I have a 1987 F-150 5.0L, it is having problems with EEC-IV codes. Teh following codes are:



KOEO - 84 - EGR vacuum solenoid circuit failure
KOER - 41 - HEGO sensor circuit indicates system lean
KOER - 33 - EGR valve opening not detected

To give you some recent history. I repalced the EGR Valve about 2 years ago, replaced the EGR Valve Postion Sensor a week ago and today repalced the EGR Vacuum Solenoid today. The 84 code is a new code. If you have any idea what it could be, please reply. Thanks is advance.

 

Ok , first off , make sure the engine is fully warmed before doing any EEC tests . You may have got Code 41 because of the engine / O2 Sensor was not fully warm . Code 84 indicates the following :

Faulty Evr solenoid
Open wiring harness
Shorted harness
Faulty Processor

If the Evr solenoid resistance is not 30 to 70 Ohms , It says to replace the solenoid . Since you have replaced it , Id have a look at its wiring and or vacuum source and supply . If the wiring checks out , post back and Ill give you the next step of the diagnostic routine .
Paul

 

I checked the wiring and the vacuum. Everything checks out. I agree with what you said about the O Sensor error. I drove it for about a half an hour then tested it; it may have been to cool. That is the easy part of the problem, I can just replace the sensor. What I can't figure out is the EGR system. I changed the EGR Valve about 2 years ago. I had it diagnosed by ford as the EGR valve so I swapped it out. It didn't change a whole lot; I still had poor gas mileage, about 10-12. I changed the EGR Valve Position sensor a couple of days ago and that seemed to help. Then I went looking for other faulty sensors or vacuum leaks. I found an air diverter valve that wasn't holding a vacuum and the EGR vacuum solenoid. When I went to get the part at Ford, I asked them how common it is for the EGR Solenoid to fail and they said, "Very common, we sell about 10 a day." When I put the new part in, I noticed a big diff. As soon as I got it back to the shop I checked the codes thinking that there wouldn’t be any, but it had the codes that I mentions in the previous post.

When I checked the voltage across the leads on the EGR Vacuum Solenoid (disconnected) it was 12V (engine off) and (13 - 14V) with the engine running. Could the voltage regulator be going bad?

Thanks for your help with this problem

Charlie

 

I have another question, with the info above; I noticed a problem when the parking brake is applied, the engine idles low then dies.

What could cause this?

Thanks in advance.

Charlie

 

I have another question, with the info above; I noticed a problem when the parking brake is applied, the engine idles low then dies.

What could cause this?

Thanks in advance.

Charlie

 

 

Did you ever get this fixed ?? What was the solution ??

 

Wow, you sure went digging to find this thread! The last post was made 16 years ago! I don't think these guys are still around...

 

lol, the post never go away on the internet. Yeah those lads are probobly long gone, but the problem trucks are still passed around... usually free.. with the same issue from 16 years ago.. Shame they don't all go to thier graves.....

Loads of good info out there, questions already asked and answered......

 

https://www.ford-trucks.com/forums/1...evp-codes.html


There are several more. Any of us would be happy to assist, but I still do not know what this guy's issue is. I am a serious DIY kinda guy, but I know when to throw in the towel. I asked for the issue, still no response.

 

It are go good with pizza.

 

Obviously I did not make myself clear to you, or you did not comprehend what I previously wrote. I’m just getting started troubleshooting this truck. I say again; I’m just getting started troubleshooting this truck.

It came to me because at least 3 others failed to solve the problem. Chances are, that from the information I am gathering, I will fix this truck without having to start a new thread. If I get stuck, I will ask the smart people on this and other forums as I have done many times on many forums in the past.

Again, it’s a waste of time to list multiple symptoms and receive duplicated answers from multiple people that are no different than what has already be posted many times.

Leave me alone and go bother someone else, this man’s questions were not answered by this forum in 2000.

“Well, because I strive for due diligence by researching existing threads first for past solutions to the related issue. I do a lot of reading, there is a lot to learn on the past post, then I start testing and developing my questions, eventually I will post my questions. I don’t believe in wasting everyone’s time by not doing my homework, that’s just lazy, and clogs the forums up with unnecessary post.

Unfortunately with half of these post, they are incomplete, and I take the time to at the least, ask the posters if the achieved a solution. Some do, some don’t, and some are long gone until they need their next quick fix attempt.

This 85’ f100 is unique, first 5.0 model year with EFI, then changes made mid 85’, so not run of the mill. There are a few lads out there that never got their 85’ trucks fixed. So in this case I’m looking in the 87’ + forums, for they have more experience with the EFI/OBD-I/EEC-IV systems. I think all the 85-86 owners cut their losses and gave them away, that’s where this one comes from…”