525td running rough

[rolli]

Hi all
This is my first ever post, so please be patient with me
I have a 1994 E34 525td which has stumped everyone I have taken it to.
The injection pump can be adjusted to make it either idle smoothly, but with no throttle, or to have throttle but run very rough - hunting, I believe is the correct term.
It has a remanufactured injection pump, reconditioned injectors, a new in-tank fuel pump, and the fuel filter has been replaced.
I guess part of the problem is I'm in New Zealand and I'm only aware of 2 of these in the country, which would be why nobody knows much about them. I believe the other one is still running OK.
Any help will be much appreciated by me and my mechanic.

[kyleabaker]

I'm honestly not familiar with the 525td's, but I'm thinking that the solution may be the same.

I'm not sure if those have an ICV unit (Idle Control Value) on them, but if you can find anything that looks similar to what is discussed in the following thread then it might lead you to fixing the idle problems you're having.

I know the following link is for e36 3-series cars, but it may help you as well:
http://www.bimmermania.com/viewtopic.ph ... hlight=icv

[rolli]

thanks for that.
I'll pass it on to my mechanic, and I'll let you know how it goes.

[rolli]

Unfortunately TDs don't have an ICV

thanks anyway

[rolli]

And.............
Before the new injection pump went in it didn't hunt as bad as it does now.
It runs well for about 4 minutes - until the engine starts to warm up - then the hunting quickly gets worse.
With the top of the pump removed (I think) the mechanic has watched the throttle device moving quickly back and forth causing the irregular idle etc.
It's taken about 4 months to get to this stage and depression is setting in and the trailer ride to the crusher is getting closer!

[kyleabaker]

You should check to make sure that there is not a unit that is similar to the idle control valve. Strictly mechanical. It may go by a different name?? I'll look into it also, because that sounds like something I went through a little while back with my own car.

That sounds very similar to how the ICV acts when it is just dirty. If that is the case then it will be a simple fix. My car would idle poorly once it warmed up and even die on me when I was stopped and it was idling. I cleaned the ICV and now it runs smooth.

Give that a shot before you send her off on the long trailer ride.