4.3L woes!

CamanoGMC · 01-15-2006, 01:39 PM

New to this forum and glad to be here!
I bought my '95 Sierra in Dec 0f '94 and it's been a GREAT truck. It has a 4.6l that, up until now, has been a very dependable engine. I have serviced it regularly since new and it currently has 154,000 miles on it.
It sat for a couple of months while I was away. When I returned, I could not get the engine to start without substantial throttle pumping and it will not idle. I pulled and cleaned plugs, checked for spark...all OK. I removed the air filter cover to check for fuel. It appeared to be excessive fuel. I disconnected 1 injector and the engine ran a bit smoother. I then did the same with the second (of 2) injectors and it ran much worse, leading me to believe I had an injector problem. This morning I installed 2 new bosch injectors expecting to remedy the situation. After 15 minutes of ranting explatives, throwing tools and preparing to dig a very deep grave for my GMC, I thought maybe I should take a few minutes to see if salvation is out there somewhere...
Any help is certainly appreciated.
Mike

chevyguy · 01-17-2006, 09:38 PM

Sounds like a temp sensor went ou to me. Check you codes for anything . Stop guessing at this, it will get expensive. You may or may not have a check engine light lite up, Pull your codes anyway, You might be surprised.

CamanoGMC · 01-18-2006, 03:36 PM

Chevyguy,
A scanner I have!Trouble code references, I don't?
I did scan the truck before starting all of my "guess-work" and couldn't find any trouble codes.
I'm hoping I can do this with an engine-off scan?
Thanks!

bry · 01-29-2006, 08:18 AM

Hi, if it's a 4.3 liter my friend's got the same problem.The scanner said it's either the TPS(throttle position sensor) or the EVAP sensor. He can get it started with throttle pumping but it still runs a little rough when he drives it. If he fixes this problem I post it.

mudseeker · 02-03-2006, 07:18 PM

check your gaskets, they may have dried up! My old 4.3 ran hard, changed the tps as mentioned and did nothing. Took some carb cleaner and sprayed around tbi, stalled the engine out. I pulled the tbi and engine had sucked in a portion of the gasket, replaced the gaskets and it ran fine.

01-15-2006, 01:39 PM	#1
CamanoGMC Junior Member Join Date: Jan 2006 Posts: 2	HEEEEELP! 4.3L...running rough & I'm puzzled?? New to this forum and glad to be here! I bought my '95 Sierra in Dec 0f '94 and it's been a GREAT truck. It has a 4.6l that, up until now, has been a very dependable engine. I have serviced it regularly since new and it currently has 154,000 miles on it. It sat for a couple of months while I was away. When I returned, I could not get the engine to start without substantial throttle pumping and it will not idle. I pulled and cleaned plugs, checked for spark...all OK. I removed the air filter cover to check for fuel. It appeared to be excessive fuel. I disconnected 1 injector and the engine ran a bit smoother. I then did the same with the second (of 2) injectors and it ran much worse, leading me to believe I had an injector problem. This morning I installed 2 new bosch injectors expecting to remedy the situation. After 15 minutes of ranting explatives, throwing tools and preparing to dig a very deep grave for my GMC, I thought maybe I should take a few minutes to see if salvation is out there somewhere... Any help is certainly appreciated. Mike Last edited by CamanoGMC; 01-16-2006 at 07:41 PM.

01-17-2006, 09:38 PM	#2
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	Sounds like a temp sensor went ou to me. Check you codes for anything . Stop guessing at this, it will get expensive. You may or may not have a check engine light lite up, Pull your codes anyway, You might be surprised. __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

01-18-2006, 03:36 PM	#3
CamanoGMC Junior Member Join Date: Jan 2006 Posts: 2	Thanks Chevyguy Chevyguy, A scanner I have!Trouble code references, I don't? I did scan the truck before starting all of my "guess-work" and couldn't find any trouble codes. I'm hoping I can do this with an engine-off scan? Thanks!

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01-29-2006, 08:18 AM	#4
bry Junior Member Join Date: Jan 2006 Posts: 1	Hi, if it's a 4.3 liter my friend's got the same problem.The scanner said it's either the TPS(throttle position sensor) or the EVAP sensor. He can get it started with throttle pumping but it still runs a little rough when he drives it. If he fixes this problem I post it.

02-03-2006, 07:18 PM	#5
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,374	check your gaskets, they may have dried up! My old 4.3 ran hard, changed the tps as mentioned and did nothing. Took some carb cleaner and sprayed around tbi, stalled the engine out. I pulled the tbi and engine had sucked in a portion of the gasket, replaced the gaskets and it ran fine.