WIW 4L80E/NP208 tranny/transfer combo - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Down south truckin · 05-29-2008, 08:58 AM

I have a truck with this setup in it and am having problems with the motor running rich so I'm considering switching to a carburetor and a sm/465/208 which is what the truck originally came with but a P/O switched it out.The p/o was a transmission shop owner so I'm sure the transmission and transfer case were checked out and should be in tip top shape.I'm not sure this is the route I want to go but would like to know what you guys think the combo is worth.Thanks in advance DST

**special-K** · 05-29-2008, 01:42 PM

I`ve only seen the 4L80E coupled with a NP241.I know I wouldn`t let my combo go for less than $1,000 knowing my trans is rebuilt.Are you offering the ECM with it?A little more info would help.What is this combo original to?Are you sure it`s a NP208?Is the ECM stand alone or from a TBI truck?The trans isn`t worth much w/o the ECM.If it`s a TBI ECM then it will need a reprogram to run in a carbed truck.

*FormerMember* · 05-29-2008, 02:50 PM

Quote:

Originally Posted by special-K

I`ve only seen the 4L80E coupled with a NP241.I know I wouldn`t let my combo go for less than $1,000 knowing my trans is rebuilt.Are you offering the ECM with it?A little more info would help.What is this combo original to?Are you sure it`s a NP208?Is the ECM stand alone or from a TBI truck?The trans isn`t worth much w/o the ECM.If it`s a TBI ECM then it will need a reprogram to run in a carbed truck.

As Tim mentioned, they don't normally come with a 208. What year is it from?

I paid 600 for a very nice 4L80E and 300 for a pullout. Both are without the TCM's (transmission control module) which is problematic.

Down south truckin · 05-29-2008, 05:06 PM

Yeah the guy who put it all together had to machine and cut something to mate them together.It came out of a 92 bread van as a 2wd then he did the modifying to mate them together.The ecm is for a tbi which is what I'm struggling with.I may try to replace the throttle position switch to see if thats the problem.It is a 208 and I would sell the ecm and small block tbi if I do the swap.Or maybe you guys may know why it is acting so silly it will crank and run really rich until it fouls the plugs but it won't rev up unless you really slowly bring the throttle up if you just mash it like you normally would it just boggs out.I replaced one of the injectors last weekend but it wasn't the problem.If i keep trying I will eventally figure out what is wrong with it but who knows how much that will cost Thanks Mike

**special-K** · 05-30-2008, 04:17 AM

It sounds like a throttle sensor (position switch) problem,like you suspected.It`s something in the electronics,I`d think.Could be the ecm itself or wiring.I`m like you,more of a carb guy.

(simple pimple)

Blue_71 · 05-30-2008, 06:39 AM

could possibly broken fuel pressure regulator; the springs commonly break, thus letting all 18 psi go through the injectors instead of only 9-12. ask me how i know that one

(hint: my k20 is tbi)

jeffspower · 05-30-2008, 06:45 AM

Check the coolant sensor for the ECM. They can go bad & tell the ECM it's 32` below zero- going full rich for cold startup. Kinda like a choke acts with a bad pulloff.

Down south truckin · 05-31-2008, 04:50 AM

Thanks guys keep the info coming.It's crazy how many things can tell the ecm to dump more fuel

05-29-2008, 08:58 AM	#1
Down south truckin Senior Member Join Date: Feb 2006 Location: Lilburn Georgia Posts: 1,240	WIW 4L80E/NP208 tranny/transfer combo I have a truck with this setup in it and am having problems with the motor running rich so I'm considering switching to a carburetor and a sm/465/208 which is what the truck originally came with but a P/O switched it out.The p/o was a transmission shop owner so I'm sure the transmission and transfer case were checked out and should be in tip top shape.I'm not sure this is the route I want to go but would like to know what you guys think the combo is worth.Thanks in advance DST

05-29-2008, 01:42 PM	#2
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: WIW 4L80E/NP208 tranny/transfer combo I`ve only seen the 4L80E coupled with a NP241.I know I wouldn`t let my combo go for less than $1,000 knowing my trans is rebuilt.Are you offering the ECM with it?A little more info would help.What is this combo original to?Are you sure it`s a NP208?Is the ECM stand alone or from a TBI truck?The trans isn`t worth much w/o the ECM.If it`s a TBI ECM then it will need a reprogram to run in a carbed truck. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

05-29-2008, 05:06 PM	#4
Down south truckin Senior Member Join Date: Feb 2006 Location: Lilburn Georgia Posts: 1,240	Re: WIW 4L80E/NP208 tranny/transfer combo Yeah the guy who put it all together had to machine and cut something to mate them together.It came out of a 92 bread van as a 2wd then he did the modifying to mate them together.The ecm is for a tbi which is what I'm struggling with.I may try to replace the throttle position switch to see if thats the problem.It is a 208 and I would sell the ecm and small block tbi if I do the swap.Or maybe you guys may know why it is acting so silly it will crank and run really rich until it fouls the plugs but it won't rev up unless you really slowly bring the throttle up if you just mash it like you normally would it just boggs out.I replaced one of the injectors last weekend but it wasn't the problem.If i keep trying I will eventally figure out what is wrong with it but who knows how much that will cost Thanks Mike

05-30-2008, 04:17 AM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: WIW 4L80E/NP208 tranny/transfer combo It sounds like a throttle sensor (position switch) problem,like you suspected.It`s something in the electronics,I`d think.Could be the ecm itself or wiring.I`m like you,more of a carb guy. (simple pimple) __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 05-30-2008 at 04:18 AM.

05-30-2008, 06:45 AM	#7
jeffspower Well, Whoop-dee-do! Join Date: Mar 2003 Location: Easton, Mo. pop.- me & scarcely a few others Posts: 2,302	Re: WIW 4L80E/NP208 tranny/transfer combo Check the coolant sensor for the ECM. They can go bad & tell the ECM it's 32` below zero- going full rich for cold startup. Kinda like a choke acts with a bad pulloff. __________________ '68 GMC shortbox 4x4 350/SM465/T221- bought it in '83 SOLD '72 K20 500 Cad/TH400/NP205 SOLD '92 Chevy 2500 6.5 mech TD 4L80E crusty daily driver '72 Monte Carlo... sweet low mile toy '11 Dodge Challenger IE 392 6spd... midlife car

05-31-2008, 04:50 AM	#8
Down south truckin Senior Member Join Date: Feb 2006 Location: Lilburn Georgia Posts: 1,240	Re: WIW 4L80E/NP208 tranny/transfer combo Thanks guys keep the info coming.It's crazy how many things can tell the ecm to dump more fuel



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