# 16v Turbo Megasquirt jumping idle issues after warmup



## VWeezly (Jul 5, 2005)

Howdy yall. I am hitting a wall with my MS tuning. 


















Motor:

1.8 16v turbo
Euro ABA intake cam
Adjustable AEM fpr (set to idle at 55psi)
Short Runner intake 
70mm mustang TB

Bosch 909 Fuel Pump... Specs:
Bosch Part Number: 0580254909
Minimum Current: 12 Volts / 13 Amp
Operating Pressure: 72.5 PSI (5 Bar)
Minimum Flow @ Outlet: 39 GPH (148 LPH)
Fuel Pump Location: In-Line 

Double stack head gasket
Stock dizzy
1.8t front mount with 2.5 tubing.
2.5" turbo back exhaust
LC1 wideband
MS1 v2.2 (fuel and spark)

It starts and runs great. As it warmed up it started to go lean and just cut out. So I let it cool all the way down and tried to tune the Warmup Enrichment. I increased the warmup enrichment as it warmed up. At 130 degrees it was at 112%... then at 160 degrees it has to be at 100%. The afr was then very erratic. Mostly lean. So then I tweaked the fuel.... it ended up being pretty rich and still erratic. I then decreased the afterstart enrichment. Maybe I should have jacked it up. But I was under the impression that once the car is warmed up to 160 degrees, the afterstart enrichment should be at 0. I have been able to drive the car decently until it warms up. Then the fuel is erratic. Here are some maps... help?


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## ValveCoverGasket (Mar 20, 2002)

first things first i guess... hows the idle when its warmed up and off the warmup map? if you havent already id get that dialed in where you want it, id start there.

you mentioned it starts and runs great, but i assumed based on the next sentence that it never idles that well?

anyway... let us know :beer:


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## need_a_VR6 (May 19, 1999)

What inj size and whats your idle pulsewidth start to look like when the problem occurs? Anything under 1ms is going to get pretty erratic on 'std' injectors.


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## ValveCoverGasket (Mar 20, 2002)

and speaking of fuel delivery... depending on how much boost youre running, you might consider lowering your 55psi base pressure, in an attempt to keep the final "full boost" fuel pressure under ~80-75psi


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## VWeezly (Jul 5, 2005)

ValveCoverGasket said:


> first things first i guess... hows the idle when its warmed up and off the warmup map? if you havent already id get that dialed in where you want it, id start there.
> 
> you mentioned it starts and runs great, but i assumed based on the next sentence that it never idles that well?
> 
> anyway... let us know :beer:


Once it is warmed up it idles like crap and/or cuts out.

When I first start the car when it is cold it actually idles solid and does not really hunt. And it is solid at 14 or 15 afr... i think. Is it off the warmup map after 160 degrees? 



need_a_VR6 said:


> What inj size and whats your idle pulsewidth start to look like when the problem occurs? Anything under 1ms is going to get pretty erratic on 'std' injectors.


I am running 42lb injectors. Where would the idle PW be located?

I can lower the idle fuel pressure. What should it sit at? 50psi? 45?


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## ValveCoverGasket (Mar 20, 2002)

you can just monitor the pulsewidth in the main tuning screen...

42#s shouldnt really be a problem, but lower that fuel pressure down to 45 or so - that would leave you about 30psi of margin for your full boost pressure (if you end up running 30psi)

that may also help the idle potentially.

also, are you running alternating or simultaneous injections?

and yeah it should be off the warmup map after 160.

but what youre describing sure sounds a lot like its trying to control to too low of a PW once its warmed up and idling. i bet if you richened up the mix at warm idle, itd be fine... but lowering the fuel pressure should help a little also.


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## VWeezly (Jul 5, 2005)

here are my EGO settings:


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## ValveCoverGasket (Mar 20, 2002)

id also turn off any closed loop AFR control youve got, until you can get the warmed up idle dialed in (or pretty close) without it

at least thats the tuning theory i follow... dont use your closed loop control to overcome short comings of your tune, get your tune close or dialed then turn that stuff on to help problems during some of the unforseen conditions you didnt tune under


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## VWeezly (Jul 5, 2005)

ValveCoverGasket said:


> you can just monitor the pulsewidth in the main tuning screen...
> 
> 42#s shouldnt really be a problem, but lower that fuel pressure down to 45 or so - that would leave you about 30psi of margin for your full boost pressure (if you end up running 30psi)
> 
> ...


My Engine Constants are set up just like yours. The injectors are set to simultaneous. I have a setup very close to yours.


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## VWeezly (Jul 5, 2005)

ValveCoverGasket said:


> id also turn off any closed loop AFR control youve got, until you can get the warmed up idle dialed in (or pretty close) without it
> 
> at least thats the tuning theory i follow... dont use your closed loop control to overcome short comings of your tune, get your tune close or dialed then turn that stuff on to help problems during some of the unforseen conditions you didnt tune under


Are you referring the "Idle Control" tab? If so it is on "B&G On-Off". All the loops are grayed out.


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## need_a_VR6 (May 19, 1999)

I'd switch to alternating instead of simultaneous with those injectors, it'll double your real PW and potentially get you out of a 'too low' zone.

Some of the 'leaning out' can just be too rich misfires as well. I'd try and lean out idle fuel (10-20%) and see what happens.


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## Prof315 (Jan 5, 2009)

With 42# injectors your VE numbers look HUGE! The 1.8T we run with 36# injectors has a similar required fuel and runs at idle with VE numbers in the high teens to low 20s. Also you've got an awful lot of timing at idle which will definately contribute to a unstable idle.


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## VWeezly (Jul 5, 2005)

Alrighty... So I went home over my lunch break to do a little idle tuning. The biggest problem was definitely the fpr adjustment. I turned it down to 45psi. It's 40 degrees out. I've never had an issue with idling. It's always been after it warms up. I decided to try one of ValveCoverGaskets old msq's... I think he emailed it to me a while back. I had used it as a base for my original tune. I calibrated the TPS for my TB and changed the flood clear to my number. I started it and let it warm up to 170 degrees. The idle is pretty steady at 1000 rpm. Though it seems a bit rich. It hunts a little but I didn't really tune it so it is a great starting point. I need to go through my warmup wizard again to tune it as it warms up. But the great thing is that it was running solid off the fuel table at temp. Driving around tuning should be alot easier now that the idle is better. More to come.

This was the fuel map it was running on:


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## need_a_VR6 (May 19, 1999)

The idle region is ~half what yours was... running lean you say?


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## VWeezly (Jul 5, 2005)

Yeah i know. Haha. It was alll about the fuel pressure. It threw off all my other settings. I changed my fpr from my old setup and never really adjusted the new fpr correctly. I know I can tune it now. Wish I had the registered TunerStudio so it could adjust on the fly. I don't think it'll take me to long to get goin fast.


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## ValveCoverGasket (Mar 20, 2002)

excellent :thumbup:
sounds like youre on the right track now

and yeah, youve got big injectors, no reason to crank that base pressure, im sure 45psi will be good


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## VWeezly (Jul 5, 2005)

thanks a bunch yall. And thanks a lot for the old msq file from your setup VCG.


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## ValveCoverGasket (Mar 20, 2002)

thats what were all here for :thumbup:


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