LLY Ficm

[mplecha]

I've got a 04.5 LLY with a bad FICM. A shop replaced the original one in 2018 when it would occasionally die. They kept my old one. It didn't bother me at the time, but I wish I had it now. I hardly drive this truck, so it probably has around 5-10k miles since that repair.

In June, the truck died on the interstate and hasn't run since. My FICM is burned up. I sent it to SIA, and they sent it back. I've shopped around, but haven't been able to find one other than a few eBay listings for $3k. Is that a realistic price? At this point, the truck has been in my driveway where the rollback dropped it off for months. I'm tempted to part it out. Where can I find another unit? What could cause two failures like this?

 

[Cougar281]

Take a look at car-part.com. I was going to say that $3k for a ficm is NUTS and anyone that is wanting that much for one is smoking some goooood stuff, but apparently, a bunch on car-part are smoking that good stuff, but I did see some 'closer to reasonable' prices.

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[TheBac]

Holy sweet Jesus! The cheapest LLY FICM I found on car-part in the entire USA is $1800!

Maybe send one of these guys an email and see if they can help?

https://siaelec.com/product/duramax-ficm-repair-return/

Chevy GM Duramax Diesel LLY Fuel Injection Control Module FICM 6.6L 2004 - 2005 REPAIR SERVICE

Check Chevy GM Duramax Diesel LLY Fuel Injection Control Module FICM 6.6L 2004 - 2005 repair service by Vehicle Module - Auto & Truck Electronics.You send your part to us, we rebuild it and ship it back to you.

vehiclemodule.com

R&R for Fuel Injection Control Module (FICM) for 6.6L Chevrolet GMC Du

This is a listing to purchase a Rebuild and Return Service, also known as a rebuild service. Once you complete your purchase, you will receive instructions to send your pump or injectors to us to be rebuilt. The price is an estimated cost including all standard internal seals and gaskets...

dieselcare.store

Chevrolet Duramax FICM Repair Service 2004-2005

Your #1 source for New and Remanufactured Automotive Electronic Parts We assist in Driving Vehicles around the Globe

www.autoecu.com

Those four came up on my searching. There may be more out there.

 

[mplecha]

SIA told me it was beyond repair.

What could cause the ficm to fail? I have a hard time believing this is bad luck. I suppose its possible, but my concern is that the truck will burn up another $2k part.

 

[2004LB7]

my guess would be shorting injector harness. I'd inspect the wires really good before putting another one on

 

[036.6turbo]

My grandson is going through the same thing now. LLY. Crazy prices on these. I didn't know they were made of gold.

 

[TheBac]

Wild thought of the day: Its too bad you cant retrofit an LB7 FICM instead. IIRC, werent firing voltages within 1 volt?

 

[Cougar281]

Wild thought of the day: Its too bad you cant retrofit an LB7 FICM instead. IIRC, werent firing voltages within 1 volt?

I don't know if anyone really knows... Supposedly, LB7's operate at 96v and LLY's at 48v, but people have been using LB7 FICMs to drive LLY injectors, but one would expect a SIGNIFICANTLY reduced injector life being driven by double the expected/desired voltage. Voltage aside, for whatever reason LLY FICMs won't talk to LLY ECMs, so I'd assume the opposite is true as well.

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[Bdsankey]

I may have one that won't cost $3k, let me check.

 

[TheBac]

I don't know if anyone really knows... Supposedly, LB7's operate at 96v and LLY's at 48v, but people have been using LB7 FICMs to drive LLY injectors, but one would expect a SIGNIFICANTLY reduced injector life being driven by double the expected/desired voltage. Voltage aside, for whatever reason LLY FICMs won't talk to LLY ECMs, so I'd assume the opposite is true as well.

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I just remember old info years ago that lb7s were 96 and llys were 95. That was probably found to be incorrect as time went on.

 

[revolucien]

Even if the voltage needs to step down from 96v to 48v, is it just a voltage difference...is there any change in firing or duration? Stepping voltage down is a simple inline regulator, if that's all it is to allow use of a LBZ. The scalping for the LLY FICM is ridiculous, but when there is nothing available I guess you gotta expect people want to cash in.
I can't let my truck rot in the driveway, and full engine replacement is not a reasonable option....if there is someone with some knowledge of the LLY FICM electronic operation and a schematic of the circuit (with values), please post.

 

[2004LB7]

is $1700 too much?

Duramax Diesel LLY FICM 6.6 Chevy Silverado GMC Sierra 2004, 2004.5, 2005 | eBay

Used Working condition Duramax Diesel LLY FICM 6.6 Chevy Silverado GMC Sierra 2004, 2004.5, 2005.

www.ebay.com

or this guy. don't know how far he is from you or if he still has the ficm

2004 lly duramax chevy Silverado 2500hd FOR PARTS - auto parts - by...

2004 Chevrolet Silverado duramax 2500hd for parts Clean title Extended cab 6.5 ft bed For parts 263xhd transfer case Alison transmission 4x4 Cloth Red duramax Lly motor 220k Call or text 678 294...

atlanta.craigslist.org

 

[revolucien]

If it was a rebuilt one with some guarantee maybe, but $1700 for one that may just die in 6 months to a year from the 220K miles of use already on it... yeah, that just doesn't make sense. There has been a few LLY's I've seen dying across the other websites, most are just crossing the 200k mark just like mine. I've inspected the harness and no issues of chafing or bare wires, hoping that the one I have maybe repairable.

 

[Bdsankey]

Even if the voltage needs to step down from 96v to 48v, is it just a voltage difference...is there any change in firing or duration? Stepping voltage down is a simple inline regulator, if that's all it is to allow use of a LBZ. The scalping for the LLY FICM is ridiculous, but when there is nothing available I guess you gotta expect people want to cash in.
I can't let my truck rot in the driveway, and full engine replacement is not a reasonable option....if there is someone with some knowledge of the LLY FICM electronic operation and a schematic of the circuit (with values), please post.

LBZ doesn’t have a FICM, I’m assuming you mean LB7?


Right now FICMs from junkyards are $1500-$2500 all day. That’s the market right now sadly. If you have one that you think may be repairable then I would send it out and get it rebuilt as it’s usually the same or less money.

 

[revolucien]

Yep, typo…supposed to be LB7. Anyway yes it is sad. I’m hoping it’s repairable. Loved everything about this motor, runs strong, clean and doesn’t leak a drop.

 

[juddski88]

I don't know if anyone really knows... Supposedly, LB7's operate at 96v and LLY's at 48v, but people have been using LB7 FICMs to drive LLY injectors, but one would expect a SIGNIFICANTLY reduced injector life being driven by double the expected/desired voltage. Voltage aside, for whatever reason LLY FICMs won't talk to LLY ECMs, so I'd assume the opposite is true as well.

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I think you meant to say [presumably] "lly ficms won't talk to lb7 ecms."

Are you sure about that?

Also, the higher voltage to the lly injector solenoids haven't caused a real reliability issue because it is being pulsed.

The real issue with running lly/lbz/lmm injectors on the lb7 ficm voltage is the frustration of custom tuning. Files built for stock injector/pump/turbo swaps are pretty readily available from a few people. Figuring in custom pumps/injectors/turbos/bowl designs took us hundreds of hours and almost a hundred little revisions, and it still wasn't 100% right.

 

[revolucien]

Before I send this FICM off to get rebuilt, let me bounce this off the forum.... I inspected the harness and found no abrasions or nicks in the harness at all, I have already added length to the #2 and #7 pigtails(about 20k ago) The truck was driving yesterday down the freeway and went into limp/tractor mode. I got it to a shop that had a code reader and it threw P2149, P0202A, P0203A, P0205A and P0208A. Normally I would have expected one or two cylinders on the same side if it was a harness issue, or one or possibly two if it was an injector issue, but four injectors on opposite sides, at the same time, just leads me to believe it goes back to the common point of the FICM. Any thoughts before I find a rebuild site for the FICM?

 

[mplecha]

I sent mine to SIA. They sent it back and said it was too far gone. My dad wanted it, so I sent it to him. He said the area under the big caps was burned, and it looked like the capacitors didn't fail; it looked like the traces under them broke off the board causing high current/heat and burned the board. I suppose we have the EU to thank for lead free solder.

 

[2004LB7]

Before I send this FICM off to get rebuilt, let me bounce this off the forum.... I inspected the harness and found no abrasions or nicks in the harness at all, I have already added length to the #2 and #7 pigtails(about 20k ago) The truck was driving yesterday down the freeway and went into limp/tractor mode. I got it to a shop that had a code reader and it threw P2149, P0202A, P0203A, P0205A and P0208A. Normally I would have expected one or two cylinders on the same side if it was a harness issue, or one or possibly two if it was an injector issue, but four injectors on opposite sides, at the same time, just leads me to believe it goes back to the common point of the FICM. Any thoughts before I find a rebuild site for the FICM?

injector banks have injectors on opposite sides of the engine. 2, 3, 5 & 8 are one bank

 

[revolucien]

injector banks have injectors on opposite sides of the engine. 2, 3, 5 & 8 are one bank

Thanks, that’s good to know.