Further Diagnosis Required

[Big_kev]

Hi folks

History:
Was driving down the road many weeks ago and put the load pedal to the floor. Car accelerated fine but after breaking and accelerating once again the car felt like it was on four cyclinders. eased the car back home and started to diagnose the problem.

Diagnosis:
Spark plugs and leads are fine, injectors and leads are fine. Changed Diverter valve, WGFR, checked all hoses for pressure etc. Checked compression in bores and found bore two none existent. Stripped head to find self tapper jammed in inlet manifold and thought that might have jammed valve open (Garage left said self tapper in after last head change, mighty Pi**ed off). Changed head gasket and timing belt and ensured all marks aligned and re-essembled engine. Engine still running lumpy but smooths out under revving. I have disconnected ISV and car gets worse so this is probably functioning correctly. checked ECU and no errors are reported. All bores are compressing to about 190PSi when running.

Could someone advise what further steps i can take to understand this issue.

Many thanks in advance

Kevin

[topsparky]

have you checked the maf ???

[Big_kev]

OK i know what the maf is but how do i check the MAF without having a spare to hand. The engine doesn't change in note when i unplug the MAF so is this an indicator that it has failed. Also would i get as dramatic and instant failure while driving if it was this component.

cheers

[AndyP]

So it's only lumpy on idle?
Have you checked for air leaks?
Have you connected all the vacuum pipes up?
Check them all, then check them again, even a small air leak will give you a lumpy idle. For what it costs I'd buy a few metres of vacuum hose and change them all, GSF sell it at about £4/m

Andy

[topsparky]

andy empty your in box mate
sorry to high jack the thread

[AndyP]

Done

[Big_kev]

Other things tried

Just an update on the ongoing problems with my baby.

Knight Rider S4 has just paid a very appreciated call to have a look over the issues i am experiencing and this is what we have found so far.

All Vacum pipes would appear to be intact.
timing is correct all TDC alignment checked.
All injectors working, and wiring sound.
All plugs and leads checked and working.
VAG checked and output tests carried out and all correct.
pots 2-5 running rich but pot 1 running lean. This does not move when injectors swapped between pots.
Lifters on pot 1 somewhat noisy and gets worse the further up the rev counter you go.

Suggestion. Could the engine running lean on one pot be down to clearences on the lifters on the intake cam on pot 1. Also would all the other pots run rich if one pot was running lean.

If i was to replace the two lifters on pot 1 would that be sufficient of should i replace all the lifters. I am planning not to change the CAM unless a neccessity.

Many thanks for your help

Kevin

[philS2]

changing no1 lifters definatly seems to be first priority.

[volcano rs]

what about the wiring for the one particular injector ?

[Knight Rider S4]

Yeah just been doing the home work on the the wiring for the injector and the pulsing system for the earth and relising the all injectors run off the same pulse as motoronic ecu has not got capabilty of ind pulses for ind cylinders so bridging the earth across is still needing done to rule this out

[DJones]

Just an update on the ongoing problems with my baby.

Knight Rider S4 has just paid a very appreciated call to have a look over the issues i am experiencing and this is what we have found so far.

All Vacum pipes would appear to be intact.
timing is correct all TDC alignment checked.
All injectors working, and wiring sound.
All plugs and leads checked and working.
VAG checked and output tests carried out and all correct.
pots 2-5 running rich but pot 1 running lean. This does not move when injectors swapped between pots.
Lifters on pot 1 somewhat noisy and gets worse the further up the rev counter you go.

Suggestion. Could the engine running lean on one pot be down to clearences on the lifters on the intake cam on pot 1. Also would all the other pots run rich if one pot was running lean.

If i was to replace the two lifters on pot 1 would that be sufficient of should i replace all the lifters. I am planning not to change the CAM unless a neccessity.

Many thanks for your help

Kevin

If you need to change them i would change the set not just the offending items. You would hope that they are all of a similar age, so it would not come as a surprise if the others started playing up!!

Just my 2p

[philS2]

what are you using to tell you no1 is lean mate?

[Big_kev]

what are you using to tell you no1 is lean mate?

Did the simple eyeball test. Pulled the plug out and didn't ssem to be burning much at all. Pulled the other four out and all were choked up. When i switched the plug over for a into another bore the replacement plug became lean and the original choked up.

Kevin