DTC help! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BR3W CITY · 10-26-2018, 10:46 AM

The brake circuit switch will take you out of lockup on the highway, which is probably why your're feeling increased RPM.

SBTork · 10-26-2018, 11:40 AM

Quote:

Originally Posted by Custom 68

I would check all of your fuses related to the swap. I wouldn't jump to the conclusion the PCM is bad.
Also check your grounds, if they have gotten loose they can play havoc on things.
Dave

I will check fuses on my break here shortly. I agree and will check grounds too, I've heard way too many stories about crazy weird electrical problems being due to a bad ground. I think I have 1 from engine to frame, 1 from engine to body and 1 directly from battery to frame....should I have more than what I currently have?

Quote:

Originally Posted by BR3W CITY

The brake circuit switch will take you out of lockup on the highway, which is probably why your're feeling increased RPM.

That's exactly what I was thinking too.

ls1nova71 · 10-26-2018, 01:16 PM

Quote:

Originally Posted by SBTork

I will check fuses on my break here shortly. I agree and will check grounds too, I've heard way too many stories about crazy weird electrical problems being due to a bad ground. I think I have 1 from engine to frame, 1 from engine to body and 1 directly from battery to frame....should I have more than what I currently have?

You need to check your engine harness grounds, there are usually three of them on a truck harness.

SBTork · 10-26-2018, 01:47 PM

Quote:

Originally Posted by ls1nova71

You need to check your engine harness grounds, there are usually three of them on a truck harness.

Thank you for the heads up on there usually being 3 of them, I will absolutely check that out!

87chevy.com · 10-29-2018, 11:24 AM

Do you have a tach hooked up?

10-26-2018, 10:46 AM	#1
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: DTC help! The brake circuit switch will take you out of lockup on the highway, which is probably why your're feeling increased RPM. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

10-29-2018, 11:24 AM	#5
87chevy.com BMW & ASE Master Certified Join Date: Feb 2004 Location: Houston, Texas Posts: 1,266	Re: DTC help! Do you have a tach hooked up? __________________ 1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes 1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD A poor man buy's it twice finally got my domain name back, 87chevy.com.... site rework in progress



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