I looked through the pages and did a little searching but couldn't find much for this problem.

I have a 94 FD, mild street port, down pipe resonated mid pipe and a nice 3" cat back. Ported exhaust manifold, ported stock twins running 14PSI, Hard intake pipes, K&N filter. Greddy Large Stock mount intercooler, elbow and hard pipe. Have recently upgraded the fuel system, High volume pump and FPR running 50 PSI (with Vacuum nipple disconnected) ID720 primary and ID1000 Secondary injectors

The issue; It seemed that while I was logging AFRs the care was running rich, and before you say "as it should" I already reduced the main grid by 24% and it was doing well, I was just logging and trying to adjust the AFRs. I log and then use Barry Bordes air fuel tuner and update the FUEL CORRECTION/INJ MAP. This worked great in the past. Anyway after a few runs (idle and cruise) and updating it seemed the AFR were staying rich, no change. I tested this and sure enough while I was making changes to the FUEL CORRECTION/INJ MAP and the using recal to update the main map, and yes I made sure the map changed, there was still no change in AFR. Went home and did some driveway no load rev logging and then made drastic changes in those cells, no change in AFR.

Any Ideas? I have disconnected the battery and held the break for a min and tried again, no change.

Any ideas would be appreciated.

 

What cells or area of the map specifically? If its the high vacuum/low rpm portion you may be at the lower limit of what the injectors can deliver. I have this issue with id725s but those cells are rarely used and the rest of the map including idle is so much improved vs the 850cc primaries I had.

 

Thanks for the response
That could be the issue while testing in the driveway. This is the 1200-4400 RPM cells and the 4th power row. It is running High 11-low 12 AFRs in that ro for those RPMs

However I noticed it when logging the idle and cruise. Not sure how to safely test this, I guess I could en-richen those cells and see if I get lower AFRs but I am at 12 now and I don't know how low the datalogit registers but the one in my car only goes down to 10 AFR.

 

Have you done a re-calc? What values are you requesting for fuel in those cells on the base map? I would load a previous map before you started pulling fuel out and try 38-40psi for base fuel pressure first and see if you can pull AFR's within target.

 

Yes I always Recalc once I test the AFR and I did recalc after the testing still no change, but that was the driveway test. So it could be the first issue you brought up.

I may try lowering the fuel pressure, if I can't get anything else to work. The ID injectors are supposed to give the best performance at higher fuel pressure. But this only addresses the low load situation, I believe the issue is across the board.

 

What are the values in the base fuel map of the cells you are having trouble with? If they are all very low numbers compared to the cells that are working well for you then the injectors may just not be able to deliver that low at 50psi of fuel pressure.

 

did you "write" the changes..

 

DriftDreamzSS, The 50 PSI is without the vacuum hooked up, at idle with the vacuum hooked up fuel pressure is 44PSI You may be correct in that the injectors (ID725) may not be able to go any lower at that PSI, If I continue to have issues I will lower it it stock at idle.

tom94RX-7, YES, but a valid question

I decided to do the Disconnect the battery and hold the brake, then I took the PFC out and inspected the connectors. Reinstalled it, loaded my original map where I had reduced fuel across the board by 24%, then went through the idle learn, that went fairly well. Then did a short drive out to a secluded road to warm up and then some logging. The map seems to be updating now. And I was only working in the idle and cruise area. It got hot out so I decided to stop, maybe tomorrow I will see if it will lean out in the driveway or if that is as low as the ID725s can go.

Thanks for the suggestions, I should know for sure soon.

 

Scaytale,
Do you also use the Base Map chart to compare rows?

You can change scale to define the lower vacuum rows better, say 0-5 instead of 0-35.

Since adjacent cells are averaged it is critical that the curves are somewhat evenly separated.

Notice the 7by7 "sway-back" of the curve around cruise and the wave resulting from acceleration as boost comes on.

Barry

 

Thanks Barry, I will check it out, I haven't been using it. I just got busy paying the bills, so haven't had much time to work with it.