Fuel system issue.

[slowyellow]

So, it's a long going issue, but I'll try and make it brief.

I got up with a buddy of mine who has a company that wanted to try out a new MAF for my car. Anyways, we got it on the dyno and they started the car. It was running like crap, and come to find out they forgot to plug in the MAF. No big deal, I just wanted that in there so that EVERYTHING is out there. Maybe it could have made a difference. Anyways, we plugged it back in and it started up fine. The tuner had a tune that he though would be safe for the new (experimental) MAF. Made first pull and it was breaking up at the top end. Second pull confirmed that. This was on a relatively new set of plugs. But based on the recommendation of the tuner, we switched them out again. It was still breaking up, so he said that based on his experience it was probably a coil pack (although I wasn't throwing a code for a misfire). So, we ordered a full set of coil packs. I replaced them and it didn't do anything for the problem. At this point, it started cutting out completely like it was running out of fuel, and it was random but it would totally fall on it's face. I hadn't changed anything since the last dyno session except the MAF. I was asked to drive with the new MAF to test drivability of it.

So, I datalogged the car, and the FPDC was at .5. The tuner said that was maxed out and the car was out of pump. Hard for me to wrap my head around because nothing had been changed since the last pull where the fuel was adequate for the power that I was making. But, regardless, I had a set of Stealth 340's sitting on a shelf in my garage that I had been planning on putting in. So I did. Didn't change anything at all. Still cutting out at random RPM's. And just so I'm clear, it only seems to be under WOT that it's an issue. But I've never gradually wrapped the car out. The Stealth pumps seem to act a little weird from watching the PSI, but it never dies or anything. And I can watch the PSI and it will drop once I go WOT, and then pick up and then fall off completely. So I think it's a fuel delivery issue. I've replaced the FRPS, no help. I'm honestly at a loss and frustrated with the car.

By the way, the car is an 04 cobra with a 2.6L KB. Fore rails with 60 lb injectors. FRPS delete and twin Stealth 340 LPH pumps. I have a KB BAP and the dual FPDM upgrade. Car made 606/540 last time it made a good run on a dyno.

So much for keeping it brief, but I REALLY would appreciate some help with this issue. It's been since early fall that it's been jacked up.

EDIT: I can go with lethals return setup, but I really don't want to spend a grand on something that I really don't need. I don't foresee myself trying to make much more power than where I'm at now, so if this setup will work, than I'd rather stay with it. I just am to the point that I just assume rip it out and start from scratch.

[slowyellow]

Nevermind guys, I'm fed up with it. I just ordered a complete return style kit from Lethal. Hopefully it solves all of my issues. Now the question is wether or not to go E85.

[Andy@PrimeTuning]

Sucks that you couldn't get it figured out.

Did you verify the BoostAPump was working correctly ?

Ive seen that before when one pump is dead/dieing or there is a leak inside the tank where between the pumps and the fuel hat.

You will need injectors if you go E85 - 80s and they will get you to 7-750 depending on how much boost you can get that 2.6 to put out.

[slowyellow]

I've got it putting out 20 lbs now. The dyno that I had it tuned on is known to put out "low" numbers. So on someone else's dyno, it might have put more out for all of the people that say that the number is low.

I think that the 2.6 is rated at 24 or 26, but IMO, if I want to do that I need to upgrade to the 2.8LC due to the heat soak issue with the 2.6's. I'd like to be around that number. Not sure if I wan't to push the stock block to the breaking point. I'm pretty comfortable around 600 to be honest, not much messes with me. But my buddy who spanked my ass in his Z06 just sold that and got a 13' GT500 so I'm looking forward to returning the favor, lol.

I'm just curious if the switch to E85 is worth it. My tuner said that he might be able to squeeze 40-50 out of my current setup with just tuning. I suppose that is pretty good, but is it worth the money? Guess that's kind of a personal decision huh?

[slowyellow]

Oh, and as far as the BAP goes, how do you verify that it's working. I checked the fuse and it was good. And with the 340's it really shouldn't matter if it's working right? I didn't install it, so I really don't much about the BAP.

[Moose Jr.]

Sell the BAP, 60's and 340's. Get the 80's and the Walbro 465's and be done with it. The 465's are E85 compatible as well. IMO, E85 is worth it if you have easy access to it. And, it sounds like you already have the return style system coming so, why not. I had HPP do a 93 and E85 tune for my setup. I rarely run the 93 setting since I have E85 a mile or two away.

[Blackpony]

I am yet to see a bap fail. With the new fuel system you will be removing all that anyways.

[Blackpony]

Oh and I would put the old maf back on and find a different tuner.

[slowyellow]

I don't think that it was the tuner. He has tuned a million cobras like mine. I ended up reinstalling the old maf and old tune and the issue is still there. So I think that it was just some sort of parts failure at a rather convenient time.

[Blackpony]

Might try watching fuel pressure at the rails? How was afr?

[slowyellow]

Sell the BAP, 60's and 340's. Get the 80's and the Walbro 465's and be done with it. The 465's are E85 compatible as well. IMO, E85 is worth it if you have easy access to it. And, it sounds like you already have the return style system coming so, why not. I had HPP do a 93 and E85 tune for my setup. I rarely run the 93 setting since I have E85 a mile or two away.

Do you think that the 340's aren't enough to support 700-750 whp? I wasn't sure on the 80's. I'm interested to hear your setup if you don't mind sharing.

[slowyellow]

Might try watching fuel pressure at the rails? How was afr?

AFR is rich as hell. And pressure at rails drops off at WOT, not consistently at any RPM though.

[Moose Jr.]

Do you think that the 340's aren't enough to support 700-750 whp? I wasn't sure on the 80's. I'm interested to hear your setup if you don't mind sharing.

If you go with E85, I think you will be pushing the limits of the 340's and the BAP to get to that 700 rwhp number. 80 lb inj. are a must. The one thing I've learned over the years is that a little overkill on the fuel system doesn't hurt anything at all.

My setup is a KB 2.8H with a Billetflow hub and 3.1 pulley. The fuel system is HPP's budget return system with 465 pumps and 80lb injectors. HPP's return system is similar to Lethal's setup except Lethal uses the stock feed line. There are some other differences that i don't recall at the moment.

I'm still running the stock mass air with a Mafia MAF extender inline with the stock air inlet tube and an Accufab single blade throttle body. It has your basic terminator cooling mods, a dual pass heat exchanger and a bigger coolant reservoir. Really nothing fancy to look at except for the KB. Also has BBK longtubes and a Bassani catback. Last summer, in 110 degree+ heat and a stock clutch, it made just under 700 rwhp on HPP's dyno. I have no doubt it would make over 700 in decent weather.

[slowyellow]

If you go with E85, I think you will be pushing the limits of the 340's and the BAP to get to that 700 rwhp number. 80 lb inj. are a must. The one thing I've learned over the years is that a little overkill on the fuel system doesn't hurt anything at all.

My setup is a KB 2.8H with a Billetflow hub and 3.1 pulley. The fuel system is HPP's budget return system with 465 pumps and 80lb injectors. HPP's return system is similar to Lethal's setup except Lethal uses the stock feed line. There are some other differences that i don't recall at the moment.

I'm still running the stock mass air with a Mafia MAF extender inline with the stock air inlet tube and an Accufab single blade throttle body. It has your basic terminator cooling mods, a dual pass heat exchanger and a bigger coolant reservoir. Really nothing fancy to look at except for the KB. Also has BBK longtubes and a Bassani catback. Last summer, in 110 degree+ heat and a stock clutch, it made just under 700 rwhp on HPP's dyno. I have no doubt it would make over 700 in decent weather.

Well hell, I suppose my thinking was all wrong, lol. I was thinking that the pumps are good to go at 700 whp, and that the injectors might need to be the 105's and not 80's. I do have E85 around here on base. But once you get away from this area it's totally different. I think that the bases are the only places that have it around here.

[Dan03mach]

You already bought a return style fuel system so that is good. That stock Returnless stuff is crap. E85 is great but if you drive the car a lot the cars milage kinda sucks but if you want to make good power and safe it's like have race fuel. Like Andy said 80lbs inj. will get you around 7-750 maxed out on E. if that is all you are looking for then 80's are fine if not put some bigger ones in there. I have 160lb injectors and a versafueler driver box and they work perfect and it was cheaper then 105lb high impedance injectors. Just a thought.