The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 02-09-2025, 12:59 AM   #1
JoePolo
Registered User
 
Join Date: Jan 2018
Location: South San Francisco
Posts: 53
TBI is Dying

I bought an 89 Suburban with a 350 TBI. The second I bought it, fired it up and went to leave the fair grounds (bought at a swap meet) and it died. Took a bit to get going again, got it going then drove about another 1/2 mile and died while driving. Pulled over and got it going again. Then drove 2 hours home with no issues at all.

Until today…..

Went to the smog station (about 3 miles from my house). It died a few blocks away from the station and started again. Then once it got to the smog station it ran and idled for a while then from that point on, it wouldn’t stay running for more than a minute. So I took it back and limped it back to my garage.

It will do it idling or driving, takes 30 seconds to a minute. It will restart every single time with a key cycle as if nothing was wrong then do the same thing again. If I try to start it without a key cycle it won’t restart.

Any ideas of where to start. When running both injectors are firing, at first they weren’t (unplugged and plugged them back in and they both work every time now) but still having the same issue. I’m baffled.
JoePolo is offline   Reply With Quote
Old 02-09-2025, 10:12 AM   #2
raggedjim
Senior Member
 
raggedjim's Avatar
 
Join Date: Jun 2002
Location: Murray, Kentucky
Posts: 3,589
Re: TBI is Dying

Happened to my '94, it was the fuel pump. Not saying yours is the fuel pump but same exact symptoms.

Good luck, Rg
raggedjim is offline   Reply With Quote
Old 02-09-2025, 12:55 PM   #3
sntrym95
Registered User
 
sntrym95's Avatar
 
Join Date: Jan 2006
Location: Big Pine Key, FL
Posts: 758
Re: TBI is Dying

You need to log data to find out if a sensor is crapping out. You can also test fuel pressure but need to add an inline gauge. Check for codes using a paper clip. There is a sticky on this forum on how to do it.
__________________
Mike
sntrym95 is offline   Reply With Quote
Old Yesterday, 12:02 AM   #4
JoePolo
Registered User
 
Join Date: Jan 2018
Location: South San Francisco
Posts: 53
Re: TBI is Dying

Quote:
Originally Posted by raggedjim View Post
Happened to my '94, it was the fuel pump. Not saying yours is the fuel pump but same exact symptoms.

Good luck, Rg
Exact same symptoms is a pretty good starting point. I’ll check fuel pressures as it happens and also change the fuel filter as a just in case.
JoePolo is offline   Reply With Quote
Old Yesterday, 09:19 AM   #5
Palf70Step
State of Confusion!

 
Palf70Step's Avatar
 
Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 47,359
Re: TBI is Dying

How old is the fuel? You could be getting some junkin the system. As others say test fuel pressure and check fuel pump.
__________________
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!
Palf70Step is offline   Reply With Quote
Old Yesterday, 10:18 AM   #6
raggedjim
Senior Member
 
raggedjim's Avatar
 
Join Date: Jun 2002
Location: Murray, Kentucky
Posts: 3,589
Re: TBI is Dying

Quote:
Originally Posted by JoePolo View Post
Exact same symptoms is a pretty good starting point. I’ll check fuel pressures as it happens and also change the fuel filter as a just in case.
I hope it's not, dropping the tank is a bear.
raggedjim is offline   Reply With Quote
Old Yesterday, 11:36 PM   #7
JoePolo
Registered User
 
Join Date: Jan 2018
Location: South San Francisco
Posts: 53
Re: TBI is Dying

Quote:
Originally Posted by raggedjim View Post
I hope it's not, dropping the tank is a bear.
I have a lift and a transmission jack so won’t be too bad but also hoping I don’t have to drop the tank.
JoePolo is offline   Reply With Quote
Old Yesterday, 11:38 PM   #8
JoePolo
Registered User
 
Join Date: Jan 2018
Location: South San Francisco
Posts: 53
Re: TBI is Dying

Quote:
Originally Posted by Palf70Step View Post
How old is the fuel? You could be getting some junkin the system. As others say test fuel pressure and check fuel pump.
Fuel is fresh 91 octane after the 2 hour drive home it needed a tank haha

I’m also gonna test ignition switch I bought one the key cycle has me thinking it’s ignition more than fuel but I’m still going to test the fuel system.
JoePolo is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:07 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com