come back and start it again later than night. I then drove it about 15 miles home, it would cruise ok but it would backfire if you tried to put your foot down. It wouldn't idle and stalled a couple more times after that. The car will not start at all now. I have tried pretty much everything I can think of to get the car going. It doesn't even try to go on any cylinders, its completely dead. I have done the following.

Changed DME and AFM
Changed Fuel Pump relay (Pump is running and ive got fuel rail pressure and fuel coming out the injectors)
Fuel rail pressure is 2.5 bar.
Changed both reference sensors (RPM counter bounces)
Changed ignition coil
Checked for a spark at the plug (Leads Cap and plugs at <1yr old)
Checked DME coolant temp sensor (4500ohms at 10deg)
Checked for vacuum leaks
Injectors fire
>120psi on 3 cylinders (cant get the meter on the 4th) the other cylinders blow the compression tester out of the spark plug hole.
Camshaft timing is correct.
Its not got diesel in the tank.I filled up at a shall garage and I'm pretty sure it was optimax. The only other option would be super unleaded or diesel wouldn't it, and its deffo not diesel in the tank.

I can only think that theres an issue with the fuel or that the ignition is totally out of whack. But surely the dizzy prevents the timing from being too far out and its not shorting across the cap. Maybe the spark is too weak but it looks ok and I swapped the coil (albeit for one of unknown quality).

The plugs are a light brown colour which I'm sure is spot on. The car showed absolutely no issues until I filled up the other day. It could just be a coincidence I guess. How long would it take to see the new fuel on the rail?

Any ideas appreciated, I'm totally stumped atm.

Have you changed all the above since the car started playing up?

We need to check that fuel is being delivered when the engine is cranking and that the spark is being delivered at the right time. This will only happen if the DME is getting a signal from the reference sender as the flywheel turns.

Firstly, swapping out components in an attempt to rectify the problem will not help as you may introduce another fault, hence I strongly recommend you leave everything as is until you have diagnosed the fault.

The above reads as if you have a test meter? (multi meter that can measure resistance and volts)? If so, go to our website and download the relevant workshop manuals (for the 944) and find the diagnostic procedures which are easy to follow and will help you diagnose the source of the fault.

Some other things to do / check

• Get the battery fully charged and make sure the AFM connector is not damp or dirty.
• Make sure the reference sensor is connected at the back of the engine.
• Make sure your fuel cap vent is not blocked.
• Check immobiliser (if you have one) is functioning correctly

Let us know how you get on.

Regards,
Andrew

 

[barks944]

Fuel is definately there, I had the rail out and saw the fuel spray from the injectors. It is sparking, I need to check it sparts at the right time though. Will it spark if I rotate the engine manually? I would say it was a decent spark, fairly bright and blue in colour.

I swapped to a good DME/AFM combo that I have tested recently and has been sat on a shelf since.

I'm pretty sure the ref sensors are ok, ive got 5 in total. One new from porsche, all the ones I tested had the correct resistances and when used as a speed sensor caused the rev counter to bounce. I dont have a means to test for the TDC pulse which I guess is the important one for ignition timing. If it is sparking the distributor should make sure it sparks on the right cylinder so shouldn't it at least try even if the advance is wrong? Although I guess if it is well out of whack it could spark on the wrong stroke..I guess the spark would arc over a pretty decent sized gap in the distributor housing. I think thats the next thing I need to nail down.

 

[AndrewS]

If you're getting spark and fuel is being delivered, we can assume either that spark/fuel is being delivered correctly (therefore the issue is mechanical)

- or -

The spark/fuel is being delivered, but at the wrong time

If mechanical, it can either be loss of compression (and 120psi is low) or timing belt related.

Personally, I would call the AA/RAC; the AA/RAC have equipment to simulate an ignition system to help isolate problems. If your DME is getting the TDC signal incorrectly, it could be firing at the wrong time. They will also have an endodcope to look into the cylinders with (to see if there is excessive moisture or other mechanical failure).

Regards,
Andrew

 

[AndrewS]

Also, check your earth connections (for corrosion) - easily overlooked but sometimes the cause of such issues.

Regards,
Andrew

 

[JamesO]

One thing to check is that the screw hasn't backed out of the rotor, allowing it to move about on the end of the cam.

 

[barks944]

ORIGINAL: JamesO

One thing to check is that the screw hasn't backed out of the rotor, allowing it to move about on the end of the cam.

Thats a good one, thanks.

 

[barks944]

[] Think it might be diesel in the tank. Apparently even with 3/4 of a tank of diesel and the rest petrol you can no longer tell its diesel. Everything I've done pointed towards fuel being wrong, well it certainly fits doesn't it . If only it had said on the receipt I would know for sure. Now the question is how do I tell for sure and if it was diesel, wtf do I do with 60 litres of diesel petrol mix. Bonfire anyone?

Bring on the abuse!

 

[pauljmcnulty]

wtf do I do with 60 litres of diesel petrol mix. Bonfire anyone?

No laughing, it's all too easily done.

All the motoring assistance companies have a service to drain the tank.

 

[craig2105]

ORIGINAL: pauljmcnulty


No laughing, it's all too easily done.

Oh yes. []

Call the AA...

 

[barks944]

Ok scratch that, firstly the stuff completely evaporates, if it was 70% diesel surely the residual diesel would remain (its just diluted). I just pumped the whole tank (a whole black bin full) out using the fuel pump and a shorted link. We noticed that it was pumping air. With the hose submerged in fuel there were periodic releases of a large quantity of air. I can't understand how it would be pumping out air. I'm wondering if one of the diaphragms in the regulation gear is gone or something. Ive changed the FPR with another one so I guess it points to the damper.

Edit: apparently when mixed its hard to separate diesel and petrol so perhaps it would evapourate. Still cant see why its pumping air though.

 

[morris944s2john]

My first thought was that you have put diesel in the tank.
Now you've drained all the fuel out, put in a can of unleaded in the tank and your car will start.

 

[barks944]

Put 4 litres of fresh unleaded in and it still wont go . Maybe there was still some disel in the lines and its diluted the petrol again. Will try draining again and adding more petrol tommorow.

 

[Alexw]

Could you check the receipt and see the price you paid for the fuel? That would tell you what it was.

Also, I thought diesel pumps were designed so you COULDN'T put diesel in a petrol, the nozzle is too big to fit?

 

[barks944]

my dad said that too. not sure if its true though.

 

[DavidL]

I'm sure I've read that you can't put diesel in a petrol car but you can do the other way round because of the pump size.

ETA possibly more substantiated by the fact that a quick search throws up lots of threads about petrol in diesel but almost nothing about the other way round.

 

[Eldavo]

Yup, you can put petrol in a diesel but not the other way round so that elimanates misfueling at least.

 

[barks944]

Argh well I'm even less sure I know whats happening now then . Back to the drawing board. Can anyone think how the fuel pump could be pumping air? I'm assuming its air. Unless its some kind of vapour release as a result of the pumping of the fuel.