BenzWorld Junior Member
Date registered: Sep 2010
Vehicle: 1986 Aust. spec 420SEL, U1700L Unimog ex.ADF
Location: Canberra, Australia
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
ICV Weirdness (among other things)
I recently bought my w126 1986 420SEL Australia model and I bought it in a hot climate so didn't realise the cold start issues it has. However, I did know it has a high idle in park and neutral (wish I had done this research more before buying the car). Anyway, it was cheap so I cannot complain too much.
So, I've been trying to track down the issues. And this is what I've found:
1) idle in park is at 650ish cold, 1150 hot. In drive 600ish forever.
2) has a strong fuel smell when idling for an extended period, like it's too rich.
3) the idle is a bit "bumpy" when stopped at traffic lights and it stutters while revving when you peg the throttle quickly (eg. no acceleration enrichment).
4) the OVP relay had a blown fuse in it (so, literally no computer or tuning, explains pretty much everything above - correct?).
5) replacing the OVP fuse causes too low an idle and the stalling condition on idle once warmer (even when driving down-hill etc, literally not drivable, so fuse removed again).
6) I tested the ICV in the car, gets a click with a 9v battery attached.
7) replaced the voltage regulator in the back of the alternator (brushes were pretty darn worn).
8) new OVP ordered (less than 2 weeks away from arriving)
9) pulled the idle controller from the passenger footwell, opened it up and noticed that two resistors were replaced with a single one in the middle of the board (not on the little daughter board part). But job looked good everything on the board appears fine (photo attached).
10) pulled the ICV out of the car, found as per the attached photos (cracked housing, hose stuffed down the guts, suspicions about the little crossover tube etc.)
My questions are:
1) do you think I'm on track/going the right way about this?
2) do the things I have encountered all add up?
3) with the ICV in the photos, why would have someone shoved a hose down into it?
4) is the little crossover tube that by passes the ICV meant to have an open end (aka so air can flow through it) or is mine correct with the closed end, as per the photo? (want to know if I need to replace that little tube too).
5) I'm going to be buying a new ICV, putting the new OVP in and provided my idle controller is okay, do you think this *should* fix my problems? (basically I'm asking does everything add up right)
1) I'm also thinking of changing all the injectors out for new
2) putting a new bosch fuel pump in
3) new fuel filter and accumulator
4) apparently the distributor and leads were done on it, but you know how can I trust that in any way (but, they don't seem to be a problem).
Be really keen to hear from people!
Appreciate any help!