[rjkardo]

Hello, I have a 1995 1.9, standard.
It has over 140K miles.

The Check Engine light is coming on after the car is driven a few miles and then comes to a stop. If I start it up and just go, it won't come on...once I stop at a light or something the Check Engine light shows up.

The car seems a bit sluggish and gas mileage is down.

The error code I get is 337, which is:
PFE sensor circuit voltage above Self-Test maximum.

Any ideas?

Thanks,
Rod

 

[LOWETGT]

Replace the sensor, it controls the EGR operation. Typically, it has an electrical connector and two hoses running to it.

 

[Intuit]

My EGR was completely clogged at 190k and likely long, long prior to that. Never saw any CE light (not burned out) though it's possible that some code may have been stored. Probably a good idea to physically check the entire EGR system as well as check for any vacuum leaks. It's also common for the intake/exhaust manifold fasteners to back-off on high-mileage/age engines. THose MUST be torqued to spec.

 

[LOWETGT]

Good point on the hoses, the ones that run to the sensor are known to deteriorate, but seeing a circuit voltage code, I didn't instantly suspect a leak but a bad sensor or wire.

 

[rjkardo]

My EGR was completely clogged at 190k and likely long, long prior to that. Never saw any CE light (not burned out) though it's possible that some code may have been stored. Probably a good idea to physically check the entire EGR system as well as check for any vacuum leaks. It's also common for the intake/exhaust manifold fasteners to back-off on high-mileage/age engines. THose MUST be torqued to spec.

I am a bit confused...
Should I replace:
• DPFE Sensor (Also called the Back Pressure Transducer (BPT).)
• EGR Vacuum Regulator (EVR) Solenoid
• EGR Valve

??

Also, is there a how-to on searching for vacuum leaks?

Sorry, am trying to learn. I have been searching the forum but a lot of the comments are either confusing or lacking the details that I need.

Thanks,
Rod

 

[juggalo]

it's the egr vacuum regulator that sits on the firewall with 2 vacuum lines going to it.

people have found vacuum leaks by using propane which increases idle when the gas seeps thru the leak.

 

[HyBrad]

I am a bit confused...
Should I replace:
• DPFE Sensor (Also called the Back Pressure Transducer (BPT).)
• EGR Vacuum Regulator (EVR) Solenoid
• EGR Valve

??

Also, is there a how-to on searching for vacuum leaks?

Sorry, am trying to learn. I have been searching the forum but a lot of the comments are either confusing or lacking the details that I need.

Thanks,
Rod

Are you sure it's not code 1337? Because if it was, that would be sweet and I wouldn't fix it just so I could keep that code!

In all seriousness though, there is no "replace this to fix code 337" rule book. The problem really does need to be diagnosed, and this is where you have to do a little work.

Start it up, let it idle. Remove the vacuum hose from the EGR valve. Does it have vacuum? If so, then replace the EGR solenoid because it should not have vacuum at idle.

If not, then apply vacuum to the EGR valve. It should start to idle rough and perhaps even stall. If it does not, then either the EGR valve itself is frozen up, or the EGR ports are plugged up. Removal of the valve at this point would be required for further inspection.

If the engine does try to stall, then the EGR valve and its plumbing is OK. At this point you'll want to remove the PFE hoses from the sensor and start the engine. There should be exhaust coming from both of those hoses (one slightly stronger than the other). If you are getting nothing then remove the hoses from the exhaust and check for flow there. It might be plugged up with carbon.

If these are ok, then remove the PFE sensor and make sure it's not all plugged up where the hoses attach. Carbon can get up in there... water can get up in there.. rust can get up there.. and the hoses themselves can deteriorate and flake apart on the inside and clog up that sensor as well. If you find debris, try cleaning it out..

Otherwise, most likely the PFE sensor itself is bad. I ALWAYS recommend replacing the hoses at the same time... it's cheap insurance.

Yes there is a slight chance that it could be a bad wire somewhere or even a bad computer, but this gets into further electrical testing...

 

[rjkardo]

I am a bit confused...
Should I replace:
• DPFE Sensor (Also called the Back Pressure Transducer (BPT).)
• EGR Vacuum Regulator (EVR) Solenoid
• EGR Valve

??

Also, is there a how-to on searching for vacuum leaks?

Sorry, am trying to learn. I have been searching the forum but a lot of the comments are either confusing or lacking the details that I need.

Thanks,
Rod

Are you sure it's not code 1337? Because if it was, that would be sweet and I wouldn't fix it just so I could keep that code!

I brought it to an O'Reilly's. They have a code reader that does both ODB1 and 2. My car is a 1, and it gave the code as 337, so I am sure.
I get your point about 1337 though...

In all seriousness though, there is no "replace this to fix code 337" rule book. The problem really does need to be diagnosed, and this is where you have to do a little work.

Start it up, let it idle. Remove the vacuum hose from the EGR valve. Does it have vacuum? If so, then replace the EGR solenoid because it should not have vacuum at idle.

Here is where I need some help. Sorry for being such a newb...but I am trying to learn...How do I know if I 'have vacuum'? I am not sure what you are meaning by this...

Again, I appreciate the help and am trying to learn, but I am not sure what you are meaning here and in other spots.

If not, then apply vacuum to the EGR valve. It should start to idle rough and perhaps even stall. If it does not, then either the EGR valve itself is frozen up, or the EGR ports are plugged up. Removal of the valve at this point would be required for further inspection.

How do I 'apply vacuum'?
My guess is to put my thumb over the hose...is that what you mean? Close it off?

If the engine does try to stall, then the EGR valve and its plumbing is OK. At this point you'll want to remove the PFE hoses from the sensor and start the engine. There should be exhaust coming from both of those hoses (one slightly stronger than the other). If you are getting nothing then remove the hoses from the exhaust and check for flow there. It might be plugged up with carbon.

OK

If these are ok, then remove the PFE sensor and make sure it's not all plugged up where the hoses attach. Carbon can get up in there... water can get up in there.. rust can get up there.. and the hoses themselves can deteriorate and flake apart on the inside and clog up that sensor as well. If you find debris, try cleaning it out..

OK

Otherwise, most likely the PFE sensor itself is bad. I ALWAYS recommend replacing the hoses at the same time... it's cheap insurance.

OK

Yes there is a slight chance that it could be a bad wire somewhere or even a bad computer, but this gets into further electrical testing...

OK, thanks, I will check that stuff out.

Thanks for the help, I really appreciate it.

Rod

 

[HyBrad]

When you remove the vacuum hose from the EGR valve, just put your finger over it. If the hose sucks onto your finger, then there is vacuum there. Just like putting your hand over a vacuum cleaner hose to make sure it is working, except on a smaller scale.

As for applying vacuum, you can use a handheld vacuum pump (like a mity-vac) or other brand... or you can find a nearby vacuum hose that has vacuum all the time and plug it into the EGR valve (such as a the fuel pressure regulator... if it will reach)...

Or you can install a piece of hose and suck on it... like trying to get a thick milkshake through a straw... but you MIGHT get a mouthful of dirt/oil/whatever in the process...