ronniejoe fuel resistors

[arrowheadracing]

Just wondered if when you dynoed your motor, what resistor did you have installed. Also have you tried different resistors ? I put a new #9 on mine, and the pmd went bad. I just unplugged the bad one and replugged into the original still on the pump. It actually seems to run better that way. I ll be pulling the bad pmd and installing a new one and thought I might try the #9 in that and see if there was any difference. But just curious to see if you played with it any.

Thanks
Todd

[rjschoolcraft]

I ran mine with a #5 until the FSD on the pump quit. When I installed the remote mounted FSD, I installed a #9. I really have no good before and after comparisons, though. When I dynoed, I had the #9 installed. There's an article in the 2003 reprint volume on the values of fuel delivery that each resistor will yield.

[JohnC]

Keep in mind that changing the resistor does not necessarily take effect immediately. The PCM reads the resistor and stores its value. Only if the value is "forgotten" or the PCM is commanded to do the TDC offset learn procedure does it check the value. (At least these are the only times we have identified).

[arrowheadracing]

So simply plugging in a new resistor will not actually make a difference unless you reset the value. I understand that, so basically am I looking at disconnecting the batteries or is there another simple way to reset the value? The first #9 was in for about a month or so before the fsd went bad.

Thanks
Todd

[JohnC]

Originally posted by arrowheadracing:
...so basically am I looking at disconnecting the batteries or is there another simple way to reset the value? ...Not even that will do it, unless you unplug it for a couple of months. Even that is not guarantied. TDC offset learn is the only sure way I know of. If you have an ODB II truck there's a way to make the PCM do it by key and pedal tricks. ODB I requires a scanner. My truck is ODB I so I don't know the trick,but it's been discussed here in the past.

[HANK1948]

I had a #5 on mine and it peeked out at 63.8 mm fuel rate (i have a snap -on scanner) so I got a new FSD and installed a #9 and the fuel rate peeked at 65.4 mm this time , not noticeable but more fuel none the less!

[JohnC]

Originally posted by HANK1948:
I had a #5 on mine and it peeked out at 63.8 mm fuel rate (i have a snap -on scanner) so I got a new FSD and installed a #9 and the fuel rate peeked at 65.4 mm this time This is a "red herring". The resistor tricks the PCM into delivering more fuel than it thinks it's calling for. The readings on the scanner will not reflect this increase, only the fuel rate commanded by the PCM. The PCM reads the resistor value and uses the value to calculate solenoid time necessary to deliver the desired amount of fuel. It then commands the solenoid accordingly. By changing the resistor you're telling the PCM it needs to hold the solenoid longer to deliver the same amount of fuel. The PCM and hence the scanner does no know it's been duped.

There is, IIRC, a parameter you can see with the scanner that reflects the solenoid hold time, and that should change based on the resistor value.

All this, of course, presumes the PCM has actually read the new resistor. There is also a parameter you can read that reflects the resistor value. If you change the resistor and this value does NOT change then the PCM has not read the new resistor value.

The only way to see more fuel on the scanner is to change the programming.