I have an 89 f-350 w a 460 that is shaking and will not idle at all and sounds like it is missing below 1300 rpm. soon as it throttles above 1300 rpm it runs smooth. Ran the codes and came up with 12,42, 33, and 13 I can not find what is wrong. Any help would be great I don't know what to do with this problem and I need the truck.

 

All of the codes suggest the EGR valve not closing when at idle.

Take the vacuum hose off of the EGR Valve and see if the idle straightens out. If it idles good with vacuum hose off you probably have a bad EGR Valve Regulator. Plug the vacuum hose and run without it until you have the time to fix it.

If taking the vacuum hose off of the EGR doesn't fix it then take the EGR off and clean it or replace it. ERG valves get carbon deposits on the pintel over time and the carbon deposits sometimes prevent the EGR from closing all the way at idle or WOT (wide open throttle)

Codes 12,13, and 33 all suggest a problem with the EGR valve or the EGR valve position sensor mounted on top of the EGR valve.

Code 42 is an "always rich" code.

Could be something else but that is where I would start. Just had the same problem myself this very morning. Mine turned out the be the EGR Valve Regulator. It was pulling the EGR valve open all the time. Hence it barely ran at idle but ran at higher RPMs.

 

Thanks for the info I just took the egr valve off a motor I had in the garage that ran great when I took it out of another truck and nothing changed. I put a direct vaccuum on the valve and it killed the engine imediately even though I had it running at the 1300 rpm range. Is this normal? I am pretty good with motors but usually work on pre-computer vehicles so I am just starting to learn about all these control devises. What else could be causing this. The truck ran good 2 weeks ago and got progressively worse. I've changed a bunch of parts guessing at it and it is a little better than when I started but will barely idle if it does at all and sounds like crap. Any other ideas?????

 

Yup, if you open the EGR at idle it will either idle poorly or die.

What happens when you simply remove the vacuum hose from the EGR valve. Does the idle improve at all?

Also, is there an electrical connector on the top of the EGR valve?

Disconnect everything and see if the truck idles correctly. If it does idle with everything disconnected try this.

Put your finger over the hose you removed from the EGR valve or better yet attach a vacuum gauge to it. There should not be any vacuum on the EGR vacuum hose at idle. If there is a vacuum on the EGR hose at ilde it means the vacuum control for the EGR is the problem.

I've got an '88 460 and it has a EGR Vacuum Regulator (EVR) just before the EGR valve. The input vacuum for the EVR is directly from the vacuum source. My EVR was leaking and applying just enough vacuum to the EGR to make the motor idle a little rough. I chased the problem for well over a year. Yesterday it finally failed completely and it was easy to find. Remember - no vacuum on the EGR at idle.

Next place to go is probably the Idle Air Bypass valve. Take if off and clean it but be careful not to damage it. Ford recommeds using carb cleaner rather than choke cleaner. You have to remove little solenoid from the from of the valve and then work the plunger as you clean it.

 

I don't have any vaccum at the egr. I do have vaccuum at the control valve for the egr. If this valve was bad I would get these codes right? That still would not be the reason for my rough idle though if the valve is closed at an idle. I'll check the air bypass today and make sure it is working. I have a parts truck that was wrecked that ran perfect, so I don;t mind swapping parts but I need some direction. Thanks-Bill

 

You have to be at operating temp to have a vacuum at the EGR (on the other side of the valve going to the EGR) but no vacuum at idle is good. Means the EGR valve should be shut hence no effect on the idle (unless the EGR is leaking).

The only code I got when my valve was going bad and after it had failed, was a 35 (idle too low - EGR). However, a lot of times when the idle is bad the EGR is a good place to start.

Idle air control, map sensor, fuel pressure regulator, etc. could all be the culprit. By the way, did you change the octane of gas you are using lately?

Also, I had a catalytic convertor go one time but it only effected the engine under load. At idle it was fine and it was OK when I opened the throttle in "Park".

A system of elimination. With a ready supply of parts you should hit on it soon. I'll look in my technical info for other clues and get back to you.


After checking - Idle air bypass is the only other clue they give. Hope that does it.

 

Found it!!!!! checked my fuel pressure and it was over 100 pounds! Changed the vaccuum pot on the fuel rails and everything is back to normal. still pulling up a code 33 though. I changed everything except the black valve in line before the egr. It is on order because I didn't have a good one. At least it is running again thanks for all the help. -Bill

 

Great! I am assuming you mean the Fuel Pressure Regulator, right? I'll keep that in mind if mine ever starts acting up like yours. If it isn't the FPR let me know.

I have a steady code 33 without the EVR (EGR Vacuum Regulator). That's the black valve in line before the EGR. I have mine disconnected and the vacuum line plugged.My wife just picked mine up for me. I'll put it in tonight and see if that cures my problem.

Bear in mind that a code 33 actually refers to the EVP (EGR Valve Position Sensor) that is mounted on top of the EGR on my vehicle. The EVP is not reporting the EGR position to the computer. With my EGR valve inoperable (vacuum disconnected) I expect to get a code 33.

 

yeah it was t5he fuel pressure regulator. I Had a long week end and wasn't thinking any more. I was tired of working on this damn truck. definately let me know if egr vaccuum reg gets rid of the code 33. It could be my v.p.s. Idon't know. Iput the one off of the other truck on, but that does not mean it was any good either. I know $96 is a lot of money for the vaccuum regulator. Ifr it does not solve my problem. Got to get it fix though. It has to pass Ca. smog in 2 months. Again thanks for the help. -Bill

 

I would get the Crane adjustable fuel pressure regulator for the 5.0 mustang of the same vintage. Lets you set the pres. for opt. power of lean it out to pass emmision tests. put one on my 89 460 and it is very nice to set my pressure where I want it.

 

Gotta pass Ca emissions. Man am I glad I don't have to go through that anymore. The code 33 shouldn't be hard to figure out. Sounds like you are almost there. I put in the new vacuum reg and the engine purrs like a kitten. Used to have a rough idle and always a code 35 in continuous memory. Old one was leaking and partially opening the EGR valve. Won't know for a couple of days if it has resolved the code. Have to sit still a couple of days and do some work in NYC.

doccamel - Thanks for the advice on the FPR. I have been going through my '88 and replacing parts as a matter of preventative maintenance. We live and work full time in our RV and being stuck beside the road is not an option. After 16 years of service on most of the emissions and engine components I figure I got my money's worth. Just changed the entire cooling system, EGR, IAC, etc. Also have a new fuel pump (high pressure), fuel filter, fuel resevoir, cat, belts, and on and on. Haven't changed the FPR or in tank fuel pump yet. Engine runs better with each new component.

Where did you get the Crane FPR? Are they available at the a particular auto parts store or are they special order?

 

broncobillc - Well, I replaced the EGR valve regulator and my engine runs fine. Best idle I have had in a long time.
Unfortunately, I still get a blinking "check engine" light when cruising and the computer shows a code 35 in continuous memory. Since I don't have this problem when the source vacuum to the EGR system is plugged I must have a vacuum leak at the EGR connection or someplace after the EVR. I have a new EGR and EGR position sensor and one of them, or the EEC could be bad, but I am going to look for a vacuum leak first.

 

mpmccarthy, Thanks again for the help I am really liking the quality of help here on the forum. You can't seem to get information from any where else on some of this stuff. Truck is running great so I guess I can tinker with it for a couple months before the dreaded Ca smog police get a hold of it. Good luck with your vaccuum leak search. Those little hard plastic lines are the worst idea ford has came up with yet. You can't move anything without breaking one!! Robbed my father-in-laws r/c plane parts for fix-it tubing(fuel line fits right over plastic like a rubber coupling. - bill

 

The reg. is in the jegs book. or just go online and you should be able to find it on their site. Made by Crane P# 270-99471-1 should be it.