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Thread: That's it! I'm effing done with this ECU! Going to megasquirt!

  1. #16
    LT1 specialist steveo's Avatar
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    Is it possible to have good fuel pressure and have lack of flow getting to the injectors cause by a clogged fuel filter?
    on any sane fuel system, lack of flow would cause a pressure drop as fuel flow requirements exceed available flow, so no. you'd see it on a pressure gauge, although revving in your driveway is quite different from driving.

    you could also have intermittent fuel pressure loss, might not be the pump, could be loose clamp in tank, cracked pickup hose, something like that.

    i agree that switching ECMs right now would be a bad idea, in fact a different ECM might 'tune around' the problem more easily, but you'd still be burying whatever is wrong.

    if 'resetting' or reflashing or whatever temporarily cures the problem, i'd say you have some kind of problem with closed loop. why don't you burn an open loop bin and see if it behaves itself?

    it's also possible your ECM is flaky, but you'd probably see other evidence of that

    i'd be interested to see some logs of when the weird behavior happens

  2. #17
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    Quote Originally Posted by steveo View Post
    on any sane fuel system, lack of flow would cause a pressure drop as fuel flow requirements exceed available flow, so no. you'd see it on a pressure gauge, although revving in your driveway is quite different from driving.

    you could also have intermittent fuel pressure loss, might not be the pump, could be loose clamp in tank, cracked pickup hose, something like that.

    i agree that switching ECMs right now would be a bad idea, in fact a different ECM might 'tune around' the problem more easily, but you'd still be burying whatever is wrong.

    if 'resetting' or reflashing or whatever temporarily cures the problem, i'd say you have some kind of problem with closed loop. why don't you burn an open loop bin and see if it behaves itself?

    it's also possible your ECM is flaky, but you'd probably see other evidence of that

    i'd be interested to see some logs of when the weird behavior happens
    I thought the same thing about the fuel pressure. I used to play with closed loop but closed loop would make my car run lean and then I learned I needed a heated o2 sensor but that did not fix it in closed loop still ran lean so I just always leave closed loop turned off by setting the enable temp closed loop as high as it goes. But now it's running lean in open loop too!

    I have a moates data logger but not sure how to record with it yet. I've been using it to see the data live on the tunerpro RT dash.

  3. #18
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    Quote Originally Posted by dave w View Post
    My post was centered on the topic or comments about changing computers, MegaSquirt computer vs. Factory computer. Generally speaking, the Factory LS1b or '0411 computer is one of the best supported computers, including support from EFI Live and HP Tuners. It's very possible there are several tuners in your area that have extensive experience with the '0411. Maybe there are tuners in your area with extensive experience tuning with Megasquirt?

    I admit, my post did not mention any possible solutions that would be helpful to fix your engine.



    dave w
    The MS2 should be a pretty straight forward install on my vette, it doesn't need any aftermarket cam sensor setup and I've built a MS1 for my turbo Miata before. The tuning part on that ecu was a lot easier than what I've dealt with trying to tune my stock vette ecu.

  4. #19
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    From what I can tell my tunes are changing based on weather conditions of the day. It's finally getting cooler in AZ and it's messing up my tune. probably has something to do with the fact that tunerpro won't accept my bosch injector offsets so I'm using the stock offsets and now it doesn't know how to make adjustments because it's using bad information.

  5. #20
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    Today I warmed up the car and it was lean cold, rich while warming up and just a little lean at operating temp. it was way lean cruising but if I stepped on the gas it was good 12.5-13.0 afr. But then it would start the lean out again at higher rpms 4500+ about 14.5 afr and I'd let off the gas.

  6. #21
    LT1 specialist steveo's Avatar
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    Quote Originally Posted by Turbo Nasty View Post
    From what I can tell my tunes are changing based on weather conditions of the day. It's finally getting cooler in AZ and it's messing up my tune. probably has something to do with the fact that tunerpro won't accept my bosch injector offsets so I'm using the stock offsets and now it doesn't know how to make adjustments because it's using bad information.
    how do you mean? lets see your bin, xdf, and target offset data

  7. #22
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    Quote Originally Posted by steveo View Post
    how do you mean? lets see your bin, xdf, and target offset data
    I mean it's hot as hell in Arizona and that's the last time I tuned the car and it's stayed hot until recently and now my tune is way off. My tune was never really too good to begin with.

    I did just have success richening it up. I got a wide open throttle run in an it was pig rich all the way! I did this by setting the 'Open Loop % Change AFR vs Temp' to all zeroes, and 'Open Loop % Change vs MAP' to all zeroes. The one that made the big difference was 'MAT Compensation Counts vs MAT' set to all zeroes. after the very rich WOT run I adjusted the affected temperature ranges to 40 down from the factory 128. it got my idle around 13.5 AFR and full throttle the same.

  8. #23
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    Why so many crazy variables on this car!? I'm tempted to set everything to zero and just run off of the fuel map alone and retune the map for it The only noticeably affective variable was the 'MAT compensation Counts vs MAT'

  9. #24
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    Here's todays bin.
    Attached Files Attached Files

  10. #25
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    I'm using the $8D-1227730-V1.xdf.php

    for some reason I was not allowed to upload it here. it said it was an invalid file.

  11. #26
    LT1 specialist steveo's Avatar
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    Quote Originally Posted by Turbo Nasty View Post
    Why so many crazy variables on this car!? I'm tempted to set everything to zero and just run off of the fuel map alone and retune the map for it The only noticeably affective variable was the 'MAT compensation Counts vs MAT'
    this isn't at all normal, there are no 'crazy variables'. 8D is supposed to be really easy to tune, with a VE table in the ballpark, it should be drivable in all conditions. i tuned an 8D car for a guy once and had no problems, in fact on the stock bin it ran alright, just sucked a lot of fuel.

    i know it's frustrating but do you want to try starting from scratch?

    i looked at your bin and i think your VE tables are probably awful. i also saw a few tables for fuel compensation vs temperature and map were zeroed out. i think those are best left alone.

    with your trouble with injector offsets, show me the injector data you're trying to enter and lets figure out why it wont take it. it should accept anything from zero to 7782 usec. just focus on getting the ~9-14v values correct, if you're outside that range, you're limping home anyway. i wonder if you're trying to put msec values in there or something.

  12. #27
    LT1 specialist steveo's Avatar
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    i looked at your bin and i think your VE tables are probably awful.
    i'd like to clarify that statement and just say that after tuning speed density for a while, you get to look at a ve table and go 'that shit will never work'. and that's exactly what pops into my head when i see yours.

    was this developed from wideband data, trims, by feel, or what?

  13. #28
    LT1 specialist steveo's Avatar
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    also how about a datalog and an adx? i want to troll it for sketchy sensor output.

    if the forum wont accept a file simply zip the thing or rename it to .bin and tell us what the old extension was.

  14. #29
    LT1 specialist steveo's Avatar
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    maybe this will give you some hope

    i put a DGV weber carb on my beater mazda truck. it's pretty stock except for some crazy handmade exhaust.

    it's a mechanical progressive carb, that means one barrel opens until half throttle, then the bigger barrel opens till wot, so a quiet and efficient cruising range with a massive (and fairly sudden) boost for heavy throttle.

    with the jets that the mfr swore would run fine, it ran great on primary barrel, but when the secondaries open, it would bog and stop accelerating, at the same time it made a ton of noise like it wanted to smoke the tires.

    they blamed the engine, so i checked everything.

    distributor mech advance, vacuum, compression, ignition timing, cam timing, fuel pressure, exhaust restriction, new plug wires, the works, and it was all the same. i even re-gasketed the entire top end, since it was leaking a bit of coolant. all checked out.

    i slapped the wideband on it, and it was at ~17:1 WOT.

    jet kits are hard to come by for this thing, so i got fed up and grabbed a regular set of drill bits (can't find my numbered ones, maybe I sold them)

    knocked the primary jet open with a 1/16th utility drill

    i figure i probably made a #160 jet instead of the #140 that was in it.

    runs perfect now. wideband avg 13:1 wot, 15:1 cruise.

    i'll order a jet kit, but it's no rush.

    moral of the story is, even with a computer, don't forget carb logic. sometimes, after you're 100% sure it's a fuel delivery problem, you just have to throw a good amount of fuel at the poor beast where it's hurting the most, then fine tune from there. a bit more gas never hurt anything, that's why you can pour fuel into an engine from a pint glass and it'll run.

  15. #30
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    Here's the bin from dyno day last January. It ran great on this tune for two weekends or so and then the car wouldn't run right on it anymore. It was too rich on the street.

    And here's the stock chip copy from my car too for comparison.
    Attached Files Attached Files

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