1997 F-150, 4.6L, 107K miles. My check engine light came on. I took it Autozone, who told me to replace the EGR valve. When I reset the light it came on again after 5-6 starts. I reset it again and it still came back on after 5-6 starts. I went back to Autozone and was given the same code " insufficent flow to EGR valve". They said to remove the valve and check the ports for carbon buildup. The old valve looked fairly clean when I removed it. My question is should I be checking anything else before I remove the valve again to check for buildup? Could there be another problem related to the EGR that isn't corrected when I change the valve? Is it possible I'm not resetting the computer correctly? Thanks for any help.

 

Hi cardone and welcome to FTE

Do you remember the actual code they retrieved?
Was it a P0401?
If it was, the most common problem is a bad DPFE sensor. If you search on here you will find lots of posts on the same problem.

 

RacerGuy, when Autozone ran the check they just told me what was wrong. I never actually saw the code. Thanks for the heads up and I'll look at other posts. I'll get back to you either way in the near future.

 

Racerguy, I took your advise and read the threads re: EGR valves. They were informative and I followed them but had no luck. I removed the new EGR valve, cleaned out the port with carb cleaner and a wire brush til it shined. I checked the voltage in the EVR as well as the resistance in ohms. I blew out the lines leading to the exhaust and the one leading to the EGR. Then I sprung for a new pressure sensor (DPFE) from Ford. The light stayed out for 2 days and 7 starts then it came on this morning while driving. Any thoughts? I'm in for $125 already. I thought I'd be saving money by doing it myself. I'm not sure the disappointment is worth it.

 

I copied this for you from a previous post of mine:

"I had the same code on my 98 F150 4.6. I checked the DPFE sensor, EGR valve, Vac Reg Solenoid, and all that. Everything was working as it should. The insufficient flow code is more likely to be because of the build up of carbon where the EGR gases enter the intake manifold. They are typically small diameter ports and are prone to carbon build-up over time. I cleaned mine thouroughly (see my post in General Performance) and the code has disappeared. Passed NJ State Inspection this morning with flying colors.

The main thing that I can relay to you is that when I put vacuum to the EGR with it running, it should have stalled and it didn't... it just ran a little rough. The reason was that the EGR was doing it's job, but the gases couldn't get through the blockage in the intake. Not sure how your engine is set up, but I'd be willing to bet that the same thing is happening to you. I would check out the carbon-blockage situation first.

P0401 is a generic code, the Ford-specific code for Insufficient EGR Flow is P1408. You may want to have someone with a better scanner do the scan. Autozone uses the generic scan tool and it doesn't tell you the specific code- just the general P0401 code. I had a friend use a Mac scanner with Ford-specific module plugged in and got the P1408 "Insufficient EGR Flow" code. which means exactly that-the flow of the EGR gases is insufficient, usually due to a blockage in the passage. Couldn't see the blockage in my 4.6 until I removed the Throttle body and upper intake elbow. Then it was apparent! "



My 'Insufficient EGR Flow' code has not returned, and it's been 4 months. Those 2 little piles of carbon at the Intake Elbow end of the EGR passage completely blocked the EGR flow and that's what caused my entire problem. I solved it using only hand tools and a can of carb cleaner... so if you're handy i would suggest trying this first before taking it to a shop.

 

Rob, I read your original post but I'm confused by the 'ports' your talking about. I removed the EGR valve. I have one hole about 1/2 " in diameter. I sprayed carb cleaner and used a wire brush to clean it out. Then I blew air into it and got a ton of black chunks of carbon out. Where are these ports your talking about and how do I check them for buildup? This is driving me nuts.

 

The ports that need cleaning are not in the EGR. They are in the throat between the EGR and the Intake Maniflod. Carbon builds up and air flow stops. Code P0401 will come and go. I was impressed with how much carbon I got out of mine but it is fixed now. 1998 F150 4.6L 112,000 miles. I had to remove the throat and clean the ports from the inside they turn 90 degrees and can only be cleaned off the intake maniflod.

Good Luck

 

With the engine idling apply vacuum to the vacuum fitting on the EGR valve. The engine should stall or close to it. If it doesnt then the ports that 50th ann mentioned are probably plugged.

 

Well it appears that the problem is now solved. Although I read similar posts that described the junk that came out of their EGR ports, I could not believe what I saw when I removed my throttle body. Thanks to Racerguy, YYZ87 and 50th Ann, who described in detail how to find and correct the problem, my check engine light is out and I don't anticipate it coming back this time. Thanks again for all your help.

 

Thanks for letting us know what you found

 

Put a reader on mine last night, got the P0401 code.
Will do the above this weekend, and let you guys
know how it goes.

'97 F150 XLT 4.6L 127K
'99 Eddie Bauer Expedition 5.4L 85K

 

Do the simple vacuum test mentioned first.

If you don't, you stand a good chance of wasting time and effort.

If the vacuum test fails (no reduction in RPMS), clean the EGR ports. If the ports are already clear, replace the EGR valve.

If the vacuum test passes (engine stalls or bogs), focus on the EVR and the DPFE sensor. The DPFE sensor is a common failure.

Steve

 

Replaced the EGR Valve, removed the throtttle body
and cleaned the EGR Ports.
They were completely closed up with an incredible amount
of carbon buildup. Cleaned them and the for more than an hour.
Installed the new EGR Valve, and cleaned the IAC since
another was on order for a couple of days delivery.
Truck cleared the PO401 code, but threw a P0701,
bank 1 running lean. Idle went up and down.
Installed the new IAC and it runs like champ.
The codes have all cleared and it's like a whole new
truck. I got my knowledge and confidence on diagnosing
and attacking the problems with my truck from this forum!
Within last week: New Alternator, EGR and IAC, cleaned EGR Ports,
replaced hose. Much better gas mileage, less knocking. Still alot of
knock with the AC running. Oh yeah, snapped the IAC bolt upon installation.
Removed throttle body again, bought a 3/32 drill bit and an extractor
kit. Worked like a charm. Reinstalled, more carefully this time.
Yeeeeehawwww!

'97 F150 XLT SuperCab 4.6L 127K
'99 Expedition Eddie Bauer 5.4L 85K

 

Wow...alot of great info! Can anyone tell me how to find the EGR valve and how to apply a vacuum to test the ports?

 

EGR valve is the the device on your throttle body housing
that looks like a disc or flying saucer, small hose off the top,
with two mounting bolts. How many miles? If you have a 4.6,
you will have carbon buildup at some point within your EGR ports.
I believe it's a guarantee. If you do change your EGR, do yourself
a favor and tackle the EGR ports at the same time. Are 5.4's also prone
to the build up in the ports? Didn't do the vacuum tests, knew what I
needed to tackle from the codes, this forum, and the way vehicle was behaving.

'97 F150 XLT SuperCab 4.6L 127K
'99 Expedition Eddie Bauer 5.4L 85K

FYI: Your IAC looks like a cylinder and is held on by 2 bolts also.
It will go bad eventually as well, but very easy to replace.