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Discussion Starter #1
I have a 1995 mustang GT I'm am getting a few codes like mass air flow, air intake tempature sensor, I have the correct firing order,new spark plugs gaped at .052 and wires, fuel pressures good 40psi , I set timing to 10btdc and it bairly wants to stay running along with pooping/backfiring out of both intake and exhaust. When you do rev it up it almost has a stutter when reving, I've tried advancing timing to 14btdc and same thing. I know there's a little screw on throttle body to turn and adjust the idle rpm, as soon as I go below 1000rpm the motor shakes the whole car. I was told when I bought it that it does have a cam, I don't know what but don't think a cam would make it shake like that. Could a mass air flow cause that much trouble? And I replaced the air intake temp sensor I may need to reset codes to see if it fixed it.Any help would be appreciated, thanks
 

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that is not an idle set screw

do you think you should address the codes, or just call it good and just advance the timing?

since you have not mentioned what this engine is made of, is it safe to assume it is totally stock?

ie the maf, intake, throttle body, maf, injectors, cam??
 

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Discussion Starter #3
Unsure of motor parts I know it's a 95 5.0 HO other than that I don't know,was told it had a cam but you know how that goes. I have replaced the intake air sensor. I'm going to clear codes and check to see if it fixed it next day I'm off

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sounds like misfiring, multiple cylinders

would recom cylinder rpm drop test, but it wont idle

verify spark firing order and that distrib is in correct position, if it is stock #1 will be labelled on cap

Also it would be wise to ID all parts, or buy known parts
 

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Discussion Starter #6
Can you explain what the little screw is on the left side of the throttle body is that I thought controlled the idle cause it screws down and pushes on the throttle I just assumed that was what it does

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the idle is controlled by the ecm

it uses spark

that screw is set to allow a known precise amount of air by the closed throttle blade

that known value is in the ECM

if you play with it, do you think you can place it back in the correct position?
 

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That screw is called the throttle stop.
It’s purpose is to stop the throttle blade when you let off the accelerator.
It’s not for adjusting the idle.*

To me, it sounds like you have the timing incorrect. But you also have a MAF code, so start there.

Is this a new issue after you did some work? Or was it like this when you acquired the car?
 

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Discussion Starter #9
i can try to get that screw back in the right position, Yea im going to test the MAF wensday when im off, and replace if i need too, Been like this ever since i got it. Wife loves Mustangs she seen it and feel in love with the look of it and here i am trying to get it running for her, lol
 

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If the cam was changed, then it is possible that the lifters were incorrectly adjusted or that the cam was not degreed properly.

Has the car run properly while you have owned it?
 

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Discussion Starter #14
No my wife bought it for the looks. If I unplug the MAF while running should the motor cut off or do anything to indicate a bad MAF.

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No my wife bought it for the looks. If I unplug the MAF while running should the motor cut off or do anything to indicate a bad MAF.

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if it is in limp mode, as you say you have a maf code, why would you do an unplug it test?
 

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Discussion Starter #16
I was just asking I was looking at some ways to test the MAF online and some one had a video saying if you unplug the MAF while running it would cause the car to shut off. I was just asking if that was right or what was a way of testing if MAF was bad or is it pretty much if Code says the MAF is bad then its bad?
 

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you check the signal voltage at the ecm

should be just under 1volt during warm idle

then you snap the throttle and make sure voltage rises accordingly

and a snap to WOT should be near 4 volts

you test at the ecm, to verify circuit integrity from the maf to the ecm

NOTE, very important

>>>>>Codes do NOT mean a part is bad, never.<<<<<
 

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Discussion Starter #19
ok so i got it to running at 14deg btdc and i had to fiddle with the throttle stop screw and the IAC to get it running but it seems to run ok and idle at about 750-800rpm i know i have a MAF Code and Intake Air temp sensor code, I did change the Intake Air temp sensor so im hoping that solved that im fixing to check the MAF. Ill try to upload a video of it running later maybe yall can hear/see something i dont,which im sure you will,lol. Its not pretty not does she run pretty but its got good compression and i want to get her back to looking and running like it should.
 

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Discussion Starter #20
Got a Video. Sorry about the last bit was trying to get Camera to see timing mark but didn't work its at 14deg btdc anyways also a few pic of the Vacuum coming off the intake manifold
 

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