Rovergauge readings - rough idling issue

[Adrianw]

Hi,
I would welcome any thoughts on the screen shot (not sure how I post the rovergauge log - PM it ?), after a 3 month lay-up the grif seems to have developed a rather rough idle (been through two tanks of optimax) . Any thoughts would be welcome.

Cheers

[davep]

The only stand out for me is that your MAF reading is low (1%) but I see you have a Bosch unit fitted, a Lucas 5AM at idle shows 3 to 4%. Since you have a Tornado chip fitted it may be worth contacting Mark Adams because he'll have programmed the PROM to work for your specific set up.

[Englishman]

Doesn't look to be much wrong from the ECU's POV, but probably worth testing the stepper using the program.

Also, what do you mean by rough? Missing, spluttering exhaust, won't pull cleanly?

One easy electrical check is to pull off the leads from the spark plugs one at a time and see if there is any difference. That will isolate an issue down to one cylinder, if your problem is cylinder specific. If you find one that doesn't make a difference try changing the plug lead, extender, plug etc. first.

[Adrianw]

Thanks for the advice i will check out the stepper motor with the program and also the Ht leads. The revs at idle are surging +/- 300 rpm almost like its hunting , maybe a leak on the inlet side of things ? Thanks for the advice

[Englishman]

Sounds like a stickey stepper motor to me, a good clean should sort it out.

[blitzracing]

Nothing nasty there on the surface- but check the long term trim, as this shifts and can mask an under laying issue, so the short term trim looks fine. Certainly hunting can be a sign of an air leak, as the mixture shifts constantly so the ECU has problems controlling the idle as conditions are not stable.

Edited by blitzracing on Sunday 10th April 17:26