Tuning woes

[stilov]

Guys...Tom has been tuning my car and we thought we had it...the drives perfectly but runs lean on the dyno so I haven't been able to make a full pull yet.

It runs @ 13.5:1 (richest) on the dyno. Tom is gone now for a month and I need this thing done so I can sell it. He sent me a tune and it was supposed to be richer...I put it on the dyno again today...and the a/f was the same. I tried richening it 14% with my xcal...same...still lean.
Tom knows what he is doing...I just want to make sure there isn't anything more I can do.

It has delphi 42's, 80 mm Lightning MAF, and a Walbro 255lph high pressure pump made for a mustang. Several months ago before putting in my new turbo...it always ran rich, but not very well. I am at a standstill, and I am prepared to just sell it as is w/o ever gettings #'s after I have spent the last 2 yrs building it!!!!

Anyone have any suggestions?

[striker2]

Whats your fuel pressure at? you could get an adjustable FPR and up the pressure at the rail.

[stilov]

I was under the impression there was no adjustable fule pressure reg for the duratec


What should my fuel pressue be at?

[Barge]

Do some datalogging and see if your injector duty cycle is going up as you increase fuel through the xcal. If the injectors are opening more and fueling the same you've got a fuel issue.

You can also check your fuel pressure... although i'm not sure what it should be... there should be some info on that in the archives.

[Keyser]

Taylor, IIRC on a return style 98 your fuel pressure should be about 45 at idle and up over 50 at WOT. There is a shrader(sp?) valve on the fuel rail that you can tap with a gauge if you have the right fitting.

[stilov]

Well I actually have a pending sale on the car, but...

My injectors are big enough right?...RIGHT (42's)... My pump is a 255lph high pressure pump...that should be big enough assuming it's working correctly.

Rails have never been a problem right?

I don't think it's the tune...I mean Tom's awesome at it...and I doubt he wouldn't be able to add fuel.

SO what do you think? COuld it be the FPR? the pump? How could you even tell if the pump is working, but just not at it's capacity???

[beyondloadedSE]

I agree, check the fuel pressure from the schraeder valve.

[Reebs]

Yes 42lb injectors are plenty big enough. A 255lph fuel pump is plenty overkill as well. Just for kicks though, check your fuel pressure as some have stated. Mine is around 47psi at idle, 55 under load, and it even creeps up to 65psi under boost (which Tom accounts for in his tunes).

I had issues with my car running pig rich, then I would mess around with things and it would go so lean I couldn't even drive it out of the driveway. It ended up being my faulty 80mm Lightning MAF. Datalogs didn't show it was faulty either, but I swapped the MAF after weeks of pain and troubleshooting and now she is perfect! Unplug the MAF to put the car in closed loop and if it runs richer by using the tables and ignoring the sensor inputs (o2's, ait, maf). Your MAF may not be the suspect, but I wouldn't overlook it.

My 2 cents.

[stilov]

I was going to do it today, but I can't find my adapter for my fuel pressure guage.

PS It will be with it's new owner Thursday.

I didn't think I was going to miss it that much, but I am gathering together all of my extra parts, and dyno runs etc...it's a little emotional.

This is by far the longest car I have ever kept, the most money I have dumped into, the most time spent, the most swear words, the most fun, and the most learned.

The new owner will have to get the #'s for this beast.

[Reebs]

PS It will be with it's new owner Thursday.

Make sure to direct the new owner to CEG!