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Fuel pressure numbers are in! Bad or good?

  • Thread starter Thread starter mo_dingo
  • Start date Start date May 30, 2004
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final5-0

Mustang Master
Apr 6, 2003
6,817
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79
DFW Texas
May 31, 2004
#21
  • May 31, 2004
  • #21
Zero Signal said:
I'd be willing to put money on the MAF. My car pinged badly for the longest time, I replaced every sensor (but the MAF) and all the fuel components and it still pinged. When I finally got a tweecer and did soem datalogging, the MAF wasn't reading enough air. To the point where the adaptive wasn't able to completely make up for it and the load wasn't reading very high. I richened the entire MAF curve by about 13% and the car ran perfectly and still does to this day. Even with 87 Octane, 5° more timing in the top end at 95+ degreee weather, it won't ping. The datalogs show the KAMRF values all ranging from just below to just barely above 1.000 and the LAMBSE hovers right around 14.7.
Click to expand...

Exatcly what I was trying to say about the maf!!!

You tweeced the maf transfer which made the a/f richer and the ping went away but used the same stock maf.

The maf in my sig is the stocker but the transfer I was using for it was far from stock.

It ain't the maf itself, its the lean values that Ford put in the cal file.


BTW, Scott your FP looks fine, that's what mine always reads. There are benefits to upping the fuel pressure. Although the EEC will tune it out, I always figure it's better to make the computer have to lean it out than richen it just to be on the safe side. If you force open loop all the time, the adaptive won't work and upping the FP will have a direct permantent effect on the AFR since the pulswidth is predtermined and not adjusted from there.
Click to expand...

A different viewpoint on fuel pressure.

All values in the pcm's cal file are based on factory fuel pressure setting.

You can just blow the whole fuel pressure thing off. Sell the afpr and use the $$$ for another go fast part. I've never had an afpr myself.

As for forcing open loop all of the time ***
I have not done it but some have said that it was the only way they could get a good idle for long periods of time due to the o2's in their lt's going cold.

Later
Grady
 

Zero Signal

Active Member
Feb 24, 2003
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Jun 1, 2004
#22
  • Jun 1, 2004
  • #22
Also, if I get the new MAF and it still reads too little air, is there anything I can do to "trick" it? Will the 22k ohm resistor in place of the ACT sensor do the trick?
Click to expand...

You know what I tried for awhile was running the stock MAF without that plate backing the sampling tube. The would allow more air through the tube thus more fuel. It worked great, but I think it ran too rich that way. I figured you could probably keep the plate but drill a small hole in it in-line with the sampling tube and keep enlarging the hole untill you feel you're getting enough fuel. Worse case scenario, you have to glue something over the hole.
 

Slow5.0

Active Member
Feb 13, 2003
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Portland, OR
Jun 1, 2004
#23
  • Jun 1, 2004
  • #23
Off topic or meybe not
Can stock MASS air meter from 01 Bullitt or 99+ GT fit in my 94 Stang , mine friend have one for cheap or meybe for free (he got Pro-M 95mm) so he gonna give to my in next a few days ??????
 

mo_dingo

20+ Year Stangneter
Aug 26, 2003
3,031
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Jun 2, 2004
#24
  • Jun 2, 2004
  • #24
The 96+ mustangs are OBDII, so I highly doubt the MAF will work from a 99+ mustang.

You know what I tried for awhile was running the stock MAF without that plate backing the sampling tube. The would allow more air through the tube thus more fuel.
Click to expand...

Hmmm......That is a great idea. I think I will try it. And it's free!!! Gotta love it.

I think I will remove the plate entirely first; to see what happens. If it doesn't detonate on 87 octane any more, then I will be one happy camper. It's hot enough lately to REALLY tell me if it's going to detonate.

Thanks John!
Scott
 
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