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View Full Version : Code 31=Bad EGR valve? How hard to replace?



phils89sc
04-07-2003, 12:03 AM
My check engine light came on tonight on my way home from my parents house. The engine did not seem to run any different, but when I got home, I ran the EEC test. All three tests, KOEO, KOER, and Continuous memory gave me a code 31. The book I have says that this one means the EGR valve valve position sensor in out of range (low).

Does this mean the EGR valve is bad, or is it the position sensor?

My 89 SC has 230k miles on the clock.

Also, if it is the EGR valve, how hard is it to replace?

Thanks in advance,

Phil

vancouverBC
04-07-2003, 01:30 AM
The EGR itself rarely goes bad but the vacuum lines going to it or to the transducer (little gray box behind the SC) do all the time. Or the EGR pipe coming off the exhaust manifold could be cracked. What kind of engine or exhaust work have you had done lately? Good luck

Shockwave
04-07-2003, 01:48 AM
The EGR can get carboned up and not close. This will throw a code. Very hard job to remove and clean. I remove cowl, and the pass side under cowl as well to have easier access to the egr bolts. Also the EGR tube is bolted to the head. I would remove EGR and tube as asn assembly and then work on it on the workbench. This isn't any fun so it might be worth buying one and replace it. Carquest had one listed for our cars last year for $57. It was a Ford part but not a number the dealer could cross reference. Also the Ford part counter guys hate when you bring in stuff from other sources. They start bitching about claibrations codes and what not. Then try and sell you a EGR for about three times that price.

Jerry

phils89sc
04-07-2003, 07:30 AM
The only real symptoms that I have are under full throttle it pings alot (running 93 octane, always). All this started yesterday when I was going to my parents house to put my new brakes on (Mark VIII 11.5" setup). I got a code 66 for MAF sensor. I replaced the sensor and that cleared that up. About 5 hours later when I left, the check engine light came on and I ran the code test to give me a code 31.

I guess I will have to pull the EGR, but it will not be till this coming weekend, not enough time during the week to do it.

Thanks for the advice and help.

Phil

Shockwave
04-07-2003, 07:45 AM
EGR is not active during full throttle or at idle. Only light acceleration will the EGR open and inroduce exhaust gasses into the comubstion chamber. Pinging at full throttle was due to MAF code and the computers short and long term fuel trims being way off making the car run lean at full throttle. I would disconnect the battery and then drive the car for a few days and see what happens. This will force the computer to relearn the fuel trims.

Jerry

phils89sc
04-07-2003, 09:56 AM
What kind of effects would I see if the EGR was always open, or if the vacuum hose was leaking? How about if the tube from the exhaust manifold was plugged?

Thanks

Phil

Mike8675309
04-07-2003, 11:10 AM
Always open
Run a little rich, power would be down as exhaust gasses are getting sucked into the intake. Exhaust gasses are non-combustable so they are just taking up space that good air could otherwise take up.

Hose Leaking
Vacuum leak. Rough idle and other problems associated with a vacuum leak.

Plugged hose
Possibly partial throttle pinging as EGR would be called for but no exhaust gases would enter when the valve opens.

vancouverBC
04-07-2003, 04:33 PM
That inocent little ping that you've been hearing, is actually detonation which is eating away at your headgaskets. Do an intake leak test with propane before you start replacing parts, you may find it to be a simple problem. Good luck

phils89sc
04-07-2003, 08:16 PM
But if there is just one thing I have learned about the SC's, there isn't anything that is truly "simple" to work on.

Phil

vancouverBC
04-07-2003, 08:43 PM
That's for sure Phil, I wanted to cut off my hand and leave it between the engine & firewall to replace that little EGR hose, even with the cowl, under cowl, and t-body linkage off. That's why I was asking if you'd had any work done on either the engine or exhaust, because that may help isolate what is wrong now. My trouble started after I replaced my SC and used the wrong type of hose that goes frome the EGR metal pipe to the transducer.

phils89sc
04-07-2003, 10:35 PM
I had my harmonic balance break off a week or so ago. Fixed that, and now I am just about proficcient enough at taking off the front of the engine to do it in my sleep!!

I never really touched the back of the engine though, although, I was back there a few days ago, but only cleaning the engine with degreaser and a high pressure car wash. Maybe that tagged the hose, but that was a couple of days before I got the code. I do know that the hesitation I have been getting (starting out in the morning while cold, the engine would hesitate at part throttle till boost came on, then it would just go away)

Anyway, compared to the harmonic balancer nightmare, I wouldn't think the EGR would be too terribly bad, but then again, it is an SC right?

What does SC stand for? Well, that depends on the day and the problem. On a good day, SC stands for Superb Car, on a bad day, when everything seems to be going wrong, it stands for Superbly Complicated!!

Well, at least I have it narrowed down to the EGR system, cheap enough to replace I guess. Any other tips or advice are always welcome..

Thanks

Phil