metromatt Posted December 11, 2007 Report Share Posted December 11, 2007 2004 SS with magnacharger. Bought the truck at dealer auction with system already installed. Under load/acceleration truck misses and or detonates like mad. Called magnacharger tech, they suggested replace grey fuel pump control unit, tried that with no success. Then they suggested try new fuel pump, still does it. Had engine light when problem started showed lean b1, lean b2, but now light off, still same problem. Fuel pressure is 48psi at idle on in dash gauge, 41-2 under load. Feel like I'm getting nowhere now. Any help? Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted December 11, 2007 Report Share Posted December 11, 2007 fuel pressure that low under load is a major problem. Did you replace the fuel pressure regulator on the fuel rail? Do 04's have that? I have it on my 03, but Im not 100% sure you have it on the 04+. But I do know 41-42psi under load is a serious issue. Your problem is fueling...Mine is 52-54 at idle and then goes to 66-68 WOT... Quote Link to comment Share on other sites More sharing options...
Krambo Posted December 11, 2007 Report Share Posted December 11, 2007 Yea, you are on a road for very short engine life if you continue to push that boosted motor through detonation into misfires. Check the infamous washers on the FPR for cracks, pinches etc. Very common issue that can be solved in a matter of 2 minutes and $4. Quote Link to comment Share on other sites More sharing options...
kelleyperformance Posted December 11, 2007 Report Share Posted December 11, 2007 yup, they nailed it. do you have a factory fuel filter? if so, change it. that could be the culprit, somtimes they get clogged. fuel pressure should be near 60 psi at all times, its not vaccum controled. the maggie shouldve come with a pressure regulator on the fuel rail, set at 58 psi. Quote Link to comment Share on other sites More sharing options...
metromatt Posted December 11, 2007 Author Report Share Posted December 11, 2007 yup, they nailed it. do you have a factory fuel filter? if so, change it. that could be the culprit, somtimes they get clogged. fuel pressure should be near 60 psi at all times, its not vaccum controled. the maggie shouldve come with a pressure regulator on the fuel rail, set at 58 psi. When I get to the truck, will check FPR. No fuel filter I can find, fuel system hacked and whacked and deadheaded by magna install. Any further info is appreciated. Keep it coming please. Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted December 11, 2007 Report Share Posted December 11, 2007 I knew 03's and 04's have slightly different fuel systems, but I didnt know what the distinct differences were. So 04's come with a set pressure regulator. 03's utilize the factory one off of the maniflolds. And our pressures are different because of the return vs returnless systme right? Quote Link to comment Share on other sites More sharing options...
wody Posted December 11, 2007 Report Share Posted December 11, 2007 welcome you came to the right place to figure this out. knowing that you bought it from an auction, you don't know what the previous owner put into it. is the tune right, fueling, ect... Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted December 11, 2007 Report Share Posted December 11, 2007 Fuel filter should inline on the frame rail underneath the truck. Looks like a little 8oz pop can...silver Quote Link to comment Share on other sites More sharing options...
metromatt Posted December 11, 2007 Author Report Share Posted December 11, 2007 Fuel filter should inline on the frame rail underneath the truck. Looks like a little 8oz pop can...silver Seriously can't find filter - 2 manufactured lines right from tank, up firewall to back of manifold (unless its relocated behind s/c & I haven't stumbled onto it yet.) Couldn't believe it, but can't find it. Quote Link to comment Share on other sites More sharing options...
Krambo Posted December 11, 2007 Report Share Posted December 11, 2007 He's got an 04. No in-line fuel filter, the "filter" is in the tank. Scanning software would be worth its weight in gold. Quote Link to comment Share on other sites More sharing options...
metromatt Posted December 11, 2007 Author Report Share Posted December 11, 2007 He's got an 04. No in-line fuel filter, the "filter" is in the tank. Scanning software would be worth its weight in gold. Glad to hear I'm not missing anything on the filter, but I thought the old strainer only fuel filtering method was Chrysler only stupidity nowadays. Quote Link to comment Share on other sites More sharing options...
wody Posted December 11, 2007 Report Share Posted December 11, 2007 He's got an 04. No in-line fuel filter, the "filter" is in the tank. Scanning software would be worth its weight in gold. Quote Link to comment Share on other sites More sharing options...
metromatt Posted December 11, 2007 Author Report Share Posted December 11, 2007 By the way, where is the fuel pressure regulator? I know there is one on the pump/sender ass'y, been up close & personal with this already, seemed ok there. Haven't seen one underhood yet that would qualify as the 2 minute fix. Quote Link to comment Share on other sites More sharing options...
PladdPezzPunk Posted December 11, 2007 Report Share Posted December 11, 2007 (edited) there is no fuel filter, an 04 has a retunless fuel system. thats not hacked by magna but by GM them selves. Fuel pressure is definately low just as other have said. check for a bad pump, or the "gray box" you spoke of is a fuel pump "booster" of sorts. I'de check the amperge draw on the fuel pump and command the fuel pump to full pressure using a bi-di scan tool. (i think hpt can do it, snap on solus, modis, Tech II of course) If you see an excessive draw, you'll be not only pulling down the tank to check the pump, but also check all wiring with a fine tooth comb to see where your loosing your power. Usually i see a bad ground (or one with excessive resistance) causing an issue like this. I can get all the factory diagrams and magna diagrams if you need them for help. Also, the ground for the fuel pump is at the left front body mount, you'll see two ground wires there, make sure you have less than a 0.10 voltage drop or you'll still have problems. Stop looking for the fuel filter, it's in the tank. if the filters clogged, the pumps are paper weights anyways. Edited December 11, 2007 by PladdPezzPunk (see edit history) Quote Link to comment Share on other sites More sharing options...
misterp Posted December 11, 2007 Report Share Posted December 11, 2007 First, Welcome to the forum. Sorry to hear you are having this kind of trouble with your truck. Agree with Krambo, the '03 trucks had a fully-plumbed return fuel system; the '04s are (stock) returnless with FPR and filter and pump in the tank. So I would drop the tank and double-check that there is a high-volume pump as well as fresh filter. And I would not take *anything* for granted, after you get the fuel pressure up to where it is supposed to be at idle, I would take the truck to a reputable tuner just to make sure it was tuned correctly. Also check and make sure you have the right heat-range spark plugs. That's the basics, I'm sure there's more but that ought to get you on the right track... wishing you best of luck and hope you get it squared away asap. Mr. P. Quote Link to comment Share on other sites More sharing options...
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