First, I will start off with truck history:

Bought truck used 12/06 with 108K miles. I believe it is original pump because it has VOID sticker on harness connector on pump but I do not know for sure.

Truck had pyro and boost gauges on it when I bought it. It appreared like the PO also had a Edge EZ installed at one point because I found it's instruction manual in the console.

Smarty installed by me 02/07.

12/07 at 125K miles. Replaced stock fuel pump with Walbro, added Draw Straw and big line kit with FP gauge at same time at (unknown fuel pressures with stock pump). Fuel pressure has been 15-18 PSI for last 14 months with 2 micron Racor filter instead of stock can on engine. I also started using 1 quart of two-stroke oil per fill up--usually about 25 gal fuel. No issues with truck at this point. All of this was done as preventative maintenance as advised here to protect the VP44.

New Mach 1.6 injectors installed 2/08.

12/08 I took my truck to emissions testing and put the Smarty back to SW0. Passed test, then turned it back up to Kung Fu where it belongs. However, I did notice the power did not come back as much. A few days later, I reloaded the Smarty and sure enough it loaded up the default settings (newest software) instead of highest level where it was. I Loaded up the Super Kung Fu settings and truck had more power, but still not like before the emissions test.

01/09 at 142K miles truck is slowly loosing power (noticable esp while towing) and taking more than a bump of the key to start. Truck dies sometimes after starting, while other times starts fine, but stumbles for a second after I am moving. It is so abrupt when this happens, it feels like I hit a kill switch momentarily while accelerating. Never had a wiretap box on the truck.

02/09 now the truck is struggling to accelerate while empty. The torque is just not there. It almost feels like a gutless gasser. I have to really work hard to get up to 75 MPH anymore.

02/09 rebuilt HO VP44 ordered from Midwest Fuel Injection for $1,030.28. I installed it and no dice. Truck does the SAME THING. Hard starting and will cough only once about 30 seconds after starting it. No driveability issues except lack of power. Still shows NO codes. I noticed the revised Smarty programming eliminated the normal Smarty fuel code.

I replaced my 2 micron Racor fuel filter thinking I overlooked something so simple. Not the filter. I adjusted the fuel pressure regulator slightly downward to 15 PSI at idle. I checked the IAT and MAP sensors. Not those either.

I reset the APPS per the FAQ. No change. I tried unplugging the MAP sensor and I got more smoke and a check engine light, but still no real difference.

My boost pressure still tops out at 26-28 PSI. I never did plug the wastegage. I am going to try checking for boost leaks, but I bought the wrong rubber adapter. It said 4" on it, but that was for a 4" PIPE. The ID of the rubber adapter measures 4.5".

I have been searching and reading about ECM, APPS, VP44, MAP issues for the last two weeks and still not found my truck's problem. I am almost ready to take my truck in because I am at wits end. Please help.

 

Another thing to check is the MAP sensor. I have gone through several.

Dave

 

I tried cleaning the MAP sensor and then tried running with it unplugged. No difference on the top end but more smoke down low. Should I just buy a new MAP or will running with it unplugged be enough of a test to force the computer to command full fuel?

I tested my truck for boost leaks and found a small leak at the wastegate hose. I removed the elbow and installed a plug in its place like so many people do. I found no other leaks. I will install a boost elbow if I exceed 35 PSI on my stock HX35.

Again, the truck will do one of two things:

A) The engine will start and immedately die, then it will restart normally and drive fine until next start.

B) If the engine starts quickly, as I drive off and the engine revs up past 1500 RPM or so, the engine dies immedately for a second, then revs back up where it left off. This is very abrupt if I am on the go pedal, or almost unnoticed if I gingerly drive off, but it happens only once after it is started.

Again, in both cases, the truck has no real top end power or torque.

I have not tried loading any different Smarty settings in case my ECM is ready to poop.

 

Maybe I missed it but have you run it with the smarty dis-connected?

 

Sounds more like a VP44 than anything else now.

Dave

 

Did you read my original post? I replaced my VP44 and it does the exact same thing as before. I replaced the cam sensor at the same time the VP was out.

I have not run it with the Smarty disconnected yet. I did not know if my ECM was the issue. If the ECM was the culprit, I didn't want to harm it further with another reflash. I know it is pretty rare, but reflashing the ECM can cause it to die.

I am replacing the APPS as soon as Timbo's version arrives in my mailbox. Not sure if that is the issue or not, but his is a better quaility part than the stocker anyway.

Perhaps I should have posted this in the Performance forum instead?

 

just a thought but you said you run a 2 micron filter to me that is pretty tight choking I had a hard start and die problem when I ran to tight of a filter. what is your fuel pressure your reading and I assuming if you have a gauge it is getting fuel reading after your filter prior to the the inj pump. the oem fuel filter I believe is 10 micron

 

Yes, 2 micron filter is what I have been running for the past 18K miles--on the same filter no less. I'm guessing this filter has at least 3X the filter media area as the stock can. I changed to a brand new filter and no change. Fuel pressure was 18 PSI at idle and I could pull it down to 15 PSI wide open. Fuel pressure measured at the VP44 inlet. I backed off the fuel pump pressure to 15 PSI at idle thinking I hurt the diaphram (?) in the old VP44.

One thing I did not think of until last night was when I went back to the Smarty program in Dec, I did not plug back in the tire size in the ABS. This made my speedo and my odometer read incorrectly, but it should not have an effect on the seat of the pants feel, nor should it make the truck cough and die on start up or when I get underway like it has been doing for two months. I added the tire size back to the ABS, but did not reprogram any Smarty settings.

Well this morning, my truck was still doing the same thing again going to work and again when I started it to leave work. However driving home, the torque was coming back and it no longer struggled to accelerate. I could also smoke on command if I mat the pedal even at speed. It no longer was a struggle to pass anyone on the freeway. My truck is acting normal again , but why?

 

Yes I did.

Dave

 

wish you can figure this out all my experience the hard start or start die was related to either my fuel leak sucking air or fuel filter. do you by chance have a pre filter before your lift pump. I know you said your pressure has been pretty good reading. is your newer vp still under warranty. good luck let us know.

 

Truck acted up again today on start-up but still seems to run normally on the top end for now. Today, I was able to keep it from dying completely on start-up when I gave it a bit of go pedal. This has me thinking my problem is really the APPS--which I am going to replace anyway.

I have not checked my cleanable prefilter pump screen yet. I also have a spare Walbro pump incase this one dies. What is the failure mode of the Walbro pumps? Do they just loose pressure--which I hope will show on the gauge--or something else?

New VP44 is under normal 1 year warranty. I do not have a wiretap box.