1988 - 1998 (GMT400) Section for all discussion related to the 1987-1998 Chevrolet and GMC trucks.

'98 K1500 4x4, Stumbles/Dies.

Old Jul 5, 2020 | 8:49 AM
  #1  
CJG_GTX's Avatar
Thread Starter
CF Beginner
 
Joined: Jul 2020
Posts: 10
Likes: 0
Default '98 K1500 4x4, Stumbles/Dies.

Hey people, I am having some issues with my truck. Keeping it short and simple. I drove it a few weeks back, parked it, the next morning it would stumble/die when the accelerator was pressed. CEL codes for CPS, IAC and MAF showed up. All have been replaced, along with the Cap/Rotor. The truck idles fine, but stumbles when the accelerator is pressed. I did a home made smoke test, and am unable to find any vacuum leaks.


Suggestions?




Last edited by CJG_GTX; Jul 5, 2020 at 8:53 AM.
Reply
Old Jul 5, 2020 | 9:54 PM
  #2  
oilcanhenry's Avatar
CF Monarch
 
Joined: Oct 2017
Posts: 4,605
Likes: 269
From: USA
Default

Originally Posted by CJG_GTX
Hey people, I am having some issues with my truck. Keeping it short and simple. I drove it a few weeks back, parked it, the next morning it would stumble/die when the accelerator was pressed. CEL codes for CPS, IAC and MAF showed up. All have been replaced, along with the Cap/Rotor. The truck idles fine, but stumbles when the accelerator is pressed. I did a home made smoke test, and am unable to find any vacuum leaks.


Suggestions?


Sounds like a fuel injection issue. Check your fuel pressure PSI.
Reply
Old Jul 5, 2020 | 10:04 PM
  #3  
CJG_GTX's Avatar
Thread Starter
CF Beginner
 
Joined: Jul 2020
Posts: 10
Likes: 0
Default

I just got ahold of a fuel pressure gauge, and I will be checking it in the A.M. 60-66 psi?
Reply
Old Jul 5, 2020 | 10:11 PM
  #4  
oilcanhenry's Avatar
CF Monarch
 
Joined: Oct 2017
Posts: 4,605
Likes: 269
From: USA
Default

Originally Posted by CJG_GTX
I just got ahold of a fuel pressure gauge, and I will be checking it in the A.M. 60-66 psi?
60 PSI is ideal, but GM say 55 to 62 PSI. I have the same year Chevy pickup as you, so this should be interesting.
Reply
Old Jul 5, 2020 | 10:14 PM
  #5  
CJG_GTX's Avatar
Thread Starter
CF Beginner
 
Joined: Jul 2020
Posts: 10
Likes: 0
Default

Originally Posted by oilcanhenry
60 PSI is ideal, but GM say 55 to 62 PSI. I have the same year Chevy pickup as you, so this should be interesting.
I am surely checking this in the morning.
Reply
Old Jul 5, 2020 | 10:49 PM
  #6  
Mr. Dude with a face's Avatar
CF Active Member
5 Year Member
 
Joined: Jun 2018
Posts: 206
Likes: 36
From: Utah, USA
Default

I agree with @oilcanhenry . I have the same truck I guess as both of you and recently my truck would take a long time to start, it would crank a long time. In my case it turned out to be a bad check valve in the fuel pump, so it was taking time to build up pressure. If memory suits me the fuel pressure point is under the hood, towards the fire wall slightly to the drivers side. I believe it is a black cap and faces upward, should be a shcrader valve in their. Conveniently placed so you can set the gauge on the windshield I might add.
Reply
Old Jul 6, 2020 | 11:18 AM
  #7  
CJG_GTX's Avatar
Thread Starter
CF Beginner
 
Joined: Jul 2020
Posts: 10
Likes: 0
Default

Originally Posted by oilcanhenry
Sounds like a fuel injection issue. Check your fuel pressure PSI.
Originally Posted by oilcanhenry
60 PSI is ideal, but GM say 55 to 62 PSI. I have the same year Chevy pickup as you, so this should be interesting.
Okay, So I ran the fuel pressure, and can post a vid if I figure out how. It starts around 55, then drops to 50 psi. When I touch the gas, the pressure jumps to 60, then I let off the peddle it drops back to 50-54. Sometimes as low as upper 40's.

Video below. (Copy/Paste)

https://m.facebook.com/story.php?story_fbid=3229881343700128&id=100000348 827766


Last edited by CJG_GTX; Jul 6, 2020 at 11:26 AM.
Reply
Old Jul 6, 2020 | 5:56 PM
  #8  
Gumby22's Avatar
CF Veteran
10 Year Member
 
Joined: May 2011
Posts: 1,578
Likes: 302
From: Central Iowa
Default

Originally Posted by CJG_GTX
Okay, So I ran the fuel pressure, and can post a vid if I figure out how. It starts around 55, then drops to 50 psi. When I touch the gas, the pressure jumps to 60, then I let off the peddle it drops back to 50-54. Sometimes as low as upper 40's.

Video below. (Copy/Paste)

https://m.facebook.com/story.php?sto...00000348827766
Was the drop to 50 PSI at key on, engine off, or just at start up? At key on, engine off, pressure should hold and not lose more than 2-3 PSI in 5 minutes.
Reply
Old Jul 6, 2020 | 5:58 PM
  #9  
CJG_GTX's Avatar
Thread Starter
CF Beginner
 
Joined: Jul 2020
Posts: 10
Likes: 0
Default

Originally Posted by Gumby22
Was the drop to 50 PSI at key on, engine off, or just at start up? At key on, engine off, pressure should hold and not lose more than 2-3 PSI in 5 minutes.
At every touch of the pedal, it jumps to 60, then back to 50-52. Once hitting as low as 48.
Reply
Old Jul 6, 2020 | 6:00 PM
  #10  
CJG_GTX's Avatar
Thread Starter
CF Beginner
 
Joined: Jul 2020
Posts: 10
Likes: 0
Default

Originally Posted by Gumby22
Was the drop to 50 PSI at key on, engine off, or just at start up? At key on, engine off, pressure should hold and not lose more than 2-3 PSI in 5 minutes.
key on engine off, it sits around 55. Overnight it dropped to 44.
Reply

Thread Tools
Search this Thread

All times are GMT -5. The time now is 4:16 AM.