New T4 Microsquirt Install, engine runs poorly

Moderator: Tom Notch

Posts: 268
Joined: Tue May 01, 2012 11:27 am
Location: Little Rock, AR

Re: New T4 Microsquirt Install, engine runs poorly

Post by luftvagon » Fri Jun 29, 2018 9:02 pm

any updates?
1981 Volkswagen Vanagon Westfalia - air-cooled Type4 1970cc CV (hydraulic lifters, 42x36 valves, stock cam, microSquirt FI)
1993 Ford F-250 XL LWB Extended Cab 7.3L IDI

Posts: 8
Joined: Sun Jul 18, 2010 9:39 am

Re: New T4 Microsquirt Install, engine runs poorly

Post by svenjamison » Tue Jul 17, 2018 7:34 am

Apologies for delay in my reply, was out of town for a couple weeks, and had some fun setbacks (defective o2 box, exhaust leak requiring time-sert). Anyway, I followed your suggestions and managed to get the engine to idle and ultimately drive. To get it idling I had to fashion a stop screw for the throttle to give it more air, likely due to the large displacement (2.4l) and big cam. Having to guess a bit on correct AFR at idle, as the cam overlap (I think) causes the o2 to read all over the place until about 1400 rpm. Going to further tune idle based on vacuum, and will mess with inj. timing to see if I can minimize fuel getting sucked out of the exhaust valve. Currently still have EGO control/accel enrichment disabled. Need to build an AFR table, not using the table generator because I really have no idea what my HP/torque is on this thing. Any idea where I can get a solid table as a base? Took advice from another thread on this forum and set up table to simulate L-Jet (can't recall who posted, or if it is accurate), but the cells are nearly all in the 13 range. Just used this to get it driving and to ensure I was not running lean, now I need a better table. I am at the moment happy I can at least drive it, but I can tell it needs tuning. Used VEAL on a couple drives and it improved significantly, but if I understand correctly it was using my sub-optimal AFR table as a guide (though maybe I still don't understand the relationship between the two), "incorporated AFR target" disabled.

Post Reply