LB7 sluggish no power until 3rd gear

[Extended-lbz]

I have a 01 lb7 truck thats been a pain since day 1 lol.
To start the truck has never been tuned. I put a set of LDS injectors in the truck 10k miles ago, has new fuel lines from tank to ficm, new fprv, fass 150 and a hellman sump, 5" exhaust, afe air intake and new filters. I have always had a p0093 code when towing any load and just recently the truck started getting very sluggish in 1st and 2nd gear. Its as if its not getting the fuel it needs to spool the turbo, once into 3rd it will spool around 2k rpm and feels somewhat normal. After the loss in power I occasionally get a p0101 maf code and a p0089 fprv code. I have cleaned the maf with maf cleaner multiple times and it seems fine and have replaced the fprv with a bosch oem unit. I have heard of the 01 OS are horrible and that the ecms can become currupt. I recently put my buddies edge cts on the truck and logged actual vs desired fp and followed within 1k. Any suggestions before spend the money on a kennedy pretuned ecm?

 

[ChrisPerry]

P0093 is low fuel pressure, but you say the actual and commanded are within 1k. This doesn't make sense to me. Was this during a free rev, or a hard throttle acceleration?

 

[JRein]

With the edge did you log what your maf is doing. Should be around 40g/s at idle and go up to at least 400ish.
Are you sure the Fass Is working?
Is it Smokey while driving? Common for them to get a hole in the driver side IC piping. I used a 2" pvc plug that I tapped for a hose fitting and then put that into a 2" to 3" rubber adapter. This will adapt it to the intake horn. Only pressurize to 10psi or so. Otherwise it will blow the pvc out and cause the turbo to spin without lube.

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[Extended-lbz]

It has been throwing low fuel pressure code whenever it has a load since i bought it. It also had a bad haze which is why I changed the injectors and HP lines. The lift pump is working as I have fuel at the engine bay when I remove the hose off ficm (stock filter head is bypassed as it leaked and I thought that was the problem). Commaned FP held within 1k of desired driving the truck and at WOT runs. I did not log the MAF as i was not having these issues at that time and I dont have the means to as I drive from NY to TX for work and the cts is back in NY. I have seen online where the ecms become scrambled and trucks will get the dreaded 0093 code when all hard parts are in good shape and the only fix was a new ecm, kennedy diesel has delt with this alot and offers a pretuned ecm to fix it. My issue is that the truck ran fine before however when I hauled anything i would get 0093 and limp so I knew it needed the ecm. However now it has no power and im getting 0089, 0101 also so im thinking its a combination of things.

 

[Extended-lbz]

Also no smoke at anytime, not at a idle or when im wot in 1st and 2nd. So i dont believe I have a boost leak, I did change the coupler on driver side as it was rubbed through when I bought the truck

 

[JRein]

Do you know what the pressure is set to on the Fass and was it doing this before the lift pump? Could be set just a little low causing the 0089. I had a 0101 before and it was in the tune. The truck was thinking it was seeing 55g/s which was setting that code

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[Extended-lbz]

Do you know what the pressure is set to on the Fass and was it doing this before the lift pump? Could be set just a little low causing the 0089. I had a 0101 before and it was in the tune. The truck was thinking it was seeing 55g/s which was setting that code

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I do not know what the pressure is set at, however I have been currious. I was getting these codes before the lift pump. I added the lift pump and replaced all the fuel lines in hopes to resolve these issues as I already had them laying around

 

[ChrisPerry]

Have you checked the wiring harness by the alternator?

 

[JRein]

You can turn it up slowly and once it start to lope at idle turn it back down. GM CP3s route the bypassed idle fuel back to the intake side of the pump. (Dodge routes it to the tank) What happens is it starts to build rail pressure which causes it to lope. This should allow you to set it for max lift pump pressure

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[JRein]

Turn it down a little then rev the engine to clear up the rail pressure. If it's begins loping again turn it down further.

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[Extended-lbz]

How does one adjust the pressure the pump supplies? And I have no checked the harness is their a common problem with the harness that I am unaware of?

 

[Extended-lbz]

Also I see both of you guys runs built trans trucks. What was the cost for that? Suncoast? Did you pull and ship the trans?

 

[zakkb787]

As far as the trans goes best thing is to call a reputable builder from this site and get their costs and opinions on your build.

 

[Extended-lbz]

Ok, hoping to get this truck figured out. Might have GM diagnose the truck or try to at least. I have asked them about flashing the latest OS or a 02 OS into my ecm but every dealer I talk to seams clueless

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[zakkb787]

Honestly I think your best option for flashing and anything ecm related will be your tuner. Rob or tony or any of the guys from her can get you what you need without the hassle of the idiots at dealerships.

 

[Awenta]

Where are you located. I think it's better to have someone look at it at this point. Dealer probably won't be much help.

While not common it is possible to be popping the fprv


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[Extended-lbz]

I am working around Toyah, TX right now. Would fuel be spraying in the valley or would it return to tank in that situation? And most tuners dont offer a pretuned ecm so I would have to send mine in to be tunes as I am almost 100% the ecm is scrambled and will not take a tune then I will be down a truck in either situation

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[aashton1206]

Put a gauge on it at the pump and set to exactly 7 psi at idle. For the other issues, what is the age of your cp3. I'm to tired to read through all that. Ideally you get 200k good miles from a cp3. Then throw a new one in. But after that point if you still exp the slug except over 2k rpm. Your torque converter is fried. I have the same problem. Just waiting till I can park the truck

Also what intake are you using and what is the age of your maf sensor. I had a code once cause my sensor was bad so the ecm sent more pressure than it needed, which then gave me a rail pressure code. Ten minute fix and it went away.

2004 Silverado Cali lb7, Airdog ll 165, fresh sticks at 325k, DSP 5 on v2 by Rick Fletes, 33x12.5 nittos at on 20 inch American Racing wheels, modded factory air box, Profab Intake Horn, Batmo Wheel, Turbo port and polish, Full EGR Removed w/ fed belt, 3.5 inch MBRP Downpipe, Full five inch MBRP Exhaust, 10mm lbz cp3 pump, Dual Yellow Top Optimas, High Output Alternator, Cognito Pittman and idler w/ support kit, Cognito Contol arms, Drilled and Slotted Rotors on all four Corners, Custom Y Bridge.

 

[ChrisPerry]

is their a common problem with the harness that I am unaware of?

Yes, where the harness makes the bend by the alternator. It rubs and pulls, can cause shorts and broken wires. If you open the loom, inspect each wire carefully for damage.

As for the trans, I made an appointment with Mike L. at Inglewood Tranmissions. Drove it to the shop one morning and drove it home that night. As for cost....... call him. Price might not be what it was for me, as your needs may be different. I will say it is nice not to worry about the trans slipping on an agressive downshift and going into limp.

 

[JRein]

Also I see both of you guys runs built trans trucks. What was the cost for that? Suncoast? Did you pull and ship the trans?

You have to look up how to adjust the Fass or maybe someone will chime in. I think there can be chafing where it goes up to the fuse box and around the FICM.

I've built a few trans so I went with a kit from Evan and put it together. In my opinion his kit is better than the Suncoast kit. I'd recommended him if you could swing it.

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