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1996 S10 blazer 4.3 v6


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Guest
Anonymous Poster
russb@pride-eng.com

Nov 10, 2008, 7:30 AM

Post #1 of 13 (3902 views)
1996 S10 blazer 4.3 v6 Sign In

It's me again, the idiot.
It's cold here now and when I start up the S1 in the morning the idle is blazing fast but comes down after I drive for a few minutes.
I need a cheap fix as our furnace went out on Saturday...help.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 10, 2008, 8:55 AM

Post #2 of 13 (3898 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

How fast is this "Bazing fast" you describe? Raised idle when stone cold is somewhat normal - does it return to normal idle when it does come down?

It may be fairly simple to fix. Please tell just how fast and more about it.

Hey - You are not necessarily an idiot. Perhaps just an "id 10 t'' computer problem we all have now and then! Select a user name next time you come back when it asks to "sign in" so you have a name other than "guest" which is fine but limits you a bit. You pick any name you wish no taken and stay annon - don't worry,

T



Guest
Anonymous Poster

Nov 10, 2008, 9:15 AM

Post #3 of 13 (3895 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

I have a user name somewhere written down...
I meant "blazing fast".
It's a very high idle like when you hit the gas in park and run the engine fast. This is beyond a warm up idle. Could it be the Idle air control valve?


Guest
Anonymous Poster

Nov 10, 2008, 9:18 AM

Post #4 of 13 (3894 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

Sorry, yes it does come down after a little while, but It won't kick down until after i drive.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 10, 2008, 9:50 AM

Post #5 of 13 (3890 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

I'm firguring it's temp sensitive item IF (you didn't say yet) it returns to normal when warmer. That could be the coolant temp sensor (usually yellow wire and a black wire screw into manifold item near thermostat) telling engine something extreme or perhaps the throttle plate sticky itself?? I don't know if this uses linkage or not but that too.

Does it behave when warm? That's a key to moving on with this,

T



Guest
Anonymous Poster

Nov 10, 2008, 11:35 AM

Post #6 of 13 (3881 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

Tom, it's fine after it warms up. Do you think it may be the Idle air control valve or the EGR?


dmac0923
Enthusiast

Nov 10, 2008, 11:47 AM

Post #7 of 13 (3879 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

Im with Tom, ive had plenty of pesky IAC valves on my fords. If the IAC is suspect, it shouldnt matter if the engine or ambient temp is hot or cold. if its bad/clogged it will act up everytime until fixed.

Anything with the EGR would trigger an DTC and result in a CEL check engine light.
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Guest
Anonymous Poster

Nov 10, 2008, 12:00 PM

Post #8 of 13 (3875 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

I had a check engine light come on recently, but that was emmisions related. A guy I work with was a mechanic and mentioned the possiblilty of the IAC. He also said the EGR would be the next step. He said that id the thermostat wasn't working properly the EGR could get plugged up. I found the IAC, should I just take it out and get a new one or how do I check this one and how do I check the EGR?? I sure appreciate your guys help!


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 10, 2008, 12:08 PM

Post #9 of 13 (3874 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

Guest: dmac and I are on the same page in that we think the engine is told it's cold - a credable wrong tidbit of info regarding how cold the engine is. The thing has gradients by the exact coolant temp of resistance to the puter to adjust both idle and mixture as like simulating a choke action. Credible WRONG info would act accordingly till perhaps a downstream sensor like O2 then overrides noting too rich or something and is cutting the corner so it will behave warm.

That's the clue - it can behave warm but is late in knowing just how warm and you are getting extreme adjustments for a minute or two. I don't think it will throw codes just yet as it doesn't seem to pass the cold "grace period" when first started and then it's fine.

The sensor for that is up by thermostat on the Chev 5.7 and many other GM engines with black and yellow wires. Was noted in a box and came with a new plug to be soldered in one once that connector was a problem spot. I have one of these to fix soon and the new sensor on in hand - tested is uninstalled another working similar GM and it behaved fine for a cold start and ohms matched a chart I found on it too.

That CTS is cheap and like I said would alter the behaviour if just plugged in without installing it for a test. It looks kinda like a spark plug and threads into coolant at manifold right near thermostat - but any wiring problem along the way could be the issue.

The raised idle for a moment is ok but you mentioned over 1800 which is too high completely so there may be more to it,

T



Guest
Anonymous Poster

Nov 10, 2008, 1:26 PM

Post #10 of 13 (3868 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

Tom, I just went out and found the CTS, it's $12.00 at the local, I can just change this out right??
Also, you don't feel that it may be the Idle Air control?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 10, 2008, 3:54 PM

Post #11 of 13 (3852 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

If you don't mind risking $12 bucks then test out the old one which is a pill but if you have the ohm meter and feel like taking it in the home and heat it up, cool it down and watch ohms go for it.

I think you can just plug in the new one without installing it - I would be some kind of realistic cold when cold and catch engine heat just setting there as a test. I'd suggest grounding the threaded part to block but last test I didn't find it needing that - was just an inline resistor that sensed temp.

Now! It's probably 19mm or 3/4" socket (both are about the same) and it uses plumbing thread into cooling system. At some age these can be headaches or worse - break - arggh! Put some PB (power blaster) penetrating oil on the threads now and hope for the best. You need to lower coolant in engine some or it would spill out at that level and either way make sure it's properly filled again when done.

There's no bargain if the sucker breaks in the engine so you decide. Testing it can be done on vehicle if you have the stuff,

T



Loren Champlain Sr
Veteran / Moderator
Loren Champlain Sr profile image

Nov 10, 2008, 5:39 PM

Post #12 of 13 (3848 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

I can tell you with (almost) certainty that it is NOT the EGR or the IAC that is causing your problem. Listen to Tom. Smile IMHO
Loren
SW Washington


Guest
Anonymous Poster

Nov 11, 2008, 4:13 AM

Post #13 of 13 (3844 views)
Re: 1996 S10 blazer 4.3 v6 Sign In

Tom, I will be busy on the farm getting the waterers ready for winter tonight, but I'll try your test tomorrow and I'll get back with you. Thanks a ton man!






 
 
 






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