hey everyone, ive been kinda silent here lately cuz ive been out in the garage every second i can. I managed to get my rebuilt b21ft installed in my car and just finished wiring up the megasquirt today. But ive ran into a problem. When i first started her up she idled excellent, afr seemed quite high- reading around 15 on my wideband controller. Then after a while i tried to start her up again and it ran very very poorly, it wouldnt even idle unless i feathered the gas. Also when i hooked up the megatune to it, the ms was reseting every time i started it up, is this normal? I am so confused as to why it would idle well and then after a few more starts barely idle at all. Any ideas?

another tid bit, my rpm on megatune is reading lower then i think it should, my tach is reading 1000rpm but the megatune sees 600?

Are you running your distributor still? Or waste-spark of sorts?

The person who's going to pwn this problem is Matt Dupuis, but whether or not he has time is the question

- R

im just running the stock volvo spark set up, no MSnS as of yet, this is a very vanilla set up. I was wondering if maybe its my 12v source that is causing the problem, as i posted on t-bricks, i remembered that the car ran fine before i hooked up the alt and did a few other things, i wonder if alt chatter is screwing up the MS????? what do you guys think? i tryed changing a few of the erichment settings as per the megatune manual and other t-bricks peep's set ups, i seemed to only get farther away from a smooth idle. Any ideas would be much appreciated

ok so i woke up early today to get some wrench time in before work and i managed to locate what is causing the problems, and to be honest i dont understand it at all. Ok so heres where i try to explain it, on the front(engine side) of the intake manifold there is a large brass nipple (Its about the diameter of your pointer finger) with a hose on it, anyways i believe this goes to the aux air valve or something I do not know. Alright so now i have successfully pinpointed when my engine started to run rough, I was pulling out of the garage to just putt on down the alley a bit cause i was so pumped to have the car running, but as i pull out i here a weird whoshing sound, so i get out and notice that hose, so what did i do? i plugged it, then i go to start here up and THATs when she wont idle.










So i tried a few things, i uplug it, it idles fine, I thought maybe the IC was clogged or something so i hooked my filter directly to the cold side of the IC and plugged the hose up again- wouldnt idle. So basically id say im doing something wrong with that hose on the intake mani. I beleive it is for an aux air valve, but i thought for initial start up i wouldnt need it, Could this be my problem??

Megasquirt doesn't care about vacuum leaks. That nipple is basically a controlled vacuum leak, which lets a little more air into the manifold. You'd think this would make the engine leaner, but because it also lowers the vacuum in the manifold it effectively changes the load/speed bin the engine's idling at. Once you plug it, you're basically doing nothing more than shutting the throttle a bit, so if you're having trouble idling with that nipple plugged, your map is screwed up and/or you need to bump up your idle speed a bit.

update on the car:


Alright! so i managed to get her running/idling pretty good, well good enough to drive a bit. I had to play with some of the constants and crank/afterstart enrichments and now she purrs nicely, also my ignition timing was hella off which may have added to my situation. Im slowly learning more and more about this whole tuning process to see if i can get a decent tune but i have to admitt i dont know a lot about it.

Thanks alot for everyones input so far and helping me to get her running! I'll update later today after i do an oil change and hook up the power steering and drive her a bit more. Thanks again!!!


Jon

hook up power steering? I dunno on that front
Glad to hear its running

hmm, so shes driveable still having a few problems, i think my timing is off as i posted on t-bricks, one guy gave me this advice though, is this right?




I always thought i was trying to get the rotor to match up with the line AFTER the distributor was inserted, not before? The way he is describing it the distributor would be about 60 away from the notch, Is he correct? At this point i think i need to fix a few more vacuum leaks and get this timing problem sorted out.