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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: pholliday1 on December 14, 2012, 02:00:29 pm

Title: 1991 gm went to the 480le how did they do that?
Post by: pholliday1 on December 14, 2012, 02:00:29 pm

Interested in the computer/harness differences to upgrade a tbi turbo 400 to 480le.Not sure if gm used a standalone computer for this or upgraded there existing ecm....anyone?

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: Captkaos on December 16, 2012, 01:19:34 pm

The ECM controlled the 4L80E.  It was a one year only in our trucks and was only available on the 1Ton Crew Cabs.

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: zieg85 on December 16, 2012, 01:37:20 pm

Wasn't the 91 C2500 Suburban one, the one I parted out sure looked factory

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: Captkaos on December 16, 2012, 01:58:10 pm

OOPS! forgot about the Burb's.  Yes it would have been.

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: ehjorten on December 17, 2012, 09:27:46 am

I can confirm what Captkaos states!  ;D

Newer trucks now have separate controllers for the transmission and engine.  One major issue with the '91 is there is no support in the tuner world for the 454-4L80e PROM.  MegaShift could be your new friend!

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: pholliday1 on December 17, 2012, 11:54:41 am

Seems like a little of a stretch you'd almost need a 91 burb donor because chances of finding donor crewcab are really slim.

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: bluecrew on December 17, 2012, 09:11:11 pm

I have a 91 crew cab.  For the right price, it could be a donor...$$$!

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: pholliday1 on December 17, 2012, 09:50:05 pm

Ha ha !thank you for your offer , I would dare say 91 crewcabs are few and far between especially as nice as ehorten.

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: ehjorten on December 18, 2012, 01:44:30 pm

Searched for 3 years for mine...across the country and in the end this one ended up within 1 hour of my home town! :)  Needless to say...I never moved so fast!  Thanks for the compliments.  It isn't without it's flaws...but I enjoy working on it and driving it!

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: bluecrew on December 18, 2012, 06:55:29 pm

Quote from: pholliday1 on December 17, 2012, 09:50:05 pm

Ha ha !thank you for your offer , I would dare say 91 crewcabs are few and far between especially as nice as ehorten.

Agreed, his IS one heII of a crew.  Kind of a pipe dream for the rest of us, but sure is nice to look at, no matter how jealous it makes me.

Title: Re: 1991 gm went to the 480le how did they do that?
Post by: Captkaos on December 23, 2012, 12:49:43 pm

They used the same standalone computer up to about 1993, so you aren't limited on your sources.