Left-side Rich Condition - Please Help!!!
Thread Starter
Registered User
Joined: Oct 2004
Posts: 809
From: Houston, TX
Left-side Rich Condition - Please Help!!!
OK guys, I've asked this before but still not getting anywhere and need your advise. I have been having a rich condition on the left-side (drivers side) and when running datamaster the BLM's on the left-side consistently stay rich anywhere from 108-120 and the right side is fine. I have done the following trying to track this down:
New Spark plugs (NGK's)
Checked, Double and Triple checked for exhaust leaks and can't find any
pulled fuel rail to pressure check injectors for a leaky one - NOPE
checked all vacuum fittings and no apparent leaks/cracked hoses
New O2's installed
Plug wires checked an all fine
Really not figuring out what is going on here, can someone let me know what could cause this and make some suggestions as to where I can look. I have been working with Bryan at PCMforless on my tune and he is tweaking it to lean it out a little to accommodate for the rich issue, but I want to solve the main issue to fix it for good. PS - No codes are being thrown as well.
FYI - Here is a list of my mods so you know what is going on:
383 - Eagle Stroke Kit
CC305 cam
SVO 30# inj
All Air and EGR are still present for emissions purposes
LT4 KM
ETC...
Thanks for your input and advise.
New Spark plugs (NGK's)
Checked, Double and Triple checked for exhaust leaks and can't find any
pulled fuel rail to pressure check injectors for a leaky one - NOPE
checked all vacuum fittings and no apparent leaks/cracked hoses
New O2's installed
Plug wires checked an all fine
Really not figuring out what is going on here, can someone let me know what could cause this and make some suggestions as to where I can look. I have been working with Bryan at PCMforless on my tune and he is tweaking it to lean it out a little to accommodate for the rich issue, but I want to solve the main issue to fix it for good. PS - No codes are being thrown as well.
FYI - Here is a list of my mods so you know what is going on:
383 - Eagle Stroke Kit
CC305 cam
SVO 30# inj
All Air and EGR are still present for emissions purposes
LT4 KM
ETC...
Thanks for your input and advise.
Registered User
Joined: Dec 2000
Posts: 2,442
From: Tacoma, WA, USA
I would still stick with what is in common to the left side, i.e. the O2 problem. Have you double and triple checked the wiring on the O2 circuit? Did you get O2's w/ factory connectors or did you have to cut/splice?
What I'm leaning towards here is, one time I worked on a lady's truck for 3 weeks w/ a rich condition. This truck ran so rich it would ruin the oil w/ carbon and gas within only a few miles. I checked voltages on sensors, pulled and cleaned the injectors, and all kinds of things. She had the O2's "professionally" installed and they were a cut/splice type. Since they were "professionally" installed I never thought for a second that the wiring was jacked up. I got frustrated with it finally and threw the towel in on it. She then caved in and took it to a dealer. The dealer found right off the bat that the wires for the new O2's were crossed....
What I'm leaning towards here is, one time I worked on a lady's truck for 3 weeks w/ a rich condition. This truck ran so rich it would ruin the oil w/ carbon and gas within only a few miles. I checked voltages on sensors, pulled and cleaned the injectors, and all kinds of things. She had the O2's "professionally" installed and they were a cut/splice type. Since they were "professionally" installed I never thought for a second that the wiring was jacked up. I got frustrated with it finally and threw the towel in on it. She then caved in and took it to a dealer. The dealer found right off the bat that the wires for the new O2's were crossed....
Thread Starter
Registered User
Joined: Oct 2004
Posts: 809
From: Houston, TX
I would still stick with what is in common to the left side, i.e. the O2 problem. Have you double and triple checked the wiring on the O2 circuit? Did you get O2's w/ factory connectors or did you have to cut/splice?
What I'm leaning towards here is, one time I worked on a lady's truck for 3 weeks w/ a rich condition. This truck ran so rich it would ruin the oil w/ carbon and gas within only a few miles. I checked voltages on sensors, pulled and cleaned the injectors, and all kinds of things. She had the O2's "professionally" installed and they were a cut/splice type. Since they were "professionally" installed I never thought for a second that the wiring was jacked up. I got frustrated with it finally and threw the towel in on it. She then caved in and took it to a dealer. The dealer found right off the bat that the wires for the new O2's were crossed....
What I'm leaning towards here is, one time I worked on a lady's truck for 3 weeks w/ a rich condition. This truck ran so rich it would ruin the oil w/ carbon and gas within only a few miles. I checked voltages on sensors, pulled and cleaned the injectors, and all kinds of things. She had the O2's "professionally" installed and they were a cut/splice type. Since they were "professionally" installed I never thought for a second that the wiring was jacked up. I got frustrated with it finally and threw the towel in on it. She then caved in and took it to a dealer. The dealer found right off the bat that the wires for the new O2's were crossed....
Registered User
Joined: Aug 2004
Posts: 107
From: Cedar Park, TX
I'll recommend a few relatively simple things to check that only cost time...if none of these yield anything interesting I'll be as stumped as you are 
1. Pull all the plugs on that side and see if any are noticeably darker. If so, there could be something going on in that cylinder such as a bad or loose plug / wire / opti connection, burnt valve, broken spring, etc.
2. Put the car on jackstands and with it running, listen to all the exhaust connections on that side with a rubber hose to your ear. If you're just looking for carbon tracking or feeling around with your hand trying not to get burned, you may not find leaks that could in fact be there. If no leaks are found at the collector, O2, etc., do the same thing both above and below the length of the header flange. You're basically listening for one 'area' to sound noticeably different or louder than the rest...take your time, turn off the radio, and listen carefully.
3. Physically remove and inspect all vacuum lines on that side - brake booster, PCV, Opti vent, and EGR line (those are the DS hoses on my 97 at least...your 95 may be slightly different).
4. With the motor running, spray the mating surface of the intake manifold to the DS head as well as each fuel injector port with carb cleaner. BE CAREFUL NOT TO HIT THE HEADERS OR ALLOW IT TO PUDDLE AND DRIP!! Use a rag to clean up the excess before it can become a fire hazard. If the idle speed / sound changes at all, you could have a vacuum leak at whatever area you just sprayed. Give a couple seconds between sprays to help isolate each port / area.
5. If none of the above pans out, the only other thing I can think of is a vacuum leak on the underside of the intake pulling air from the lifter valley into one or more of the cylinders. Very rare but it has happened. Only way to fix this is replace intake gaskets and/or machine the intake / head sealing surfaces. I seriously doubt this is your issue but it's worth mentioning as it does happen from time to time.
Hope this helps....please post results. I'll check back and try to help based on what you find.
1. Pull all the plugs on that side and see if any are noticeably darker. If so, there could be something going on in that cylinder such as a bad or loose plug / wire / opti connection, burnt valve, broken spring, etc.
2. Put the car on jackstands and with it running, listen to all the exhaust connections on that side with a rubber hose to your ear. If you're just looking for carbon tracking or feeling around with your hand trying not to get burned, you may not find leaks that could in fact be there. If no leaks are found at the collector, O2, etc., do the same thing both above and below the length of the header flange. You're basically listening for one 'area' to sound noticeably different or louder than the rest...take your time, turn off the radio, and listen carefully.
3. Physically remove and inspect all vacuum lines on that side - brake booster, PCV, Opti vent, and EGR line (those are the DS hoses on my 97 at least...your 95 may be slightly different).
4. With the motor running, spray the mating surface of the intake manifold to the DS head as well as each fuel injector port with carb cleaner. BE CAREFUL NOT TO HIT THE HEADERS OR ALLOW IT TO PUDDLE AND DRIP!! Use a rag to clean up the excess before it can become a fire hazard. If the idle speed / sound changes at all, you could have a vacuum leak at whatever area you just sprayed. Give a couple seconds between sprays to help isolate each port / area.
5. If none of the above pans out, the only other thing I can think of is a vacuum leak on the underside of the intake pulling air from the lifter valley into one or more of the cylinders. Very rare but it has happened. Only way to fix this is replace intake gaskets and/or machine the intake / head sealing surfaces. I seriously doubt this is your issue but it's worth mentioning as it does happen from time to time.
Hope this helps....please post results. I'll check back and try to help based on what you find.
Thread Starter
Registered User
Joined: Oct 2004
Posts: 809
From: Houston, TX
I'll recommend a few relatively simple things to check that only cost time...if none of these yield anything interesting I'll be as stumped as you are
1. Pull all the plugs on that side and see if any are noticeably darker. If so, there could be something going on in that cylinder such as a bad or loose plug / wire / opti connection, burnt valve, broken spring, etc.
2. Put the car on jackstands and with it running, listen to all the exhaust connections on that side with a rubber hose to your ear. If you're just looking for carbon tracking or feeling around with your hand trying not to get burned, you may not find leaks that could in fact be there. If no leaks are found at the collector, O2, etc., do the same thing both above and below the length of the header flange. You're basically listening for one 'area' to sound noticeably different or louder than the rest...take your time, turn off the radio, and listen carefully.
3. Physically remove and inspect all vacuum lines on that side - brake booster, PCV, Opti vent, and EGR line (those are the DS hoses on my 97 at least...your 95 may be slightly different).
4. With the motor running, spray the mating surface of the intake manifold to the DS head as well as each fuel injector port with carb cleaner. BE CAREFUL NOT TO HIT THE HEADERS OR ALLOW IT TO PUDDLE AND DRIP!! Use a rag to clean up the excess before it can become a fire hazard. If the idle speed / sound changes at all, you could have a vacuum leak at whatever area you just sprayed. Give a couple seconds between sprays to help isolate each port / area.
5. If none of the above pans out, the only other thing I can think of is a vacuum leak on the underside of the intake pulling air from the lifter valley into one or more of the cylinders. Very rare but it has happened. Only way to fix this is replace intake gaskets and/or machine the intake / head sealing surfaces. I seriously doubt this is your issue but it's worth mentioning as it does happen from time to time.
Hope this helps....please post results. I'll check back and try to help based on what you find.
1. Pull all the plugs on that side and see if any are noticeably darker. If so, there could be something going on in that cylinder such as a bad or loose plug / wire / opti connection, burnt valve, broken spring, etc.
2. Put the car on jackstands and with it running, listen to all the exhaust connections on that side with a rubber hose to your ear. If you're just looking for carbon tracking or feeling around with your hand trying not to get burned, you may not find leaks that could in fact be there. If no leaks are found at the collector, O2, etc., do the same thing both above and below the length of the header flange. You're basically listening for one 'area' to sound noticeably different or louder than the rest...take your time, turn off the radio, and listen carefully.
3. Physically remove and inspect all vacuum lines on that side - brake booster, PCV, Opti vent, and EGR line (those are the DS hoses on my 97 at least...your 95 may be slightly different).
4. With the motor running, spray the mating surface of the intake manifold to the DS head as well as each fuel injector port with carb cleaner. BE CAREFUL NOT TO HIT THE HEADERS OR ALLOW IT TO PUDDLE AND DRIP!! Use a rag to clean up the excess before it can become a fire hazard. If the idle speed / sound changes at all, you could have a vacuum leak at whatever area you just sprayed. Give a couple seconds between sprays to help isolate each port / area.
5. If none of the above pans out, the only other thing I can think of is a vacuum leak on the underside of the intake pulling air from the lifter valley into one or more of the cylinders. Very rare but it has happened. Only way to fix this is replace intake gaskets and/or machine the intake / head sealing surfaces. I seriously doubt this is your issue but it's worth mentioning as it does happen from time to time.
Hope this helps....please post results. I'll check back and try to help based on what you find.
Excellent suggestions and thank you. Here is a list of your points and what i have already done:
1. Done that as I just changed the plugs 2 weeks ago to NGKs, the drivers side plugs (where the rich condition is) were noticably darker I presume from being fouled over time. The valve train looks good (rockers and springs) with a visual inpection under the VC.
2. Done that as well but can't find one, I even had to remove the DR header to put the new plugs in and made sure it seated well and all bolts were tight as well.
3. Need to make a closer inspection of all the lines and I'll do that this weekend.
4. Very interesting suggestion and I'll give that a try after I double check 2 and 3.
5. I really hope not as that would be a PIA.
I'll keep you posted. Lastly, do you think this could be as simple as a sticking or slightly off injector and would it be a good idea to pull the injectors off and have a shop flow test and match them? If so, do you know of a good place to do this or even better a place locally in Houston?
Thread Starter
Registered User
Joined: Oct 2004
Posts: 809
From: Houston, TX
Ok guys, just an update. I checked everything and still had issues, so I broke down and pulled the fuel rail and flip-flopped the injectors. Lo and behold when I ran it again the problem/rich condition flipped sides to the right side/passenger side. I'm positive now it's the injectors and one or more is sticking. I have send them off to an outfit to have them flow tested and cleaned with the pintails, orings and filterbaskets replaced. The outfit is called Witch Hunter Performance and I should have them back later this week. I'll keep you posted and hopefully this solves my issues.
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