Accel Enrichment / Stall issues (90-93 DIYPnP)
#1
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Hey there!
I got the MS running perfectly, the car is idling pretty fine, and the VE table needs some adjustment but otherwise they're good enough to perform some running tests...
Now I have a slight issue. I tee'd a pipe off the FPR and into the cabin for the MAP sensor, and even so I still don't get a proper throttle response. When I press the pedal, even if it's ever so slightly, the car stalls for a fraction of a second and then revs. I'm pretty positive this is the Accel Enrichment acting up, because the AFR on the wideband shows me a very very lean mixture the moment I press the gas pedal. MAPdot wasn't set, so I set it (previous owner had TPS and I missed this bit) and that didn't solve me problem either.
Here's the settings I'm using:
![](https://www.miataturbo.net/attachments/megasquirt-18/42338-accel-enrichment-stall-issues-90-93-diypnp-capture1.png?dateline=1335887083)
![](https://www.miataturbo.net/attachments/megasquirt-18/42339-accel-enrichment-stall-issues-90-93-diypnp-capture2.png?dateline=1335887083)
![](https://www.miataturbo.net/attachments/megasquirt-18/42340-accel-enrichment-stall-issues-90-93-diypnp-capture3.png?dateline=1335887083)
Remember this is a '91 Miata running a 90-93 DIYPNP, aspirated, with no TPS or AFM. All stock except cone filter and cat-back stainless exhaust. Also, using a sealed element sensor for IAT.
Can it be that the pipes for the MAP are too flexible or something?
I got the MS running perfectly, the car is idling pretty fine, and the VE table needs some adjustment but otherwise they're good enough to perform some running tests...
Now I have a slight issue. I tee'd a pipe off the FPR and into the cabin for the MAP sensor, and even so I still don't get a proper throttle response. When I press the pedal, even if it's ever so slightly, the car stalls for a fraction of a second and then revs. I'm pretty positive this is the Accel Enrichment acting up, because the AFR on the wideband shows me a very very lean mixture the moment I press the gas pedal. MAPdot wasn't set, so I set it (previous owner had TPS and I missed this bit) and that didn't solve me problem either.
Here's the settings I'm using:
![](https://www.miataturbo.net/attachments/megasquirt-18/42338-accel-enrichment-stall-issues-90-93-diypnp-capture1.png?dateline=1335887083)
![](https://www.miataturbo.net/attachments/megasquirt-18/42339-accel-enrichment-stall-issues-90-93-diypnp-capture2.png?dateline=1335887083)
![](https://www.miataturbo.net/attachments/megasquirt-18/42340-accel-enrichment-stall-issues-90-93-diypnp-capture3.png?dateline=1335887083)
Remember this is a '91 Miata running a 90-93 DIYPNP, aspirated, with no TPS or AFM. All stock except cone filter and cat-back stainless exhaust. Also, using a sealed element sensor for IAT.
Can it be that the pipes for the MAP are too flexible or something?
#10
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You choose whether you want to make the enrichment MAPdot or TPSdot based, and also if you want RPM based enrichment to go with either. AFR is of no importance as far as configuration goes, except you'll want to check whether you're too lean or too rich on acceleration.
For mine (no TPS) I chose MAPdot with no RPM accel enrichment, and used the values I provided above. It still gets a bit on the rich side when I press the pedal, but it's hardly noticeable while driving, and when the car is warm. When the car is cold, I stil get a bit of a lean spot when the car is cold (right after start).
You can see all of my settings above, they change a bit on the Accel Enrichment Wizard if you're using TunerStudio, but they're pretty straight forward. Even if they don't suit your car, they might be a good starting point
For mine (no TPS) I chose MAPdot with no RPM accel enrichment, and used the values I provided above. It still gets a bit on the rich side when I press the pedal, but it's hardly noticeable while driving, and when the car is warm. When the car is cold, I stil get a bit of a lean spot when the car is cold (right after start).
You can see all of my settings above, they change a bit on the Accel Enrichment Wizard if you're using TunerStudio, but they're pretty straight forward. Even if they don't suit your car, they might be a good starting point
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#11
Boost Czar
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Pretty much. you're adding in extra fuel based of a %/sec rate change in MAP or TPS.
the value you are entering is litterally how much extra pulse width to inject.
the rate value is a % change / sec.
ideally you'd tune it so when you hit the gas off idle, or between shifts, you have plenty of fuel for smooth engagement...otherwise you'll have lean spikes and youll feel the car hesistate.
you'll tune off a curve where heavier inputs may need more fuel, and just little blips not so much. make sure you outer extreme rate isn't so far off the scale that you'll never move the throttle fast enough to hit that area, it's a waste of resolution.
For mine (no TPS) I chose MAPdot with no RPM accel enrichment, and used the values I provided above. It still gets a bit on the rich side when I press the pedal, but it's hardly noticeable while driving, and when the car is warm. When the car is cold, I stil get a bit of a lean spot when the car is cold (right after start).
increase the cold accel multipler to maybe 110% if you need a little more enrichments in the cold.
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Mikel
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09-28-2015 04:46 PM