Megasquirt 12a bridgeport ms2 NA tune
05-15-16, 07:52 AM
#27
Old [Sch|F]ool
I've never seen any rotary crank that fast. With a strobe tach, I generally see in the 200-250rpm range. (Critical for quantifying RX-8 hot start problems!)
I seriously think you may be having some RPM signal issues and this is the first thing you need to address. I bought my MS2 as a prebuilt unit straight from DIYAutotune and I just plugged it in, there wss no messing with trim pots or diodes or whatever. You're taking RPM signal from the negative side of the coil, right?
There is no sense in "tuning" anything until the computer is reading the correct inputs - correct RPM, correct temperatures, correct throttle position, correct manifold pressure. That all needs to be corrected and baselined first. Then you can calibrate the VE table to reflect what the engine is actially doing.
If you are trying to run alpha-N, your TPS absolutely, positively needs to be calibrated accurately. This is why I have shied away from alpha-N on anything because, even on OEM drop-in installs, I have never seen a TPS that responds the same way twice. There's too much mechanical slop in the throttle shaft for the plates to be in the same place relative to the throttle body and the TPS relative to the throttle shaft.
I seriously think you may be having some RPM signal issues and this is the first thing you need to address. I bought my MS2 as a prebuilt unit straight from DIYAutotune and I just plugged it in, there wss no messing with trim pots or diodes or whatever. You're taking RPM signal from the negative side of the coil, right?
There is no sense in "tuning" anything until the computer is reading the correct inputs - correct RPM, correct temperatures, correct throttle position, correct manifold pressure. That all needs to be corrected and baselined first. Then you can calibrate the VE table to reflect what the engine is actially doing.
If you are trying to run alpha-N, your TPS absolutely, positively needs to be calibrated accurately. This is why I have shied away from alpha-N on anything because, even on OEM drop-in installs, I have never seen a TPS that responds the same way twice. There's too much mechanical slop in the throttle shaft for the plates to be in the same place relative to the throttle body and the TPS relative to the throttle shaft.
Last edited by peejay; 05-15-16 at 07:59 AM.
05-15-16, 08:31 AM
#28
I've never seen any rotary crank that fast. With a strobe tach, I generally see in the 200-250rpm range. (Critical for quantifying RX-8 hot start problems!)
I seriously think you may be having some RPM signal issues and this is the first thing you need to address. I bought my MS2 as a prebuilt unit straight from DIYAutotune and I just plugged it in, there wss no messing with trim pots or diodes or whatever. You're taking RPM signal from the negative side of the coil, right?
There is no sense in "tuning" anything until the computer is reading the correct inputs - correct RPM, correct temperatures, correct throttle position, correct manifold pressure. That all needs to be corrected and baselined first. Then you can calibrate the VE table to reflect what the engine is actially doing.
If you are trying to run alpha-N, your TPS absolutely, positively needs to be calibrated accurately. This is why I have shied away from alpha-N on anything because, even on OEM drop-in installs, I have never seen a TPS that responds the same way twice. There's too much mechanical slop in the throttle shaft for the plates to be in the same place relative to the throttle body and the TPS relative to the throttle shaft.
I seriously think you may be having some RPM signal issues and this is the first thing you need to address. I bought my MS2 as a prebuilt unit straight from DIYAutotune and I just plugged it in, there wss no messing with trim pots or diodes or whatever. You're taking RPM signal from the negative side of the coil, right?
There is no sense in "tuning" anything until the computer is reading the correct inputs - correct RPM, correct temperatures, correct throttle position, correct manifold pressure. That all needs to be corrected and baselined first. Then you can calibrate the VE table to reflect what the engine is actially doing.
If you are trying to run alpha-N, your TPS absolutely, positively needs to be calibrated accurately. This is why I have shied away from alpha-N on anything because, even on OEM drop-in installs, I have never seen a TPS that responds the same way twice. There's too much mechanical slop in the throttle shaft for the plates to be in the same place relative to the throttle body and the TPS relative to the throttle shaft.
Reason why I changed from speed density was because the map would barely move at cranking, but then I read that at cranking it will barely pull until it actually starts so I'll try speed density again. Any suggestion on the noise filtering trigger masking time and percentage? I think I'll run another shielded wire straight from the coil to the ms and see if that helps. Right now I am using the original wire for the signal and that one is unshielded. I appreciate all the help. I'll post back once in get the rpm signal to cooperate. Thanks
05-15-16, 09:58 AM
#29
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
Don't expect MAP to move much at all while cranking a bridgeport. There is virtually no vacuum due to the overlap. Actually that's true for a stock port as well. The engine just isn't spinning fast enough to draw very much air.
Speed density is going to be the way to go. You'll really only need alpha-N with short intake runners and/or ITBs.
As for the noise filter, get the car running first. If you then see false triggering, increase the noise filter settings until it goes away. Keep increasing until you lose legitimate ignition events. Then back off until it is again stable.
Speed density is going to be the way to go. You'll really only need alpha-N with short intake runners and/or ITBs.
As for the noise filter, get the car running first. If you then see false triggering, increase the noise filter settings until it goes away. Keep increasing until you lose legitimate ignition events. Then back off until it is again stable.
05-15-16, 12:33 PM
#30
Don't expect MAP to move much at all while cranking a bridgeport. There is virtually no vacuum due to the overlap. Actually that's true for a stock port as well. The engine just isn't spinning fast enough to draw very much air.
Speed density is going to be the way to go. You'll really only need alpha-N with short intake runners and/or ITBs.
As for the noise filter, get the car running first. If you then see false triggering, increase the noise filter settings until it goes away. Keep increasing until you lose legitimate ignition events. Then back off until it is again stable.
Speed density is going to be the way to go. You'll really only need alpha-N with short intake runners and/or ITBs.
As for the noise filter, get the car running first. If you then see false triggering, increase the noise filter settings until it goes away. Keep increasing until you lose legitimate ignition events. Then back off until it is again stable.
The false triggering is very bad, I really doubt it will turn on without filtering. I'll post a log of no filtering so you can see how bad it is without it.
05-21-16, 11:53 PM
#31
Thank you all for the help. It finally started.
I am ashamed to say that i had installed my front pulley 180 out of phase, which it was why it did not turn on.
https://www.youtube.com/watch?v=OHep...ature=youtu.be
I am ashamed to say that i had installed my front pulley 180 out of phase, which it was why it did not turn on.
https://www.youtube.com/watch?v=OHep...ature=youtu.be
Thread
Thread Starter
Forum
Replies
Last Post
zachkendall
New Member RX-7 Technical
2
03-29-16 01:14 PM