This is topic 91 5.0 lean codes/ and backfiring on decell/ low power in forum Tech Talk at Northern California Ford Owners  .


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Posted by dean-93 (Member # 9401) on :
 
working on a buddys 91 5.0 mustang when he got it it was a basket case.now it runs and idles good, tuned up, cleaned maf ,fixed all the vac/exhaust leaks.

the only problem is that its not full power and it backfires on decel. also it thru codes 41 and 91 so its running lean forsure

also it has good power till about 3500rpm then it kinda gets weak.dosent sound like its missing tho

were going to throw a fuel pressure gauge on it tomorrow.

just wondering if anyone has any ideas for us to check

thanks ,dean

[ 2014-04-20, 05:34 PM: Message edited by: dean-93 ]
 

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Posted by dean-93 (Member # 9401) on :
 
also we timed the car at 10 12 and 14

it liked 14 the best
 

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Posted by dean-93 (Member # 9401) on :
 
we found a orange wire that wasnt grounded that was o2 senseor ground,runs good now just still not full power
 

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Posted by nasty93 (Member # 8935) on :
 
One of my of motors started doin that when the rings started going..
 

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Posted by Tom Renzo (Member # 13165) on :
 
Check the leak down and compression. Then post back.

[ 2014-04-24, 04:58 AM: Message edited by: Tom Renzo ]
 

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Posted by dean-93 (Member # 9401) on :
 
fixed it it was the fuel pressure only had 25 psi running,put a new 255lph walbro and all is good
 

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