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Discussion Starter #1 (Edited)
I got a 1992 Freightliner FLD120 with a 3406B PEEC motor, 13 speed, 390's on air. VIN:1FUYDSYB3NP525277

I can't find the engine serial anywhere, there is no tag on the valve cover and I couldn't see anything on the passenger rear of the block. The tag in the glove compartment is worn down too far to read. I believe it to be all original.

The problem I have is a hunt at idle, especially when cold. Not much of a problem until your truckin and try to clutch on an off ramp or at a stop light and it hunts once or twice and dies. Really a pain cause I run mostly around town.

Other than the hunting it runs fine, makes 20psi of boost sounds smooth and is ok on power, feels like about 400hp.

I'm into this truck for a little more than the salvage yard will give me for it. I don't really want to dump a ton of cash into it. If it costs a fortune to fix, I'll probably just junk it. I'd like to try a few things before I junk it, It seems to be a fairly decent little truck.

Any help would be appreciated.


 

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Change your fuel filters, clean you battery connections and grounds, clean the ECM wiring and check the fuses and holders are not corroded.
 

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Change your fuel filters, clean you battery connections and grounds, clean the ECM wiring and check the fuses and holders are not corroded.
Or, you could just say...."welcome to owning a PEEC".
 

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I got a 1992 Freightliner FLD120 with a 3406B PEEC motor, 13 speed, 390's on air. VIN:1FUYDSYB3NP525277

I can't find the engine serial anywhere, there is no tag on the valve cover and I couldn't see anything on the passenger rear of the block. The tag in the glove compartment is worn down too far to read. I believe it to be all original.

The problem I have is a hunt at idle, especially when cold. Not much of a problem until your truckin and try to clutch on an off ramp or at a stop light and it hunts once or twice and dies. Really a pain cause I run mostly around town.

Other than the hunting it runs fine, makes 20psi of boost sounds smooth and is ok on power, feels like about 400hp.

I'm into this truck for a little more than the salvage yard will give me for it. I don't really want to dump a ton of cash into it. If it costs a fortune to fix, I'll probably just junk it. I'd like to try a few things before I junk it, It seems to be a fairly decent little truck.

Any help would be appreciated.


Hate to rain on your parade, but this is common to a PEEC engine. IF, you ever do get it to stop, you WILL have a small fortune in it...only to have it come back and do it again.

UNPEEC and be done...
 

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Discussion Starter #6 (Edited)
I've cleaned connections, both battery and harness, have new fuel lines and filters on it, no change.

I don't want to spend the $2,000 to unpeec it and have no cruise and iffy jakes. Right now I can sell it to the salvage yard for $4,000 and keep the 10 virgin tires for one of my other trucks.... may just take that route.

Thanks for the input though guys, I searched this site for a week before posting, lots of great info on here.
 

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We found using a Fleetguard 211 secondary filter cut down on a lot of fuel problems, especially when cold but also a lower RPMs. A PEEC can do unusual things.
 

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It's the rack senser. You aren't married to the truck it sounds like so scrap it if that's an option. If not it's $2000 either way you go. :(
 

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There is someone selling an entire peec pump with all the sensors on ebay right now. You could buy something like that and rob the rack sensor to see if that fixes you for a bit, plus you'd have extra parts. It's a cheaper way to go if you don't want to spend a pile of money on it. I'd post the link, but, I am not sure how to do that. I did the same thing about a year ago. I bought the whole pump assembly from a guy with everything attached cheaper than I could have bought a rack sensor from CAT. I think they wanted $350 for the rack sensor. We removed the rack sensor and I still have the rest of it sitting in a shed. I still want to un-peec mine, but, it has been running fine, and I didn't have the money to do it at the time. Just a thought though, might be better than scrapping the whole truck. I think I only had about $650 in it between those parts and the labor, and that was 80k miles ago.
 

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The other guy
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There is someone selling an entire peec pump with all the sensors on ebay right now. You could buy something like that and rob the rack sensor to see if that fixes you for a bit, plus you'd have extra parts. It's a cheaper way to go if you don't want to spend a pile of money on it. I'd post the link, but, I am not sure how to do that. I did the same thing about a year ago. I bought the whole pump assembly from a guy with everything attached cheaper than I could have bought a rack sensor from CAT. I think they wanted $350 for the rack sensor. We removed the rack sensor and I still have the rest of it sitting in a shed. I still want to un-peec mine, but, it has been running fine, and I didn't have the money to do it at the time. Just a thought though, might be better than scrapping the whole truck. I think I only had about $650 in it between those parts and the labor, and that was 80k miles ago.
It's a PEEC, so like always, it's the labor. Only hi end parts are BTM's and the transducer.
 

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You wreck it, I'll fix it
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I went through that like 3 times on my old Ford wrecker. I loved the old Cat, but it seemed to be an ongoing dance that I lived with because she was still a lot more truck than my N14
 

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I just bought a 93 tractor for near salvage price with a 4CK that was converted back to manual and the mileage is 961k with lower bearings rolled in 300k ago. The only oil consumption seems to be coming from a leak on the front end that I have been told is a gasket leak on the gear cover behind the air compressor. I have a mind to leave it as is and run it a while to see how bad it is. Also can you still buy a manual throttle control that can be used to hold the throttle open while sitting still?
 

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pete junkie
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I just recently aquired a 94 frtliner with a unpeeked 4ck17862. somebody put a older single scroll pump from a 4mg. I looked up the cam and its a 0r 3757. i bought the truck for parts mainly. my question, is this engine something that would be suitable for making horsepower since it is a 350 from the factory? and could it produce 525-560 to the wheels with pump mods and injectors?
 

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The other guy
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I just recently aquired a 94 frtliner with a unpeeked 4ck17862. somebody put a older single scroll pump from a 4mg. I looked up the cam and its a 0r 3757. i bought the truck for parts mainly. my question, is this engine something that would be suitable for making horsepower since it is a 350 from the factory? and could it produce 525-560 to the wheels with pump mods and injectors?
490HP unless you change cam. Mechanical max :(
 

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4ck

Are all 4ck engines 350hp from the factory. The truck I just bought is a 1993 4ck that was converted back to manual and the owner didnt know the current output. Doesnt matter to me either way due to the lightweight loads that will be pulled but just curious.
 

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Are all 4ck engines 350hp from the factory. The truck I just bought is a 1993 4ck that was converted back to manual and the owner didnt know the current output. Doesnt matter to me either way due to the lightweight loads that will be pulled but just curious.
no they were available in 460 hp,300 hp, 425,400 and so on
 

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The other guy
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ok thanks tony,i got 1 more question would 8785 marine nozzles be suitable for this style single scroll pump?:bdh
8785's are for dual scrolls. If you don't have a 5888 pump housing they won't burn rite. Sorry. 3423's will match up to the pump and cam tho. ;)
 
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