Hey lads, always lurking around here soaking up the info, always searching hard before asking (as I've done now).
I know yer all sick of this question but after reading through every similiar post, i'm at my wits end.
3 weeks ago, I did the timing belt, water pump & got my head rebuilt (skim, valve stem oil seals, re-ground valves), put in a G40 Schrick cam (lift/duration unknown because I bought it about 6 years ago & can't remember), put it all back together with new inlet/exhaust gaskets, new thermostat housing, new blue & black temp sensors, & new CO pot. Fired it up, ran fine but advanced. Had to wait 3 days to time it fully due to not having a timing light.
When evetually timing it, did everything accordingly, (unplugged blue temp sensor, all the throttle blipping, set ignition timing, set idle speed, ensured CO pot was connected to correct connector, same for knock sensor, plugged blue temp sensor back in, revs dropped to approx 950-ish).
Car ran grand for around 3 days then developed a mis-fire. It doesn't happen at idle, just under load.
It's constantly intermittent (if ye get me?) but most apparent when accelerating at 1/2 to 3/4 throttle in 3rd or 4th below 3k revs.
She coughs,splutters, hesitates, sometimes producing no power & and actually dropping in revs regardless of throttle position.
Been doing this for approx. 2.5 weeks now.
Not so apparent on full throttle accelration & less so up around 5k.
Also, on cold start up, she's really lumpy for around 30secs. Again, it sounds like I'm down a cylinder. But after 30secs, it goes away until It's driving under load.
I've checked:
all earths, removed & sanded
boost leaks
vacuum leaks
hall sender being loose (relatively new distributor <5k miles)
points are clean
HT leads are magnecor competition leads (<5k miles)
Plugs look ok (Bosch platinum (<5k miles)
CO pot set to 600 ohms
ECU vacuum pipe untouched at 500mm
new alternator regulator & producing loads of volts
coil was replaced with a Seat Arosa item a good while ago.
fuel pump (< 15k miles)
fuel filter (< 5k miles)
Charger isn't torqued but belts are tight with around a 5-8mm deflection
sprayed a show of WD40 into the ISV in case it was sticking.
I've considered dirty injectors & have a set of standard G60 items on the shelf but are un-cleaned and slow to use them.
Threw in some Redex injector & fuel system cleaner yesterday because I did run the tank a little low 2 weeks ago but I'm sure the mis-fire was there before that.
I noticed the black rubber sheathing over the knock sensor has degraded & come off in all the work that was done. Is it possible it's receiving some kind of magnetic interference? Would magnetic interference even affect it?
Have considered the coil is breaking down again but not convinced because the thing that is getting to me is that it ran grand before all the major work, ran ok before the final timing (was advanced timed to 1500k for a few days, due to not having a timing light), & now it runs like a pig.
Everything appears to be plugged in & plugged in correctly. No apparent wire breaks (except at the blue temp plug- wires got bared from all the plugging & unplugging, but continuity to ECU pins is good & revs still rise when unplugged. Have wrapped a little insulation tape around them for time being).
The scuttle tray cover was left out after the final timing for a few days due to forgetting to replace it & not being able to retreive it from the garage where I did the work. In that time, the car got rained on alot. Is there anything in there that could have gotten damp that cause the issues. ECU damage maybe??
The rest of the spec is: R1 charger, standard airbox for road use, ashley manifold, de-cat, jetex exhaust.
There is a slight leak between manifold downpipe & centre section but again, hasn't cause problems before.
Any help/advice would be greatly appreciated because after finally getting it back on the road 5 months ago, keeping the revs down whlie trying to afford the work that's been done, I'm still afraid of driving it on & causing damage & yet more expense.
Donie.