91 chevy pu 350tbi running problems - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 06-07-2008, 05:29 PM
Registered User
 
Join Date: Jun 2008
Location: washington
Posts: 2
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
91 chevy pu 350tbi running problems

Where to start i have a 91 chevy pickup with a 350tbi 213,000 miles Truck has a problem starting and staying running runs rough and will die and wont start again for a while when it finally decides to start it will idle pretty good then it will jump up to 1400 rpm give it a little gas and will die and of course won't start again. it's getting fuel it also puts out black smoke under power

I have replaced or checked the follwing
egr valve
ecm
ignition module
fuel pump
gave it a full tune up
fuel filter
throttle sensor
Please help thanks Chris

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-07-2008, 05:32 PM
King of my Man-cave.
 
Last photo:
Join Date: Nov 2003
Location: Michigan
Age: 55
Posts: 2,899
Wiki Edits: 0

Thanks: 3
Thanked 15 Times in 12 Posts
Quote:
Originally Posted by ubtoolate
Where to start i have a 91 chevy pickup with a 350tbi 213,000 miles Truck has a problem starting and staying running runs rough and will die and wont start again for a while when it finally decides to start it will idle pretty good then it will jump up to 1400 rpm give it a little gas and will die and of course won't start again. it's getting fuel it also puts out black smoke under power

I have replaced or checked the follwing
egr valve
ecm
ignition module
fuel pump
gave it a full tune up
fuel filter
throttle sensor
Please help thanks Chris
O2 sensors are probably history by now.

tom
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-07-2008, 05:37 PM
Registered User
 
Join Date: Jun 2008
Location: washington
Posts: 2
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks Tom i will try that now
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-07-2008, 06:16 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 57
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Check your PCV valve operation, and look for any vacuum leaks, including the crankcase for a intake gasket vacuum leak. Pull the throttle body and clean out the PCV port on the bottom, and remove the idle air control valve, and clean the pin-tel and port out.

The O'2 sensor is most likely history and would have been my first guess along with fuel pressure. Normally 8-15 psi on your vehicle.

Also take the exhaust pipes loose at the manifolds and see if it will rev up. The catalytic converter could be plugged, causing your engine to not be able to "fart".

My 2 cents worth.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-07-2008, 06:18 PM
racecar100's Avatar
Registered User
 
Join Date: Feb 2008
Location: Tennessee
Age: 54
Posts: 255
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
There one small tempature sensor on the intake mainfold next to the thermosat housing is bad and cause one to puff out black smoke. Unplug it and see if it run..
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-08-2008, 06:34 PM
Registered User
 
Last photo:
Join Date: Jan 2008
Location: Kemah TX
Posts: 425
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I had the same type of issue with my 88 with 293K on it the temp sensor and conector took care of it. The O2 sensors don't do anything till they get to 600 degrees and put the ECU in closed loop.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-08-2008, 06:52 PM
King of my Man-cave.
 
Last photo:
Join Date: Nov 2003
Location: Michigan
Age: 55
Posts: 2,899
Wiki Edits: 0

Thanks: 3
Thanked 15 Times in 12 Posts
Quote:
Originally Posted by Mike H
I had the same type of issue with my 88 with 293K on it the temp sensor and conector took care of it. The O2 sensors don't do anything till they get to 600 degrees and put the ECU in closed loop.
Good call. A faulty engine coolant temperature sensor (NOT coolant temperature sending unit) will tell the computer that the engine is stone cold ALL the time, resulting in an over-rich mixture, regardless of real ambient temperature.

But the O2 sensors are probably waxed, too.

tom
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-08-2008, 07:12 PM
curtis73's Avatar
Hates: Liver. Loves: Diesel
 
Last wiki edit: How to find cheap parts
Last journal entry: Found an LQ9 today
Last photo:
Join Date: Dec 2005
Location: Carlisle, PA
Age: 41
Posts: 5,173
Wiki Edits: 16

Thanks: 7
Thanked 9 Times in 6 Posts
Leaky injectors are common on the TBIs. That would cause the issues you're describing
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 06-09-2008, 11:22 AM
n-gin's Avatar
Registered User
 
Last photo:
Join Date: May 2008
Location: Parma heights, Ohio
Posts: 148
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Take a reading of the intake vacume. Also check to see if the intake gasket has sucked in and actually causing vacume in the crank case. To check take your pcv out and see if you have a vacume in the valve cover.

Black smoke is caused by a lot of things. Leaking intake. Leaking egr. temp sensor, o2 can be lazy too. That just a few things.

It sure sounds like a fuel related problem. You did not specify the psi you have on your fuel. Best thing to do is put a psi gauge on the fuel rail, most of the tbi did not have a shradder valve, so your might have to dead head the system into the gauge. It will read higher with it dead headed about 40-75 psi. Sometimes you can just pull the return line off and see if it sprays out of the tbi. If it just leaks out or trikkles a little then you have a bad fuel pump.

I have had the egr valves not leak through the pintle but leak through the base to valve. So depending on how you tested the egr will give you different results. I take the valve off and put exhaust gasket matterial between the intake and the egr vavle with no holes except the bolts. That way you know that the valve is not leaking in any way.

I would check the base timing too. Along with timing chain slack. Take the dist. cap of and turn the engine by hand take note of how far the crank moves before the rotor starts to turn.

Last edited by n-gin; 06-09-2008 at 11:44 AM.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
the history of chevy v8's savman1 Hotrodders' Lounge 43 03-02-2012 06:57 PM
1987 Chevy Tbi Problems hiball Engine 6 02-10-2007 05:15 PM
My Chevy is running better with a Ford part on it. CrashFarmer2 Hotrodders' Lounge 3 12-08-2006 10:02 AM
help please chevy 350 problems wickedenvy Hotrodding Basics 14 08-15-2006 09:23 AM
ID Plate, 50 chevy pu, goes where fat50chevy Body - Exterior 3 08-11-2005 11:39 AM


All times are GMT -6. The time now is 08:17 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.