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93 s10-Blazer Tahoe Hesitation during acceleration

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Old 08-11-2010, 02:46 PM
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Default 93 s10-Blazer Tahoe Hesitation during acceleration

Hello everyone i am new here and just stumbled onto this site doing google searches for my problem and thought who better then people on a forum specifically for blazer owners.

Anyway on to my problem, I recently aquired a 93 s10 blazer tahoe 2wd with the 4.3L vortec(W) I got it for free from a guy that had it just sitting behind his barn for 6+ years and said if i got it out of his yard it was mine lol. So i put in some gas and a new batt and it fired right up and seemed for sittin so long to run actually very nice. It has 197k miles on it and doesn't leak a drop of oil or burn it from what i can tell and when i asked him why it was just sitting all that time he explained to me that it was stalling on him all the time when he let off the gas and came to a stop anywhere so he just parked it and just never bothered to get it fixed or looked at.

So i managed to get it home but like he said it would stall and try and die on me everytime i let off the gas. So my first thought was the EGR valve was bad because i had read this was a common issue with these blazers infact there was a recall on some faulty egr valves installed on these blazers new i just forget what years were included in it. So a buddy removed the egr and cleaned it for me and reinstalled it and sure enough the stalling stopped so i thought that was the end of the problem, However it is hesitating when i accelerate and idling a bit rough after it warms up. When it is cold the hesitation seems to be minimal if at all and idles smooth but only for about 2 mins down the road until it gets warmed up a bit which my first guess was that it was still a egr problem because when it is cold it is in loop from what i gathered from reading various posts here.
But i thought to check other posibilities first so since it was sitting for such a long time AND has 197k miles on it i assumed the fuel filter maybe needed replaced and it was just starving for fuel, However the fuel filter seemed to have no blockage at all air passed thru it easily without any effort when i tested it but i replaced it anyway and appears to be getting plenty of fuel. But i can hear a hissing sound that is coming from behind the rear drivers tire, At first i thought was the tire going flat but when i shut off the engine the hissing stopped and i was told by a friend not to worry it was just the fuel pump. I have owned alot of vehicles and i have never heard a hissing like a tire deflating coming from a fuel pump it sounds more like a vacuum leak to me but is there vacuum lines going back that far behind rear tires to the gas tank ?

Also the hesitation is only present when driving, When it is in park in my driveway it revs fine no hesitation at all but put it in gear and accelerate down the road and it starts to hesitate.

I then thought to check for codes even though the check engine light is not on showing any malfunctions, And sure enough it is throwing a code 32. BUT i thought maybe the code was never cleared from before when it was stalling so i pulled the ecm fuse and waited 10+ seconds and put it back in and without even starting the vehicle just turning the ignition to on position it was still throwing the code 32 which i find odd. The ecm wouldn't allready have detected a bad egr if engine hadn't even been started for egr to be active yet would it?? It was like the ecm didn't even erase the code.
But even after disconnecting the battery for a hour or so ( i had to replace the passenger headlight anyway and to get to the connector i had to remove the battery to get to it easier ). It is still showing a code 32.

So my main question is do i need a new egr ? Apparently just cleaning it didn't solve anything other then the stalling because from my researching about hesitation on acceleration on various sites it 99% of the time comes up that it is a bad egr that usually causes this so maybe the eletronic part of the valve isn't working right. But to put it mildly i don't have alot of money falling out of my pockets and i can't offord to go replacing 50 parts trying to solve this problem nor can i even offord the cost of a new $170 egr valve.

A small update since i started posting this i stopped for a bit to go to town to run a few erands and out of nowhere it started stalling on me again but after i restarted it a few times and it stalling at 2-3 stop lights and got a few miles down the road and stopped again it magically stopped stalling lol. So i am no expert but it sure seems to point to a bad egr to me.

My BIG question for you all is should i just cut bait and try and sell it as is to some one that is more finantually qualified to repair it or should i just try and get a used egr out of a scrap yard blazer and try that first or do you think it is a vacuum leak coming from the back causing it or something else ?

My main goal was to use it as vehicle to get around for work and i was excited it didn't cost me anything and it run when i have little money but i can't offord to take it to a shop obviously to find out exactly whats wrong with it plus with 197k miles on it it's most likely not worth the R&R to have anything fixed on it. Which is kinda sad because for the age and way it was stored not even garaged but out in the weather for 6+ years other then rusting below the doors along the rails on both sides the body and paint is scratch and dent free and inside looks near brand new and everything still works even the windshieldwasher wasn't plugged lol!

I would hate to get rid of it and find out later it was a simple fix and i let it go when obviously it was a reliable vehicle to have near 200k miles on it and could have gone another 100k.

Sorry for the long book of a post just trying to be as thorough as possible.

But seems to me to be a egr issue now wether it is a bad valve or that hissing is a vacumm leak or both i dunno but i would appreciate your opinions on what i should do with it. Either fix it or just get rid of it.
 
  #2  
Old 08-11-2010, 06:15 PM
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I would go through and replace all of the vacuum lines. Remove and clean the EGR valve. And run a fuel pressure test, specifically watching the leak down rate (shouldn't drop more than 3-5psi after the pump shuts off.

I would also do a complete tune up if at all possible.
 
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Old 08-12-2010, 11:02 AM
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Originally Posted by swartlkk
I would go through and replace all of the vacuum lines. Remove and clean the EGR valve. And run a fuel pressure test, specifically watching the leak down rate (shouldn't drop more than 3-5psi after the pump shuts off.

I would also do a complete tune up if at all possible.
Thx i will do that for sure when i can, Today i just took off the egr valve since my code reader was throwing a code 32 and it had allready been cleaned before a month or so ago when it was doing nothing but stalling which it doesn't do now at present, But so far and at first glance it seems fine other then black inside from carbon but no build up or any peices breaking off or anything but i dunno if this is normal or not but the torx screw in the middle spins around freely i was under the impression it wasn't suppost to just spin like that but rather have tention on it am i wrong ? The pintle moves up and down freely so it doesn't appear to be sticking but yet the ecm is throwing a code 32 so maybe the solenoid on the egr is bad?


Also another question, The vacuum line that connects right above the egr to what appears to be the intake near the air cleaner hose connection what is it for and more importantly should there be vacuum in that line when engine is running at a idle? The hose was off when i got the blazer and i thought it might have been a reason for my problem but when i put it back on nothing changed at all and i can put my finger over the hose and there is no vacuum on the line that i can tell at all.
 

Last edited by KrAzY; 08-12-2010 at 12:20 PM.
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Old 08-12-2010, 05:44 PM
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The pintle (torx thing) shouldn't turn real free. There should be pressure against it.

Can you snap a picture of the vacuum line you are talking about and post it?
 
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Old 08-12-2010, 06:43 PM
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the vacuum line that goes into the throttle body, should be connected.
 
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Old 08-13-2010, 12:41 PM
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Hello.
I also am leaning toward the fuel side of this problem,but do yourself a big favor and check you alternator and make sure its functioning properly.I also have a couple of these engines.One is still in a 95 Blazer.After installing a used alternator it perked up a bit.I think yours should be either 105 or 140 amp output.It makes a huge difference in the performance of these vehicles.
 
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Old 08-13-2010, 01:27 PM
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Im sure everyone know what Im going to suggest checking...

Fire up your truck, pop the hood, and down behind your alternator you will see and red and blue wire going into the intake... Grab a hold of those wires and pull and push them a little... Does the engine change how it runs? Nothing should happen. If the idle changes or it stalls, then its getting a ****ty connectoin to the injector cause the insert in the harness that keeps it tight is rotted away from the oil rich environment that it lives in. Its a rubber part, and rubber doesnt like petroleum products.

That stalling at lights and when i stop happened to me, its a loose injector harness. It would never do it sitting in the driveway because there is no bumps to make the harness move. Its an 8 dollar part and the new one has a silicone insert. Ive been towed home 2 times due to this crappy part.

The EGR you can test with your multimeter. Take it off, and put your Ohm-meter on the 2 outer pins (or 2 left pins) where the plug goes into the EGR. It should read about 4ohms... Then push the plunger down most of the way, the resistance should jump up to around 9.... If it doesnt, then there is a problem inside it. Did you buddy clean real well where the egr flows into the intake too? And shove a wire pipe cleaner in there to make sure it flows through? GimpyBlazer wrote to me how to test them if you search for EGR threads you should be able to find out chat about it.
 

Last edited by ohsofly; 08-13-2010 at 01:31 PM.
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Old 08-13-2010, 01:52 PM
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Originally Posted by swartlkk
The pintle (torx thing) shouldn't turn real free. There should be pressure against it.

Can you snap a picture of the vacuum line you are talking about and post it?
Yes i can i'll post pic in a bit.

Originally Posted by 94BlazerPA
the vacuum line that goes into the throttle body, should be connected.
Yes i believe that is the vacuum line i was refering to thx for your response, throttle body cables are on passenger side and the vacuum hose connects on oposite side on drivers side. It was disconnected when i got the blazer and seems previous owner had issue with it coming off or something because there is a ziptie on the end like they tried to tighten it down to keep it from falling off, But i would think if there is suppost to be vacuum on that line that alone would hold it on, But like i said there is no vacuum on the line from what i can tell enless the vacuum is only activated at certain times or engine speed because when it sites at idle in my driveway i can pull off the vacuum line and there is no vacuum on it or difference in engine performance.

Originally Posted by Mag-300
Hello.
I also am leaning toward the fuel side of this problem,but do yourself a big favor and check you alternator and make sure its functioning properly.I also have a couple of these engines.One is still in a 95 Blazer.After installing a used alternator it perked up a bit.I think yours should be either 105 or 140 amp output.It makes a huge difference in the performance of these vehicles.
Alternator seems to be working fine but i don't have any kind of tester to check the amps but gauge inside works and shows above 12 volts when it is running.

Originally Posted by ohsofly
Im sure everyone know what Im going to suggest checking...

Fire up your truck, pop the hood, and down behind your alternator you will see and red and blue wire going into the intake... Grab a hold of those wires and pull and push them a little... Does the engine change how it runs? Nothing should happen. If the idle changes or it stalls, then its getting a ****ty connectoin to the injector cause the insert in the harness that keeps it tight is rotted away from the oil rich environment that it lives in. Its a rubber part, and rubber doesnt like petroleum products.
Jerked up and down on the blue/red wires and any others in a harness in engine compartment lol and engine didn't change at all so they seem to be all ok. It starts and idles fine that isn't a issue and even revs up with throttle smooth with no hesitation in my driveway it only happens when your actually accelerating down the road driving only way i can try and explain it by a example so you can get a idea of what it is doing is, it acts like it would if you were pressing accelerator then releasing it slightly then pressing it again it hesitates for a second or 2 then accelerates then hesitates for a second or 2 then accelerates gradually ect ect until you finally get up to speed you want it at lol.



UPDATE: I was driving home from work today ( in my car not the blazer ) and happened to see 2 blazers sitting in a guys yard i hadn't seen before and i pulled in and inquired about them and 1 of them had a blown motor he said so i asked if i could buy the egr off it and he said sure lol So i paid $20 for the used egr off his blown up engine and cleaned it up and put it in today and drove the blazer down the highway at about 58mph for about 5-10 mins then returned home and put my code reader back on it and the code 32 is now gone so there was "something" not right with my old one because even cleaning it and reinstalling it still thru code. So i thought that might have solved the hesitation problem but sure enough it didn't lol.

However since it had been sittin for a few days when i took it for a drive it didn't hesitate at all at least not enough i could notice it and took off and seemed to accelerate great i was all excited! It was shortly after it got warmed up ( which didn't take long with indiana humidity and 95 degrees out today haha ) that i noticed it start hesitating again and not wanting to accelerate smoothly anymore. So the egr might have been a issue before but it doesn't appear to be malfunctioning now as the code 32 is gone but the hesitation remains.

I dunno if this matters or not but the temp gauge doesn't work in the blazer either it hasn't since i got it so either the gauge is bad ( doubtful ) or the temp sensor is bad, Would the temp sensor have anything to do with it running pretty good cold then crappy when warmed up or does that sensor just run the gauge and not send anything to ecm that effects engine performance?

My next thing to do when i can is have the fuel pressure checked as suggested but if it runs good cold and starts hesitating when warmed up i wouldn't think that is a fuel pump or pressure problem, I would think it would hesitate all the time if there was a fuel pump/pressure issue but i'm no expert just guessing but i'll have it checked anyway just to rule it out anyway.

Then i suppose the next logical thing to check is rotor and cap and points ( if it has points ? ) and see if needs replaced and sparkplugs. It has afterall been sitting for at "least" 6 years outdoors and not garaged so it could be like finding a needle in a haystack trying to figure out why it is hesitating it could be anything from rusted/dry rotted or broken stuff from sitting for so long.

But i did afterall get it for free and i'll post pics in a bit for you all to see it really doesn't appear to be in that bad of cosmetic shape at all considering how long it just sat in the extreme heat and cold over the years.

3rd pic i think i zoomed in a little too much LOL but the vacuum line is in red and u can see the ziptie that some one put on it but it wasn't even on when i got it but there is zero vacuum on that line enless i am not testing it for vacuum right.
 
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Last edited by KrAzY; 08-13-2010 at 04:05 PM.
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Old 08-13-2010, 04:27 PM
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I can't really tell what it is you have circled in that picture. Nothing for reference.

Here is the vacuum diagram for your truck:
 
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Old 08-13-2010, 10:52 PM
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I would suggest doing a complete tune up, plugs, wires, cap and rotor. Trace all vacuum lines and check for cracks or broken lines.

If you can get a fuel pressure gauge, hook it up and only turn your key to the ON position, dont start it. Pressure should be 58-60psi. Turn key off and watch to see if pressure drops right away. If it does then you have problems, bad fuel pressure regulator. If it slowly(5 mins) drops then your good.
 

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