Limp mode, '97 2500 454 Suburban - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TCLARK · 11-27-2024, 08:30 PM

Sometimes it goes to limp mode but no engine light. Sometimes I can restart and it's OK. Today I unplugged the battery, and it worked....Could it be fuel pump?

OutlawDrifter · 11-29-2024, 01:10 PM

What is limp mode, and what are the symptoms?

Typically a fuel pump on its way out works better with the tank full of fuel and before it heats up. Easy to test fuel pressure at the port with a gauge.

What is the condition of battery cables, your grounds, when was the last tuneup?

**Palf70Step** · 11-29-2024, 04:37 PM

Never had one of these years go into limp mode and have had fuel pumps and distributors die on me. With the fuel pumps it just quit and would not go again. Distributor just ran like poo, or if it was module it just died.

I amjust guessing. That limp.mode on these earlier years would be throttle body related, but that is just a guess..

OutlawDrifter · 11-29-2024, 04:55 PM

Quote:

Originally Posted by Palf70Step

Never had one of these years go into limp mode and have had fuel pumps and distributors die on me. With the fuel pumps it just quit and would not go again. Distributor just ran like poo, or if it was module it just died.

I amjust guessing. That limp.mode on these earlier years would be throttle body related, but that is just a guess..

Not sure Bill, his 97 should be black box MPFI, I'm not saying there isn't a limp mode, but we need some more info to help figure it out.

Black box isn't super advance but it is a step above OBD1 TBI stuff and if there is a problem, chances are there may be some pending or stored codes.

TCLARK · 11-30-2024, 01:20 PM

It may not be "limp mode", it just will not take gas and barely move. First time it did it was low on transmission fluid, filled it up and was find, transmission never slipped. Few months later did it again but transmission level was fine, turned it off and started it back and it was fine. Last time turning it on and back on a couple of times did not work, unhooked the battery and it worked fine. Have not used it since and it's too cold to run a scan right now. Thanx for the input.

sixty8HDC30 · 12-05-2024, 01:42 PM

I bet it’s the throttle position sensor(TPS)

TCLARK · 12-05-2024, 08:44 PM

Quote:

Originally Posted by sixty8HDC30

I bet it’s the throttle position sensor(TPS)

Starts and idles fine.

11-27-2024, 08:30 PM	#1
TCLARK Registered User Join Date: Jun 2009 Location: COOKEVILLE,TN Posts: 150	Limp mode, '97 2500 454 Suburban Sometimes it goes to limp mode but no engine light. Sometimes I can restart and it's OK. Today I unplugged the battery, and it worked....Could it be fuel pump?

11-29-2024, 01:10 PM	#2
OutlawDrifter Registered User Join Date: Aug 2012 Location: Northeast KS Posts: 1,789	Re: Limp mode, '97 2500 454 Suburban What is limp mode, and what are the symptoms? Typically a fuel pump on its way out works better with the tank full of fuel and before it heats up. Easy to test fuel pressure at the port with a gauge. What is the condition of battery cables, your grounds, when was the last tuneup? __________________ 1999 GMC Suburban K2500 SLT, 454/4L80E 1991 Z/28, 6.0L/T56 1949 GMC 250, S10 Frame, 6.0L/4L80E Instagram @aceshighspeedshop

11-29-2024, 04:37 PM	#3
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,228	Re: Limp mode, '97 2500 454 Suburban Never had one of these years go into limp mode and have had fuel pumps and distributors die on me. With the fuel pumps it just quit and would not go again. Distributor just ran like poo, or if it was module it just died. I amjust guessing. That limp.mode on these earlier years would be throttle body related, but that is just a guess.. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

11-30-2024, 01:20 PM	#5
TCLARK Registered User Join Date: Jun 2009 Location: COOKEVILLE,TN Posts: 150	Re: Limp mode, '97 2500 454 Suburban It may not be "limp mode", it just will not take gas and barely move. First time it did it was low on transmission fluid, filled it up and was find, transmission never slipped. Few months later did it again but transmission level was fine, turned it off and started it back and it was fine. Last time turning it on and back on a couple of times did not work, unhooked the battery and it worked fine. Have not used it since and it's too cold to run a scan right now. Thanx for the input.

12-05-2024, 01:42 PM	#6
sixty8HDC30 Registered User Join Date: Feb 2023 Location: Nunya Bizz Posts: 87	Re: Limp mode, '97 2500 454 Suburban I bet it’s the throttle position sensor(TPS) __________________ ____________________________________ 1968 Chevrolet C-30 327 4spd flat bed dually 157" WB 1997 Chevrolet k1500 5.0 auto ECSB

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