Hi
I've been having a problem with starting my Golf TDI (1Z engine) for the last few months. I checked and replaced glowplugs and wiring but that was not the problem. Someone suggested I should check the injection timing as it may be too far retarded. I bought myself the VAG-COM software and lead, plugged it all in and discovered the timing was indeed too retarded.
A couple of weeks ago I advanced the timing and set it within the specified limits and since then it has been starting faultlessly. Great!
The car had been difficult to get warmed up for sometime and last week a local garage changed the thermostat for me. Car now warms up much quicker. Car was still starting OK.
Car had been difficult to warm up as I mentioned previously. On tuesday I got the garage to replace the thermostat and it has been much better the last few days and still been easy to start.
Yesterday morning I got in the car, its not particularly cold and its difficult to start again! Back to where it was before! When I got to where I was going, the engine was nice and warm, I checked on the VAG-COM and the timing it says on the graph is too advanced (above the top line). So I thought maybe I'd advanced it too far and needed to retard it a bit. Not sure why it would have changed?
Left the car round a friends house for 6 hours or so. Started it up and it started OK. Turned it off straight away, went indoors for a coffee, came out half an hour later and tried to start it and it was rough again!
Drove home, plugged in VAG-COM, plotted out the TDI-timing graph again and its back to saying "Timing to retarded to be plotted!"
I thought maybe the pump was loose, but I opened the bonnet and from the marks I made then it looks to be in the same place.
I read out the fault codes and it found two (below). The top one was on there a couple of weeks ago, but I ignored it. Not sure what either of them mean.
Control Module Part Number: 028 906 021 AF
Component and/or Version: 1,9l R4 EDC SG D80
Software Coding: 00000
Work Shop Code: WSC 00000
2 Faults Found:
01117 - Generator Terminal DF Load Signal
27-10 - Implausible Signal - Intermittent
00550 - Start of Injection Regulation
17-10 - Control Difference - Intermittent
Any ideas anyone?
Thanks
Rob
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Rob
I think that the 1Z uses the alternator for it's engine speed signal. The wires fron the alternator break inside that plastic sheathing.
The start of injection regulation is your timing fault - something's loose or able to move; maybe even a timing solenoid error.
Did you say that you move the pump? Checked the adjuster bolts on the belt pulley? It might even be a good idea to have a look at the belt tension - particularly as there's been work done recently.
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Thanks for the reply,
Yes I moved the pump to advance it when i found it was retarded a couple of weeks ago and it solved the starting problem for two weeks but it has suddenly become hard to start again and the timing is apparently retarded again. The pump is still in the position it was in after I adjusted it as I made some marks of "before" and "after" adjustment.
The timing belt has been on there for over 40,000 miles (60,000 replacement interval). I am wondering if the injector pump has skipped a tooth on the belt, maybe because of a worn or loose belt? I have taken the top cover off the belt, but I'm not sure how tight it is meant to be.
Is the timing solenoid the same thing as the "cold start valve" that VAG-COM shows the duty cycle for? At warm idle I know this is meant to be less than 10%, but mine is showing as over 50% - like it was before I made the adjustment a couple of weeks ago.
If it is the timing solenoid, then is this repairable or am I looking at a whole new pump?
Thanks
Rob
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Rob
You're getting too far ahead. Just confirm that you don't have the adjustable pump pulley - there are three 10mm boltheads as well as the centre bolt on those.
Do you have the type of pump with a 3-pin and a 5-pin plug?
Sort the alternator wiring first; it should be a red and black wire. Without a revs signal, the ECU won't be able to time anything.
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No I don't have the type with the adjustable pump pulley.
This one has two bolts into the pump accessible through the pulley and a couple more on the other side.
I will check to see how many pins I have on the plugs. I know there are two plugs on the pump.
I think the ECU is getting the revs signal. It has measures the revs fine in VAG-COM and the rev counter works.
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Rob
Yes; it's got a crank sensor as well, so maybe it does analyse the W terminal on the alternator for electrical load and make compensations?
On the 3-pin plug; you should have a key-on battery-voltage feed on the black/yellow wire on one end pin.
With the plug disconnected; you should measure 12-20 ohms from that pin through the timing sensor winding to the brown[/black] wire on the centre pin.
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Thanks Screwloose,
When I get home I'll get the meter out and check.
Rob
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Hi
There is 14.3 ohms between the pin for the yellow/black wire and the centre pin.
There is 12V at theend pins with the key turned on. Plugging the connector in with the key on results in an audible click from the injector pump, so something is happening!
Started after about 3 attempts and 10 seconds worth of cranking and spluttering, when it hit 900 revs it ran perfectly as if nothing had happened!
Edited by Robble on 18/11/2007 at 19:54
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I thought 'start of injection' related to the (no.3?) injector sensor.
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Thanks, yes I think the wiring is OK to the third injector. I know the car idles incredibly rough with it disconnected and chucks out lots of smoke.
After my last bout of starting a few hours ago I now have a new fault code!
01237 - Fuel Shut-Off Valve (N109)
31-10 - Open or Short to Ground - Intermittent
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The needle lift sensor on #3 is the detector of start of injection. I'm not ruling it out; but there's nothing showing on it yet.
That fuel shut-off code was probably generated by disconnecting the 3-pin plug - it's the other pin.
Work on the alternator wiring and see what turns up.
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