Fixing rough idle on a 2500cc V-6: finally fixed!

twinrider · Post by **twinrider** » Sun Mar 18, 2007 6:16 pm

Hi all, nOOb here

I've had a '97 Bongo V6 for a couple years now but just discovered this site tonight. Wish I had found it sooner!

Lately my Bongo's started to idle a bit roughly when the transmission's in drive and the car is stopped at red lights, etc. The tach needle hovers around 700, then suddenly dips down to 600 or so, then back up. The car starts up no problem and seems to run fine at speed. I replaced the air filter but no change in the idle problem. Thanks in advance for any advice on how to fix this.

Cheers,
jim

Peg leg Pete · Post by **Peg leg Pete** » Sun Mar 18, 2007 6:25 pm

Welcome to the site

not able to answer your question, sure someone will know.

francophile1947 · Post by **francophile1947** » Sun Mar 18, 2007 6:25 pm

Hope you get a response. Unfortunately, you are very much in the minority with a V6.

dandywarhol · Post by **dandywarhol** » Sun Mar 18, 2007 11:20 pm

Hi twinrider - a TDM eh??

...sounds like the idle control valve is sticky. It should be on the inlet side of the engine before the butterflies and is there to stablise the idle.
It can usually be removed and cleaned out with carb spray - it gets gummed up and affects the bypassed inlet air flow.

Keep it on the black stuff

francophile1947 · Post by **francophile1947** » Sun Mar 18, 2007 11:25 pm

Sounds good dandy, I'd forgotten about that. I used to put some petrol treatment stuff in when my tickover went a bit lumpy.

twinrider · Post by **twinrider** » Mon Mar 19, 2007 1:32 am

Thanks for the advice. I'll look into this. Any idea if cleaning the idle control valve is something that someone with little mechanical experience can do themselves? Will a gasoline additive work or do I need to remove the part and manually clean it?

Thanks again.

francophile1947 · Post by **francophile1947** » Mon Mar 19, 2007 1:41 am

twinrider wrote:Will a gasoline additive work or do I need to remove the part and manually clean it?

It used to work on my son's Daewoo Matiz.

twinrider · Post by **twinrider** » Mon Mar 19, 2007 2:17 am

Not sure if the same brands are available here but any recommendations on a good additive?

dandywarhol · Post by **dandywarhol** » Mon Mar 19, 2007 11:48 am

After you locate (and I don't know where it is on the V6) the idle control valve, remove the rubber air intake hose leading to it and squirt in a dose of carb/injector cleaner - it should loosen off the gum around the valve.

If it's still "hunting" at idle you'll need to remove/strip/clean the valve.

A worse senario is that the electric servo motor for the idle control valve is faulty or that the ECU is giving it the wrong instructions.

twinrider · Post by **twinrider** » Mon Mar 19, 2007 12:06 pm

Thanks dandy. Btw, do you think new spark plugs and wires would help? The Bongo's got 150,000km on it. I bought it at 136,000km, and have no idea when the plugs and wires were last changed.

francophile1947 · Post by **francophile1947** » Mon Mar 19, 2007 12:11 pm

Sounds like they may be due, just depends on if you know when it was last serviced. I'd still try injector cleaner in the tank if you can't find the Idle Control valve as do as Dandy suggested.

twinrider · Post by **twinrider** » Mon Mar 19, 2007 2:21 pm

I started up the Bongo tonight in the driveway to check out the problem again. On closer scrutiny I realized that in park it idles perfectly steady at 700 rpms (the top of the tach needle is at the bottom of the 3/4 mark on the tach).

The problem starts when I shift into drive and keep the brake down (as I would at a stop light). Then the RPMs drop down to about halfway between the 3/4 and 1/2 mark and get unsteady.

Any new theories?

dandywarhol · Post by **dandywarhol** » Mon Mar 19, 2007 3:42 pm

Nope!

mikeonb4c · Post by **mikeonb4c** » Mon Mar 19, 2007 3:59 pm

In the old fashioned world, you might try scewing up the tickover stop (oooh matron!) a tad as a get-you-by and if it doesnt leave the tickover too high in P and/or cause a lurch when you put it into D. Dont know what advice Dandy would give on that

francophile1947 · Post by **francophile1947** » Mon Mar 19, 2007 4:28 pm

twinrider wrote:The problem starts when I shift into drive and keep the brake down (as I would at a stop light). Then the RPMs drop down to about halfway between the 3/4 and 1/2 mark and get unsteady.

Naughty twinrider - think of the poor b*gger behind you!!

Fixing rough idle on a 2500cc V-6: finally fixed!

Fixing rough idle on a 2500cc V-6?