My first race results - would like some input

[jpowel29]

Just got back from my first race - I made it to the semi-finals which was nice but the truck's performance was off significantly vs what I had expected. Traction is my biggest hurdle.

60ft - 2.20
330ft - 5.90
1/8 et - 9.06
1/8 mph - 78
1000ft et - 11.76
1000ft mph - 90
1/4 et - 13.90
1/4 mph - 96 (slowest) 99 (fastest)

I left the line about 2200-2400 rpm each time (leaving in 2nd gear). I also tried a 1st gear launch and it did nothing to improve the short times. I ran passes with and without T/H on. T/H seemed to help in the middle of the run but the truck did not seem to want to shift the same as it did with T/H off. I was running the slicks at 14psi with tubes installed. Burnout time did not make much of a difference with the M&H Nostalgia slicks. Truck left straight with the Cal-Tracs set to 1/4 turn of pre-load (each side). It felt like I spun through the 1/8 mile but I did not get a video of any of my runs. The slicks spun on the rims about 1-2" on each side (will try a beadlock rim or rim screws).
I was the only 2wd and most of the 4x4 trucks would be out on me by a few lengths and I could run some of them down in the last 300ft when the truck hooked and the turbo was up good.

I did not log any of the passes (that will come on a test & tune night). During each run (except the very first pass) the truck ECM would throw the P0087 FPR code. That is what really puzzles me. My truck should not run out of fuel. I recently added an ATS twin cp3 with 60% over nozzles. I am running some relatively conservative EFI Live tunes so I would love to hear from anyone who can help me track down that gremlin. My truck is supposed to have had the FPR shim done (I did not do it myself).

 

[malibu795]

big turbo= high shift points... ie 3500-3800 wot shift point with the 4202

you are falling under the charger when you shift IMO

as for the low fuel rail code... that would be between you and nick

 

[rushingbc]

It felt like I spun through the 1/8 mile but I did not get a video of any of my runs. .

Wow, do you mean ALL the way through the 1/8th? I always expect to spin as soon as I shift in to third, but I'm still running my Michelins.

Did you have any weight in the bed, or were you running empty?

 

[JoshH]

I would to a bottle test to make sure you aren't leaking past the FPRV. It may not be sealing up properly.

 

[jpowel29]

I am going to get some data logged and I will try the bottle test.

Thanks
John

 

[slowlmm]

I am going to get some data logged and I will try the bottle test.

Thanks
John

just shim it cheap insurance edit saw it was done then yea bottle test or race valve. did you port the rail fittings as well when you did your dual cps ? also your rpm looks a bit low on launch for second gear.

 

[LB7Diesel]

Lift pump seems a little small for all those goodies. 95gph???? I'm sure twin cps are sucking that one dry.. Damn you got alot of cash tied up in that Z WOW!!! Once you get it fig out it will be a screamer.

 

[jpowel29]

My first time trial pass (the very first pass ever) I went 1/2 to 3/4 throttle and the truck seemed to accelerate smoothly through the entire run. All of the rest of the passes were more aggressive full throttle (trying to ease in/out to manage better traction). I would see the CEL (the P0087 code) by the time I was going through the traps.

The FASS could be a restriction. I am making a list of fuel options to look into:

1. Bottle test the rail.
2. Data log a full pass (launch to the finish).
3. Test a larger lift pump.
4. Race valve and/or ported fittings

Trans & Chassis options:

1. Increase shift rpms (I assume that I can capture these via EFILive)
2. Remove rear overload springs
3. Adj shocks
4. Lower psi in the slicks and possibly a beadlock or rim screws to locate the slicks on the rims better.

Thanks guys - keep them coming.

 

[jpowel29]

I logged rail pressure last night. Once I go past 1/2 throttle it is dropping from around 25k down to 5k and hanging there. It only slightly rebounds at the end of the run. Once I clear the code the truck runs fine under normal driving and pressures stay constant/consistent.

 

[LarryJewell]

Log a few runs and send them to Nick, I'm sure he can figure out where the code is coming from

 

[LarryJewell]

You might consider the ported fittings also, they cant hurt, and they sure don't cost an arm or leg

I also am seeing the Banks 6 gun bundle in your signature, are you running this at the same time as EFI, if you are, that just might be your problem.

 

[jpowel29]

I get the same low rail code running with the Banks unplugged. We are going to check for possible leaks at the rail port and junction block provided in the ATS twin CP3 kit. We are also going to check pressure coming in from the Fass pump. I'll post where this leads.

 

[LB7Diesel]

I would see/ask if 95gph is enough flow for 2 cp3s. I would think psi isn't as important as being able to supply enough volume. Maybe it's starving the cp3pumps for fuel. Could be a couple of diff things. Just throwing out ideas.

 

[jpowel29]

You might be right about the Fass 95 being on the small side. It is working fine (holds 7psi under all loaded conditions and over 10psi at idle). Once I get the rail pressure steady we will re-test.

I believe the stock CP3 is the only pump supplying fuel. We will un-hook the second CP3 and test the input voltage to the second pump. I also need to load test both of the truck's batteries. I have had some strange things happen with voltage spikes from a battery going bad.

 

[jpowel29]

Fuel delivery issues (and low rail pressures) have been solved with a new ATS CP3 control unit.

Truck runs extremely strong at all levels of throttle input. I have not made it back to the track yet as I am trying to troubleshoot some TCM DTCs. I have read some existing threads and will try some basic fixes. I will post these on another thread.

 

[LarryJewell]

Fuel delivery issues (and low rail pressures) have been solved with a new ATS CP3 control unit.

Truck runs extremely strong at all levels of throttle input. I have not made it back to the track yet as I am trying to troubleshoot some TCM DTCs. I have read some existing threads and will try some basic fixes. I will post these on another thread.

what is this cp3 control unit your talking about and is it used only for duel cp3's or will it work for single cp3's too

 

[jpowel29]

It comes with the ATS dual CP3 kit. It helps integrate the second CP3 (control input voltage, etc). I am sure there is more to it than that (just my explanation).

 

[bullfrogjohnson]

I would see/ask if 95gph is enough flow for 2 cp3s. I would think psi isn't as important as being able to supply enough volume. Maybe it's starving the cp3pumps for fuel. Could be a couple of diff things. Just throwing out ideas.

FYI.... Climax (crankitup pulling truck) runs only a 95gph pump with 3 cp3s and big enough injectors to look through and the 95gph supplies more than enough fuel from his studies