Get a Megasquirt, You will love it, They said |
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Get a Megasquirt, You will love it, They said |
RickS |
Jun 4 2020, 11:03 PM
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#1
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Senior Member Group: Members Posts: 1,408 Joined: 17-April 06 From: 'False City', WA Member No.: 5,880 Region Association: None |
Ok had a Megasquirt system installed on the 3.0. Much better throttle response and looks oh so sexy. Tuning was something else but it runs pretty well. Two issues:
1. After a cold start, the car is not drivable for at least two minutes, until it warms up. If you try to drive it cold it just stalls. Is this normal behavior? 2. The throttle is a tad touchy. Unless you slowly squeeze the throttle accelerating is like an on/off switch, with a millisecond of hesitation and then off we go. Is that normal or can that be tuned out? |
mb911 |
Jun 5 2020, 05:33 AM
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#2
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914 Guru Group: Members Posts: 6,841 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
Ok had a Megasquirt system installed on the 3.0. Much better throttle response and looks oh so sexy. Tuning was something else but it runs pretty well. Two issues: 1. After a cold start, the car is not drivable for at least two minutes, until it warms up. If you try to drive it cold it just stalls. Is this normal behavior? 2. The throttle is a tad touchy. Unless you slowly squeeze the throttle accelerating is like an on/off switch, with a millisecond of hesitation and then off we go. Is that normal or can that be tuned out? My old 3.0 with megasquirt ran well even cold.. Did you enrich the cold start cycle. |
BeatNavy |
Jun 5 2020, 06:05 AM
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#3
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
So I'm hardly and expert (been running it on a 2.3 for about 4 weeks now), but I do grapple with the cold start idling issues. I've got no issues with throttle response, however.
So I wouldn't think it's a Megasquirt issue, because that's got so much flexibility in tuning. Your issue is either the tune and/or the components used in the build aren't sized or configured properly. Ben's right - you have a lot of capability to enrichen during start and warm up as needed. You probably knew that, but it takes a fair amount of time to fiddle with it as you only get one "real" cold start per day to test changes. In my cold idling issue I'm thinking the IAC may just not be big enough to let in the air this engine wants when cold even when fully open. I believe it's a Kia IAC, and at some point I may look for something bigger if I can't get figure it out through tuning. |
sixnotfour |
Jun 5 2020, 06:09 AM
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#4
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914 Wizard Group: Members Posts: 10,428 Joined: 12-September 04 From: Life Elevated..planet UT. Member No.: 2,744 Region Association: Rocky Mountains |
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roblav1 |
Jun 5 2020, 08:52 AM
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#5
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Senior Member Group: Members Posts: 528 Joined: 18-September 12 From: KY Member No.: 14,943 Region Association: MidAtlantic Region |
For the on/off issue, another thing to look at is the mechanical opening of the throttle plates. You want less movement at low throttle and more movement at higher throttle. Generally, at full throttle plate opening, you want the actuating mechanism at 90 degrees.
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JamesM |
Jun 5 2020, 09:36 AM
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#6
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Senior Member Group: Members Posts: 1,895 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
1. After a cold start, the car is not drivable for at least two minutes, until it warms up. If you try to drive it cold it just stalls. Is this normal behavior? Short answer, yes. This isnt a deficiency of Megasquirt, this would be related to details the build or the tune, but cant really say without more information. What sort of induction are you running? Is an idle control valve being used? Has the warmup curve been tuned? What does the mixture look like while its warming up? 2. The throttle is a tad touchy. Unless you slowly squeeze the throttle accelerating is like an on/off switch, with a millisecond of hesitation and then off we go. Is that normal or can that be tuned out? Again, need more information, its either the build or the tune. What induction is being used? Has the fuel map been dialed in, have accel enrichment been properly tuned? What does the timing look like? what does the cam look like? Seeing datalogs would help as well. The thing with megasquirt is you get out of it what you put into it. Just slapping parts on a motor doesn't guarantee it will work well, there is a quite a lot of proper planning and follow up tuning involved to maximize results. |
RickS |
Jun 5 2020, 10:48 AM
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#7
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Senior Member Group: Members Posts: 1,408 Joined: 17-April 06 From: 'False City', WA Member No.: 5,880 Region Association: None |
Cold starts are fine but it has to warmup for two minutes before being drive able. Drive ability is great if I mash the throttle, no hesitation. But in normal around time driving, when I grab a new gear, I get that slight hesitation. I do have an intake air control for good cold starts, it’s just my impatience to get going after starting by not waiting 2 minutes gets me to stall it unless I keep the revs way up.
Great advice, I will look into your suggestions. Thanks |
Mark Henry |
Jun 5 2020, 03:11 PM
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#8
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Again, need more information, its either the build or the tune. What induction is being used? Has the fuel map been dialed in, have accel enrichment been properly tuned? What does the timing look like? what does the cam look like? Seeing datalogs would help as well. For a third, 4th or maybe the 5th time what do you have? (IMG:style_emoticons/default/confused24.gif) I don't want to waste my time writing about ITB's with hot cams, if you have a stock engine with a stock intake. It's why your post isn't getting much traction. |
RickS |
Jun 6 2020, 10:51 PM
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#9
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Senior Member Group: Members Posts: 1,408 Joined: 17-April 06 From: 'False City', WA Member No.: 5,880 Region Association: None |
Stock 3.0 from an 82 SC. No mods.
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sixnotfour |
Jun 6 2020, 10:55 PM
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#10
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914 Wizard Group: Members Posts: 10,428 Joined: 12-September 04 From: Life Elevated..planet UT. Member No.: 2,744 Region Association: Rocky Mountains |
In your backyard..
http://thedubshop.com/contact-us/ |
Matty900 |
Jun 7 2020, 12:05 AM
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#11
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Senior Member Group: Members Posts: 1,269 Joined: 21-February 15 From: Oregon Member No.: 18,454 Region Association: Pacific Northwest |
(IMG:style_emoticons/default/agree.gif) Mario is the man when it comes to getting the tune right. At the end of my build we to the car to a dyno and had him log in remotely and do the final tune. Give him a few bucks and take lots of time off of figuring it out. It is still good to learn it all but I would rather do it while I'm enjoying the car. Hope that helps. (IMG:style_emoticons/default/beerchug.gif) |
Mark Henry |
Jun 7 2020, 07:11 AM
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#12
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Stock 3.0 from an 82 SC. No mods. What are you using for the TB? stock? You would be better off using a 3.2 intake. Try picking up the MAP vacuum signal from a different port on the plenum. Check the fuel cut parameter, if you are using fuel cut you will always have the sharp decel anytime you let the gas fully off. You can fine tune the fuel cut so it has less of an effect, but you will still have to feather the throttle so you don't hit the fuel cut value. With a stock intake you should be able to run with no fuel cut. |
BeemerSteve |
Jun 7 2020, 08:41 AM
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#13
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Member Group: Members Posts: 239 Joined: 2-September 15 From: Van Zandt, Wa Member No.: 19,123 Region Association: Pacific Northwest |
Ok had a Megasquirt system installed on the 3.0. Much better throttle response and looks oh so sexy. Tuning was something else but it runs pretty well. Two issues: 1. After a cold start, the car is not drivable for at least two minutes, until it warms up. If you try to drive it cold it just stalls. Is this normal behavior? 2. The throttle is a tad touchy. Unless you slowly squeeze the throttle accelerating is like an on/off switch, with a millisecond of hesitation and then off we go. Is that normal or can that be tuned out? I had on on my 2056 and had similar issues. Make sure all your grounds are good. |
falcor75 |
Jun 7 2020, 11:04 AM
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#14
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Senior Member Group: Members Posts: 1,579 Joined: 22-November 12 From: Sweden Member No.: 15,176 Region Association: Scandinavia |
Sounds like you could needs som fiddling with acceleration enrichment for the hesitation. Do you know your AFR values right after startup, are you lean or rich?
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RickS |
Jun 7 2020, 11:29 PM
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#15
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Senior Member Group: Members Posts: 1,408 Joined: 17-April 06 From: 'False City', WA Member No.: 5,880 Region Association: None |
I did not setup or program the system so am useless with technical questions. The system uses PMOS. Sounds like the dubshop will be the next stop.
Thanks all |
falcor75 |
Jun 8 2020, 12:36 AM
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#16
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Senior Member Group: Members Posts: 1,579 Joined: 22-November 12 From: Sweden Member No.: 15,176 Region Association: Scandinavia |
Mario @thedubshop is super supportive, I know he is very busy at the moment but hopefully he can squeese you in.
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VaccaRabite |
Jun 8 2020, 07:28 AM
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#17
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En Garde! Group: Admin Posts: 13,442 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
1) This is a tuning issue. Do you have a modern AAR on the car? If so this is fairly easy to work out. You just tell the ECU to adjust the AAR for the "coolant" temp of the car (which is probably your head temp - that's usually how air cooled cars are wired for MS.) The AAR is a fairly crucial part, and is sometimes skipped. You can tune without one, but it gets harder. The AAR in a modern system is constantly adjusting to keep the car running at idle no matter what the engine temp is or load on the car is (lights and windsheild wipers and radio, etc. will drop your idle)
2) Issue 2 - do you have a wide band AFR? Do you have data logs? My MS2 car was doing the exact same thing, and the issue was unless the car was at WOT, it was lean. Lean enough that going from idle to part throttle the car would hesitate and sometimes try to stall. You want to be sure your engine is getting the same values that you have in your fuel table and your AFR table. In my case I put too much faith in the fuel and AFR table and not enough faith in my actual LOGS that were telling me I was going too lean. Learn to trust your logs and use them to adjust your tables. Post up your log files (with AFR). Also, you can save your MSQ file to your post. Do that too so we can see what you are doing. Zach |
colingreene |
Jun 8 2020, 10:42 AM
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#18
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Senior Member Group: Members Posts: 729 Joined: 17-October 13 From: Southern California Member No.: 16,526 Region Association: Southern California |
you may want to indicate what AAR is for the people that dont know.
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VaccaRabite |
Jun 8 2020, 10:57 AM
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#19
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En Garde! Group: Admin Posts: 13,442 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
you may want to indicate what AAR is for the people that dont know. Aux Air Regulator, AKA Idle Air Control (IAC) valve. I don't know about the /6 engines, but the /4 had a VERY rudimentary AAR (the valve just closed about a minute after the car started. A modern IAC/AAR works worlds better. You can find them in 2 wire, 3 wire and 4 wire versions. The IAC that I am using is the 3 wire unit from a Hyundia and cost about $12 on amazon. How you wire them differs depending on which kind of valve you have. Zach |
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