Hi all,
Do any of you know what problems a bad EVP (EGR Valve Position sensor) would cause?

 

It would cause a error code in the computer. So get the codes out of the computer.

The computer tests the sensor itself. It will tell the solenoid to open and send vacuum to the egr. Right after it does that it looks for a voltage change from the EVP sensor. If it doesn't see what it likes, then it will give an error code.

 

Thanks for your quick response Franklin2...

I'm at my wits end, I CAN NOT find this annoying hessitation/surging problem I've been trying to diagnose I just changed the EVP Sensor today with no change nearly all of my sensors are new minus the knock sensor...

Vacuum is at a steady 16 hg., I can duplicate the problem if I idle it in park for 20 minutes with the high beams on, & the blower fan on high... My mechanic friend seems to think it's the main wire harness, becuase when the weather is cold it does'nt give me allot of problems, but at over $500.00 for the harness it's a big gamble....
We all seem to have the same problems TPS, EGR, O2 Sensor, Etc. but what ever I do DOES'NT solves the problem...

Any thoughts?

Thanks again

 

Do you have any codes? Even if it was the wiring harness, you should be getting codes since the computer would be looking for a sensor, and if the wiring was bad it would not see it sometimes and spit out a code. Make sure to check the memory codes too. This site has a lot of info on this system, and tells you how to read the codes with a testlight or voltmeter. Ford Fuel Injection

 

Hi Franklin2,
Thanks for your quick response last time I checked I had only code 11 which is fine...I did go to the Ford Fuel Injection site (GREAT WEB SITE) Is there a difference between codes & memory codes?

Thanks again

 

A memory (or History) code is a code that is not currently active, but has appeared in the past.

So if you have a intermittent problem, it might not be acting up at the moment you scan the truck for codes, but the computer stored it as a history code when it happened.

I don't know if your truck has this capability (mine certainly doesn't!) but it is exactly what you need it sounds like.

Got to run, I'll try and add more helpfull comments later.!

 

I am too lazy to look it up, but it depends if you are looking at the codes when the engine is running, or when the engine is off but the key is in run. One of those modes gives you the memory codes.

Also there is a wiggle test. See if you can find this on that website. You can put the computer in the wiggle test mode, and then start shaking the wiring around. During the wiggle test, the computer looks at all the signals, and if during the wiggle test it detects a signal going haywire, it will send out a pulse on the code reader.

All the EECIV computer systems have these features. It's really a nice system if you get to know it and how it works. That's why it's so frustrating when someone wants to change their efi truck over to a carb. I know electronics can be hard to understand, and I also don't like working on something I don't understand, but a little bit of reading and studying, and anyone can get the hang of it.

If after all this, you are still getting code 11, then you have some sort of other problem like fuel pressure, timing, etc.

 

A memory (or History) code is a code that is not currently active, but has appeared in the past.

So if you have a intermittent problem, it might not be acting up at the moment you scan the truck for codes, but the computer stored it as a history code when it happened.

I don't know if your truck has this capability (mine certainly doesn't!) but it is exactly what you need it sounds like.

Got to run, I'll try and add more helpfull comments later.!

 

I'll be checking for codes tommorow in the mean time I had a thought that maybe the PIP Sensor is bad do you know how to test it? or maybe the stator

 

I know how to test it, it's pretty easy, but you have to have a lab scope >shrug<

If you have a really fast switching multimeter, you could probably use that in it's place.

You hook the scope (or multi-meter) up to the output from the PIP. As the motor (or distributor, if bench tested) is turned, the PIP should output a square waveform, between 12 and 0 volts. A meter would be able to give you a rough idea, if you saw it change between 12 and 0 over and over again. Usually when a CKP (PIP here) dies, it stops sending a signal all-together, so the meter idea would be somewhat helpfull.

If your PIP is behind the harmonic balancer, make sure the teeth on the ring are all clean, and check that the sensor itself isn't too far away from the ring's teeth. I can find you the spec tomorow, if you need it, but it's pretty close.

Oh, and also if you have the one behind the balancer, check the wiring harness. They can come loose from the mounts, and rub on your belts or pulleys.

I'm really bad at "remote diagnosing" things, but I will gladly help you as much as I can It's far more fun to work on a Ford (even remotely) than it is to work on Audi's all day!

 

If the PIP signal is lost and then comes back guess what? A code will be set in the computer. A signal/no signal condition is what the computer is good at. It can be fooled sometimes, but not with simple ones like that. And if it did give you a PIP code, that means it didn't see the signal, it doesn't necessarily mean the module or the pickup is bad. It could be a wiring problem, and in this case, some of this wiring is shielded, and sometimes the shield can short out the signal wires.

 

Hi there Franklin2,
I just ran a scan of the computer with the engine running and got a code 32 (EVP circuit has intermittently failed below minimum voltage of 0.24 volts) does that mean it's an old code or is that a code that is currently the cause of the problem?
I'll be checking around there to see what I can come up with...

Thanks again

Buy the way I did change the EVP Sensor the other day

 

Hi there HANDEGARD thank you so much for your reply

I replaced the EVP Sensor the other day & it did not help the problem...I just ran a scan of the computer with the engine running and got a code 32 (EVP circuit has intermittently failed below minimum voltage of 0.24 volts) does that mean it's an old code or is that a code that is currently the cause of the problem?
I'll be checking around there to see what else I can come up with...

Any ideas what I should look for beside a bad wire or a bad ground?

Thanks again for your help you guys are great help!!!

 

With the engine running, that is a hard code that the computer sees right then after it does some tests. If you want memory codes, you will have to set the scanner up and turn the key to run, but do not start the engine.

You might want to try finding the computer, disconnecting the battery, and then unplug the large plug going to the computer a couple of times and see if that helps. That large plug has been known in the past to get bad connections.

 

Hi,
I watched a video on youtube on how to test for codes... With the engine running your supposed to boost the throtle (move the throtle all the way to the open throtle possition quickly & then let it go) once you get a signal light from the tester... when I do I get a code 32, if I don't boost the throtle I get more codes, I got a code 77,25 & 32 I think these are old codes as well as new ones it also said that in order to clear the codes you should remove the tester while it's giving you the codes, when I do it does'nt clear the codes...I'll unplug the large computer plug & test it again, I also checked the voltage of the EVP Sensor & I get 5.22 volts on thr VREF side of the EVP Sensor & 5.17 volts on the EVP terminal of the EVP Sensor, it should be 5.0 volts from what I read!!!

With the engine off I only get code 11 which is good!!!

If the EVP circuit has intermittently failed below minimum voltage of 0.24 volts, do you have any ideas what I shuold look for?

Agian thanks for your quick response