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Item Posts    Sort Order

Hesitation, Stumbling

 
5lites
New User
Posts: 6
Joined: 07/05
Posted: 07/23/05 12:43 PM

I'll just be cruising and all of a sudden it'll start hesitating and stumbling. It has a 347 stroker. fuel pump is a 255lph. fuel pressure set at 38psi, 76mm m.a.f. calibrated to 30lb inj. distubutor and coil are new and egr valve +sensor + tps sensor + IAC are also new. edelbrock performer rpm intake, canfield heads, 70mm T.B. msd digital 6 plus ignition. and it smells like it runs rich, but plugs are clean. are my injectors to big? is my fuel pump to big? I'm clueless. Need Your Help.       Thanks   

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hotwheels
New User
Posts: 26
Joined: 10/04
Posted: 07/25/05 08:13 PM

are you showing any codes at all from the ecu?


 


 


 


 


hotwheels of www.insanemustangs.com

I own 3 mustangs, 1) 1992 mustang gt twinturbo'd 2) 1988 mustang gt bottle fed  3) 2004 mustang mach 1 resting in my garage


here is a link to my web site: www.insanemustangs.com

 

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5lites
New User
Posts: 6
Joined: 07/05
Posted: 07/25/05 11:28 PM

Yes, the only code is for the charcoal canister. and  that's not hooked up anymore, plus I have all the smog stuff unhooked. my timing is set at 14 degrees and the distrubutor is stock.  

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hotwheels
New User
Posts: 26
Joined: 10/04
Posted: 07/26/05 08:32 PM

i would first say that your injector's are probably to large for your application, are you going to run boost on the car?

I own 3 mustangs, 1) 1992 mustang gt twinturbo'd 2) 1988 mustang gt bottle fed  3) 2004 mustang mach 1 resting in my garage


here is a link to my web site: www.insanemustangs.com

 

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5lites
New User
Posts: 6
Joined: 07/05
Posted: 07/27/05 11:06 AM

No, not going to run boost. but I've seen other 347s with 30lb. injectors, 255lph fuel pump. what if I added a bigger mass air and throttle body?

 

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hotwheels
New User
Posts: 26
Joined: 10/04
Posted: 08/08/05 06:29 AM

the larger mass air, calibrated to 30lb injector's will help some.......
K, if my car was hesitating and stumbling, this is exactly what i would do first: get a .010 feeler gauge, and under the throttle body where the linkage is, you will see a little adjustment nut, back that out till the feeler gauge feels somewhat snug between the screw the the throttle linkage.......with that done, you will need a volt meter and 2 needles.....take your first needle and stick it in the green wire on your tps (located on top of the throttle body), take the second needle and stick it in the black wire. Now, turn the key on, but engine off. Take your volt meter and check your tps voltage, should read .096. If it is lower or higher, loosen the two phillip head screw's on the top of the tps and move the tps to get the voltage to read .096. Once you get that number, shut the key off, and recheck your throttle plate linkage on the bottom and make sure it is still snug at .010..........if it is, start the car and take it for a drive. If it wasn't and you have to adjust it, go ahead and adjust it, but you will need to recheck the tps voltage again..........may take a couple of try's, but it will help alot on your hesitation and stumbling..........

hotwheels of www.insanemustangs.com

I own 3 mustangs, 1) 1992 mustang gt twinturbo'd 2) 1988 mustang gt bottle fed  3) 2004 mustang mach 1 resting in my garage


here is a link to my web site: www.insanemustangs.com

 

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min301
New User
Posts: 23
Joined: 08/05
Posted: 08/11/05 06:19 PM

Have you checked the fuel pressure regulator? If the diaphram leaks or doesn't back off the pressure at low throttle it will run overrich, which loads up the plugs.  
Just here to help,  
 Professional Automotive Technician, Engine Builder, and Ford guru.
Bill Voorhees

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5lites
New User
Posts: 6
Joined: 07/05
Posted: 08/11/05 11:08 PM

Yes, and the regulator is not even 5 moths old.  

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min301
New User
Posts: 23
Joined: 08/05
Posted: 08/12/05 04:50 AM

Have you checked the basics, tps, yada yada yada?  
Just here to help,  
 Professional Automotive Technician, Engine Builder, and Ford guru.
Bill Voorhees

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5lites
New User
Posts: 6
Joined: 07/05
Posted: 08/19/05 11:42 PM

yeah, tps is set at 0.96 volts.  

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