What is wrong with my Audi?

**whoppadom** · 31-10-2016,06:24 PM

Hi, I bought my second car 3 months ago, a 2002 Audi A4 1.9 tdi (130). The guy I bought it off sort of pulled the wool over my eyes as after I bought the car (after him giving a lengthy test drive as i was uninsured) i discovered it had a juddering problem (which he told me was the fuel filter) which is still unsolved to this day. Apart from this the car is absolutely sound, and drives fine, just judders very badly as you accelerate at low revs, and then further up the revs the juddering eases off.

First i went to my local garage and had a diagnostics test. The mechanic took it for a test drive and diagnosed a misfire. So he plugged it vcds and it came up with no faults. Basically wasted £40 as he had no decent advice on what to do next apart from change the maf and map sensors which i had already done.

Recently i have had my father who has access to vagcom plug his laptop in and look at the car for me. After driving up and down he said there is nothing abnormal showing up on the test results apart from the MAF sensor reading being high, which he says is to be expected as the car has had an EGR delete.

The engine bay has been scrupulously checked for air leaks, both maf and map sensors changed, The car boosts well after about 2500 revs which suggests that the turbo is probably ok. Also a common problem is the lobes on the camshaft can wear, but this had been checked and is ok. A few people have told me it could be the DMF. Another thing i should state is the the car somtimes seem to reach its rev limit before it should ie only getting 40mph max out of 2nd gear

Hoping sombody out there can shed some light on this problem
Many Thanks, Guy

**nevo** · 31-10-2016,07:43 PM

If your guy who diagnosed it as a misfire is right then I would be looking at the injector harness,could be the dmf also,is the judder transfering to the steering wheel?

**whoppadom** · 31-10-2016,09:58 PM

Thanks, that will be my job tomorrow. The juddering doesn't transfer to the wheel, but saying that it is quite a violent judder and the gear stick goes crazy. I have heard about the injector wiring loom becoming damaged due to heat

**nevo** · 01-11-2016,03:29 PM

That sounds too violent for a misfire,have a good look at all the mountings.

**whoppadom** · 02-11-2016,11:04 PM

Sorry to keep posting back, took the rocker cover off and the shaft seemed fine with no major wearing on any of the lobes, and the visible wiring was also fine. fairly confident the problem is within the engine but did check the mounts and gave the engine a good rock but all seemed well. I think my next step is just to graph the results from the vcds and take to a specialist

**Crasher** · 03-11-2016,12:01 AM

If it has an illegal EGR delete I think the ECU must have been remapped to take away its ability to detect the modification, if I had it I would be putting it back to standard and fitting a new genuine AMM and taking it from there.

**rowdy-999** · 03-11-2016,11:30 AM

Originally Posted by whoppadom

Sorry to keep posting back, took the rocker cover off and the shaft seemed fine with no major wearing on any of the lobes, and the visible wiring was also fine. fairly confident the problem is within the engine but did check the mounts and gave the engine a good rock but all seemed well. I think my next step is just to graph the results from the vcds and take to a specialist

Looking at the injector loom won't give you any idea if it's not working correctly. Replace it.