unsteady idle

[rjudgey]

Hi Guy's still having problems with my UKDM B20A, i've just gone through everything with a fine tooth come, i changed all the vac hoses with new silicone ones all with a nice tight fit, no ECU codes, modified the TB a little with knife edged outer mouth, knife edged the throttle plate, and put in countersunk screws into the spindle and ground flat onto the spindle. now i've disconnected the fast idle valve selaed it off with some thick card between the manifold and the valve, i also tried disconnecting the IAT, and also the anti stall device is disconnected too as well as the Air con control valve on the side of the inlet manifold. But i'm still getting the engine idling unsteady it just wobbles and stumbles at around 800-1000rpm, and sometimes if you rev it hard for a few seconds it stumbles under 700rpm and then stalls??
Any ideas as this is starting to do my head in now!! Just thinking of ditching the whole thing and putting carbs on or a custom ECU.
UK version only has TPS, IAT, WTS, Map sensor, no O2 sensor or EGR valve in the exhaust manifold.
Thanks Rich.

[Oldblueaccord]

Hi Guy's still having problems with my UKDM B20A, i've just gone through everything with a fine tooth come, i changed all the vac hoses with new silicone ones all with a nice tight fit, no ECU codes, modified the TB a little with knife edged outer mouth, knife edged the throttle plate, and put in countersunk screws into the spindle and ground flat onto the spindle. now i've disconnected the fast idle valve selaed it off with some thick card between the manifold and the valve, i also tried disconnecting the IAT, and also the anti stall device is disconnected too as well as the Air con control valve on the side of the inlet manifold. But i'm still getting the engine idling unsteady it just wobbles and stumbles at around 800-1000rpm, and sometimes if you rev it hard for a few seconds it stumbles under 700rpm and then stalls??
Any ideas as this is starting to do my head in now!! Just thinking of ditching the whole thing and putting carbs on or a custom ECU.
UK version only has TPS, IAT, WTS, Map sensor, no O2 sensor or EGR valve in the exhaust manifold.
Thanks Rich.

dont know how you could check this but maybe the TB blades is letting a little air slip thru since its been worked on.

is your reading on the TB within specs?


wp

[carotman]

Yeah the TB might be the problem. I messed up with mine and I'm having the same kind of problem as you describe (to a smaller extend).

Try a different TB and see if the problem goes away.

[rjudgey]

Oops sorry forgot to mention i tried two other TB's as well and still having the same problem!!
Could it be maybe one of those vac valves? I'm going to try plugging all the vac hoses that go into the control box and unplug it from the ECU, plus disconnect all the sensors and see if it idles steady will it still work with all of this disconnected and then i'll try re-connecting them one at a time to see what upsets it!! Will that work??

[A20A1]

It's trying to tell you something...


Carbs are your friend

[rjudgey]

Yeah i know tell me about it, but i don't really want to be able to smell gas inside the car anymore!!! I'd like to just dump ITB's in with custom ECU but their's next to no room for a crank trigger and sensor and that the small fact that it would cost around $2500-3000 to do properly, which does make carbs look even better but Weber just can't make carbs that don't make the car smell of gas!!
Just another thought could the bad idle be down to worn injectors? these ones have done 121K miles now? But they have been serviced by previous owner couple of times but last time was 6 years ago.

[Blkblurr]

My injectors lasted for 228,000 miles and never serviced. I replaced them because they were leaking gas.

[Oldblueaccord]

My injectors lasted for 228,000 miles and never serviced. I replaced them because they were leaking gas.

mine too i got 260K but if somebody had serviced them maybe there leaking internally but i dunno how you could tell really.
Sure the TPS (the sensor) is set right. I think its .5 v at idle and 4.5-4.8 WOT just a guess.

wp

[A20A1]

why not build an enclosure and run a cold air pickup to the bumper, it should limit the gas smell.

[Civvy]

yea theres a company called Reverie, they do carbon fibre airboxes for anything including twin DCOE's then you run a CAI to the front as if you were fuel injected.
I wonder if the valves arnt closing properly? or you got a cracked head?
You didnt over tighten the valve clearances?