350 TPI falls on its face when gas pressed quickly (tune/msl
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
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nathanklein
- MegaSquirt Newbie
- Posts: 24
- Joined: Sat Mar 05, 2011 8:19 pm
350 TPI falls on its face when gas pressed quickly (tune/msl
I have a megasquirt 2 assembled unit running my chevy 350 Tuned Port Injection. I have set it up for HEI. I have been trying to iron this problem out with no luck. It basically falls on its face when you press the gas quickly but if you slowly accelerate its fine. just quick pulses on the gas it almost kills the engine completely. I have attached a Tune file and the data log. The data log shows me pressing the gas quickly and what happens during and afterwards. I have looked over everything with no luck. can someone take a few minutes and check them out. Any help would be great.
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Re: 350 TPI falls on its face when gas pressed quickly (tune
AE needs tuning, right away I notice you have huge MAPdot and TPSdot thresholds.
95 Dakota, 5.2, 5 speed, 4x4, Holset H1C (Remote) 8PSI, MS2/Extra (fuel only), 42lb Bosch Design 3 Injectors, AEM UEGO.
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nathanklein
- MegaSquirt Newbie
- Posts: 24
- Joined: Sat Mar 05, 2011 8:19 pm
Re: 350 TPI falls on its face when gas pressed quickly (tune
Ya I know I tried auto tuning it at idle with no load and that spot where it chokes out wont go away. I dont know if its a sensor malfunctioning or the tune itself. I kindof lost motivation when i couldnt get it to smooth out. I have had this runing before with this megasquirt and it was smooth. But when i turboed the engine I had to change maps and then it started this bs. is there anything in the timing that looks messed up?
Re: 350 TPI falls on its face when gas pressed quickly (tune
AE cannot be auto-tuned... Sounds like you need to go over the manual some more 
95 Dakota, 5.2, 5 speed, 4x4, Holset H1C (Remote) 8PSI, MS2/Extra (fuel only), 42lb Bosch Design 3 Injectors, AEM UEGO.
Re: 350 TPI falls on its face when gas pressed quickly (tune
looks like flooding same way my was, lean out whole VE table below idle kPa level in whole RPM range, als IAC over 160 
have You checked Your maximum IAC motor steps Did You calibrated TPS
best regards
have You checked Your maximum IAC motor steps Did You calibrated TPS best regards
Pontiac Firebird 305 LT1 intake, L82 cam
MegaSquirt II with mod's + TPI adaptor board, MSExtra 3.3
MegaSquirt II with mod's + TPI adaptor board, MSExtra 3.3
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Bernard Fife
- Master Squirter
- Posts: 475
- Joined: Thu Oct 29, 2009 12:54 pm
Re: 350 TPI falls on its face when gas pressed quickly (tune
nk.
Hahns5.2 gave you some good advice, you should follow it.
If the engine runs fine with the throttle steady or moved very slowly, but stumbles when the throttle is moved quickly, you need to tune the accel enrichments, not the VE table.
If the accel thresholds (TPSdot/MAPdot) are too high, then the accel enrichment won't work, so you likely need to lower these back down to somewhere near the default values (the thresholds should be as low as they can be without falsely triggering accel when the throttle isn't moved).
You can find out how to set the accel parameters in the manual: http://www.megamanual.com/ms2/tune.htm#accel
Lance.
Hahns5.2 gave you some good advice, you should follow it.
If the engine runs fine with the throttle steady or moved very slowly, but stumbles when the throttle is moved quickly, you need to tune the accel enrichments, not the VE table.
If the accel thresholds (TPSdot/MAPdot) are too high, then the accel enrichment won't work, so you likely need to lower these back down to somewhere near the default values (the thresholds should be as low as they can be without falsely triggering accel when the throttle isn't moved).
You can find out how to set the accel parameters in the manual: http://www.megamanual.com/ms2/tune.htm#accel
Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it.” - George Bernard Shaw
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nathanklein
- MegaSquirt Newbie
- Posts: 24
- Joined: Sat Mar 05, 2011 8:19 pm
Re: 350 TPI falls on its face when gas pressed quickly (tune
Well i think i made a noob mistake. Since this engine is now turbo'd I have added 80 lb ford racing injectors... I had the accel enrichment adding up to 16ms of pulse width because thats what the stocker 24lb injectors were running. I did a quick fuel injector calcuator and it said at the MAX my injectors should be open 8ms on the pulse width. makes sense but I have cut it down just havent had time to test.( raining the last 2 days). If you look at the accel enrichment in the msq u can see that there was up to 16ms of pw added on accel.... ;/ im an confused person but I'm slowly learning. even with all the problems ive had getting this engine goin right I still think megasquirt is bad behind!
I know i have read the manual and I go over it and over it. Alot of things are different between tunerstudio and megatune, i have tunerstudio. alot of the % are in volts and other things. I have leaned things out on my ve so we will see what happends. I had megasquirt for years on my un turbod jeep and you would be suprised at what you forget when you havent tuned anythig in a while.
I know i have read the manual and I go over it and over it. Alot of things are different between tunerstudio and megatune, i have tunerstudio. alot of the % are in volts and other things. I have leaned things out on my ve so we will see what happends. I had megasquirt for years on my un turbod jeep and you would be suprised at what you forget when you havent tuned anythig in a while.