idling really high and tacho bouncing like crazy suddenly!!!

pristic · Post by **pristic** » Mon Jul 21, 2008 9:17 am

Hey guys,

Rebuilt my carby today, everything is basically the same
The idle has skyrocketed and the tacho is bouncing around like crazy

I cant find a vacuum leak anywhere in the system... if I jiggle the wires (pip/saw and tacho) on the MJ unit the light flashes a little and the idle drops back down, let it go and it goes up really high (3000rpm but cant tell as tacho is bouncing
Driving along, tacho is normal though... looks to me like a vacuum leak but I cant find one

Help!

Pete

pristic · Post by **pristic** » Mon Jul 21, 2008 9:25 am

oh, just to add, if I disconnect the MJ (power it down) the idle drops again (to normal) but I cant see tacho as its connected through MJ.

HEEELP please

Pete

pristic · Post by **pristic** » Mon Jul 21, 2008 9:31 am

oh also, vacuum on the boost guage is reading right so I dont think its a leak... will double check though...

luke6040 · Post by **luke6040** » Mon Jul 21, 2008 12:02 pm

sounds like a loose wire, funny advance can make an engine rev higher, you just of knocked somthing when doing your carb.

pristic · Post by **pristic** » Mon Jul 21, 2008 12:28 pm

Doubt it, the wiring is nowhere near the carb...

Someone suggested that the jiggling of wires I did and it fixed the idle was because megajolt was losing power... so the timing changed, therefore idle changed.

ill disconnect the tacho first, if that doesnt help the idle, ill check the carby. It might have to do with the butterfly in the carb... will test tomorrow.

Pete

pristic · Post by **pristic** » Mon Jul 28, 2008 6:07 am

Ok,

I connected the tacho to the pip line (spliced into it) and its better... BUT things still bounce intermittently.
It almost feels like the thing loses its signal now and again... power is there, earths all good, redid the wiring to ensure its all correct and its fine... but something feels 'loose' now but only occasionally.

When it acts up, the idle drops, and it runs rough (I am assuming MJ and EDIS are losing connection and therefore its going into limp mode for a second or so... then back to normal.

Please help, I installed the MJ to make it run smoother, and now its intermittent and making life quite unpredictable... not a good thing on a turbo motor lol

Pete

Post by **brentp** » Mon Jul 28, 2008 6:33 am

If you unplug the MJLJ, do you ever see this intermittent problem?

What do you observe using a timing light, with and without the MJLJ plugged in?

pristic · Post by **pristic** » Mon Jul 28, 2008 7:07 am

Hi Brent,

Thanks - with the MJ unplugged, the idle is lower and stays low... and its definately runnign in limp mode then.
I can see that when the MJ is plugged in the timing is correct (as per the settings actually) so the MJ is controlling the timing - I cannot test with a timing light as its usually intermittently interrupted while driving (almost like the pip/saw to MJ 'disconnect' then reconnect is the feeling (if you follow)

I cant get it all hooked up to log what its doing as I am still having the problem with the stupid USB -> Serial and the software freezing, but I think I have a laptop to test with now.

All in all, what it feels like is as if you are driving off in first gear, then power to MJ drops for 2-3 seconds and then returns... its like a flat spot or something ... but its definately MJ/EDIS/VR issues... when it works, its fine, no issue at all.

More noticable when car is cold though, as the change in timing makes more 'impact'

Any way I can 'test' the MJ and what its doing? I guess the answer is plug-in the laptop and log everything ay...

Pete