Engine stall
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Cross-Country
Joined: Feb 2007
Posts: 87
Likes: 0
From: Arizona
Expensive guess!
Let's start from the beginning. You posted about the truck not running right but didn't mention the check engine light. Then you say the check engine light has been coming on for months.
At this point I believe you have more than one problem and no diagnosing of any of them. A plugged catalytic converter can easily be diagnosed with a simple low pressure gauge and drilling a small hole in the pipe before the converter and measuring back pressure. Interesting that you stated that the catalyst looked like it had been changed once before, a lot of people guessing. it sounds like the code stored has been chased after before and doesn't directly relate to your performance problem.
How did you get the truck to a shop to replace the catalyst? Is it still not running good? I would start with the very basics of making an engine run, easiest to check is fuel. Check fuel quantity and pressure, a real pressure test with a gauge not pushing on the valve and seeing a little fuel squirt. When was the last time the fuel filter was changed?
Let's start from the beginning. You posted about the truck not running right but didn't mention the check engine light. Then you say the check engine light has been coming on for months.
At this point I believe you have more than one problem and no diagnosing of any of them. A plugged catalytic converter can easily be diagnosed with a simple low pressure gauge and drilling a small hole in the pipe before the converter and measuring back pressure. Interesting that you stated that the catalyst looked like it had been changed once before, a lot of people guessing. it sounds like the code stored has been chased after before and doesn't directly relate to your performance problem.
How did you get the truck to a shop to replace the catalyst? Is it still not running good? I would start with the very basics of making an engine run, easiest to check is fuel. Check fuel quantity and pressure, a real pressure test with a gauge not pushing on the valve and seeing a little fuel squirt. When was the last time the fuel filter was changed?
The fuel pressure is good 50/15
Catalytic converter changed by me this morning
Oxygen sensors upstream are new
The fuel filter is new
CEL will come on and stay on for a week and go off for a month
Luck of diagnostic laptop what else do I check manually
Thread Starter
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Cross-Country
Joined: Feb 2007
Posts: 87
Likes: 0
From: Arizona
Falowup
Can this have something to do with the problem?
Throttle Position Sensor (TPS) or Accelerator Pedal Sensor: These sensors are part of the electronic throttle control system. If faulty, they can cause stalling or unresponsiveness when accelerating
Throttle Position Sensor (TPS) or Accelerator Pedal Sensor: These sensors are part of the electronic throttle control system. If faulty, they can cause stalling or unresponsiveness when accelerating
Logistics Pro
Joined: Jan 2010
Posts: 4,121
Likes: 1,645
I agree that you need to get some live data from a scan tool to see what's going on, even if it doesn't run long, a little is better than nothing.
Something I have done multiple times in the past when faced with an engine that will start but dies shortly after, is unplug the MAF sensor in the intake tube (don't remove it, just unplug it). Often this will let the engine run relatively properly, as it defaults to a set of parameters stored in the computer. It WILL set a code when you do this. Typically, plugging the sensor back in causes the vehicle to almost immediately die, and return to its 'start but die' state. It generally means the MAF is bad and needs to be replaced. You can try cleaning it but I have never had good luck with that.
Something I have done multiple times in the past when faced with an engine that will start but dies shortly after, is unplug the MAF sensor in the intake tube (don't remove it, just unplug it). Often this will let the engine run relatively properly, as it defaults to a set of parameters stored in the computer. It WILL set a code when you do this. Typically, plugging the sensor back in causes the vehicle to almost immediately die, and return to its 'start but die' state. It generally means the MAF is bad and needs to be replaced. You can try cleaning it but I have never had good luck with that.
Laughing Gas
Joined: May 2024
Posts: 912
Likes: 294
From: E TN
Guessing time is over. live data is the best way to begin in diagnosing. If you suspect the TPS test it. What does 50/15 fuel pressure mean? Did you take a fuel sample in a clear container? With the truck running and fuel pressure gauge on it what does it do when you try to accelerate? What does it do when you remove the vacum from the pressure regulator? Have you checked for a vacum leak?
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Cross-Country
Joined: Feb 2007
Posts: 87
Likes: 0
From: Arizona
Problem solved
After all the work I did I dint erase the code so the problem persisted the mechanic give me that little tip and walla she runs and drives grate.
So remember to erase the codes after each part you replace.
So remember to erase the codes after each part you replace.
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