Go Back   Blazer Forum - Chevy Blazer Forums > Mechanical & Maintenance > General Tech Help > 1st Gen S-series (1983-1994) Tech
Sign in using an external account
Register Forgot Password?
Search


Welcome to Blazer Forum!
Welcome to Blazer Forum,

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to start new topics, reply to conversations, privately message other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Blazer Forum today!


Closed Thread
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 09-18-2010, 08:46 AM
New Member
1994 Chevrolet Blazer
 
Join Date: Sep 2010
Posts: 3
oopackmanoo is on a distinguished road
Default Intermittent running rough under load and at idle

I have a '94 Chevy Blazer Vin W. I have totally rebuilt and replaced almost all sensors and components. These are heater core, distributor, cap, rotor, wires, plugs, ecm, map sensor, tps, egr valve, coolant temp sensor, oxygen sensor, fuel pump, fuel injector, fuel line kit, ac compressor, ac drier, lf window motor, water pump, fan clutch, reman cylinder heads, ignition coil, front and rear brakes and wheel cylinders, new shocks, iac motor, starter, battery, and knock sensor. Some days the vehicle runs fine. Other days it searches for idle and runs rough under load. It kind of makes a popping noise. I have a lot of money invested in this vehicle and I'm hoping someone can help. We first thought it was a fuel problem with the way the truck was acting, but replaced all fuel compents with and put on a new fuel injector. The only thing that I think it could possibly be is the pcm. That's the only component we haven't replaced. Any ideas would greatly be appreciated.
  #2  
Old 09-19-2010, 03:27 AM
Magmotor's Avatar
Starting Member
 
Join Date: Jul 2010
Posts: 123
Magmotor is on a distinguished road
Default

You didn't mention the cat. If that is plugged, it can cause a lot of problems.
__________________
  #3  
Old 09-20-2010, 02:28 PM
New Member
1994 Chevrolet Blazer
 
Join Date: Sep 2010
Posts: 3
oopackmanoo is on a distinguished road
Default The cat has flow

The rough idle and roughness underload are both intermittent. The cat seems to have good flow. Took it off and cleaned it. Maybe it needs replaced. I actually found out that the pcm has been changed. Don't know if I got a faulty one of those or not though. Any other ideas of what to test??
  #4  
Old 09-20-2010, 04:17 PM
Junior Member
 
Join Date: May 2010
Location: Philadelphia, PA
Posts: 289
94BlazerPA is on a distinguished road
Default

Its probally the fuel injector connector, that plug that connects onto the top of the Spider inside the plenum. The rubber spacer goes to mush from being exposed to fuel and cause's a loose connection. Theres 2 wires, red and blue that run out the front of the plenum on the driver side. Wiggly them while its idling and see if it acts up. I figure its this, becuase you say underload, so the connector vibrates and causes a poor conection. Its a $10 fix at Autozone.
__________________
'94 Jimmy SLE 4dr 4x4 4.3 CPI - Daily Driver - R.I.P
'94 Ford Mustang 5.0 Summer Fun
'98 Plymouth Grd Voyager SE - Wife's Old - Traded In
'06 Mercury Mountaineer Premier - Wife's New
'00 Blazer LS 4dr - Late Dad's Truck, New Daily Driver
  #5  
Old 09-27-2010, 07:23 AM
New Member
1994 Chevrolet Blazer
 
Join Date: Sep 2010
Posts: 3
oopackmanoo is on a distinguished road
Thumbs up Problem solved

After more careful inspection, I got the bright idea of unplugging the egr to see what would happen. Idle smoothed out and could rev engine with no hesitation. There is a three way check valve on the back of the intake. When I inspected it, I noticed a small crack that was allowing the intake to get too much air. It was intermittent b/c when it was turned one way the crack closed and the other opened the crack. Replaced the three way valve and the truck is running like new. Thank you to the people who helped me narrow it down. I just wanted to post the fix in case anyone else runs into the same problem.:icon_raz z:
  #6  
Old 09-27-2010, 09:33 AM
ohsofly's Avatar
Super Member
 
Join Date: Jan 2010
Location: Camrose AB... Canada
Posts: 1,532
ohsofly will become famous soon enoughohsofly will become famous soon enough
ohsosofly
Default

Quote:
Originally Posted by 94BlazerPA View Post
Its probally the fuel injector connector, that plug that connects onto the top of the Spider inside the plenum. The rubber spacer goes to mush from being exposed to fuel and cause's a loose connection. Theres 2 wires, red and blue that run out the front of the plenum on the driver side. Wiggly them while its idling and see if it acts up. I figure its this, becuase you say underload, so the connector vibrates and causes a poor conection. Its a $10 fix at Autozone.

x2 - That part is my friggin nightmare. My fix was to solder on a new connector, then before putting it on the injector I put 2 of the tiniest Orings on the pins, then press the connector on and its tight as all hell now. Its a whole $8.00 and the dude will give you 4 of the tiniest rubber rings hes got. You need the ones that stretch a little over the pins on the injector.
__________________
2007 Silverado LT Z71-Pantom Grey, 5.3L, loaded, CAI, HID projectors, LED exterior, AirAid, tinted 15% over factory, color matched and debadged, 20" Platinum Boulevard wheels, ProComp 2", RollPan, custom duals, RST spoiler
1993 S10 Blazer Tahoe LT-Green/Grey, 4.3 Vortec (W), 4x4, loaded, LT265/70R17 (33"), jacked 3+3, ALPINE and JL system 880watts, K&N, 6000k HID, complete LED upgrade, lots of new stuff. Slowly modding and restoring - got a build thread going
Old 09-27-2010, 09:33 AM
 
 
 
Closed Thread

Tags
1993, 43, 50, blazer, chevy, ford, idle, idles, knock, load, rough, rought, runs, s10, sensor


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are On
Pingbacks are On
Refbacks are On


Advertising

Featured Sponsors
Vendor Directory
Our Sponsors

All times are GMT -5. The time now is 04:09 PM.

Internet Brands, Inc.