2.1 dj misfiring and poor running in rain

[chavan]

Right then I have a Whitestar with 2.1 injection(DJ) engine and occasionally when it rains it aquires a misfire and will idle at about 3-400 rpm. If I switch of ignition it will start and run fine with a normal idle but may misfire again under load but not always. In the dry the engine is faultless and pulls well and idles spot on. Engine has since the first time it happened has had new plugs,leads,cap and rotor arm and been serviced and happily returns 25mpg average and recently covered about 800 miles in a week in all weather without fault. It did it this morning as there was a lot of surface water on road but it was doing it within a 100 yards of pulling off. I opened hatch with engine idling at 400ish and whole engine and electrics were bone dry. Are there any vulnerable electrics for fuel system or ignition under van that could be affected by spray from road? Any advice greatly appreciated.

[Aidan]

fuel pump is underneath

[chavan]

Cheers for that Aidan, where abouts roughly is it. The van is very low so any venture underneath requires a jack . By the way the new first gear you supplied me a few months ago went in a treat and its been my daily since.

[Aidan]

on the chassis rail behind the tank on the off side I think, I don't have 2wd to check, get a syncro easy to go under and check even if you are fluffy like me

[chavan]

Thanks found it hiding behind Hydronic Eberspacher and associated plumbing. Will disconnect it all and clean all terminals and check all wiring as it looks very prone to water ingress. Cheers

[GBA 88 WEST LA]

when i had my 2.1 i had a similar issue seems as though the rain was gettin into the rear air ducts dripping down into the cavity behind the pass tail light where the idle control unit is located ...corroding the connections and apparently eventually bad ICU... something to check