I'm getting very frustrated and thought I'd ask to see if any of you may have had similar experiences so maybe I can get my truck back on track. Most of my mods are listed in my signature so look there for any details.

My problems transpired when I took the 3.5 inch upper pulley off and went to a 2 3/4 upper (9 inch lower for all applications). I figured this would be no problem and a new program would fix her right up. Instead I have now been convinced to change my fuel pumps(which didn't help) and I have run 4 different programs with no help. I can't even come close to making a full throttle stab. It is pinging at about 1/4 to half thottle. I could see problems arising at full throttle but this is ridiculous. If I pull the chip it is not there till later when the mass air pegs. This leads me to beleive that it has to be timing especially when it shouldn't even be close to maximum pump capacity at that time. It did the same thing before and after the pump swap. The pumps I am using are Mustang 255 lph pumps with a part number of gss307 or something like that. The timing I have been told is less than factory, but my Predator shows that it is alot higher when this occurs. Sounds like that should be it, but ...........

Anyone else have any experiences like this that might help???

Thanks Mike

 

Well, first off, GSS307s are way wrong for pumps, so you might want to verify what you installed. Second, it sounds like you MAY have a problem with your high side fuel pump circuit. And lastly, you haven't gotten a chip from me, so don't rule out that you just might not have a good tune .

 

I'm running a 2.75 upper on my KB with a Diablo chip burned by JLP with no
problems, even in the colder temps here in Pittsburgh lately. Also have a 2.5
pulley that I'm going to try. Might need a reburn for that though.

From the Ghead

 

Thanks for replying guys.

Sal I was under the impression that the 255 lph pumps used for Fox body mustangs would work? Thats what I have. They are not high pressure pumps , but from the information I gathered the pumps I have deliver 49 gph at 60 psi (12 volts)and the high pressure 255's deliever 50 gph at 60 psi (12 volts). The only thing I see that is differnent is the amperage draw with 10.6 amps for the small pumps and 8.9 for the larger pumps, again at 12 volts. I asked about these pumps a few weeks ago and got only one response of yes they will work.

Being that I had this problem before and after the pump install I can only assume it has to be something else. It happens at around 1/2 throttle or maybe a little less. If I'm on the stock program you only feel it running out of fuel under these conditions which is expected because it is not programmed to add that much fuel and when the mass air pegs it really doesn't know.

As far as programming goes I may have to try other options if it comes to that, but I've spent alot of money and time with the chip I have now and it would go to waste. I'm trying to stay with the factory mass air and injectors too. I thought about jumping to a Pro m 92 mm cald for 50's and 50 lb injectors with no chip and trying that if I can't get this worked out. That should be a perfect combo by my fuel calculations for what I have. The only thing that bothers me is fuel mileage.

You mentioned the high side fuel circuit, where and how can I check it?

Thanks Mike

 

9" lower and 3.5" upper I get around 16 psi.
9" lower and 3.0" upper I get around 21 psi.
9" lower and 2.5" upper I get around 26 psi.

There is a huge difference between going from a 3.5" upper to the 2.75" upper. You are going to need a different program to run 7 psi more boost, or whatever the difference was between the 3.5 and 2.75...

 

9in lower and 3.5 upper I am getting 13-13.5 # of boost.

 

Easteriland--I realize that. It's listed in the original statement. I've been through 4 programs since and nothing has changed. I didn't buy my KB to run factory Eaton boost levels. I was looking at 18 to 20 psi on the factory long block and calling it a day. Plus my truck seems to be about 2 psi lower per the same pulley combos on others trucks, which could be the lower pulley size or other variables.
Thanks Mike

 

Okay I finally got to do a little R&D today. I datalogged with my Predator (for my Cobra) so I could see the timing.

I can't go WOT yet, but the situation I'm using is a 3rd gear half throttle pull(high load). All programs used are close to the same when cruising in 3rd at around 50ish, 25 degrees-27 degrees of total timing. If I give it half thottle heres what happens:

STOCK- timing drops to 5 degrees and less quickly (roughly 16 psi at this point)

JDM CHIP(cal'd for my mods with the Eaton and 6 psi lower)- timing drops almost the same as stock to around 5 degrees

Diablo Chip-(tuned for my current mods/KB) timing drops to 15 and she pings

Surprisingly enough I can almost go full throttle with the JDM chip, but of course it would be lean I'm sure. The following to me shows that it has to be to much timing would everyone agree or am I missing something? The stock programming and the JDM can go almost WOT, but of course they do not have enough fuel in either program. The Diablo chip can't get even close to that and seems to have problems at a lower boost level also.

Thanks Mike

 

Have you discussed this with Johnny yet? If so, what did he say?

The Ghead

 

Actually I was tryng to leave who tuned it out of this topic because I didn't want it to turn into a tuner war or anything. I have spoke to the tuner and we are now on the forth program. I was mainly trying to see if anyone had a experience that might be similar and maybe I was just missing something.
Thanks Mike

 

Hey Mike! If ya need another Lightning to compare things to, I can bring mine over. I have to keep Toluene or race fuel in mine or it detonates even in 80 deg. heat. Im running the JDM J69 program thats pretty agressive and I like it that way. We could swap chips or whatever to see if it would help.
Im getting laid off this week, so Ill have all kinds of free time!
email me and Ill give ya my cell phone # or Im in the phone book.
studduck66@aol.com

Rodney

 

Twinturbo Ranger,
I am no expert but I would like to share some thing with you...

I have port and polished heads and intake
a buil lower end
1 mm over sized valves
and run 16 lbs. on a daily driver. I had a bosch rep do the math on my set up and he told me that my fuel system would not keep up. He said that my 42 lb injectors are at 98% of their duty cycle. When we put my big pulley on and took it to 24 lb of boost the injectors went statick! They actualy shut the truck down. This was on the dyno.
Since then I have put the 255 pumps and 55 lb injectors.

I have learned the hard way about lack of fuel... I am now replacing 3 pistons 3 valves and a damaged block. I know what detenation sound like and feels like but you cant always hear it or feel it. Just my 2 cents.

Suavy

 

Skank dog thanks for the offer. I'll let you know if I need anything to compare to.

Sauvy- I know I'm at or near my stock injectors limits, BUT not at part thottle ?? To add even more to the fire I went back to my 3.5 pulley, which I had run for months and it wants to ping like mad with the Diablo chip. I can actually go WOT with this pulley on the stock programming and JDM (Eaton programmed) chip without any detonation, although I do not stay in it do to the fact they may be lean. I'm at a loss right now. The only possible thing I can think of is my chip is not taking the new programs, but even at that it should have worked with the 3.5 pulley easy because it was originally programmed for it. My only other thought is the pumps are not working properly? I appreciate your thoughts though.

Thanks Mike

 

Sauvy here is what I'm using to base my truck off of since I have no local dyno anymore.

Kenne Bell test - 2 3/4 pulley with the 9 inch lower on a stock truck made 493 with the factory airbox, which is what I have on there right now. If I add in my exhuast, and ported plenum it may add a extra 30 rwhp or so, which puts me in the 525 rwhp range. According to the test it shows their truck was good to 540 at the wheels before porblems occurred. I know every truck is different but this is what I have to go by.

Now I take 525 and add 15 percent to get 605 crank horsepower. I take 605 times .65 BSFC (which is generally good for superchargers) and I get 393 which is lbs/hr and is my TFC(total fuel consumption). Now I divide it by 8 (number of injectors) and 49 lb/hr. I then take 49 and divide it by 42(actual injector size) and get 1.167 which I mulitiply by itself to get 1.362. I then multiply 1.362 by the rated fuel pressure of 39 psi to get 53 psi. This is the fuel pressure that is needed with these inejctors to support that horsepower at 100 percent duty cycle. So with 60 psi I'm right on the verge at WOT. Normally you would like at least a 15 perecent cushion, which would mean adding 15 percent to 393 and redoing the equations. That would be 452/8=56.5 lb hr/ 42= 1.345x1.345=1.809 x 39psi= 70 psi with the 42 lb injectors. I personally think 50's would be perfect for my truck with the correct meter. I'm just trying to keep things simple.

Thanks Mike

 

Off the wall, do you think your actual computer could be f'ed up? Maybe not reading the chip fully?