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 Post subject: running too lean
PostPosted: Sun Sep 20, 2015 10:36 am 
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CSM Junkie

Joined: Wed Jan 30, 2008 7:55 pm
Posts: 447
Location: Saskatoon, Saskatchewan
so my 1980 colt has always had an issue with cold starts i havent been able to figure out. i have done great investigations into the coolant temp sensor
checked the wiring contenuity etc

just installed a wideband and a maf translator and the car ran much better initially although it still a little too lean.
yesterday i enriched the idle and got it down to 16.5 ish and its never idled smoother.
today it still hard to start but much better
then i took it for a drive and its way lean, like 12 to 1 wot. should be around 9.5, cause the wot knob is zeroed out
now the idle is super lean again and enriching it just causes it to run rough. it idles best at zero setting, and is lean off the guage, which isnt of high concern because stock idle is like that too. but i had 16.5 in my other colt always

there are so many weird little problems here i dont even know where to start.
i will install my fuel psi guage

this maf translator/wideband/maf combo was in my other colt and worked fine. ran good at base setting, leaned out about 3 clicks wot to get 10.5 to 1

i guess ill just swap parts around till o figure out the problem, cant see what other course pf action to take


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 Post subject: Re: running too lean
PostPosted: Sun Sep 20, 2015 8:12 pm 
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CSM Junkie

Joined: Wed Jan 30, 2008 7:55 pm
Posts: 447
Location: Saskatoon, Saskatchewan
i checked just to make sure and it runs 13.5-1 at wot with the stock maf!!

i have swapped
injectors/fuel rail/fpr
ecu
injector resistor

i installed an n/a fpr and it brought the fuel ratio close to where it should be
this is messed up!
n/a fpr should make it 20-30 percent rich!
so what could possibly cause it to be so lean in the first place?

like the only sensible thing is that wideband must be pooched...


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 Post subject: Re: running too lean
PostPosted: Sun Sep 20, 2015 9:52 pm 
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The Silent Administrator
User avatar

Joined: Wed Dec 24, 2003 3:32 pm
Posts: 9524
Location: Ottawa, ON, Canada
You have to use a turbo FPR. It gives you a rising rate of 1 psi fuel pressure for every lbs of boost over atmospheric.

If you are using an N/A FPR, you will not get the rising rate.

Something does not add up here.

What are the numbers on your FPR?

What fuel pump are you using?

What size wiring is going to your fuel pump?

Do you have a stock Mitsubishi alternator?

What voltage is it putting out from 4000 RPM on up to redline where you shift?

Also, what wideband and sensor are you using?


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 Post subject: Re: running too lean
PostPosted: Sun Sep 20, 2015 10:33 pm 
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CSM Junkie

Joined: Wed Jan 30, 2008 7:55 pm
Posts: 447
Location: Saskatoon, Saskatchewan
no i know for a fact the n/a ones have the rising rate, i used this same one on my other colt. its a cheap and easy way to get more out of stock injectors. its 45 psi base instead of 37 and has same rising rate.
i have had an in cab fuel pressure guage on this car in the past, and it was fine.
alternator is 4g63, i onviously had to change the plug on the car, sure it must be wired properly, cause it works.
cool idea about checking the voltage, ill do that!
its an aem and i used it in my other colt with all the same fuel related components and it worked well. i used this same na fpr and i had the base setting on maft leaned out about 5 clicks to compensate.


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