motronic conversion nearly there, just wont run, help please

[Speedtouch]

Have you tried disconnecting the ICV? Sounds like it's running smoothly enough other than the reluctance to keep running

[mattyb]

if i disconect it, thwn try to start it what should happen.

[Speedtouch]

Not sure tbh, though I owned a 325i Sport with Megasquirt and ran it for a few weeks with no ICV; it stalled easily when cold unless you kept revving it but once warmed up within a mile or so, all was well. So, they can run without them, and if yours is playing up, it may be worth a try...

[Brianmoooore]

The idle control valve is just an electrically operated air valve that's connected across the throttle butterfly.
The butterfly stop is set so that the engine would idle at very low revs, on the point of stalling, and the ICV lets a small extra bit of air in to bring the revs up to the correct idle. If the engine load increases, the ICV opens a little more to compensate and keep the idle stable.
If you want to try it without the ICV, wedge the throttle butterfly slightly more open.

[mattyb]

will do lads, ill try it tomorow when i finish work. just thought that the only thing i havnt checked, is the air flow meter. is there a way i can test it with a multimeter or some other way

i did try to screw the throttle stop in and the engine did run but idle was very unstable. when doing this if i touched the throttle. even the slightest bit the engine revved up to about three. and it was vey hard to use the accel pedal to get it to rev lower than 3 almost as if there was a rush of air in to the engine causing it to rev high.

im goin to have a look at the air flow meter tomorow too.

thanks again for everything, i would be in a real mess without your help, thanks

[Speedtouch]

It's just a variable resistor/rheostat/potentiometer, easily tested with a multimeter; see this thread from another forum which features the world-famous Brianmoooore:

http://www.msportster.co.uk/faq.asp?FAQ=13

The Motronic system is evidently working reasonably well if the engine starts and revs to 3,000rpm, so with a bit of perseverce, I'm sure you'll crack the problem. What happens if you give the throttle a good steady and gradual bootfull?

Don't forget, when you first fit a new chip or ECU, the new settings will need to be learnt over a period of time - the engine needs to be revved over the full rev range for this to happen.

[mattyb]

if i rev it gradually as you say speedtouch, it works fine. the thing just wont bloody idle. lol.

right i have taken off the idle control valve. and unpluged it. when i look inside it and then plug the wiring in, it snaps shut. should it not be open a little bit so it controls the idle.

also checked the afm and if i measure resistance between pin 2 and 3 it inreases as i open the door inside it. so it looks as if afm is ok.

[Speedtouch]

Well, there can't be too much wrong if it revs OK. Normally on these with the ignition switched on, the ICV hums; I don't think it should snap shut, but I may be wrong on this.

Did you try the steps mentioned in the link above, and the link at the end of it?
http://www.verrill.com/car/e30_idlefaq.shtml

Maybe another thing you could try, is to leave the engine on a fast idle for a while (use a length of wood between the seat and throttle pedal, or similar) until it warms up, then see what happens...

[mattyb]

number 4 of icv diagnosis says when 12 volts applied to icv it should close tightly and it should open strongly when voltage is removed. mine stays shut if i remove the connector. so it looks like the icv is cattled. im gona get one from the scrappy tomorow and hope its good if not zaust has one and ill just have to wait for it. thanks for your help maurice and you too brian and all others that helped. ill let you know when shes running. thanks again.

matty

[mattyb]

it works. and first of all i would like to say im an idiot. i left the old gasket on cylender six so there was a massive air leak in to all the other cylenders. what a fool.

so thankyou brian and speedtouch(maurice) for all the help. and i must say speedtouchs wild chip is fantastic. mid range tourque feels like a different engine. thanks again all who helped. cheers.

[gooner1]

Trust me. you are not the first to do that, took me weeks to find the fault.
Well spotted.

[mattyb]

im so glad iv found it, was alomost in tears looking for what was wrong. she feels like a new car with the wild speedtouch chip in though. i would recomend one to anybody.

[Speedtouch]

Great stuff, Matty - knew you'd get there in the end! This thread should be made a sticky, for anyone wanting to do an L-Jet to Motronic conversion...