Golf struggling to start

[JDR33]

Hi all,

I have a mk4 golf GT tdi I recently bought which seems to struggle when starting. In the morning or after work when the engines cold and been sat a while it takes a little longer than normal to start up. It'll crank then once fired it struggles before running normal.
When hot like I've noticed a couple of times after filling up or popping in a shop it cranks, splutters and cuts out. I have to keep trying to start it a minimum of 5 times before it fires up properly again. The only time it plays up when driving is when I come to a full stop at lights, it slightly stutters very briefly other than that it's great.

The previous owner said he took it to 3 garages and all said it was fuel running back to The tank although I beg to differ. I've done Google digging and only seem to come across two different faults.
One being the "in tank fuel pump" being faulty and the second a fault with the "high pressure fuel pump" being retarded when a cambelt is changed to which it had been done near the end of last year.

Any help would be great, I am taking it to my local garage for inspection Friday but just need a few ideas that might help the mechanic with labour time as he's always busy.

[JDR33]

So I took it to one garage yesterday and the guy said it might need the timing adjusted but wasn't overly sure... he advised me to go to a diesel specialist to which I did. Described the situation and he said it's possibly an issue with the injector seals and is charging £190+ vat.
Think I'm going to do the injectors myself and go from there see if there's any improvement.

Problem is, I done more digging on Google and for dodgy seals, they don't show up the same symptoms as what I have so i don't know what to do.

[Olas]

when was the cambelt last changed? as the belt stretches with age the injection timing goes further and further out. IIRC there is small adjuustment in the cam pulley, maybe 5 or 6 degrees.

its quicker to use a fuel pressure tester to see if the pump is the problem, before you start pulling all the injesctors out to test&reseal them.

glow plugs known to be good? they would explain hard starting..

compression and leakdown tests?


get the Carly app or the Torque app on your phone & do a code read, it might point you to something obvious

[JDR33]

Olas said:

when was the cambelt last changed? as the belt stretches with age the injection timing goes further and further out. IIRC there is small adjuustment in the cam pulley, maybe 5 or 6 degrees.

its quicker to use a fuel pressure tester to see if the pump is the problem, before you start pulling all the injesctors out to test&reseal them.

glow plugs known to be good? they would explain hard starting..

compression and leakdown tests?


get the Carly app or the Torque app on your phone & do a code read, it might point you to something obvious

The cambelt was changed alongside the uprated camshafts around 2 months ago it was suggested the timing may be slightly out but the mechanic couldn't guarantee that without physically working on it and charging me £100 for the Labour.

The diesel specialist I'd like to believe but he said he doesn't have testing equipment for a PD so identifies problems going balls deep under the rocker cover which again is costing me and not solving the issue. I can't afford to go by guesses.

The only thing that got thrown up on the 1st mechanics code reader was a MAF sensor issue even though the CEL doesn't show on dash. That got cleared off. I bought some multi cleaner today so going to clean the MAF and let it dry tomorrow, possibly clean the EGR too and put in some wynns injector cleaner down the tank.

I'd guess the plugs are ok but I only see issues with them on a cold start where I have it with both hot/cold (worse when hot)

I'm not familiar with the Carly and torque app, do I have to buy an OBD code reader with Bluetooth? What one would be recommended?

Thanks for the reply.

[Olas]

You need to ensure the cam timing is 100% correct. Before that happens you will chase your tail round and round in circles. Sort the cam timing.

Unplug the Maf and see if the problem goes away to confirm/eliminate it causing the problem.

Buy a fuel pressure tester.

Google the apps to decide which one you prefer but you will need a Bluetooth adaptor for either/both of them

[JDR33]

Olas said:

You need to ensure the cam timing is 100% correct. Before that happens you will chase your tail round and round in circles. Sort the cam timing.

Unplug the Maf and see if the problem goes away to confirm/eliminate it causing the problem.

Buy a fuel pressure tester.

Google the apps to decide which one you prefer but you will need a Bluetooth adaptor for either/both of them

I'll look in to those items later and will try starting by taking the MAF sensor off first. Eliminate the little things before spending excessive amounts of money.

[Matt_E_Mulsion]

I'm guessing you bought it fully in the knowledge it had problems???

[JDR33]

Matt_E_Mulsion said:

I'm guessing you bought it fully in the knowledge it had problems???

Yes I bought it as a project and for £600 can't really moan. The guy who sold it to me didn't want to sell it but had lost his job so couldn't afford to rectify the problem.

[JDR33]

Had a quick look at the car earlier mainly the MAF sensor. I disconnected it and it made no difference when starting up.

I did however notice the fuel pump does make a grinding noise before cranking the engine rather than a normal hum so if I'm correct that's a sign the fuel pump has gone bad? I have read that these tend to go around 100-150k Mark which mines at 150k now and all the symptoms seem very alike as the car can lose a bit of power sometimes but not all times and the start ups are poor. More so when hot.