Car dies after foot off accelerator

mops · Post by **mops** » Sun May 28, 2006 12:54 pm

as I said beofre....

did you try to adjust timing ?

I pretty much fixed my idle issue this weekend by:

1. incerasing timing at map/rpm bins as it is approached idle point - my car idles at 800rpm@40kpa, so abouve rpm and below that map are "approaching idle" points

2. richening a few % around approaching idle aswell

3. my deccel fuel is 100%

4. I allowed a bit more air at idle I decerased timing at idle point to keep the rpm's the same - that manouver made idle alot better and stronger... and I still can idle at 14.7:1 AFR

once i got few values right, idle is really good. there's no rolling to find idle... once i relase the throttle rpm's decerase to idle point and stay there with +-25 rpm

air deccel 150% you are probably flooding the engine.

arnold · Post by **arnold** » Sun May 28, 2006 10:53 pm

Thx guys, I run the MS1, no ign control yet, the only way I can get a bit more advance at idle is to reconnect my vacuum advance to the dizzy. I removed that one because I fear detonation (supercharged).

The car is running pretty well, no hesitation or flooding. The cold I have to tackle a bit more and my main problem is the idle. I raised the idle to 1400 rpm, so it won't reach cranking mode.

I'll go and modify the VE values near idle a bit too see if I can improe it and reconnect vac advance

keithmac · Post by **keithmac** » Mon May 29, 2006 2:24 am

Either running a dashpot or the extra code with an Idle Stability Valve will make your car a lot more reliable at idle, I couldn`t set hot idle below 1200 rpm without the ISV, car would die more often than not coming back down to idle..

I run a super charger and map at idle is in the 60`s.

arnold · Post by **arnold** » Mon May 29, 2006 4:01 am

keithmac wrote:Either running a dashpot or the extra code with an Idle Stability Valve will make your car a lot more reliable at idle, I couldn`t set hot idle below 1200 rpm without the ISV, car would die more often than not coming back down to idle..

I run a super charger and map at idle is in the 60`s.

Thanks, what kind of ISV do you use and how is it triggered? Do you use a byepass valve in your setup? I am worried abou my 70 kPa and higher idle MAP readings...

keithmac · Post by **keithmac** » Mon May 29, 2006 5:14 am

I run a 2 wire ISV off a mk2 golf gti 16v, this valve is closed at 0 DC which makes it easier to set up. You have to replace the fidle transistor with a TIP122, that`s the only mod I made to the board (fitted a TIP122 using flyleads and heatsink).

It`s well worth doing, I get factory idle and faultless cold and hot starts, makes it a different car to drive.

arnold · Post by **arnold** » Mon May 29, 2006 5:29 am

Is that with the MS1 with extra code? Or MS2? If I remember well, the MS can only trigger a FIdle valve (on / off), no idle controll as fa as I remember though

MegaScott · Post by **MegaScott** » Mon May 29, 2006 11:07 am

arnold wrote:Is that with the MS1 with extra code? Or MS2? If I remember well, the MS can only trigger a FIdle valve (on / off), no idle controll as fa as I remember though

The MSnS-extra code has both PWM warmup, and closed loop idle. I recommend the "warmup only" for starters. The nice thing about PWM idle is the nice range of adjustability you have to get a nice idle speed. Much better than simple on/off.

The US domestic (older) turbo Fords have a boost controlled diaphram that gives spark advance at vacuum, and spark retard at boost. IMHO much better though to eventually use Megasquirt to control your spark.