3.2 not starting

[Fuchs915]

Evening.

I have (I believe) put everything back following my dive into the Triangle and stripping off the intake, injectors, set valves, etc.  Topped up with oil and tightened the last few clips today so I could start the car. Disconnected the DME so I could get the oil moving without firing the engine up - all good.  Reconnected the DME and tried the key.

Engine turns over and tries to fire but then just keeps turning over.  If I try again, it seems to nearly start at the beginning of the attempt, and then just turns over without really getting close to firing.

I have a spark (only tested no.4 so far but new dizzy cap and rotor so should be OK on others) - will confirm tomorrow.

There is fuel at the rails under some pressure, don't have a gauge so can not say if it's enough pressure.  Spark plugs on 4 and 5 sooty but dry so maybe no fuel getting into the cylinders, but something must be getting through for it to nearly run...??  When I did the injectors, they all seemed to operate just fine so will maybe check the other spark plugs first and then the harness before dismantling anything.

Timing seems to be spot on.

Have checked the resistance on the crank and speed sensors, all seem to be within spec for both sensors.

Any thoughts what might be amiss?

Thanks

Kevin

Edited July 18, 2020 by Fuchs915
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[osc911]

I've had trouble with injectors getting stuck on my 3.2. Remove and DIY clean worked for me. There is a handy injector pulse tester for about £20 on Amazon.

Edited July 18, 2020 by osc911

[Fuchs915]

1 minute ago, osc911 said:

I've had trouble with injectors getting stuck on my 3.2. Remove and DIY clean worked for me. There is a handy injector pulse tester for about £20 on Amazon.

Thanks.  I've just had the injectors off, new seals and cap and a DIY clean and they all looked fine, ie nice spray pattern, so hoping they still OK.  But they are on the list to check...

[Roy M]

Simple things first  - firing order?

[Nige]

Have you jumped the DME relay terminals so the fuel pump runs?  Can't remember which ones.

[Chris_911]

Given my almost identical experience I would check that all your injectors are operating.

Mine were sent away to a specialist for cleaning and new seals. When I tested them I found I had one faulty non-operating injector. This was my issue - that one injector was stopping the car from starting.

Have a look towards the end of the 3.2 fuel lines thread for details of the tester in use.

 

[Fuchs915]

10 hours ago, Roy M said:

Simple things first  - firing order?

Thanks Roy.  Firing order is correct and so is timing.  I had really hoped it was going to be this simple.  When my son did his Beetle engine, it would run but really badly as he had set the leads up for the dizzy running in the other direction  I am not going to be that lucky

9 hours ago, Nige said:

Have you jumped the DME relay terminals so the fuel pump runs?  Can't remember which ones.

Not yet, Nige. I have fuel in the rails and it does catch from time to time so I am getting some fuel through.  I'll check Bentleys for the jumper.

1 hour ago, Chris_911 said:

Given my almost identical experience I would check that all your injectors are operating.

Mine were sent away to a specialist for cleaning and new seals. When I tested them I found I had one faulty non-operating injector. This was my issue - that one injector was stopping the car from starting.

Have a look towards the end of the 3.2 fuel lines thread for details of the tester in use.

 

Thanks Chris, I remember the tester you used, another purchase incoming!  Can it be used in situ or do the injectors need to be off to be tested?  Were your symptoms similar, ie would nearly fire up?

[Chris_911]

1 hour ago, Fuchs915 said:

Thanks Roy.  Firing order is correct and so is timing.  I had really hoped it was going to be this simple.  When my son did his Beetle engine, it would run but really badly as he had set the leads up for the dizzy running in the other direction  I am not going to be that lucky

Not yet, Nige. I have fuel in the rails and it does catch from time to time so I am getting some fuel through.  I'll check Bentleys for the jumper.

Thanks Chris, I remember the tester you used, another purchase incoming!  Can it be used in situ or do the injectors need to be off to be tested?  Were your symptoms similar, ie would nearly fire up?

Yep, read my thread. Unless you have a 12v power source near the engine bay you'll need to extend the power leads. And you'll need to make up a small patch lead as the connectors to go on the injectors are too large.

My symptoms were very similar. Initially my car started but wasn't happy and this quickly developed into a no-start similar to what you're experiencing.

The injectors can be tested in situ. I had one that was just totally dead.

Good luck - will be very interested in what you find.

[Fuchs915]

1 hour ago, Chris_911 said:

Yep, read my thread. Unless you have a 12v power source near the engine bay you'll need to extend the power leads. And you'll need to make up a small patch lead as the connectors to go on the injectors are too large.

My symptoms were very similar. Initially my car started but wasn't happy and this quickly developed into a no-start similar to what you're experiencing.

The injectors can be tested in situ. I had one that was just totally dead.

Good luck - will be very interested in what you find.

Thanks for the info, Chris.  I have a spare battery in the garage so can use that and I can use the lead/connector from my injector cleaner kit, with a couple of spade connectors added.  Fingers crossed!

[Fuchs915]

So the tester arrived and had a play with it.  None of the injectors were responding at all on the car.  Took one of the fuel rails and injectors off and still nothing.  I thought it strange that they would all fail at the same time so connected them in turn directly to the 12v battery and clickety clickety click they all sang.  Checked the tester and it seems to be putting out around 2v using my very crude approach of attaching a voltmeter.  So looks like a duff tester, but may mean I can eliminate the injectors from the non-start problem.  Next up, fuel pump, delivery pressure and flow.

Edited July 22, 2020 by Fuchs915
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[Lesworth]

Have you got a spare DME relay Kev? 

[Merv]

56 minutes ago, Lesworth said:

Have you got a spare DME relay Kev? 

+1

[Lesworth]

Also wondering if its something to do with this:

'Disconnected the DME so I could get the oil moving without firing the engine up - all good.  Reconnected the DME and tried the key.'

Everything seated properly and all the connectors ok, etc?

[Fuchs915]

3 hours ago, Lesworth said:

Have you got a spare DME relay Kev? 

 

2 hours ago, Lesworth said:

Also wondering if its something to do with this:

'Disconnected the DME so I could get the oil moving without firing the engine up - all good.  Reconnected the DME and tried the key.'

Everything seated properly and all the connectors ok, etc?

I don't have a new spare, schoolboy error, but have kept the unreliable one that was replaced about 1000 miles ago for real emergencies

It's a good point though, I will be jumping the DME to see if the pump runs and then will test pressure and flow, so will check seating and connectors then and go shopping for another DME relay.

[Fuchs915]

Jumped the DME, terminals 30 and 87b, to test the fuel pump.  It runs but it sounds horrid, like a bag of gravel in a washing machine.  I know they are not the quietest units but that can't be right (can it?) so it's good that I have a replacement on it's way. I'll test the pressure and flow over the weekend.  Working through the list...

[Chris_911]

12 minutes ago, Fuchs915 said:

Jumped the DME, terminals 30 and 87b, to test the fuel pump.  It runs but it sounds horrid, like a bag of gravel in a washing machine.  I know they are not the quietest units but that can't be right (can it?) so it's good that I have a replacement on it's way. I'll test the pressure and flow over the weekend.  Working through the list...

Doesn't sound right. I fitted a new Bosch pump when I did my lines and I wouldn't say it's especially loud. It makes exactly the sound you'd expect a fuel pump to make.

IIRC Bentley quotes 0.85l flow in 30 secs - mine new pump was just under a litre in 30sec.

Edited July 24, 2020 by Chris_911

[Fuchs915]

So a few jobs done today to see if I can sort the non-start.

Fuel rail pressure test - slightly under at 2.4 bar (should be 2.5) but I did have a leak at the joint so that might explain the slightly lower reading.  Anyhow, there is a new pump sitting in the garage waiting to be installed but have to drain the tank first and new jerry cans haven't arrived yet.  They should be here tomorrow so can make a start syphoning the petrol.

Tried turning car over again - same, no start, the occasional attempt to fire, usually when the key is first turned, then nothing.  Rev counter and oil pressure gauge jump a little when it almost fires, then settle back to zero - not sure if that is a clue...

Plugs removed - all wet, so all cleaned up and re-gapped as had them ranging from 0.7 to 0.9 and they were all pretty black.

Followed the Bentleys checks for the DME relay.  All seemed OK but have ordered another just in case.  I needed a spare anyway.

Coil shows battery voltage when key is turned.  Then tested resistance.  Primary coil shows 1.1 ohms, max should be 0.8 accordingly to Bentleys.  Secondary coil showing within spec at 5.5k ohms.  New coil ordered.

Plug leads all showing correct resistance at about 3 ohms.  Leads to be re-connected.

Dizzy cap and rotor removed and re-seated.

Volume airflow sensor - Tested the resistance of this and assumed it would increase or decrease as the flap opened, however mine seemed to increase at first then decrease as flap opened.  Will check this again as it was not what I expected, unless someone tells me otherwise.

More bits to check this week...we'll get there 

On the plus side, I have some new side stripes and I have my seats booked in for some TLC in November.

[Chris_911]

It's possible to swap the pump by clamping the hoses from the tank.

[Fuchs915]

30 minutes ago, Chris_911 said:

It's possible to swap the pump by clamping the hoses from the tank.

Thanks Chris, I will probably replace the hose when I do the pump and will also treat him to some fresh new petrol, hence draining it.

[angusb]

If the pump is working- even if it were  really duff it would still supply enough petrol to start the car, it just would not have any uuumph at speed.

This sounds much more like a bad electrical connection, like plug to AFM , or the earth point at Inlet manifold not connected.

[Fuchs915]

7 hours ago, angusb said:

If the pump is working- even if it were  really duff it would still supply enough petrol to start the car, it just would not have any uuumph at speed.

This sounds much more like a bad electrical connection, like plug to AFM , or the earth point at Inlet manifold not connected.

Cheers, Angus. I am slowly working my way through the electrics because:

1. That is where I believe the issue is more likely to be given the injectors seem ok, I have fuel at the rail at about the right pressure and plugs were wet, and 

2. Electrics are witchcraft and should be treated with ducking st00l and pitchfork style suspicion.

On the second point, I know the coil was out of spec so have a new one arriving today - thanks Matt @Type911 - but am going through all components one by one and learning as I go. Spent my lunch hour yesterday learning about checking grounds so will be putting some of that into practice this week. Other than the coil, all seems OK so far, which isn’t necessarily good news as I am effectively working back towards the brain and hope I find the problem before I get there.

 

Edited August 4, 2020 by Fuchs915
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[PeterK]

A not infrequent electrical  issue is loosing power to the ignition circuits when the key switch goes to the starter position.  All will seem fine when you test electrics with the key in the ‘run’ position, but the ignition feed power disappears, or goes low voltage in the ‘start’ position.  Cleaning the switch contacts will help if that’s an issue.

Peter

[Fuchs915]

4 hours ago, PeterK said:

A not infrequent electrical  issue is loosing power to the ignition circuits when the key switch goes to the starter position.  All will seem fine when you test electrics with the key in the ‘run’ position, but the ignition feed power disappears, or goes low voltage in the ‘start’ position.  Cleaning the switch contacts will help if that’s an issue.

Peter

Thanks Peter, I'll take a look at this as it's similar to what is happening.  Is there a way to test for this?

Spent my lunch hour today looking at a few more bits:

Injector resistance checked and within spec.

Noticed the inlet ground bolt was a little loose and it became apparent the thread had stripped as bolt could not be tightened well.  A quick rummage and a longer bolt was found which runs through the inlet and is secured with a locknut so it's now a nice secured ground again.

With ignition on, there is battery voltage at the injector connectors. It is present on both terminals for each connector.  Using a noid light with each pin in the connector terminals, there is no light when ignition is switched to start, so looks like no pulse, or maybe Peter's idea of complete voltage drop.  With one pin earthed, I get a nice bright light, as expected from the first test, then it just dims when ignition is switched to start.  According to Bentleys, lack of pulse could be a brain issue.

This could be another culprit:

A bird's nest of wires and different connectors from the alarm, so this is going to take some checking too.  

I have whipped the ECM off the car and will have a quick check to make sure chip hasn't come loose, etc. and will continue with the Bentleys check.  The fun continues... 

 

 

[proporsche]

that looks ugly like a mickey mouse job get rid of it;-)

Ivan

[Fuchs915]

36 minutes ago, proporsche said:

that looks ugly like a mickey mouse job get rid of it;-)

Ivan

Agreed Ivan, I will pay someone to did it through fear of making my own mess