Intermittently sluggish KR valver

[MillSpeed 0]

I'm running out of ideas on this one. It almost feels like the ECU is retarding the ignition, the exhaust note changes and she pops and back-fires on the overrun. I'll be driving along quite happily and then all of a sudden the car just bogs down and feels 'flat' for want of a better description. Sometimes when accelerating, all of a sudden it'll just clear and she's pulling like a train again. Really weird. I was thinking maybe the injectors were getting blocked and preventing the fuel from atomizing properly, but I've used injector cleaner and changed the fuel filter and it's made no difference. Any ideas folks?

[MillSpeed 0]

Anyone?.........Anyone?.........Bueller..........Bueller

[veeDuB_Rado 0]

im having same sort of roblem..any help would be appreciated :)

[saysomestuff 0]

check your cat (if you have one) /lamba probe

Another similar thread - you can check what others have done

and here

[Louie Lungbubble 0]

Dizzy mechanism on the way out?

 

Had exactly the same prob on an old astra once. Very intermittent, very annoying.

Spent a fortune replacing all kinds, then a £20 dizzy from a scrappy sorted the lot.

 

Worth a shot if you can get hold of one a cheap one.

[veedub 0]

Ive got the same prob with my 2ltr 9a.

check out the car is hesatant thread, u will find a load of things 2 try in there!!

[MillSpeed 0]

Had a good rummage through the 'car is hesitant' thread, some good info in there. Haven't got a cat, lambda probe or knock sensors so that's three less things to worry about!! Defo gonna check the dissy mechanism, cheers for that Ian. I'll report back tomorrow with my findings, ain't gonna let this mofo beat me!

[MillSpeed 0]

Hmmm.....very little play in the dissy shaft, although there is some rotation in the cap with the spring clips off. Can't see how it'd move on the go though. Am I right in saying that the KR ECU can alter ignition timing dependant on the amount of vaccum it sees? Still feels like the ignition is intermittently retarding, will have to carry the strobe with me and check the timing as soon as it starts acting up! Also, is it common for injectors to block? She's running pig rich at the moment so I was thinking if there's big gobs of fuel getting dumped into the engine from a partially blocked injector then it's not going to combust properly.

[sciroccotune 0]

Could well be the injectors, it’s recommended that they last 80k lol but everyone has them in way longer. Stick some cleaner through first off. Could all sorts causing it to run rich, co set wrong to start WUR, sticking fuel distributor shaft- many things.

 

The Kr ecu can alter the timing as you say. And a small amount of cap movement with the clips off is ok. Have you checked all ht leads etc

[MillSpeed 0]

80k?! I've got double that on my motor and I'm pretty sure there the originals! What sort of $$ are we talking about for new injectors? I ran a bottle of wynn's injector cleaner through them to no avail but for £4 it might be worth doing it again. HT leads are fine as far as I can tell, she doesn't seem to be misfiring at all. I deffo need to get my CO set on an analyser. Now that you mention it, I did have trouble with the metering head when I first got the car....she kept flooding and wouldn't start. Turned out the fuel distribtor shaft was stuck.

[sciroccotune 0]

I would pull and test the injectors first mate, bridge the fuel relay and put each injector in turn into a jar whilst pulling the metering flap up and watch for the spry pattern. should be fine conical shape.

 

Could be the electrical connection on the wur, check for 12v with car running..

 

edit: would also get the co sorted befor new injectors if spray pattern ok..

[MillSpeed 0]

Will do, cheers sciroccotune. Does the car have to be warm when checking the voltage on the WUR?

[sciroccotune 0]

no should be constant iirc.

[MillSpeed 0]

WUR is actually seeing 13.8v when the engine's running. Just made a discovery! The car started acting up again earlier so I pulled over and tested the ignition timing with the strobe. 6deg BTDC at tickover, no problems there. However, when I revved the engine, the ECU was not advancing the timing. The vacuum line going to the ECU seems to be fine (well, it's not blocked anyway) so could it be the hall sender acting up? My rev counter has been known to jump from time to time (you'd also see the ignition timing jump with the strobe) but today on the motorway it was going nuts, jumping all over the place! Can the hall sender be replaced or is it a case of bolting on another dissy?

[MillSpeed 0]

Feel free to chime in folks. Thinking about it, if my hall sender was knackered then I wouldn't be getting an RPM reading at all would I? The wiring from the hall sender to the ECU looks ok, no visible cuts or breaks. So the ECU uses vacuum and engine speed to determine the amount of advance needed, could it be that the vacuum sensor in the ECU is faulty?

[corradophil 3]

Thinking about it, if my hall sender was knackered then I wouldn't be getting an RPM reading at all would I?

 

It would also not be running if totaly knackered.

[MillSpeed 0]

Great stuff, I can rule that out for now then. Any other usual suspects? I'm pretty sure there can't be a vacuum leak between the manifold and the ECU since the car is idling quite happily. Think I might just try swapping the ECU.

[MillSpeed 0]

Getting closer. Noticed that after starting the car up, if I let it idle for any length of time whilst driving (i.e whilst sat at traffic lights) then the problem would re-occur. If I just blipped the throttle whilst stationary I could stop it from happening. This lead me to think that maybe it was the closed throttle switch telling the ECU that the throttle was closed when it wasn't, thus the ECU wouldn't bother to advance the ignition. Just disconnected the closed throttle switch and she's running lovely (touch wood). Any of this makin sense?

[MillSpeed 0]

Any way of testing the closed throttle switch?

[bcstudent 0]

Measuring the resistance across the pins ought to do it.

[MillSpeed 0]

Problem now sorted, ta.

[randal 0]

And it was? :scratch:

[aide 0]

am guessing.... but an intermittent throttle switch fault was contradicting what the ISV and WUR should have been doing :)

[MillSpeed 0]

Certainly looks like that was the problem, put a spare throttle switch on and now she's running lovely. In addition, the tab on the throttle lever wasn't activating the switch half the time. Probably just needed adjusting but I bunged a replacement switch on there just in case. Whatever it was it was upsetting the ECU, perhaps putting it into limp mode or something (asuuming the KR ECU has a limp mode!). Strange, cos there was never a problem with the idle, usual symptom of a faulty closed throttle switch is a high idle.

[PurpRado 0]

where is this switch located at I am having the exact same problem with my 1.8 and am trying to figure out ways to trouble shoot please give any info possible thanks