Hydra 2.5 Idle gone crazy
 

I have a MSM with the FM2 kit along with RC550's and 2560 turbo

I've had the car since August last year and really haven't had a problem until Friday night.

Pulled up to get some beer, back in car mins later with said beer an proceeded home ~ 30 sec. up the road. Noticed the idle was sitting a lil' high, thought not much of it and proceeded to get pissed for the night.

Roll around Saturday morning, started the car and after a couple of minutes of idling I could hear her revving high and that's when I remembered.

It was holding a steady 1700rpm and the it climbed higher to around 2000rpm.

Pooped the bonnet and could here a something clicking on and off which was in time with the now oscillating revs between 1700 to 2000rpm, up and down, up and down, repeat. It sounded like it was either the EGR? at the back of the inlet manifold or the little solenoid with a Mitsubishi star going nuts. That seemed to stop once the car was close to temp but the idle was still going nuts.

Only things to note is the car is not and has not been running an O2 sensor since I've had it.

With the stoopid cold morning the other day ~10F, it took forever to get her started. Had to give it some part throttle to get her to actually idle then all was good. It was cranking but not getting there and was almost backfiring.

I haven't been able to get my laptop to talk to the Hydra yet. FM suggested it's due to using windows 7 on my laptop and I'd have to upgrade the Hydra.

So essentially I have no way of getting into the Hyrda at the moment.

I'm in NJ.

I haven't had a need to play with the Hydra yet and don't really know enough about the ECU side of things so wouldn't know even where to start.

Any suggestions s to what the problem could be?

Try disconnecting the idle valve - does the idle drop to "normal"? If not, then you have a leak somewhere, after the throttle body.

Just disconnected what I think was is the ISC (cylindrical solenoid under the TB) and no change.

revving up and down from ~1700 to ~2100rpm pretty quickly.

It seems to drive fine otherwise.

Sorry for the noob 1st post ladies.

OK, can't find any obvious leaks afther the TB.

There's a gas you can spray around to check for leaks but for the life of me I cannot remember what it is. Any suggestions?

Also anyone have any other ideas for the cause of the oscillating idle?

It's driving me nuts and I'd like to fix it myself rather than take it to someone but not sure where to start.

EDIT:
used some propane and some carby cleaner. No change in idle.

I did notice however that when I remove the hose that runs to the Hydra internal MAP sensor, the revs became rough but settled to normal. Could this be the culprit?

Well, had a smoke leak test done today and no vacuum leaks which kinda makes me a sad panda.

Anyone got any other suggestions?

Well, I collected the dead original motor this morning and process of elimination points to either TPS or ISC valve.

Swapped over the TB and car is back to normal.......yippeeeeeeee!

------- stoked but pissed I wasted so much time tracking a vacuum leak that didn't exist:crx: