2.0L Mk 4 Golf won't start

[Mcralphie]

Hi, and thanks for reading. Long story follows. I own a 2003 2.0L Mk4 with low kms (<90000). For any other readers in future with similar problems, I promise to post a final outcome no matter what.

A few weeks ago, it had trouble starting, particularly after the engine had been running. This problem got worse over time, and within a week, it would hardly start at all. The car would turn over fine but won't catch. New battery, so it wasn't the battery.

I managed to get it to my mechanic who couldn't diagnose because he said he couldn't get a reading from the computer. Recommended it go to a specialist auto electrician.

Auto electrician said the same thing. After inspecting the ECU, they noticed some corrosion on the harness and cleaned this up as best they could and returned the car to me. It started well enough for a week but the same problem came up the next week - we drove back from Wollongong to Canberra and the car wouldn't start after we got back home.

Took it back to the auto electrician who returned it to me without much more to say. They said they could replace the harness ($1300 each side, plus labour at $130 an hour) or the ECU ($2500, plus labour) but unlikely to be worth it for a car of this age. More realistically, they offered to replace the starter motor for $550 which sounds like its straining. I should note that the starter motor is working.

Car finally died on the weekend. Cut out and stalled on a major road and wouldn't re-start. Had to get it towed home.

After some research, I ordered a new cam shaft sensor from bosch and manage to fit it. The problem persists, but it's possible in replacing the sensor, it's possible I nicked the black wire leading to the harness. I could splice it but I'm not sure this is the main problem.

I only need the car for a few more months, so I'm reluctant to plough a heap more cash into it. Equally, I'd rather not write it off if there is a reasonable fix for it.

Grateful any ideas you might have. I'd rather have a car in summer to drive the missus and little one around in - she's only two and can't walk very fast.

[Snail Style]

Sounds like the wiring loom has cancer in it. Disconnect the engine's coolant temperature sender and have a look in the connection, if there is a green taint to the electrical pin then the loom has corroded back all the way to the ecu. It has likely done the same to many other components/sensors which will probably cause a big repair bill.

When the car is running get a scanner into it and see what it comes up with.

[Martin]

Throw a new engine/crank speed/position sensor at it

You may also want to do a compression and leak down test - both hot and cold

[Mcralphie]

Thanks Snail Style and Martin. I'll have a look at the connection to the coolant temperature sender and report back.

I bought a copy of vagcom with the cable and tried it out but couldn't get anything reliable from it. I think I got about 5 codes, one of which was 'camshaft position sensor implausible signal'. I'll try again after I charge the battery some more.

I tried putting in a new crank sensor because it was the cheapest and easiest thing to do. No luck.

Also, I can't reliably do a compression test at home and don't want to pay someone to do it just now. Still thinking about whether its worth spending any more money on it.

[Martin]

>camshaft position sensor implausible signal
That's not a good sign - if you keep getting that then you know where the problem is

Otherwise - start looking closer at the fuel system

[JustCruisn]

If you have cleared that code and replaced the sensor and it still throws the error then perhaps the wiring to that sensor is bad.
Have you tried to trace the line and buzz it, how much resistance on the wire, does it vary if you move the wiring about ?
Could be a bad at the connector, loose or corroded, or the wire may have corrosion at another junction somewhere.

[brad]

If you're in Canberra then why aren't you going to Canberra VW Centre. They'd probably be able to give a diagnosis for a minimal fee. At least you'll know what's wrong rather than guessing

[Mcralphie]

Thanks for more suggestions. I didn't even pop the hood on it this weekend.

I will run charge the battery and run a scan over it next week.

The car gets regularly serviced at the Tuggeranong VW Centre. Michael very good but I think he's passed on trying to fix this. He gave it straight to Tuggeranong Auto electrics.

I'll write post the codes later. Thanks again.

[Mcralphie]

No result from the scan. Vag-com keeps crashing and nothing it tells me is going to be anything a qualified mechanic won't learn first.

Recharged battery over the last day and put it back in. Same problem - car cranks well enough, but never starts.

Spoke to a wrecker today who is surprised that it can't be fixed. May take it out to see him next week. Stay tuned for the finale.

[Mcralphie]

Bump with a result - finally. This is for the record for anyone else looking for ideas about how to fix a similar problem on a 2L Golf Mk4 - hard to start, stall and no start, or speedo not working.

I took the car to A&R Auto Repairs in Mitchell, ACT - VW specialists and wreckers. Left it with them for a week. Tony approached it with a dogged curiosity to find out why it wasn't working and fixed it.

Main problem seemed to be with the wiring to the fuel injector (good guess Martin). He fixed the wiring to the injector and it started again, probably caused by corrosion. Also he had to fix the speedo sensor (separate issue, also probably corrosion).

So at least the car is working again and hopefully for a while yet. I really appreciate their help and persistence and the ideas on this forum +10 points.

To Canberra car buyers - buy local if you're buying second hand. Cars last forever here.