Help: 300tdi skipping/misfiring

[Devans]

Hi guys,

A couple of days ago I noticed in reverse at low revs and releasing the clutch my 300tdi seems to skip/stop/stall for a split second and then fire up again. This also happens in first gear and has happened once when changing from 2nd to 3rd.

Prior to this occurring I had an immobiliser installed and also rewired the headlights and spotlights of my car. Neither of which I assume would have this effect.

At the moment if the revs aren't high enough the car will stall, but if the revs are high it will skip and then fire up again.

I'm not the most mechanically minded person but am certainly working on it. It seems to me to be a fuel problem, but since the problem started I have replaced the fuel filter and primed the system, skipping still occurs.

I'm thinking it may be dirty/blocked/old injectors or injector pump.

Any advice on this would be greatly appreciated as well as respective costs and ease of doing so at home.

Thanks,

David

[redrovertdi]

have you checked the ignition wire plug on the injection pump, if it is loose or has a poor conection that will give similar problems, you may need to pinch the female plug end

[Devans]

have you checked the ignition wire plug on the injection pump, if it is loose or has a poor conection that will give similar problems, you may need to pinch the female plug end

I just went out and had another look, I found two wire plugs into the pump, one at the back (white cable) and one at the bottom (white - above the oil filter) Both of these plugs looked pretty bad and were loose with average contact. I tidied up the contact at the pump and and stuck the plugs on again and this seems to have solved the problem!!

So if these were the plugs you were talking about, thanks! If not, thanks for making me go and look again.

I'll need to tidy those up in the near future though.

[Devans]

UPDATE: (sorry to dig up this old post)

It seems that what I thought was a solution has not worked, the only reason it worked is because I had driven the car for a sustained period of time before this.

I have discovered that it is in fact the immobiliser that is causing the problem, I also took the car and unit back to the mechanic that installed it and after rewiring it and putting in a new unit the problem was still there. He has now referred me to another company that he thinks should be able to solve the problem.

What is happening at the moment is that if I start my car from cold and then create a load on the engine (either taking off in 1st or reverse) the immobiliser cuts power to the engine, sometimes only for a moment before I can continue driving. Most of the time however the car stalls, cuts all power and I lose power steering, powered brakes and the dash lights come on again.

Once I am driving though the problem does not occur again for the remainder of the trip, even if under load. If I start the car again shortly after I have finished driving recently the issue does not occur.

The product is the one which I have linked here:
Cyclops - Innovative Vehicle Solutions: Products > Immobilisers > Remote Immobiliser (http://www.mycyclops.com.au/products_immobilisers_p275.html)

I'd prefer to have an immobiliser installed for the security of my car as well as for insurance reasons.

I am just having a stab in the dark here but I feel for some reason unbeknown to me, there is a voltage drop somewhere while the vehicle is under load, occurring only at the beginning of a drive, and this is making the immobiliser seem to think something is wrong hence causing it to cut out.

Also, just FYI the immobiliser is attached to the ignition/start key positions and not the fuel pump (I think).

Does anyone have any ideas as to what it could be? How to fix it? Has anyone had the same issue before?

I'm sorry about the essay…

David

[Jode]

David -
It sounds as if the issue is related to the engine temperature, as once the engine has warmed up the problem goes away, but comes back when starting from cold. This suggests that something within the imobiliser circuitry (a relay, maybe?) is temperature-sensistive, such that the fault occurs when that component is cold.

I think that sounds logical but whether or not that is your problem is another issue... your imobiliser expert should be able to assist.