madden

Ok, Here' the low down on installing an intank walbro 340 in an 03 Silverado SS. I ordered the pump from Magnusson for the 04+ model. The pump does not come with any fuel line or electric plug. I went to Autozone and found a screen for the pump that worked with minor trimming of the pump. I also picked up a pair of electric connectors that crimp and solder to the wire..... these fit the walbro. The factory harness had a black wire (ground) and gray wire (12 volt) running the stock pump. Regarding the fuel line, I was able to reuse the stock line. Here's how to do this: Break the stock fuel pump prong inside the stock fuel line. Then take a drill bit and carefully drill the prong out of the fuel line. Be very careful with this part and go slow. I found that the prong started spinning inside of the line and heated it up enough that I was able to pull it out of the line without damaging the line. For installation of the new pump, I used a small hose clamp to hold the factory fuel line onto the new walbro pump. See my pictures for part numbers and illustration on how everything works. The truck runs perfect now with air fuel in the high 11s and low 12s. With HP Tuners data logging, I found that the truck was doing 0 to 60 in about 4.2 seconds and hit 101 mph in only 11.5. This is in full street trim/weight with a fiberglass bed cover and spare tire intact and some junk in the trunk I will get some track times on the truck as soon as our local track opens. I do notice that the truck is pretty sensitive to warm/hot weather but I feel like it will lay down some awesome times on a nice cool day.

http://s869.photobuc...0316_142030.jpg http://s869.photobuc...0316_135235.jpg http://s869.photobuc...0316_142216.jpg http://s869.photobuc...0316_142904.jpg http://s869.photobuc...0316_135154.jpg http://s869.photobuc...0316_145603.jpg http://s869.photobuc...0316_135229.jpg http://s869.photobuc...0316_135200.jpg Installed and maintaining steady fuel pressure under boost through the gears! Still needs tuning as it is lean but I believe the fuel system is good to go now. I'll post details regarding the install and tuning later. FYI: I was able to reuse the stock fuel line in the tank. Gotta go now...

I have an update: Here's a video of the truck gauges while going wot (after I fixed the fpr hose). Watch the fuel pressure go up with boost and then falter and drop. http://s869.photobucket.com/albums/ab257/madtunesracing/?action=view&current=VID_20110309_175848.mp4 I just got the walbro 340 pump today and I'm about to start the install. Here's some pictures of the pump. http://i869.photobucket.com/albums/ab257/madtunesracing/IMG_20110316_103518.jpg http://i869.photobucket.com/albums/ab257/madtunesracing/IMG_20110316_103533.jpg Hopefully I can get it swapped without too much trouble. Off to the shop to get started..............

Thanks

chase, The truck seemed to be holding 58psi with the fpr hooked up incorrectly. When I corrected the previous owner's mistake I started seeing boosted fuel pressure (the pressure was jumping to 64ish psi under boost) That was yesterday evening. Upon driving it today, I saw an initial spike to 64ish and as load and rpm increased there was an erratic drop in pressure. I definitely fixed part of the fueling issue with the fpr being hooked up to see boost from the charger. I ordered the walbro to eliminate the possibility of a failing stock pump. BTW, the pump is for the 04 + truck so I'm sure it will take some modifications. I didn't order the entire bucket assembly, just the pump. I've installed many in tank pumps on other trucks cars. My 99 transam has a walbro that I installed... that thing sucked as you had to hack the stock fuel bucket up and use clamps and zip ties on stuff. No joke, that was the "correct" way to do the upgrade. Anyway back on topic.......... I'm going to take everyone's advice regarding checking the magnacharger install. The original owner had this 12 second capable ride running around 15s judging from the way it was when I picked it up. It's running strong now, just a bit on the dangerously lean side. My main question is this regarding the fuel pump swap: Using a 340 Walbro, will I have to "hack" up the bucket on the 03 to make it work? I was planning to use the inline pump that I already have as an auxillary "lift" pump. I spoke to a tech (Simon) at Magnusson today and he indicated that the inline pump they include in the 03 kit is a "flow through" design. Hopefully I can get a consistent, adequate supply of fuel to the engine and I can safely dial her in for some good ol quarter mile action. I can't wait to pull on a newer mustang or maybe a bolt on ls1 fbody at the strip. Any and all responses on any of this subject matter in this thread is greatly appreciated.

Krambo, Thanks for the tuning help. I think I've discovered another problem with the fuel system that I'm going to address before trying to get the tune finalized. The fuel pressure is dropping after the rpms go up. I ordered a walbro 340 from Magnuson. I'm going to install it in the tank and see what happens. Hopefully it will cure all my fuel issues and I can focus on tuning it out. Anything I should know about the in-tank pump swap on an 03? I'm sure it's not a plug and play setup.

Ok, Still have not data logged but ran it a bit with the wideband on it and it stayed around high 12 afr. Better but not where it needs to be. I'm going to data log it with hp and see if I can richen it up with the tune. Being that the MAF has been maxing out at 12k hz I'm wondering if I will indeed have to go Speed Density to get it fueling correctly? I'm sure in the summer months it won't be maxing out but it is now

I plugged the port on the passenger side of the manifold and tapped into one of the two fittings on the drivers side to plumb the fpr. It immediately hits low 60 psi when I brake boost the truck. I launched from a dead stop and it was spinning all 4 leaving the line. I'll do some extensive testing and datalogging asap and I'll post the results. I imagine I'll have quite a bit of tuning to correct now that it's building the correct fuel pressure. Thanks again. I'll also take another picture (and post it) to show a proper hook up of the fpr which fixed the pressure problem. That will help others in the future.

Thanks Krambo and Mr. P Mr. P: I'm not offended by anything you have said I didn't build this truck but I'm going to get it right! (and I prefer to have all of the experienced help that I can get so I don't intend to make you mad either ;) FYI: I've tuned around 400 lsx cars/trucks but have limited experience with boosted applications. Any help is greatly appreciated. As for the external fpr... I didn't think that I had one other than the stock style that is mounted in the fuel rail (in the photo). I'll look at this tonight in detail and try to get the vacuum/boost lines sorted out and then see what results that I can get. From researching old threads, I had found that 03 trucks fuel correctly when set up correctly. I remember reading about an 03 that Zippy was working on and it seems like the fpr was hooked up improperly on his as well and once he got it corrected it fueled great. Hopefully I can fix this without replacing the intank pump. (Although I'm sure it would be better to swap it anyway) Oh and the injectors are deatsch werks : http://cgi.ebay.com/ebaymotors/Chevrolet-Silverado-4-8L-5-3L-6-0L-60lb-Injectors-Chevy-_W0QQcmdZViewItemQQhashZitem2551b5462aQQitemZ160284624426QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories They are a plug and play flow matched set. The 42lb injectors were tapping out at 127% duty cycle (although they may have worked ok if the fpr had been hooked up correctly).

I thought that the fuel system was plumbed exactly as magnusson intended by looking at it.... ?? Here's some pictures: http://i869.photobucket.com/albums/ab257/madtunesracing/IMG_20110309_110730.jpg http://i869.photobucket.com/albums/ab257/madtunesracing/IMG_20110309_110743-1.jpg http://i869.photobucket.com/albums/ab257/madtunesracing/IMG_20110309_110716.jpg How is this setup?

I hear you on the sd tuning. (I tuned my 404 is tuned with sd and it runs great but I prefer using the maf if I can make it work.) If the weather is warmer it hovers just below the max hz but when colder outside it maxes. Like I said though, even when I use the vcm controls to command the tuning richer it does not change. I think a few guys on here are maxing out the maf with a radix setup and still fueling ok??? Am I correct? Thanks for the reply

I'll get some photos up later. I did not install the charger. I bought the truck from a customer of mine and started trouble shooting several issues. I will post the latest tune file (its from a beta version of HP Tuners). I don't think that tuning is the problem as it will fuel really close to my comanded afr when it's working correctly and when it goes lean I can't even force it rich with the VCM controls on the scanner. The truck has a new fuel filter (installed by me at the start of all the trouble shooting). I also replaced some crappy iridium plugs with autolite 103s gapped at .035. FYI: The iridium plugs were causing really bad issues making the truck cut out at wot. The vacuum line is properly connected from the manifold to the regulator. The fuel pressure gauge does indicate that under vacuum it is down to 52 psi and then jumps to 58 at 0 psi........... just does not go above 58/59 even under full boost. I may log the fuel pressure but I can watch the gauge and determine that it just isn't getting up to where it should be. Yes I'm running the MAF and I even tried speed density and it didn't seem to help. I am maxing the maf out at 12000k hz but it was giving me plenty of fuel the other day. Another minor note: the wideband is downstream of a cat so it may be slightly richer than what I'm reading. Looks to be the magnuson fuel rails with the fpr in the elbow as you are describing. I was thinking of swapping the fpr with another stock replacement part and then going on to an upgraded in tank pump if that doesn't fix the issue. I thought I'd leave the pusher pump in place to "help" the in tank unit. I'll try and post a tune file. Thanks for the help guys! Supercharged silverado ss file 2003 mod 032 final.hpt

I have a 03 Radix SS with long tubes, 60lb injectors, wide band, boost gauge, and fuel pressure gauge. I've been tuning the truck and had it consistently fueling in the 11.5 to 11.9 afr range and running great. (FYI: I think it has a 2.9" pulley). I have run into a fueling issue that I can not fix with the tune. Some times I am only fueling 13.0 to 13.5 at WOT and at other times it fuels fine. The autometer gauge shows 52 psi under vacuum and jumps to 58 psi at 0 boost but never rises above 58-59 psi. I have the return style fuel system with the vacuum/boost operated fuel pressure regulator. The truck has the inline booster pump from magnacharger and I guess has the stock in tank pump. I bought it with the radix already installed. I just got the fuel pressure gauge working after I ran into this problem. I have searched the forum and found that other 03 boosted trucks are getting higher fuel pressures under boost (like 62 to 64 I believe). I suspect a weak in tank pump or maybe a problem with the fpr as it does not ever get the psi above 59. Please help if you have any ideas. The truck really runs well when its fueling correctly but I'm afraid its going to hurt itself if the lean condition continues. FYI: When it does run lean it is lean all across the RPM range; not just at higher rpms.

I just picked up a 2003 Silverado SS complete with a radix (MP112). I'm starting to data-log the truck and will start tweaking on the tune soon. I was wondering how much "softening" of the IAT/Spark table should be done. Obviously the supercharger will cause the IATs to go higher than a stock truck and the stock tuning pulls quite a bit of timing at 130 degrees IAT and up. Any thoughts on how much of the timing pull can be removed without causing issues? In a quarter mile run I noticed the truck starts to fall on its face around the 1000ft mark. I want a nice running street truck that has a safe tune but 10 to 12 degrees total timing near the end of the quarter mile seems very weak to me. FYI: The truck is making 8 psi on an autometer gauge. Thoughts?

Pretty racy yet not too loud when driving it. It will sound wicked with a nice cam.