Help a newb please

A little history first I have had five shops look at my truck and charge me money and through parts at it. My truck has 5.3 whipple charger 42LB injectors, Walbro intank pump high output, tholy headers no cats 3'' exhaust and nelson tune. I have had poor AllenTalk to three of these Utarded Mechanic's. Allen has been nice enough two send out two PCM'S of course and listen to my struggle over the last few month's. Any help or idea's would be great. First off the truck runs fine at low RPM if you get into the throttle it acts like it is starved for fuel and falls on it's face if you slowly get into it it runs better. It also runs much better when cold. The first shop told me I needed a new fuel pump, installed a Walbro high flow pump. With the fuel pressure at 60 psi Wot and foot on the brake the truck fell on it's face for a quarter of a mile still like it was starved for fuel. With a snap on Modis it showed not one misfire in live data and no codes. A computer later I gave up on those guys. Next shop has a tech 2 scan tool. No codes they said they even disconnected 2 plug wires and let it run for 15 minutes still no codes and no misfires in live data. They have some exhaust sniffer tool and said it is rich at when it is poping. Still had one of the PCM'S so they put that in there again no change. I skipped a few mechanics but this last one taught at a college and seems to know the most. He has still had my truck for 3 weeks and run dozens of tests. Same result. I have note's on all the shizz I have been through on this if anybody needs more info. Thanks in advance

Does it have a Ford or Doge emblem anywhere on the body?

:lol:

Sorry, couldn't resist. Hope you get it figured out.

They are checking the fuel pressure while driving at wide open throttle and the fuel pressure is 60 PSI? What are the spark plugs gapped at? They should be no more than .030" with a blower. How much HP do you suppose the engine is capable of producing? The Walbro is pretty much limited to a max of 550 hp in optimal settings. Fuel pressure is definitely what I'd be monitoring the closest during these issues.

its probably somthing stupid like maf sensor or iat or somthing dumb like that. Mybe try a stock pcm or take blower off and inspect for damage? Its weird that the engine didnt throw a code though. Stupid question but u using 93octane and how much boost, maybe too much.

Like Red said check the plugs. The stockers won't work well as you will need the TR6 plugs. Strange no misfires. Maybe a bad knock sensor, TPS or MAF?

Does it have a Ford or Doge emblem anywhere on the body?

:lol:

Sorry, couldn't resist. Hope you get it figured out.

Ouch
you didn't have to be so hurtful.

The plugs are TR6's gapped to what Allen told me. Mass air is reading normal knock as well and the fuel pressure was tested while driving. The truck by coach Nelson is well under 550 horse. I run 91 octane which is what it was tuned for. It did run great with his mods for about 2 month's. I am really at a loss and I have taken it the supposed best Mechanics in St. George, UT I might run it to Vegas. :duh:

Borrow a known good crank and cam sensor and swap them out. They may be losing their sensitivity/accuracy.

On a side note, have the PCM grounds checked at the head. You would not be the first person to have bad grounds from the PCM to the driver side cylinder head.

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Originally Posted by RedHeartbeat

On a side note, have the PCM grounds checked at the head. You would not be the first person to have bad grounds from the PCM to the driver side cylinder head.

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:slice:

Side thought...belt slip at high RPM?

ive had a simular problem with the porcelain being cracked on a spark plug, no codes just break up wile under a load

The Plugs have been replaced 3 times. No change the last mechanic pulled two wires and let it run and it set no codes. What could cause the truck to not show or set a code? I have not replaced the crank sensor but doesn't that make the truck idle and start bad or not start at all? The last mechanic suggested putting a stock pcm on it as well but not taking off the blower. The problem started out intermitent and got to really bad and has been here for a couple month's.

I could post up some vid if that would help?

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Originally Posted by SCIV

:slice:

Side thought...belt slip at high RPM?

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this would make allot more sense. Maybe its to loose or tight. post vid, I bet we can all figure this one out together. or not lol
but it seems like the pcm might have learned wrong or somthing. Just a theory but lets say you get a nelson tune, and somthing is wrong but not noticeable. like a sensor that is reading incorrectly. Wouldent that make the relearn mess up because it had currupted data? truck relearns but with the pretence that all is well. does this make sence guys? Maybe a stock pcm would unmask the problem, if its not a stated problem. Or I could be full of it.

when i had my tuned pc and i bent a valve surpirsing no knock sensor codes, or and codes at all, and when i broke my rocker arm 2 nights ago ( witch im working on at the moment ) no missfire codes, so ob2 dosnt always find the problem

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Originally Posted by sliverado rst

when i had my tuned pc and i bent a valve surpirsing no knock sensor codes, or and codes at all, and when i broke my rocker arm 2 nights ago ( witch im working on at the moment ) no missfire codes, so ob2 dosnt always find the problem

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I can see that but the last mech said he pulled two plug wire's and still no code. Any reason's why that wouldn't shoot a code? I got a cam and a crank sensor. I'm going to install them and see what happen's.

Do you have the crank pulley pinned? The pressure from the blower may be spinning the pulley on the crank. How many PSI are you running?

Jamest

Fuel pressure test/verify: Pressure looks good on the schrader valve, but are the injectors just clogged? Maybe you finally scooped up enough poop from the tank to slowly build up in your tiny injector holes over time. PLENTY of pressure...on the goop-side, but no gasoline can pass through them into the engine. i dunno what to do about that, known good stock injectors might lead to dangerously lean condition(i am not versed in blowers)

Done compression test to verify rings/valves/headgasket?

Do the RPM's drop when you pull the wires? If not they are either 'dieseling' from bad timing/too hot temp and just firing without spark lol OR that cylinder is dead as a doornail and wasn't doing anything to begin with. Get ahold of the misfire enable criteria or conditions are for the "misfire" code that should be showing up.

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Originally Posted by Jamest

Do you have the crank pulley pinned? The pressure from the blower may be spinning the pulley on the crank. How many PSI are you running?

Jamest

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Same line of thought I have. Belt or pulley issue. It would show up on the boost gauge though.

It still runs ok I mean better then any stock truck, if I ease into it and don't give her more then half throttle. The belts are good and I am setup for 5 psi of boost and when cold it will run decent with boost. I replaced the crank sensor no dice there. I am going to try to get the camshft sensor in today. I will also get some vid up later today.

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Originally Posted by RedHeartbeat

What are the spark plugs gapped at? They should be no more than .030" with a blower.

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??? Can you enlighten me. Why only .030?

i had a problem with pulsator in the tank being ripped, and wile under a load it would loose pressure, i know you have a new pump but they usaly dont come with the pulsator, i replayced it with just rubber hose

Under boost you can literally blow out the candles if you have too much gap.

Are the stock coils that weak?

Boost creates more static compression and it's harder to fire a spark in high compression. The coils are great but things start working against you. Even nitrous applications require you to pull the gap down. GM even recommends only .045" gap on plugs now instead of .060" like they used to call for on HEI vehicles.

First of all look at o2 sensors on bank 1/2 sensors 1/2 mine still work and set no codes .. but dont work correctly.. they never see rich.. they just go from .440-.460 in a loop over and over... Next with the whipple .. did you disconnect the whipple box? .. There is a resisor in the harness... Mine was on the MAF plug.. it will show the truck reading -40 degrees at all times... Looking for Codes .. Thats Simple Autozone Stuff... Someone that can Read Data will be a much better help... Bolth scanners have that option.. I will be its the Intake air temp.... it will read well below zero all the time...

OK Is your Intake Air temp sensor relocated? It won't matter that much but I know exactly what your problem is. At least I believe it is the same problem I have. The whipple gets hot and your intake temps get high. REAL HIGH. This causes knock and well it just sucks. Feels like the truck falls on its face. If it has been sitting all night and is a COLD morning. I bet it runs like a raped ape for a minute or 2. I hope it is something else but I feel your pain.Even in 40 degree temps my whipple gets HOT. The intake air temps will be over 125 just cruising. If you nail it or 1/2 throttle the temps sky rocket. I have see over 250 degrees with just a half throttle. My meth kicks in and it will drop down to the 80's but as soon as I let off the gas the temps sky rocket. My truck just gets slower and slower. I ordered a 10lb pulley from whipple and they sent me the wrong one. I was hoping to see if turning the boost up would help at all. I am also going to put the factory air box back on in hopes that it will lower intake air temps. :puke:

I am currently looking for an engine and a nitrous kit and will most likely be selling the whipple real soon. I am really unhappy with them for not making the truck system with an intercooling setup.
If I don't find and engine I might build a custom intercooler system for it by putting an edelbrock carb style intake with intakeelbows.com. I think that would cure my problem.

Read this also.
http://www.silveradoss.com/forums/in...141&hl=whipple

Good luck.

The resistor will be placed in the harness by who ever installed the kit.. its not built into the box... it makes the computer see Sub Zero intake Air temps.. so it keeps it really rich... The am not 100% sure on your Problem Zeake .. What did you do with the Vacume lines on your truck when u removed the Whipple electronics?? !!! I have an idea on whats going on with yours as i am typing this..... The Bypass valve on the Lower left side of the whipple ( its controled by the whipple Box with an electric solonoid) whats going on now is your whipple is in boost mode ALL the time... It never gets to relive that case pressure/heat... At cruise speeds does your boost guage read Vacume also ? mine would cruise around 15" ... you need to Re route the Vacume lines on your truck Zeake so that the Bypass will work ... Its on the under side of the whipple.. its a round Black box with 2 sets of Vacume lines... also just a little upstream will be the small solonoid with two wires that run to that to on/off that controls that vacume... so at light throttle it will relive the case pressure and the blower will spin free...

As far as Plug Gap... .30 gap is fine like Red Said.... No Matter what type of engine it is... I think the big caps in stock form Help Idle a motor idle clean for Sniffer testing.. but its very hard on the Coil and Wires... I run an Whipple on a Big car with an MSD 44 and gap the plugs @ .015 That isnt a typo !!

I'm new to the LSX motors but no stranger to boost. There is no way I would run a plug gap that small unless I was running a Mag.

SangerRat .... U think .030 is small??...

I have ditched the whipple tuner for Nelson's whipple tune beleive it or not Whipple recomended Nelson performance to me for my PCM rather then use thier setup. Also the intake temp is if anything a little high I don't have the exact #'s but the mechanic with the tech2 has all of theose live data #'s documented. He is gathering as much info as he can and going to talk with Nelson. the truck does run better when cold but still like ace. I still have not replaced my cam sensor yet, my 2yr old daughter spent the night at the hospital dehydrated from chucking everything she put in fro two days. Thanks for all the help and I will get a vid up tomorrow after the cam sensor.

While you're back there installing the cam sensor, check the grounds to see they're tight and wires aren't broken. They're located on the driver side head next to the firewall.

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Originally Posted by casey23

SangerRat .... U think .030 is small??...

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I myself wouldn't run smaller than .035. I run .040 in my 468 bbc. I believe over .045 you start stressing the coil. I assumed the LSX's would have an advantage with the individual coil pack and the short plug wire.