This is topic motor running lean! cant fix with fuel pressure.... in forum Tech Talk at Northern California Ford Owners  .


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Posted by SVT Fox (Member # 1837) on :
 
Im no expert on mild tuning at all so forgive me if I sound like an idiot. I have an electric air/fuel guage hooked up to the single purple wire from the ECU. A very credible buddy did it this way, so I trust it was the right way. With my fuel pressure was at about 29 PSI, and the air/fuel guage never went in the rich area at all and would go off the guage deep in the red (lean) when coasting or idling. I bumped the fuel press up to 39 PSI and it no longer goes deep off the guage lean, but I still can not get it into deep green at wide open.

I have pro M shorty 80mm with 24# injectors, 70mm accufab race TB, timing I beleve is at 17 advance, (but i think my balencer may have slipped)
 
Posted by Jeff S (Member # 371) on :
 
The A/F gauge you have is complete crap and should NOT be used for any type of tuning. If you want to check your A/F using a gauge you will need a wideband 02 sensor and kit like the DynoJet Wideband Commander or Innovate LM-1.

You said at first your fuel pressure was at 29psi. Was that with the car idling and with the vacumn line attached to the regulator? You should have your fuel pressure set to 40psi with the vacumn line disconnected from the regulator and make sure to reattach the vacumn line after setting it. At idle/cruising your fuel pressure will be lower than 40psi but at WOT and should go to 40psi and stay there without dropping.

[ July 06, 2005, 14:38: Message edited by: Jeff S ]
 
Posted by CDT (Member # 5004) on :
 
ditto on what Jeff S said..
 
Posted by SVT Fox (Member # 1837) on :
 
thanks guys Ill do that in the morning, i wont even bother with the guage any more..
 
Posted by two-gun kid (Member # 5325) on :
 
would that mean the aem wideband a/f gauge isnt worth getting?
 
Posted by CDT (Member # 5004) on :
 
no, a wideband is what you want.
 
Posted by two-gun kid (Member # 5325) on :
 
so narrowband=bad, wide band=good
 
Posted by CDT (Member # 5004) on :
 
you got it
 
Posted by jordan0806 (Member # 5528) on :
 
also with 17 degrees of timing...you'll tend to get a lean condition as well....try the way CDT has told you but you might have to back timing off a slight tad to get it running a little richer....maybe around 15 degrees
 




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