TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

1992 c1500 305 sluggish down low

Old 11-09-2018, 10:21 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Nov 2018
Posts: 1
1992 c1500 305 sluggish down low

Serious answers or thoughts only please!!!
my 1992 305 tbi feels like it's running out of fuel down low in Rpm's, 1st gear is fine then in 2nd it'll slug until about 50mph and pick up power really hard and does the same through 3rd and 4th, also something to mention that might be important is as soon as it shift it shoots a huge black cloud out of the exhaust but I already know my valve stem seals are SHOT!!! Please help me out anyway you can
92c1500 is offline  
Old 11-09-2018, 11:31 PM
  #2  
Supreme Member
 
Join Date: Feb 2011
Posts: 1,064
Re: 1992 c1500 305 sluggish down low

Connect a scan tool, look at the data stream while someone else drives the vehicle. Connect a fuel pressure gauge, look at fuel pressure as they're driving and the vehicle is acting-up. Perform a cranking compression test. Buy a spark tester for HEI ignitions--or an adjustable spark tester--and verify that the ignition coil isn't weak.

I'd want to know O2 voltage and cross-counts, short- and long-term fuel trim, coolant temperature, knock sensor activity, and anything else that looks suspicious.

Is there anything left of the catalytic converter? Original? Gutted/removed?

If the valve stem seals are that bad, the plugs might be fouled and the chambers filled with deposits. Oil in the air/fuel mix lowers the octane rating of the fuel, and the deposits can raise compression. Both lead to detonation, detonation leads to knock sensor going crazy, and that leads to retarded timing and poor power. Look at the plugs when you have them out to perform the cranking compression test.
Schurkey is offline  
Old 11-10-2018, 01:53 AM
  #3  
Senior Member
iTrader: (1)
 
Galaxie500XL's Avatar
 
Join Date: Sep 2015
Location: Knoxville, TN
Posts: 585
Car: 1988 IROC-Z
Engine: 350 TPI
Transmission: T56 swap ongoing
Axle/Gears: 2.77 9-bolt Posi
Re: 1992 c1500 305 sluggish down low

Good to see you Shurkey...used to see you all the time on W-body.com.

I was thinking if he’s got an oil control problem, the O2 sensor is probably already hosed...but the sensor info you asked for would tell the tale.
Galaxie500XL is offline  
Old 11-10-2018, 02:53 AM
  #4  
Pro
Supreme Member
 
Join Date: Oct 2003
Location: DFW
Posts: 1,008
Car: 1992 Z28 and 1995 Silverado
Engine: 5.7 TPI and 5.7 TBI to TPI convert
Transmission: 700R4 and 4l60E
Axle/Gears: G80 3.23 and open 3.42
Re: 1992 c1500 305 sluggish down low

Its a truck, and the only place to plug in for checking pressure on a TBI is under the drivers seat along the frame with an adapter between the tank and the fuel filter, so lol please dont drive down the road, door open looking down at the pressure.
Pro is offline  
Old 11-10-2018, 11:15 AM
  #5  
Junior Member
 
Join Date: Sep 2018
Location: NV
Posts: 18
Car: 1991 S10 v8 AWD
Engine: 5.7 TBI
Transmission: 700r4 with vette servo upgrade
Axle/Gears: 3.73
Re: 1992 c1500 305 sluggish down low

I use This adapter , and plug it directly behind truck tbi, and just put gauge under windshield wiper to hold it down.
Uno122 is offline  
Old 11-10-2018, 04:55 PM
  #6  
Supreme Member
 
Join Date: Feb 2011
Posts: 1,064
Re: 1992 c1500 305 sluggish down low

Originally Posted by Pro View Post
Its a truck, and the only place to plug in for checking pressure on a TBI is under the drivers seat along the frame with an adapter between the tank and the fuel filter, so lol please dont drive down the road, door open looking down at the pressure.
That's the advantage of having a long hose. Allows the gauge in the cab while the adapter is in place near the fuel filter or by the throttle body. I found it impossible to connect my pressure adapter on a van--there was no room behind the throttle body assembly. Had to use the adapter that fits in place of the fuel filter.

Schurkey is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
3400beretta
Transmissions and Drivetrain
0
02-18-2007 01:53 PM
techno101
Engine Swap
1
12-19-2006 09:23 PM
91_B4C_RS
Firebirds Wanted
10
06-20-2006 04:44 PM
flamenchevy
TPI
6
07-03-2003 09:32 AM
tpic1500
TPI
8
01-05-2001 01:17 PM


Thread Tools
Search this Thread
Quick Reply: 1992 c1500 305 sluggish down low


Advertising
Featured Sponsors
Vendor Directory

Contact Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: