Maf mystery question.

Keith5.0GT · Nov 17, 2018

So, long story short.
I had a long term cold start issue. Eventually I solved it by changing the maf. I did go through the troubleshooting list from jrichker too. (Sorry if I misspelled his name.) With the new maf, it ran and started so smoothly, so much better. But over time,(several months) the cold start stumble came back. Cleaning maf doesnt help. So do you think it’s doing this because I have a stock maf in a cold air intake? Anyone ever go through this? And Incase it helps, my mods are cai, larger throttle body, upper/lower intake, headers, exhaust. Stock heads. In my quest to have a great running turd, I’ve replaced almost everything. So most things are new. Sensors, hoses, gaskets, everything. Thanks a lot for any insight.

90sickfox · Nov 17, 2018

So...I take it that you replaced the intake air temp. sensor...

Keith5.0GT · Nov 17, 2018

90sickfox said:
So...I take it that you replaced the intake air temp. sensor...

Had to think.....that is probably the only one one I didn’t replace. Pretty sure I checked voltage on it back then. It was last year when I was really going through everything. Probably worth looking at again though.

95BlueStallion · Nov 17, 2018

In my experience, when replacing sensors try to always find the Motorcraft versions. Parts store sensors go bad fast.

Keith5.0GT · Nov 18, 2018

95BlueStallion said:
In my experience, when replacing sensors try to always find the Motorcraft versions. Parts store sensors go bad fast.

Yeah I agree. I do that when possible now.
I read through some old posts on here and decided I’m gonna just get a maf sensor calibrated for a cold air intake. And then I’ll go from there. I’ll update Incase anyone comes across this when they are googling the heck outta stuff like I do. But we will see how this works.

General karthief · Nov 18, 2018

You didn't mention if you checked for codes.

Keith5.0GT · Nov 18, 2018

General karthief said:
You didn't mention if you checked for codes.

Yeah I thought that might come up. Codes for koer are 33 44 94 and I assumed that was because of my smog system being halfway removed/inoperative. So I didn’t mention it.

General karthief · Nov 18, 2018

So you got the 11 (system pass) koeo, check your iat and the coolent temp sensor. I would like to some pics of the engine compartment.

Keith5.0GT · Nov 18, 2018

General karthief said:
So you got the 11 (system pass) koeo, check your iat and the coolent temp sensor. I would like to some pics of the engine compartment.

Alrighty. What area of the engine compartment would you like to see? I have replaced the coolant temp sensor a few thousand miles ago when I was going through it. I can check it now though. I recall checking for voltage based on the coolant temperature if I remember correctly.

General karthief · Nov 18, 2018

Area around the maf, just a couple of the engine compartment to see if anything jumps out, I should be able to zoom in on anything curious.

Blown88GT · Nov 18, 2018

It's the aftermarket CAI, the factory air box was a CAI. ATS rarely goes bad, it's just a thermistor, a type of resistor that changes value with temperature.

Keith5.0GT · Nov 24, 2018

Blown88GT said:
It's the aftermarket CAI, the factory air box was a CAI. ATS rarely goes bad, it's just a thermistor, a type of resistor that changes value with temperature.

Well I have now replaced the maf with a pro m unit calibrated for my car, and replaced the air charge temp sensor for the heck of it. Still stumbled on cold start. Always fine the rest of the time. I know the right thing to do is re-check every sensor and hose on the car....maybe someday. I’ve always wondered if a dyno tune session would get everything in perfect working order. It has stock heads and cam but everything else is aftermarket pretty much. Maybe it’s just an old turd? I don’t know.

OneSick99GT · Nov 24, 2018

Keith,
Have you tested the TPS to make sure its getting proper voltage. If its a little hesitant at start you can bump up the voltage a bit on the TPS. Check out the link below.

View: https://www.youtube.com/watch?v=wQXnMku7UHE

OneSick99GT · Nov 24, 2018

And BTW the ford performance 90 MAF Sensor is trash for mustangs. I was told this by a mustang tune shop that races mustangs. The SCT Tuner X4 and SCT MAf sensor is the way to go I was told. I was having some issues until I changed out my MAF to a different one.

Keith5.0GT · Nov 24, 2018

Onesick99GT said:
And BTW the ford performance 90 MAF Sensor is trash for mustangs. I was told this by a mustang tune shop that races mustangs. The SCT Tuner X4 and SCT MAf sensor is the way to go I was told. I was having some issues until I changed out my MAF to a different one.

Yeah I’ve checked tps several times. I think I set it around .90 last time. Next year I want to get it dyno tuned to see if air/fuel/timing everything is good and see if they can work out the bugs for me.

OneSick99GT · Nov 24, 2018

Keith5.0GT said:
Yeah I’ve checked tps several times. I think I set it around .90 last time. Next year I want to get it dyno tuned to see if air/fuel/timing everything is good and see if they can work out the bugs for me.

Have it dyno tuned! If you got cams this is a must. You will need a tuner too. They should be able to fix your idle issue with the tune once its calibrated.

2000xp8 · Nov 24, 2018

You absolutely do NOT need it tuned.
It would be like throwing $500 to $1000 in the dumpster.
The stock computer can put up with quite a bit.

And tuning is NOT a substitute for proper repairs.

Tuning a 225rwhp stock headed foxbody is a joke.

OneSick99GT · Nov 24, 2018

Doesn't sound stock to me. I've been told anytime you do a cam swap or upgrade to have it tuned. American muscle and comp cams technical support both told me this. However if it's stock or has slight mods then tuning shouldn't be required.

2000xp8 · Nov 25, 2018

Onesick99GT said:
Doesn't sound stock to me. I've been told anytime you do a cam swap or upgrade to have it tuned. American muscle and comp cams technical support both told me this. However if it's stock or has slight mods then tuning shouldn't be required.

That information is completely false.
Consider this, modding fuel injected 5.0's has been going on since pretty much the existence of the 86 4 eye.
Dyno's didn't go mainstream until around 1996.
I've run cams from mild to wild, no tune ever. (Some of which were customs from comp cams)
I've also seen car run well upwards of 600rwhp no tune (650rwhp I've seen, but I've heard of guys going to around 750rwhp).
If a car doesn't idle is not the cam or the computer's fault, there is a problem.

Tuning is a choice and on a NA mustang in most cases it accomplishes nothing more than an empty wallet.

Blown88GT · Nov 25, 2018

Onesick99GT said:
Doesn't sound stock to me. I've been told anytime you do a cam swap or upgrade to have it tuned. American muscle and comp cams technical support both told me this. However if it's stock or has slight mods then tuning shouldn't be required.

In the Fox body era, a tune was something you listed to on the radio. AM techs know little or nothing except how to sell you stuff you don't need. The experts are here, on this forum, listen to them.

Maf mystery question.

Keith5.0GT

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90sickfox

Wasn't a pretty sight...and I've got big hands

Keith5.0GT

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95BlueStallion

My assy trans to myself

Keith5.0GT

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General karthief

wonder how much it would cost to ship you a pair

Keith5.0GT

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General karthief

wonder how much it would cost to ship you a pair

Keith5.0GT

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General karthief

wonder how much it would cost to ship you a pair

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OneSick99GT

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2000xp8

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