Megasquirt Light throttle cut
06-02-11, 11:07 AM
#1
3 rotor
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Light throttle cut
Just got my squirt 2 installed and if I so gently touch the throttle it acts like it cuts fuel. My gauge jumps to 22 afr's and acts like you are turning the car off. If I quick the throttle its very responsive. Ive tried adding fuel but nothing. Its very light throttle pressure only. So anytime I try letting out the clutch I have to rev the pee out of it to go.
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06-07-11, 10:33 PM
#9
3 rotor
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Well I have it apart. I found a vacum leak on the lower intake manifold. That could be my issue? The car had better response to very light load when cold. Also noticed a whistle when cold hence why I started checking for vacum leaks. I hope that is my issue. Im not dropping ignition.
07-27-11, 09:36 AM
#11
Junior Member
We're still trying to get rid of this crazy tip-in behavior, FYI.
Car idles perfectly - but as soon as we barely open the throttle, it's like shutting the engine down. Except, we're still getting spark & fuel.
I've focused on TPS enrichments (I've never had troubles before) and VE table just above idle - but no matter what, this engine will not run between 2000-3000RPM.
Other things I checked:
-make sure decel overrun fuel cut is disabled
-make sure ignition is firing during the misfires (it is, good strong behavior)
-made sure ignition was calibrated correctly
-make sure injector staging wasn't kicking in, dumping too much fuel
I'm going to post up a datalog here shortly, as well as an MSQ maybe you guys can find something. If not, I'm thinking we'll have to take it to the dyno and try to steady-state that area of the map.
If anyone has time to take a look and give us some input, I'd appreciate it! I am obviously missing something as I've never once had such a hard time tuning tip-in behavior even on the craziest of engines. And this one is bone stock!!
-Scott
Car idles perfectly - but as soon as we barely open the throttle, it's like shutting the engine down. Except, we're still getting spark & fuel.
I've focused on TPS enrichments (I've never had troubles before) and VE table just above idle - but no matter what, this engine will not run between 2000-3000RPM.
Other things I checked:
-make sure decel overrun fuel cut is disabled
-make sure ignition is firing during the misfires (it is, good strong behavior)
-made sure ignition was calibrated correctly
-make sure injector staging wasn't kicking in, dumping too much fuel
I'm going to post up a datalog here shortly, as well as an MSQ maybe you guys can find something. If not, I'm thinking we'll have to take it to the dyno and try to steady-state that area of the map.
If anyone has time to take a look and give us some input, I'd appreciate it! I am obviously missing something as I've never once had such a hard time tuning tip-in behavior even on the craziest of engines. And this one is bone stock!!
-Scott
07-27-11, 09:56 AM
#13
Junior Member
OK, been trying to upload attachments here for a while with no luck. Also searched the forums for how to attach files or problems with attachments. I'm sure it's something I am doing wrong - but, in the interest of helping get this poor car running right, if anyone here can PM me an email address I can send an MSQ and datalog.
07-27-11, 10:56 AM
#14
Junior Member
OK, how about this? uploaded .ZIP file and it worked. Two datalogs and an MSQ are in the zip file.
Note, the VE table is a little ugly because I was trying More fuel, Less Fuel, More Accel enrich, less accel enrich, etc. etc.
thanks,
-Scott
Note, the VE table is a little ugly because I was trying More fuel, Less Fuel, More Accel enrich, less accel enrich, etc. etc.
thanks,
-Scott
07-27-11, 02:55 PM
#15
Right off the bat I see one issue. Your TPS is incorrectly calibrated. If it goes into the negative numbers, I've found that it can have adverse effects. Try doing a re-calibration of it, then lower the shut number a little bit, then raise the full open number a little bit. That way, you'll never get -2 or 101 for throttle position.
I'm still looking at the log though. I'm having some issues with mine and have gotten quite intimate with megalog viewer.
Also, try using MAP based AE as well. I started with using 100% MAP accel enrich, and slowly added TP based enrichment.
I'm still looking at the log though. I'm having some issues with mine and have gotten quite intimate with megalog viewer.
Also, try using MAP based AE as well. I started with using 100% MAP accel enrich, and slowly added TP based enrichment.
07-27-11, 02:59 PM
#16
Junior Member
Right off the bat I see one issue. Your TPS is incorrectly calibrated. If it goes into the negative numbers, I've found that it can have adverse effects. Try doing a re-calibration of it, then lower the shut number a little bit, then raise the full open number a little bit. That way, you'll never get -2 or 101 for throttle position.
I'm still looking at the log though. I'm having some issues with mine and have gotten quite intimate with megalog viewer.
I'm still looking at the log though. I'm having some issues with mine and have gotten quite intimate with megalog viewer.
07-29-11, 08:59 AM
#18
Junior Member
07-29-11, 09:03 PM
#19
Look at the battery voltage.... I'm having very similar readings and it freaked me out. I just had the alternator tested yesterday to verify that its voltage regulator is still working. Is it normal to see voltage swings that big on a datalog? I can't see why it'd do that? The dash voltmeter shows pretty constant, and I'm not having starting or charging issues, so WTF is going on here?
I seriously thought it was part of my problem.
I seriously thought it was part of my problem.
07-31-11, 04:43 AM
#20
What's the point??
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Check and see if your board has a capacitor across the boot jumper (on the main board) I had the same issue with mine, and a cap there solved it. Most people just use the C30 cap, since it's seldom used. This is MS2/MS3 only, and WON'T work with MS1.
08-03-11, 11:02 AM
#22
Junior Member
UPDATE:
I think this problem is NOT tps related.
I put the timing light back on the engine and, while the timing is where it's supposed to be (when fixed) I noticed that the leading plugs are firing TWICE as often as they should. COme to think of it, I think our RPM readings are DOUBLE what they should be as well.
This tells me I still have a config issue in my wheel decoder or ignition settings...
One thing that I saw was the config that says "cam wheel speed" for the 24-2 sensor, but I thought this turned at engine speed?? I tried setting "crank speed" and couldn't get anything but backfires and kickbacks when trying to start.
Can any of you experts take a look at my ignition/wheel configs and point me in the right direction? There are a number of new options that do not match Aaron's documentation - I know I have a mistake somewhere but... where?
thanks,
-Scott
I think this problem is NOT tps related.
I put the timing light back on the engine and, while the timing is where it's supposed to be (when fixed) I noticed that the leading plugs are firing TWICE as often as they should. COme to think of it, I think our RPM readings are DOUBLE what they should be as well.
This tells me I still have a config issue in my wheel decoder or ignition settings...
One thing that I saw was the config that says "cam wheel speed" for the 24-2 sensor, but I thought this turned at engine speed?? I tried setting "crank speed" and couldn't get anything but backfires and kickbacks when trying to start.
Can any of you experts take a look at my ignition/wheel configs and point me in the right direction? There are a number of new options that do not match Aaron's documentation - I know I have a mistake somewhere but... where?
thanks,
-Scott
08-03-11, 12:57 PM
#23
MegaSquirt Mod
You have teeth cut out of the CAS?
Assuming that's the case, then you have to set it up as a 12-1 at crank speed instead of 24-2 at cam speed.
the 24-tooth setup is if you're using 2nd trigger, in which case you'd want to turn on the 2nd trigger, and set it up with 24 teeth at cam speed with 2nd trigger every rotation of the crank.
Ken
Assuming that's the case, then you have to set it up as a 12-1 at crank speed instead of 24-2 at cam speed.
the 24-tooth setup is if you're using 2nd trigger, in which case you'd want to turn on the 2nd trigger, and set it up with 24 teeth at cam speed with 2nd trigger every rotation of the crank.
Ken
08-03-11, 01:06 PM
#24
Junior Member
You have teeth cut out of the CAS?
Assuming that's the case, then you have to set it up as a 12-1 at crank speed instead of 24-2 at cam speed.
the 24-tooth setup is if you're using 2nd trigger, in which case you'd want to turn on the 2nd trigger, and set it up with 24 teeth at cam speed with 2nd trigger every rotation of the crank.
Ken
Assuming that's the case, then you have to set it up as a 12-1 at crank speed instead of 24-2 at cam speed.
the 24-tooth setup is if you're using 2nd trigger, in which case you'd want to turn on the 2nd trigger, and set it up with 24 teeth at cam speed with 2nd trigger every rotation of the crank.
Ken
08-04-11, 04:09 PM
#25
Junior Member
anyone? buehler? lol
I'm pretty much stuck here. I can't see what it is in my MSQ that I am missing, however since the new firmwares mean different menus than Aaron's instructions - I am kinda screwed.
I'd rather not kill a starter or multiple sets of plugs guessing...
I'm pretty much stuck here. I can't see what it is in my MSQ that I am missing, however since the new firmwares mean different menus than Aaron's instructions - I am kinda screwed.
I'd rather not kill a starter or multiple sets of plugs guessing...