added AFPR and dyno'd car

mto502 · Apr 5, 2004

It was running way too rich and couldn't back down the AFPR enough so we put the stock FPR back on. Even with the stock FPR it was running at 10 and 11:1 at WOT !
My dyno numbers were worse today than last time I dyno'd it, even with the pullies. Looks like some type of custom tuning will be the next thing in the works.
I may be able to get a deal on a DFI. If so I'll make some money back on my Pro M since this DFI is a speed density unit and deletes the mass air sensor.

I was obviously mistaken when I mentioned I thought the car was running at 13.5. I must have been looking at the idle AF. Either way todays concentration went on fuel pressure and wideband readings and I now know why I'm lacking in hp.

RIO5.0 · Apr 5, 2004

Odd the AFPR didn't work for you???

mto502 · Apr 5, 2004

RIO5.0 said:
Odd the AFPR didn't work for you???

Nope. In fact the car was already running rich with the stock regulator. I landed up putting the stock regulator back on.

RIO5.0 · Apr 5, 2004

Where the frick is all the fuel coming from???? Whats your pump size, just outta curiousity???

Edit...just seen your sig....24s and a 255...

RIO5.0 · Apr 5, 2004

Curious...you recently add the 24s??? Im about to add 24s to mine...Tell me this isn't what i got to look forward too.. Did you run 19s with that combo??

final5-0 · Apr 5, 2004

Is your 255 pump the high pressure or high volume unit?

I have seen some say that they had probs getting the pressure down with the high pressure unit.

Later
Grady

mto502 · Apr 5, 2004

When I did the heads cam intake etc I also changed to 24's. I did everything at the same time, including exhaust. It was a one shot deal becuase I was too impatient to do 1 or 2 mods at a time, plus I figured I'd save on labour in the long run.

The fuel pump is the Holley/Walbro 255 lph pump. I don't think it's anything special other than your typical 255 lph pump.

Zero Signal · Apr 5, 2004

Well have you tested your fuel system to see if it has too much pressure? You must REALLY be dumping gas in there since you may be maxing the EEC adaptive control.

Didn't you say you had a chip? What happens if you put your stock MAF sensor back on and/or remove the chip? Maybe give those a shot for a couple days (remember to disconnect the battery while you change them to reset the EEC).

I've never heard of anyone going to speed density from MAF, is this a common thing?

tistan2 · Apr 5, 2004

You might want to check and make sure your O2 sensors are working right. I had a problem with my car dumping alot of fuel and it would spit and sputter and blow black smoke. I changed the O2 sesors and that took care of it

Rootus · Apr 5, 2004

Definitely check O2's, and if you can get something on there to check out what the EEC is doing. Fuel pressure is only temporary, the EEC can adjust mixture plus or minus 25%, so something is wrong -- either the EEC itself, or the information being given to it.

mto502 · Apr 5, 2004

I don't have a chip. I'm running on the stock EEC.

I hooked up a guage to the fuel system with the AFPR and it was close to 40 psi. With the stock FPR it's 39 psi. At WOT I thought the O2 sensor kicked out anyway. While at an idle or part throttle the AF was bouncing between 14 and 13:1 which to my understanding is where it should be. I don't get black smoke. Last year when I tried a stock MAF calibrated for 19 lbs I lost 40 rwhp on the 24 lb injectors. I've never had a check engine light or smoke so I would assume the o2 sensors are working properly. The car never spits or sputters.

Accel DFI's are speed density setups which completely delete the MAF. Yes this is the norm for DFI's and I think the Holley Commander is a speed density setup as well.

S/CBlack95GT · Apr 5, 2004

Remember guys the O2s DO NOT control the air/fuel ratio under wide open throttle, they are ignored and the computer reverts to MAF readings. One thing is making your car too rich, the MAF tune. Sadly, the 75mm Pro-M meters are not calibrated real well. I know the guys at AFM have had some trouble with them. You may want to look into a used or new Pro-M 80mm with an AFM PowerPipe. That combo would gain you about 12rwhp and most likely more b/c of the better AF/R. The 80s are highly tuned and always seem to put out a great A/F ratio curve.

Another thing, did you try bumping the timing to 14+ degrees? Advancing the timing will also lean out the mix and possibly make more power.

mto502 · Apr 5, 2004

S/CBlack95GT said:
Another thing, did you try bumping the timing to 14+ degrees? Advancing the timing will also lean out the mix and possibly make more power.

Timing is at 16 degrees. The car likes 16.

Thanks, I have a feeling you've pegged my problem.

mto502 · Apr 6, 2004

P.S. I could also see the MAF being the reason we didn't get the power expected out of my car since day 1.

Rootus · Apr 6, 2004

S/CBlack95GT said:
Remember guys the O2s DO NOT control the air/fuel ratio under wide open throttle, they are ignored and the computer reverts to MAF readings.

During closed loop, the EEC uses feedback from the O2's to learn how to achieve the desired mixture. It does this with narrow band O2's that work right around stoich, which is good enough because during closed loop it's always aiming for stoich.

During open loop, such as on cold startup or high load & WOT, it no longer wants a stoich mixture, and the O2's are pretty useless (being narrow band). The EEC has a table of RPM vs load and the desired A/F ratio, this is what it uses for open loop. For WOT it uses the highest load values, optionally multiplied by a WOT fuel multiplier (based on RPM), to determine the desired A/F ratio.

Anyway, back to the topic. The EEC does in fact use information that it learned previously from the O2 sensors in order to deliver the correct mixture in open loop. So if you have fugged up O2 sensors, it is going to adapt incorrectly and you will not get the mixture you want, at any RPM or load, closed or open loop. O2 sensors are important.

Dave

S/CBlack95GT · Apr 6, 2004

HairyCanary said:
Anyway, back to the topic. The EEC does in fact use information that it learned previously from the O2 sensors in order to deliver the correct mixture in open loop. So if you have fugged up O2 sensors, it is going to adapt incorrectly and you will not get the mixture you want, at any RPM or load, closed or open loop. O2 sensors are important.
Dave

Ummmm...well when my car was in N/A form I was having some idle issues. I unplugged both O2s so the car would run off the MAF only at idle. This way I could tell if the MAF was at fault. My A/F ratio under WOT was the same and the check engine light never came on either. Turned out my AFPR was leaking, but at any rate I was always told the O2 were ignored at WOT and after that I believed it.

mto502 · Apr 6, 2004

S/CBlack95GT said:
You may want to look into a used or new Pro-M 80mm with an AFM PowerPipe. That combo would gain you about 12rwhp and most likely more b/c of the better AF/R. The 80s are highly tuned and always seem to put out a great A/F ratio curve.

From what I've heard the 80 mm won't fit with my BBK CAI. Will the 77 mm fit and are they as highly/properly calibrated as the 80 ?

jghood13 · Apr 6, 2004

I have been having idle issues and running rich lately intill I took out my 6al that also shut off my abs light that came on once and a while

Zero Signal · Apr 6, 2004

but at any rate I was always told the O2 were ignored at WOT and after that I believed it.

Yeah you're right, it doesn't use them. But the EEC uses a reference value based on their readings in closed loop. If you are forcing open loop, those reference values defualt to 1.

mto502 - It really does sound like a MAF issue, is there anyway you could try different ones at no cost to you?

mto502 · Apr 6, 2004

Zero Signal said:
mto502 - It really does sound like a MAF issue, is there anyway you could try different ones at no cost to you?

Yes there is but my engine builder told me today as well as his assistant who used to be a tuner for Ford, that the MAF is cut out during WOT as well

At least now I know why I'm not getting great trap speeds etc. I wonder how much power I'll pick up once I get this unfer control. Man, between 10 and 11.1:1 is so rich !

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