Forg
Well-known member
- Joined
- Sep 17, 2003
- Location
- Retirement Village, Sydney
Project Big Red Car has a MAP-sensed MoTeC M84 running Bosch -363 injectors, KG2T, LS1 coils (custom crank wheel plus dizzy-mount sensor), and a static CR that's probably too low for the KG2T. IAC valve is a MotorCraft unit off an EEC-IV mid 80's Falcon, these should be large enough to feed a B23E+T.
Given the lack of low-revs manifold pressure, it's running open loop.
Now I drove it to work this morning (first time in 6 months) and once it got warm it became apparent there's an idle issue. It sits on the target ~900rpm for maybe 20secs at a set of lights, then ramps down to about 500rpm where it's struggling to keep going. I didn't bring the dongle with me so haven't bunged a PC on it yet, so I'm kinda brain-dumping in order to start looking at it ... also looking for suggestions.
I guess the first place to start would be checking that it's getting a correct RPM reading (should be or it wouldn't work at driving revs), and then look at what it's trying to do for idle-air, fuel & spark at those revs/load? I don't recall there being a massive number of options regarding how it tries to do stuff, it seems odd that it can keep struggling along at 500rpm but not hold at a much smoother & easier-to-maintain 900rpm though, unless the IAC isn't big enough & maybe it's adjusting timing &/or fuel once it drops a reasonable amount below ~900? So maybe there are parameters on how it deals when it struggles - would that make sense?
[Yeah the manual is online on the MoTeC site if I can't get to the back of the garage to drag it out - will look later]
Given the lack of low-revs manifold pressure, it's running open loop.
Now I drove it to work this morning (first time in 6 months) and once it got warm it became apparent there's an idle issue. It sits on the target ~900rpm for maybe 20secs at a set of lights, then ramps down to about 500rpm where it's struggling to keep going. I didn't bring the dongle with me so haven't bunged a PC on it yet, so I'm kinda brain-dumping in order to start looking at it ... also looking for suggestions.
I guess the first place to start would be checking that it's getting a correct RPM reading (should be or it wouldn't work at driving revs), and then look at what it's trying to do for idle-air, fuel & spark at those revs/load? I don't recall there being a massive number of options regarding how it tries to do stuff, it seems odd that it can keep struggling along at 500rpm but not hold at a much smoother & easier-to-maintain 900rpm though, unless the IAC isn't big enough & maybe it's adjusting timing &/or fuel once it drops a reasonable amount below ~900? So maybe there are parameters on how it deals when it struggles - would that make sense?
[Yeah the manual is online on the MoTeC site if I can't get to the back of the garage to drag it out - will look later]