96 Rough Idle. Need Help.
Thread Starter
|
New User
Joined: Oct 2002
Posts: 16
Likes: 0
From: Colorado Springs USA
96 Rough Idle. Need Help.
I have a 96 Explorer XLT 4wd. The problem is when I come to a stoplight or just to a stop and the truck is at idle. The RPM's drop and the Eng. sounds like it wants to die. I ran the codes and they say "EGR flow insufficent". I replaced the EGR valve and reset the Check Eng. light. Still have the idle problem and the light is back on. Ran the codes again and same thing. I pulled the vac line from the EGR and there is no vac. Should there be some vac? Even at higher RPM's there is still no vac. I pulled the line completely and blow out the line. There's nothing blocking it. Could the EGR solinoid be bad? Also heard something about a DPFE sensor. Could that maybe be the problem?
Thanks for any advise.
Thanks for any advise.
Senior User
Joined: Jan 2002
Posts: 218
Likes: 1
From: Syossett USA
96 Rough Idle. Need Help.
There are three parts to your EGR system. The Pnuematic EGR valve. The EGR Solenoid, And the DPFE
The EGR valve opens and closed to allow Exhaust gas back into you intake manifold.
The Solenoid takes the lectric signal from the computer and converts it into the Pnuematic signal for the valve
The DPFE senses the differential pressure across the EGR valve.
I had the same code on my '95.
I replaced the EGR valve first.It was the hardest componant of the three to change and it was not the answer
I replaced the Solenoid second. it was easier to change then the EGR valve and it was not the answer.
I replaced the DPFE sensor third. it was the easiest to change. I was also told that they are notorious for going bad. It was the answer.
If it sounds like I did it backwards. I DID. (But at least I am not the only one
If you look at the the exhasut pipe the EGR is connected to you will see two rubber vaccumm hoses. Follow them back and they both plug in to the DPFE.
The DPFE is about $70. It is held on by two screws. Don't confuse the Vacuum Lines when you hook the new one up.
The EGR valve opens and closed to allow Exhaust gas back into you intake manifold.
The Solenoid takes the lectric signal from the computer and converts it into the Pnuematic signal for the valve
The DPFE senses the differential pressure across the EGR valve.
I had the same code on my '95.
I replaced the EGR valve first.It was the hardest componant of the three to change and it was not the answer
I replaced the Solenoid second. it was easier to change then the EGR valve and it was not the answer.
I replaced the DPFE sensor third. it was the easiest to change. I was also told that they are notorious for going bad. It was the answer.
If it sounds like I did it backwards. I DID. (But at least I am not the only one
If you look at the the exhasut pipe the EGR is connected to you will see two rubber vaccumm hoses. Follow them back and they both plug in to the DPFE.
The DPFE is about $70. It is held on by two screws. Don't confuse the Vacuum Lines when you hook the new one up.
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
96 Rough Idle. Need Help.
Unless an EGR valve is stuck open it usually wont cause an idle problem. I think you may have 2 problems. The PFE is the most common problem for an EGR flow condition. The valve is probably working ok but the sensor doesn't think it is. The PFE is easy to change too.
Your idle problem could be caused by a vacuum leak. Most of the time on a 4 litre engine with a vacuum leak, the problem is the fuel rail gaskets....both above and below the rail. With the engine idling you can take some carb cleaner spray and aim it at the fuel rail. If the idle changes at all...either goes up or wants to stall, you've found the leak.
Your idle problem could be caused by a vacuum leak. Most of the time on a 4 litre engine with a vacuum leak, the problem is the fuel rail gaskets....both above and below the rail. With the engine idling you can take some carb cleaner spray and aim it at the fuel rail. If the idle changes at all...either goes up or wants to stall, you've found the leak.
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
96 Rough Idle. Need Help.
The fuel rail is where the injectors go into the heads, in between the upper intake and lower intake. You remove the upper intake manifold and then the fuel rail is held to the lower intake with some studs. There is a gasket above and below it. I can email you a pic if you want.
Post Fiend
Joined: Jan 2002
Posts: 5,859
Likes: 7
From: USA
96 Rough Idle. Need Help.
also ,we assume you chk your plugs and wires .
and the lower intake manifold gaskets tend to leak on 4.0 v6s .
yes as stated if the egr is not seated at idle and leaking by it will cause rough idle.
did you scan again after you changed the sensor?
sometimes you have more than one pending code .
Rich
and the lower intake manifold gaskets tend to leak on 4.0 v6s .
yes as stated if the egr is not seated at idle and leaking by it will cause rough idle.
did you scan again after you changed the sensor?
sometimes you have more than one pending code .
Rich
