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Discussion Starter · #1 ·
Does anybody know where the variable valve timing solenoid and it's filter is located on a 1992 2.8l? I'm a non mechanic trying to fix what I can, I'm having issues with it hesitating and running rough when I try to accelerate especially once it's warmed up. I'm getting code 42 and 44. I've cleaned my pvc valve ( and replaced the grommet), the egr valve, and the air cleaner temp sensor. I'm going to get a multimeter to test the coolant temp sensor sending unit (and a host of other things lol) as the connector wire is missing it's insulation so have to replace it. I'm not getting any codes referencing the coolant sensors though. Also just figured out what the thermal valve switch is while trying to figure out how to test the charcoal canister ( don't think I can since I don't have a hand vacuum). I have to get the right size socket so I can take the sensors off and try cleaning them.
It runs better cold. Once it warms up after a couple of miles it starts running rough and I get the check engine light then it doesn't want to accelerate. It will hesitate then it takes off then sluggish again. I'm only getting 14 mpg. I'm thinking it's more than one thing but trying to do the easiest first. I replaced the ignition switch module a 1 1/2 yrs ago.
 

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Discussion Starter · #2 ·
Does anybody know where the variable valve timing solenoid and it's filter is located on a 1992 2.8l? I'm a non mechanic trying to fix what I can, I'm having issues with it hesitating and running rough when I try to accelerate especially once it's warmed up. I'm getting code 42 and 44. I've cleaned my pvc valve ( and replaced the grommet), the egr valve, and the air cleaner temp sensor. I'm going to get a multimeter to test the coolant temp sensor sending unit (and a host of other things lol) as the connector wire is missing it's insulation so have to replace it. I'm not getting any codes referencing the coolant sensors though. Also just figured out what the thermal valve switch is while trying to figure out how to test the charcoal canister ( don't think I can since I don't have a hand vacuum). I have to get the right size socket so I can take the sensors off and try cleaning them.
It runs better cold. Once it warms up after a couple of miles it starts running rough and I get the check engine light then it doesn't want to accelerate. It will hesitate then it takes off then sluggish again. I'm only getting 14 mpg. I'm thinking it's more than one thing but trying to do the easiest first. I replaced the ignition switch module a 1 1/2 yrs ago.
I have a fairly new O2 sensor. I don't get the codes until after it warms up. Before I cleaned the egr valve I got the code 32 and it flucuated more and I would have problems with it idling quite high at times. Now it is idling low and nearly stalling but hasn't yet.
The charcoal canister that I have doesn't have a filter on the bottom. From what I have read, it is supposed to?
 

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You can do a search of parts by typing in the part number and specify images on the browser, this way you can look at the part and compare it to what you have.
A 92 is On Board Diagnostics 1 (OBD1) you should be able to look up the codes on line using the 2 digit codes for explanations and how to fix them. You posted the year, we can assume it's a GM 2.8l but we don't know what model you have....
This may be a help: How to Replace a Variable Valve Timing (VVT) Solenoid | YourMechanic Advice
 

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If the temp sensor. the one with yellow and black wires is faulty or the wiring or connector are bad you'll get the exact symptoms you describe. An open circuit will make the ECM think the engine coolant is at -40°. That will cause it to give the engine too much fuel.
AFAIK a 92 2.8 doesn't have variable valve timing.
Nov 30, 2009 — GM has announced that all V-8 powered Chevrolet and GMC trucks now feature variable valve timing (VVT) for the 2010 model year.
 

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Discussion Starter · #5 · (Edited)
You can do a search of parts by typing in the part number and specify images on the browser, this way you can look at the part and compare it to what you have.
A 92 is On Board Diagnostics 1 (OBD1) you should be able to look up the codes on line using the 2 digit codes for explanations and how to fix them. You posted the year, we can assume it's a GM 2.8l but we don't know what model you have....
This may be a help: How to Replace a Variable Valve Timing (VVT) Solenoid | YourMechanic Advice
Thank you for replying. I have a 1992 Chevy s10 2.8l v6 extended cab truck. I have found the explanation of the codes but they seem vague to me as Im not a mechanic. I have the Haynes manual but its index is pretty worthless for looking something up. I have googled the parts and find pictures of the filter but not a picture of where it is on my truck. Insee a part on my truck that might be the VVT but is the filter on it or somewhere else? Apparently the symptoms can be caused by many different reasons...sigh. Its like an easter egg hunt. I just got a multi meter so now im going to attempt checking the coolant sensors, ignition module, vvt valve if i have one, etc.
 

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Discussion Starter · #6 ·
If the temp sensor. the one with yellow and black wires is faulty or the wiring or connector are bad you'll get the exact symptoms you describe. An open circuit will make the ECM think the engine coolant is at -40°. That will cause it to give the engine too much fuel.
AFAIK a 92 2.8 doesn't have variable valve timing.
Thanks for replying. I just got a multimeter so I can test the coolant sensor and the coolant sensor sending unit (the one with one green wire as it's connector wire has lost some insulation but it's not throwing a code). Now I just need to get the correct size sockets....sigh. As I keep reading I'm learning that these other problems can cause the same symptoms so I figure that I should check all them too such as a bad charcoal canister and the temperature valve switch it's connected to, a bad/dirty vvt solenoid and filter, a bad ignition switch module, and what is an HEI module? Is it the IAM or distributor or a part in between... lol.
Hmmm... I'll have to take a picture of what I'm thinking is the VVT on my truck as I can't find any diagram or picture that says what it is. It's on the drivers side on the block maybe?
 

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Your truck does not have variable valve timing.


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The sender with the green wire is strictly for the temp gauge and that green wire goes directly to it. Has no effect on driveability, just the gauge. Not connected to anything else.
Best manual to get is a factory service manual. The same one that I used daily when working at a GM dealership. They have GM engineered diagnostic steps for most issue in them. Actually they are an investment because if you sell the truck down the road you can likely get more than you paid for it as prices on the limited number of them rise. Don't buy a CD they're as lacking as the Haynes or Chilton comic books.
Here's the least expensive 92 on eBay at the moment, make him an offer for $10 less:
In 1992 the electrical diagrams were in a separate book. They are very complete and big so they're easy to read.
Schematic Font Rectangle Engineering Parallel
 

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Discussion Starter · #10 ·
Your truck does not have variable valve timing.


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Well that explains it... lol. A couple of people now have said that. Now I have to figure out what I am looking at then. thank you
The sender with the green wire is strictly for the temp gauge and that green wire goes directly to it. Has no effect on driveability, just the gauge. Not connected to anything else.
Best manual to get is a factory service manual. The same one that I used daily when working at a GM dealership. They have GM engineered diagnostic steps for most issue in them. Actually they are an investment because if you sell the truck down the road you can likely get more than you paid for it as prices on the limited number of them rise. Don't buy a CD they're as lacking as the Haynes or Chilton comic books.
Here's the least expensive 92 on eBay at the moment, make him an offer for $10 less:
In 1992 the electrical diagrams were in a separate book. They are very complete and big so they're easy to read.
View attachment 361780
Thanks! I can usually figure things out with good instructions but with so many things that can cause the same symptoms .... what a pain lol
 

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@zan, have you checked for vacuum leaks. Best way is to put a vacuum gauge on hose coming out of the intake manifold.
Not one on the throttle body. It should read somewhere in the 15-18 inch range, but more importantly it should be steady.
 
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Or smoke test it. Instructions for making a DIY smoker are readily available on the interwebs. I prefer propane while watching fuel trims, but that requires a DME that can show fuel trims on a scan tool which I don’t think yours can do.


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Discussion Starter · #13 ·
Partly solved! I had a bad idle air control valve. I have a lot more power and fuel milage is getting better but I still have some issues. I am still getting a code 32 which is about the egr stuff. I cleaned the egr valve and it's seal is good (held my finger over vacuum port and diaphragm didn't move till I removed my finger). I replaced the gasket. It still seems to get worse after it warms up. It will run great then I feel it get rough or lose power then it starts hesitating then take off. That's when I get the code 32. Arg.... I've read that the egr solenoid can run bad after heating up? or bad tps? I'm still wondering about the charcoal canister as it is connected to a thermal control valve. Trying to look at things that are affected by the motor warming up. I'm not getting the codes 42 or 44 now so that's good. I tried to find vacuum leaks by spraying brake cleaner around the vacuum hoses and gaskets. No changes in rpms anywhere so guessing no vacuum leaks. I'm almost there... I think LOL
 
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