Rough idle, gas smell, and frustrations
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Rough idle, gas smell, and frustrations - 8/15/2005 2:24:19 AM
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ShadowHawk
Posts: 72
Joined: 8/15/2005
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Last spring (over a year ago) I changed the plugs, Dist. cap & rotor, and plug wires on my '95 S10 Blazer (4dr 2wd).
Ever since then, it runs VERY rough when at idle (stopped or at a red light, etc.). I have checked to make sure I got all the wires going to the correct cylinders from the distributor cap. (I've now got 118,000 miles on the beast)
Then this last spring I made a cross country trip from Texas to Virginia... halfway through Tennessee, the Check Engine light came on intermittently... I took it to 2 dealers (Tennessee and Virginia) and neither could figure out what was wrong. One changed my thermostat,and the other charged me $300 to change 6-inces of vacuum line and to spray out the carbon from the intake.
The check engine light still came on intermittently for the trip home.. Mentally frustrating for me at that point....
After I returned to Texas, I replaced another 6 feet of cracked/falling apart vacuum lines.. but I still have a VERY rough idle.. I'm getting some dieseling when I shut off the Blazer, and when I start it up, I smell a DISTINCT smell of gasoline - and sometimes a rotten egg smell.
a) I had the catalytic converter changed about 2 years ago - I don't *think* that would be the problem. Though the rotten egg smell reminds me of that..
b) When changing the plugs/wires - I *did* get a couple of them swapped for a second. I fixed it immediately.. But could I have done any valve damage by starting it up with a bad firing order?
c) I changed the o2 sensor when I returned to Texas.. still rough & smelly (the Blazer - not me).
d) EGR valve was changed waaaaayyy back at about 50,000 miles - under Mfg Exhaust system warranty. Both dealers on my trip to Virgina told me that EGR valve couldn't be the problem I was experiencing - though to ME it gave the same symtoms - rough idle, almost wanted to die at low idle...
Would it be worth my time to simply get a timing light to see if my timing was knocked out of whack when I changed the distributor cap & rotor? Or does anyone here have any other suggestions? The code retreived by the first dealer was for a "lean condition". THough I know it wasn't running lean, as I was only getting 14MPG highway miles... I should have been getting closer to 20-22 MPG on the Hwy...
The Service Engine light no longer comes on.. but the mechanical symtoms are still here. Any ideas?
Thanks,
Rex S.
Richardson, Tx
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RE: Rough idle, gas smell, and frustrations - 8/15/2005 3:15:27 PM
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dbo98
Posts: 17
Joined: 8/9/2005
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if you didnt loosen the dist. itself when you ghanged the cap you shouldnt be out of time. although that could make sense with the diesiling and rough idle. it wouldnt hurt to check it though. check to see if any of your new wires are arcing on to something in there. as far as rotten eggs........................
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RE: Rough idle, gas smell, and frustrations - 8/16/2005 8:26:28 PM
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ShadowHawk
Posts: 72
Joined: 8/15/2005
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Okie dokie...
I picked up a timing light at Harbor Freight - Not a bad deal at $24.95. THe Haynes manual says that I need to bypass the timing system by disconnecting a tan wire with black stripe from the distributor - yet it also says to leave the wiring harness connected to teh distributor...
For the life of me.. I can't find any wire going into the distributor that's tan/black stripe. Can anyone here give me a pointer as to where that wire is?
There are 2 wiring harnesses plugged into the lower right hand side of the distributor (when looking at the engine from the front of the Blazer).. but the distributor/cap is behind the engine,a nd just about impossible to (a) see anything back there.. and (b) get my hand in there to pull a wire, even if I were able to see it...
So - where's that mysterious tan/black striped wire?
Thanks,
Rex
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RE: Rough idle, gas smell, and frustrations - 8/16/2005 8:57:17 PM
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zero psi
Site Moderator
Posts: 1075
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From: maynard, MA
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quote:
ORIGINAL: ShadowHawk
The code retreived by the first dealer was for a "lean condition".
this could be an o2 sensor problem. if the sensor is bad, it may send a code stating "too lean". it will then try to richen up the mixture as much as possible. pull the sensor out and see if it is contaminated. if it is, replace it. if you havent done it yet and you have that many miles, then its about time to do it anyways.
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01 jimmy, 95 blazer, 01 sonoma, 75 kawasaki kz400, 87 starcraft popup lol!
 
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RE: Rough idle, gas smell, and frustrations - 8/16/2005 9:26:33 PM
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ShadowHawk
Posts: 72
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Yeah - that's the first thing the guy at AutoZone told me as well... So I did replace the o2 as soon as I got back to Texas from Virginia (this last March). Granted.. I have not seen the service engine light since then... But I haven't driven for any extended period of time (i.e. 4+ hours at a time) since then either... but it still runs rough at idle, and diesels when I turn off the ignition...
On a whim, I jumpered my freaky OBD (OBD-I Blazer, but an OBD II connector) connector to see if I had any codes in there... All I get are the 12 code over.. and over.. and over... and over...
Still, I'm unable to find the mysterious tan wire with a black stripe to check my timing (by disabling the timing system)... But I'm wondering if it could be a fuel delivery problem. It's just kind of got me in a quandry... I'm gonna change the fuel filter again, too.. Cheap, and needs to be done periodically...
Something I noticed this morning when I fired up the Blazer... The exhaust seems to have a prety consistent "fft ffft ft ft ft ft ffft" kind of sound emitting from the exhaust pipe.
This weekend I'll see about replacing the plugs again.. and will see if they seem to be sooty... I need to pick up a swivel adapter for my socket wrench though. Several of the plugs are a booger to get out and install!
Rex S.
'95 S-10 Blazer 2WD 4Dr
< Message edited by ShadowHawk -- 8/16/2005 9:30:04 PM >
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RE: Rough idle, gas smell, and frustrations - 8/16/2005 9:45:32 PM
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zero psi
Site Moderator
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From: maynard, MA
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sorry, i just noticed that you changed it in your first post. im not sure about that wire though. ill see if i can find something out tomorrow.
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01 jimmy, 95 blazer, 01 sonoma, 75 kawasaki kz400, 87 starcraft popup lol!
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RE: Rough idle, gas smell, and frustrations - 8/17/2005 2:50:29 PM
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Hanr3
Wheels & Tire Moderator
Posts: 3479
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I had a great post, however I got an error message saying I didn't have sufficient permission. Somehow I was logged out and logged back in as a guest. Arrggggg
I'll try to recreate it.
When is the last time you replaced the air filter?
Have you ever replaced the IAC (idle air control) valve?
Get the ignition control module tested. Realatively easy to take off and most autoparts stores can test them. Call first, AZ didn't have the right wiring harness, however O'Rielly's did.
Egg smell could be your charcoal canister, fuel canister, or wahtever you want to call it. Look it up in the Chilton/Haynes manual. They do a good job covering it.
I never found the wire either, although it sounds like you put more effort into it then I did.
Simple test for O2 sensor. Disconnect the wire. IF the engine smoothes out the sensor is bad and needs replacement. The pcm uses the signal from the O2 sensor to tune the engine. When it doesn't get the signal, it goes into a default mode. Not great for gas mileage, however it will tell you if the sensor is bad or not.
< Message edited by Hanr3 -- 8/17/2005 2:56:01 PM >
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'87 S10-Blazer - SOLD
'93 S10-Blazer 4x4x4 - Sons DD, engine swap is done.
'00 S10-Blazer 4x4x4 - My
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RE: Rough idle, gas smell, and frustrations - 8/17/2005 3:43:30 PM
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ShadowHawk
Posts: 72
Joined: 8/15/2005
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quote:
When is the last time you replaced the air filter?
March of this year - just before my trip to Virginia
quote:
Have you ever replaced the IAC (idle air control) valve? Get the ignition control module tested. Realatively easy to take off and most autoparts stores can test them. Call first, AZ didn't have the right wiring harness, however O'Rielly's did.
IAC: Not that I'm aware of. I'll check on the ICM as well this weekend, and will report back...
quote:
Egg smell could be your charcoal canister, fuel canister, or wahtever you want to call it. Look it up in the Chilton/Haynes manual. They do a good job covering it.
Will do...
Thanks for the suggestions! I'll go through and see if anything seems to do the trick...
_____________________________
Rex S.
'95 S-10 Blazer 2WD, 4-Dr
'82 XJ650 Maxim
'82 XJ750 Seca
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RE: Rough idle, gas smell, and frustrations - 8/21/2005 9:27:26 AM
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Phatboy
Posts: 35
Joined: 8/12/2005
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That tan w/black wire your talking about is under the carpet on the passenger side floor on my '93 blazer. Sometimes it is on the passenger firewall wiring harness. Disconnecting this wire puts the ignition in "base timing" mode and will set a code, so clear the code after your done setting the timing.
It really sounds as if your engine needs to be decarboned, mine has a digital EGR valve and ALL of those EGR valves are notorious for getting little pellets of carbon trapped in the pintle area, thus resulting in erratic idle, stalling, check engine light coming on and going off and a distinct "rotten egg" smell". The EGR valve is easy to remove and depress the pintle with a small screwdriver and the carbon pellet will fall out. While the EGR valve is off (if you have access to it), blow compressed air in the EGR hole in the intake. This will blow any other pellets or chuncks of carbon out of the intake and passage.
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Paul
'93 S-Blazer 4.3 "W"
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RE: Rough idle, gas smell, and frustrations - 8/21/2005 12:01:30 PM
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ShadowHawk
Posts: 72
Joined: 8/15/2005
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Under the freakin' carpet?? Geez - no wonder people rag on the Hanes manuals for inaccuracies and misinformation...
On another note.. Yesterday, I opened the hood, and removed the air intake (air filter housing) & disconnected & tested the air temperature sensor. Filter is clean... Sensor thermister working properly... It still runs rough - especially when I put it into drive, with the brake on.
I'll check the wiring harnesses and wires under there this afternoon... And de-carbonize the EGR as well...
Thanks,
Rex
_____________________________
Rex S.
'95 S-10 Blazer 2WD, 4-Dr
'82 XJ650 Maxim
'82 XJ750 Seca
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RE: Rough idle, gas smell, and frustrations - 8/21/2005 5:32:43 PM
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Phatboy
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Yeah, it's pretty amazing they decided to put it there. It took me a while to learn where they hid it also. You should be able to pull the front of the carpet down under the dash enough to see the wire there and it will have a little plastic connector to unhook.
_____________________________
Paul
'93 S-Blazer 4.3 "W"
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RE: Rough idle, gas smell, and frustrations - 8/24/2005 9:50:34 PM
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ShadowHawk
Posts: 72
Joined: 8/15/2005
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I glanced under the carpet - but need to spend some time taking the kick-panel off so I don't mess up the carpeting...
On another note.. I *did* take off the EGR valve last night.. soaked it thoroughly with some Deep Creep (pressurized SeaFoam) to remove the carbon from it... Geez.. after putting it back on - the Blazer had a kind of "throaty" sound, and I can actually hear the valve in the EGR moving open & closed. I'm wondering if I've got a faulty EGR, yet it's not tripping any engine codes... I warmed up the Blazer last night and took it around the block... left it in gear, but came to a stop, and where it would normally shake the car like crazy.. this time it felt smooth. I'll take itout again tomorrow to see if it still is working right... Crossing my fingers!
< Message edited by ShadowHawk -- 8/24/2005 9:53:13 PM >
_____________________________
Rex S.
'95 S-10 Blazer 2WD, 4-Dr
'82 XJ650 Maxim
'82 XJ750 Seca
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RE: Rough idle, gas smell, and frustrations - 8/25/2005 9:45:52 AM
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ohsingltrakr
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I hope that fixes it for you. I worked in a shop thru the mid 90's and soon learned that GM products with a rough idle and occasional light were often a stuck EGR, they carbon up and won't seat closed leading to really rough idle, or may outright stick close and never open throwing a light for EGR. I believe you have the diaphragm type on a 95, with it idling you can stick your finger underneath and pull up the diaphragm a couple times and it will usually reseat closed and rough idle will go away immediately. The diaphragm valves seemed to need replacement every 3-4 years on many gm motors, especially the four cylinders. I think I paid around $40 for the last one I bought for myself and it lasted the rest of the life of the car. I haven't had much experience with the newer linear egr valves. If it appears it is EGR related and replacing or cleaning valve fixes it, I'd run your next couple tanks with Sea Foam or equiv. in the gas to clean up your intake valves, they're probably carboned frum running with valve stuck open all the time. Keeping clean oil would help too, your older engine would probably benefit from viscosity enhancer like STP or lucas to decarbon your rings and control blowby which leads to the carboned up egr in the first place.
< Message edited by ohsingltrakr -- 8/25/2005 10:02:55 AM >
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RE: Rough idle, gas smell, and frustrations - 8/25/2005 11:49:48 AM
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ShadowHawk
Posts: 72
Joined: 8/15/2005
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Took about a 30 mile drive this morning while running errands around town.. I think it is, indeed the EGR valve.. Although it *did* get rough again at idle, when in gear, stopped at stop-signs.. but not nearly as rough as it was before... so at least I'm on the right track. Maybe I need to do a better de-carbonizing job...
Mine is the V6 Vortex engine - and does have the linear (according to the Haynes manual) EGR... I'll look around for a replacement.. although when I had to have it replaced waaay back at 50,000 miles, the Stealership charges me just under $400 for the job... I'm presuming they charged 2x RETAIL for the EGR, plus about 1 hour's labor... so probably sound about right...
Rex
_____________________________
Rex S.
'95 S-10 Blazer 2WD, 4-Dr
'82 XJ650 Maxim
'82 XJ750 Seca
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RE: Rough idle, gas smell, and frustrations - 8/25/2005 1:10:16 PM
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gmyoyo
Posts: 33
Joined: 3/28/2005
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Hey, I am having same problem...95 s10 blazer 4.3 vortec odbI computer
I just replaced my EGR valve. Not too tuff to do, getting to the bolts was hardest part. I think its the linear EGR set up. Where would that diaphragm be at if otherwise. Of course after you read my input hear you may say I should have gone to a shop. But, right now I've only spent retail cost for the part.
Anyway, the check engine light came back on. It returned a code 32. EGR valve. This was after spending 4 days of normal driving, but knowing it was going to happen sooner or later I got on the interstate and was up around 70 at one point (Speed Limit). Anyway, as I came back off of that speed and was exiting the interstate in a big loop (I say this so you understand I slowed down considerably) and the engine light came on. Yes it does still idle a little rough, however there hasn't been any dieseling as it did before...
Anybody have any suggestions of what may have occurred. I'm picturing the carbon build up being so intense from the previous valve not working for so long that this one possibly has a carbon pellet just clogged back up from excessive carbon burn off when I basically kicked-it-in on the interstate . Is that a valid thought, or could it be something else?
I won't be able to take this one back off until the weekend...
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RE: Rough idle, gas smell, and frustrations - 8/25/2005 1:15:28 PM
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gmyoyo
Posts: 33
Joined: 3/28/2005
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Oh, by the way...
Previously the engine code returned both a 32 EGR valve and a 45 rich or lean exhaust O2 sensor. That code isn't being returned this time. So I think the EGR valve is effecting that fix...once again, is that valid thinking? Or can I expect the 45 to show up soon?
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RE: Rough idle, gas smell, and frustrations - 8/26/2005 8:14:13 AM
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ohsingltrakr
Posts: 7
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In my past experience with egr problems your situation is when you could see it, hot engine dropping to idle and the light would come on if the valve's stuck open. If it won't open at all the light will appear at highway speed. The lean 02 you saw early also makes sense as egr related as you'll get a lean mix when the valve is stuck open when it should be closed leading to a lean mixture. When you removed the valve was the passageway underneath clogged up with carbon, and did you clean it up when you changed the valve. This could be tough to see as the passageway is in the intake as opposed to external in a stainless tube like other types of engines. If so it's hopefully clogged up or partially restricted just at the valve location and could be cleaned up improving the EGR flow so that the computer sees the desired effect in the exhaust flow when it commands it, thereby not getting the egr light. If you remove it again and clean the passage out suck out the dirt with maybe a shop vac so you don't send big chunks of carbon into the intake valves. I've seen these passageways on other types of engines filled completely solid with carbon from one end to the other, this was usually in engines that were blowing by a lot or were consistanly being run way beyond the service interval for clean oil.
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RE: Rough idle, gas smell, and frustrations - 8/26/2005 9:43:45 AM
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gmyoyo
Posts: 33
Joined: 3/28/2005
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OK,
I don't know the complete history of this vehicle, there were no service records. However engine looked to be in good shape overall for 200,000 miles but I am not a mechanic.
I took the EGR off again last night and it was definitely clogged back up. All I could do was spray some carb cleaner and work the valve back and forth. There was a lot of carbon build up already again.
Yes, I did inspect and spray carb cleaner as best I could the passage way from the engine into the valve, it didn't seem out of order...
Any ideas or thoughts on what I can do to clean the internal part of the engine (sprays, additives).
By the way, the computer came back on the first driving cycle and threw the code this time. I thought it would cycle at least three driving times... Yes, I did disconnect the battery for about 30 minutes while pulling the EGR valve...
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RE: Rough idle, gas smell, and frustrations - 8/28/2005 9:37:30 PM
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Phatboy
Posts: 35
Joined: 8/12/2005
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If you have access to compressed air you need to blow right in that passage with a blow gun or you can even start the engine with the valve off and rev it up one time and blow any carbon out.
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Paul
'93 S-Blazer 4.3 "W"
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RE: Rough idle, gas smell, and frustrations - 8/30/2005 11:43:35 AM
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gmyoyo
Posts: 33
Joined: 3/28/2005
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I removed the EGR and rev'd the engine. On rev, there is a fine black mist that emits from the open passageway where the egr goes. I had a rag in place to try and catch some of the bigger chunks. However none were detected. I only ran it for a short time and rev'd it maybe 10 times maximum. Should I have let it get up to a real hot tempature or anything? The engine light came on again this morning, but, actually turned back off before I got here to work. I haven't pulled the code yet for what it may have said. I still think it's idleing a little rough. I think I may go axchange this EGR for another new one, just because I can...
Could I have damaged the replacement EGR valve already? It's been clogged a couple of times through this, but it was not clogged last night when I took it off to blow out the passageway...
Should I be more patient about the Fuel additive and changing the spark plugs and wires to effect the amount of carbon buildup or the cleanup of the carbon already built up?
So far I've:
Replace Fuel pump
Replace Fuel filter
I don't think it really applies to this problem as I'm still receiving 60psi at the Schrader valve and only a few psi drop when cranked.
Concerning Service Engine Soon code 32 light I have:
- Changed Oil
- Replaced the EGR valve, then cleaned several times since replace, usually with carbon pellets obstructing it (not this last time though)
- Replaced PCV valve
- Sprayed Carb cleaner into intake while revving
- Added STP gas treatment to new tank of gas
- Replaced Spark Plugs and Wires
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