audi a4 tdi 130 injectors???

[gaz7216]

hi, i am just wandering what the symptoms are for dodgy wiring looms? the car is misfiring, it has just coverd 150,000. if i have the car in neutral and hold the revs at say 2,000, it jumps up and down in 2 second stages although my foot does not move on the pedal . any help would be greatfully appriciated. past experiences and costs of new wiring loom, injectors or whatever you think it could be.many thanks in advance. gareth

[Columbo]

Injector loom will be reported in a fault code.

Get a scan done to be sure.

Could be the tandem pump. Check at the back of the engine for any diesel leaks.

[gaz7216]

does it need to go on a main dealarship dionsotic machine?its just that ive had the car with a privately owend mechanic's machine and he said it showed no faults.

[Columbo]

If you can find someone local with the vagcom OR vcds(newer version) they would scan it for you.
It depends on the type of scaner your garage is using, i think most will pick up a code if there was one. It's the interpretation of the codes more than anything.

So assuming there are no codes then it looks like afuel delivery or mechanical problem.

Are you having problems starting?

Any smoke?

Does it idle OK?

Could be sticky VNT vanes in the turbo?

[zollaf]

do you mean its surging or misfiring. the loom usually first shows as a misfire on tickover. surging is usually unmetered air.

[gaz7216]

it does have a bit of a starting problem yes.i have to give it some throttle as im starting otherwise it will just die out. once started it idles a notch over 1000rpm then slowly works its way down to a notch under 1000rpm. but if i hold a steady foot on the throttle at about 2000 rpm it jumps up and down :-/ .any ideas?lol thanks again.it doesnt misfire when idling.only when driving.

[zollaf]

you really need to start with a code read, post the results and go from there.
just read your post and you've had it on a computer. was it obd or vcds. look in the vcds and see if someone local can help you. obd won't always show codes that vcds will pick up. also, check the airpipe from the airfilter to the turbo for leaks, allowing air in when revved.