95 c4 fuel mixture issues............?..
Thread Starter
Heel & Toe
Joined: Oct 2014
Posts: 23
Likes: 0
From: Prescott Arizona
95 c4 fuel mixture issues............?..
Okay here goes..... new fuel filter, fuel pump, cat back with magna flow (high flow) cats, new O2 sensors on the pipes...........new ignition crap all MSD, just hit 100K miles. We live at 1 mile high and just hit winter.
Dilemma.....Car starts sounds awesome! Runs great until it hits op temp....then it smells wicked rich! At idle it runs like it is missing for about 40 seconds then I can feel it pop into limp mode like its shifting gears and the service engine light kicks on. The car no longer smells rich and idles like its brand new. Last code thrown says its running lean and the O2 sensor in bank 1 needs changed..............HELP PLEASE!
Dilemma.....Car starts sounds awesome! Runs great until it hits op temp....then it smells wicked rich! At idle it runs like it is missing for about 40 seconds then I can feel it pop into limp mode like its shifting gears and the service engine light kicks on. The car no longer smells rich and idles like its brand new. Last code thrown says its running lean and the O2 sensor in bank 1 needs changed..............HELP PLEASE!
Instructor
Joined: Jun 2006
Posts: 175
Likes: 1
From: Cave Creek Arizona
One thing I have learned in more than 40 years of being an electronic technician is that more problems are created by humans than by component failure. That being said, you mentioned that you have replaced a plethora of components, but did you replace these items as part of your trouble shooting or did the problem occur after the components where replaced?
To me it sounds like a bad O2 sensor, but you replaced them. Could one be defective? I had a similar problem with a Camaro once and it turned out to be a vacumn leak. Any chance you have a hose cracked, missing or disconnected?
Post up the code. Maybe somone with an FSM can pipe in with some suggestions on trouble shooting steps.
To me it sounds like a bad O2 sensor, but you replaced them. Could one be defective? I had a similar problem with a Camaro once and it turned out to be a vacumn leak. Any chance you have a hose cracked, missing or disconnected?
Post up the code. Maybe somone with an FSM can pipe in with some suggestions on trouble shooting steps.
Last edited by jsdomino; Dec 16, 2015 at 10:31 PM.
Thread Starter
Heel & Toe
Joined: Oct 2014
Posts: 23
Likes: 0
From: Prescott Arizona
I did all of that...Sorry I should have been a bit more in depth. All the coolant is new, I have traced wires, I have unplugged the mass air flow sensor and the car immediately reacts, I have traced wires, vacuum lines etc...... I'm seriously stumped.......
Thread Starter
Heel & Toe
Joined: Oct 2014
Posts: 23
Likes: 0
From: Prescott Arizona
basically I rebuilt the front of the motor as it was my father in laws from Florida and was a mess!! new radiator, coolant, heater core, (not FUN!), full ignition system, everything but the harmonic balancer!!! I am so ready to do an LS1 swap.......ughhh...
Thread Starter
Heel & Toe
Joined: Oct 2014
Posts: 23
Likes: 0
From: Prescott Arizona
One thing I have learned in more than 40 years of being an electronic technician is that more problems are created by humans than by component failure. That being said, you mentioned that you have replaced a plethora of components, but did you replace these items as part of your trouble shooting or did the problem occur after the components where replaced?
To me it sounds like a bad O2 sensor, but you replaced them. Could one be defective? I had a similar problem with a Camaro once and it turned out to be a vacumn leak. Any chance you have a hose cracked, missing or disconnected?
Post up the code. Maybe somone with an FSM can pipe in with some suggestions on trouble shooting steps.
To me it sounds like a bad O2 sensor, but you replaced them. Could one be defective? I had a similar problem with a Camaro once and it turned out to be a vacumn leak. Any chance you have a hose cracked, missing or disconnected?
Post up the code. Maybe somone with an FSM can pipe in with some suggestions on trouble shooting steps.
That is all I can think man is that I am missing a leak somewhere! I have checked and checked. There is no code other than "Bank one O2 sensor bad running lean" is what the OBDII reads..... Im seriously at a loss.... I can say this, before popping into limp mode the car SCREAMS!
Thread Starter
Heel & Toe
Joined: Oct 2014
Posts: 23
Likes: 0
From: Prescott Arizona
Okay, here is a much more precise time line. We acquired the car 9-2014, had it shipped from Florida to Prescott AZ. I did the once over which took several days! New tires and brakes right off the bat! No heater at all (bad heater core), but more pressing issues. The entire ignition system needed gone through! 95K and still had the OEM plugs, wires, and coil. MSD was my friend at this point. Due to it being Opti-spark a new water pump was a given. That harmonic balancer was a 3 day PB blaster issue in and of itself! finally after a month of tinkering it was time to address the heater issue......two days later I swapped the heater core BBBAAAMMMM HEATTTT!! (not really needed in Florida). Then the new high flow cats. Following that, we drove the beast up until a few weeks ago... Yes sir just over a year. Started with the running lean codes. That is when I swapped all of the O2 sensors. Then the fuel filter and today the fuel pump......And here I sit......daized and confused missing my AMG Mercedes!
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Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Possible injector bad and leaking.
If a O2 runs to rich to long it can kill it and not work anymore.
Make sure your digital temperature in the spedo is working and displaying correctly.
A OBD1 scanner would be a great help. I would clear codes and check codes again.
Is this the first start of the engine since all that work was done?
Or has it run good at one time.
If a O2 runs to rich to long it can kill it and not work anymore.
Make sure your digital temperature in the spedo is working and displaying correctly.
A OBD1 scanner would be a great help. I would clear codes and check codes again.
Is this the first start of the engine since all that work was done?
Or has it run good at one time.
Thread Starter
Heel & Toe
Joined: Oct 2014
Posts: 23
Likes: 0
From: Prescott Arizona
Possible injector bad and leaking.
If a O2 runs to rich to long it can kill it and not work anymore.
Make sure your digital temperature in the spedo is working and displaying correctly.
A OBD1 scanner would be a great help. I would clear codes and check codes again.
Is this the first start of the engine since all that work was done?
Or has it run good at one time.
If a O2 runs to rich to long it can kill it and not work anymore.
Make sure your digital temperature in the spedo is working and displaying correctly.
A OBD1 scanner would be a great help. I would clear codes and check codes again.
Is this the first start of the engine since all that work was done?
Or has it run good at one time.
its been running perfect up until a few weeks ago. That is what started the O2 sensors and the fuel pump/filter swap.
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
and 02 againon my 94 I just jack up the right rear and let it bubble out. did you find both bleeders?
Last edited by antfarmer2; Dec 17, 2015 at 08:39 AM.
Safety Car
Joined: Jul 1999
Posts: 3,946
Likes: 63
From: Marianna FL
Sounds a lot like what happened to my 95. I had bad luck with anything but ac Delco o2 sensors. Check your ground on the o2 sensor in question. I ended up replacing the computer to finally solve my issue.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
In thinking about the problem, when first started it's in open loop and the O2s are not being used. Maybe a injector is stuck open for a while then starts to work proper. I would try to find what cylinder is missing in the first 30 seconds.
That might account for the lean code you are getting. Check the connections for the injectors and the plug wires. Make sure all the wires are ON the plugs ALL the way.
That might account for the lean code you are getting. Check the connections for the injectors and the plug wires. Make sure all the wires are ON the plugs ALL the way.