Rough idle when warm.....!?

quattrodave · Post by **quattrodave** » Sun Jul 16, 2006 4:01 am

Hiay guys,

OK after quite a few hours of trying to tune my MS i have finally began to get somewhere. From cold to almost normal operating temp it idles beautifully but from then on the idle gets worse and worse, it misfires then hunts then misfires again etc.

I've spent the last couple of hours playing with the VE table and warm up settings but i can only make it idle worse...

A friend suggested head gasket, did a compression test warm and cold and it came up fine. I can't for the life of me think what to look at next...

Any comments would be greatfully recieved. MS2 V3 fuel only 57lb low imp injectors. Audi 200 Quattro Turbo 5 Cylinder 10 Valve 1B Engine
(http://www.toffnet.net/MS/audi.html).

Many thanks

Dave

bens_cab · Post by **bens_cab** » Sun Jul 16, 2006 5:02 am

snap

im having the exact same problem with a 20vt mk1 golf

idle is all over the place i though i was getting hot fuel but i think where the filter is the heat from the engine is warming it up

the bigger i tell ms my injectors are the better it gets and i know ive only got 240cc injectors bizarre

im at the giving up stage its taken me 2 weeks so far and i still cant figure it out

quattrodave · Post by **quattrodave** » Sun Jul 16, 2006 9:13 am

LOL, thats insane, i'll have to give it a go...

Interesting you mention fuel getting too hot, i was starting to think about the air getting too hot as the air filter is quite close to the turbo & manifold..!?

Stripped the entire ignition system today, replaced and/or cleaned it all in a vain attempt, no luck

Many thanks

Dave

quattrodave · Post by **quattrodave** » Mon Jul 17, 2006 7:12 am

Bens_cab,

When you built your megasquirt, what bias resistor did you install?
I've just realised if you installed anything but 2.49K Ohm you need to change the value in the 'calibrate thermistor' menu. I installed 2.2k Ohm therefore i need to change the value to 2200 ohms.

I'll try it tonight and let you know

Dave

bens_cab · Post by **bens_cab** » Mon Jul 17, 2006 8:50 am

hi mate i had the ecu built be bill shurvinton to spec so im guessing thats ok

what i have just found tho is i was giving my wide band to much authority
turned step size to 0
gamma e off
and active above to 900rpm

now it idles sweet so guessing thats my problem solved with idle just need to tune it a bit now fingers crossed

quattrodave · Post by **quattrodave** » Mon Jul 17, 2006 12:09 pm

Hiya,

OK i was wrong, i did initally install the 2.49k bias resistors...
Back to the drawing board...

Dave

keithmac · Post by **keithmac** » Mon Jul 17, 2006 2:11 pm

Dave, your hot Idle VE bins could be to low, causing a lean idle mixture? or the IAT could be getting heatsoaked due to the car being sat still. Try adjusting hot VE`s in steps of 5 and see how you get on, warmup enrichment could be compensating for a lean condition at idle.

quattrodave · Post by **quattrodave** » Tue Jul 18, 2006 9:17 am

Keithmac :

Hiya, thanks for the input. Unfortunatly i've tried tuning the rough idle out with the VE table to no avail. Really beginning to get me down now.

Just pulled a log, starts from warm, idle really nice & smooth, going to hot where its really lumpy. All at idle. If your interested pls have a look.
http://www.toffnet.net/MS/warmingup.xls

Many thanks

Dave

ae1969 · Post by **ae1969** » Wed Jul 19, 2006 10:22 am

Raise your map/tps threshold in Accel enrichment.
You can see them really start to swing as the car gets warmer.

quattrodave · Post by **quattrodave** » Thu Jul 20, 2006 12:41 pm

Hiya mate,

thanks for your help, i raised the TPS threshold from 10 to 25 and the MAP threshold from 100 to 120. No difference i'm afraid...

Any other ideas??

Many thanks

Dave

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Rough idle when warm.....!?

Rough idle when warm.....!?

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