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Microtech 3500 rpm hessitation

Old May 10, 2003 | 06:56 PM
  #1  
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3500 rpm hessitation

My car has a hessitation at 3500rpm. I have tried going back to the base maps ect and I can't seem to find the culprit. Think it could be grounding issues? Any other stuff? It is not fuel/load related it happens on boost and in vacuum.
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Old May 10, 2003 | 07:15 PM
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What's your MAPstg setting? What's your REVstg setting? What are your MAP readings when it stumbles?

Brandon
BR7 Racing
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Old May 10, 2003 | 09:21 PM
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It is not related to any of those settings, it is not at all load dependant, purly RPM. But FWIW MapSTG is 00hg and RPM stage is 3000, it pulls through that with no trouble at all.

Daniel
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Old May 11, 2003 | 02:54 PM
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Do you have a laptop?

What does your datalog show when the car stumbles? Look at injector ms value.
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Old May 11, 2003 | 03:11 PM
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Smooth, datalog shows nothing.


Daniel
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Old May 11, 2003 | 03:43 PM
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Do you have anything reading A/F ratios? I doubt it is grounding, since you have a new harness and everything goes back to the Microtech. Too rich? Too lean? Your secondaries are coming on at 3000 as long as you hit the other triggers.
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Old May 15, 2003 | 07:14 AM
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I'm experiencing the EXACT same thing. For me it's constantly between 33-3500rpm...WOT thru it seems OK some of the time, but if I cruise around 3-4K I get a "burp".

I'm going to check these settings to make sure mines the same.
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Old May 15, 2003 | 07:22 AM
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Okay, some cars have that hiccup, and some don't. It's caused by t*inj. The apparent solution is to move all of your t*inj values to 180 all the way down to idle. That should take care of it!

Brandon
BR7 Racing
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Old May 15, 2003 | 07:31 AM
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Originally posted by No7Yet
Okay, some cars have that hiccup, and some don't. It's caused by t*inj. The apparent solution is to move all of your t*inj values to 180 all the way down to idle. That should take care of it!

Brandon
BR7 Racing
What exactly does that effect (i'm away from my manual at the moment )?
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Old May 15, 2003 | 07:37 AM
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It changes the crank angle at which the injectors fire. Dunno why this causes a hiccup, but it does. I personally suspect it's a firmware problem that'll need to be ironed out... till then, just band-aid it.

Brandon
BR7 Racing
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Old May 15, 2003 | 09:58 AM
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I would also like to poll, are thos with the hiccup using non stock and non nippon denso injectors?

Daniel
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Old May 15, 2003 | 10:30 AM
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Stock injectors here.
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Old May 15, 2003 | 02:25 PM
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For a better explination of what the funtion does you need some basic fuel injection theory.

The function basically sets the time the injector can fire in relation to the position of the crank on its 360deg rotation. IE 500 - 3000 is set to 150deg on the base map with 3500 - 4000 being 180deg. The reason this needs to change as you go up in RPM is that the motor is turning faster. I don't think this is as big of a deal on a rotary as it is on a piston engine. On a piston engine if you let the injector fire to early you could end up with fuel sitting on top of a closed intake valve, or if it fired to late you could have the valve closing before the injector was done spraying.

What causes the stumble, beats me, but according to Jon setting them to 180 across should fix it. At that point my Microtech will be issue free and I can get down to some load tuning.

Daniel
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