3VOLUTIONIST

So Ive just finished swapping my built 4G63 into my Lancer GSR (Like an Evo 3) and Im trying to get it running relatively smoothly. It's got Kelford 264/268 cams, standard ignition system, and I've converted the harness to run the Evo 7 ECU (also have Evo 7 MAF and 560 injectors). Running 90550701 Tephra v7.
It used to run and idle fine with the old 4G93T, yet now, it has a difficult time idling. The rpm's will drop and it will nearly stall, sometimes it catches itself, sometimes it dies. It's worse with the AC on.
When driving, if you put it in neutral and roll to a stop it wont die, but if youre in 2nd for example, come to a stop and clutch in it'll sputter and die.

The other little thing thats bugging me is the tacho, at idle, it'll bounce all over the place at about the 500-1000rpm mark, or just sit at 0 (the engine isnt actually doing what the tacho is showing). Yet it works everywhere else in the rpm range and while cruising.
However if you accelerate from cruise, the tacho will plummet, then spike back up again (again, the engine doesnt actually do that, its just the tacho).

Thoughts?..

4b11slayer

The stalling issue could be cam and tune related.

The crazy tacho, check speed sensor and gear it self. Common grounds and tacho ground.

3VOLUTIONIST

i dramatically improved the idle by playing with the timing and a couple of other things i saw mentioned in the forums.
as for the tacho; its an electrical signal from the ignitor (which i swapped out for one that was known to be good). No change in the problem.
With the idle set to 950/1000 the tacho works alright-ish. but if the revs drop a little; the tach just dies and sits at zero.

its also still dropping like a stone for a second when you put the engine under load. No clue whats causing that.

RightSaid fred

Did you degree the cams?

What BOV does it have?

Your bad idle, that happens when it's idling too lean.
Does the O2 sensor work?
What do the fuel trims show?

3VOLUTIONIST

Yeah degreed the cams and they came up bang on spec pretty much
BOV is recirculating. Pre turbo intake piping is original.
The AFRs seem to correct themselves after a short while. after a fresh reflash it idles at like 11AFR but it brings it up to the mid 14s.
o2 sensor does work; i put an oem replacement delphi sensor in.
the short term fuel trims are quite close; i think theyre about 5% or so. ill have to look at my log; im at work at the moment (this damned keyboard doesnt have have a comma or apostrophe..)

bonnie sacer

hi, friend. The crazy tacho, check speed sensor and gear it self. we are a manufacture of car parts for high quality and best price in China,we will provide best service to every customer, welcome to contact with me for any question.