Well I changed out my plug wires this weekend and checked and adjusted the timing on my '91 F150 5.0 litre automatic. My gas mileage had dropped recently. One of my plug wires was broken so this didn't help.

Truck is running smooth and has lots of power, but under a load there's a pinging sound, but not all the time under a load. I checked the timing and it was spot on. Finally I tried the left foot on the brake, truck in drive and the right foot on the gas. My friend was checking for a possible spark jump problem and found that the EVAC (called a Ford dealer to see what the name was) solenoid was doing all of the chattering.

Anyone have this problem? It sounds just like the timing is out. This solenoid is in front of the EGR valve. There's a 3 inch vacuum line coming from the throttle body to a T fitting at the bottom of the solenoid. The other vacuum line goes down to the cannister for gas recirculation.

I think I will disconnect the solenoid to see if the "pinging" stops.

 

It turns out that the EVAC solenoid is doing all of the chattering due to the EGR valve. It's either faulty or plugged. This is why I only hear the noise at cruising speeds and not WOT.

I will attempt a cleaning this weekend before replacing it.

 

What does EVAC stand for? I ask because I have heard a similar noise and will check mine out. Thanks

 

I answered this yesterday, but I must have forgotten to post. Anyway E I'm guessing stands for Electronic or Exhaust and VAC stands for vacuum. I haven't found any information on the terminology, but check out this link.

http://www.niehoff.com/techtips/techtipidx.html

and more specifically

http://www.niehoff.com/techtips/egr.html

Gerald

 

Are you sure you don't mean EVAP? The EVAP solenoid is the one that controls vacuum to the vapor canister.

 

If that's its name then yes. I problably heard wrong when talking to the dealership. So what eactly does this do and how does it work in conjunction with the EGR valve or does it?

As I'm typing it just dawned on me that if the EGR passage is blocked then the amount of vacuum is going to be a problem for when the EVAP demands more hence the chattering. Sound logical?

Mine chatters so bad (cruising speeds) it sounds like the timing is out, but it's at 10 degrees.

I'm going to concentrate on the EGR valve and a blocked passage. I'II post what I fine.

Check out this posting. Now don't shoot me as it's in relation to a non Ford. What I found interesting is that there's mention about it throwing a code. Twice, in the last two weeks, my CEL came on, but reset on the next restart. Maybe this weekend I will read the codes to see what, if anything was stored. When my EVAP was at its worse there was no CEL nor is there ever on cruising speeds. It came on once while backing out of the drvieway. (Restart reset it) The next time I was coasting down the back lane to my garage and it came on.


http://www.s10forum.com/forum/showthread/t-65575.html


I'd better stop editing this post before I run out of room. I finally found information on the EVAP. Check this out.

http://www.asashop.org/autoinc/feb2002/techtips.cfm

Gerald

 

Every time you see the MIL (Malfunction Indicator Lamp, aka: Check Engine Light) come on, the ECM makes a personal note of it. It will retain this info for 80 cycles of the ignition switch (every time you turn the key on and off is one cycle). If you get the chance to pull the codes before you've gone through 80 cycles, the info will be in there, stored under Continuous Codes.

 

http://www.thesmokemachine.com/TechTips.html

Here's some more useful information

Gerald

 

This EVAC (Evaporator emissions) soleniod has many names depending on who one talks to. It seems like this little feature is rare on the 5 litres. Anyway I found that my EGR valve, although nothing was plugged, was not functioning properly so I replaced it. The pinging sound I'm now getting is my timing for sure so I guess it's time to check my timing chain although if it was stretched I would think my timing would be out of wack.

I just had the starter drive motor replaced last Friday and this morning the starter packed it in. The starter motor actually jammed during starting and everything quite. The garage will be by later to pick up the truck which I had to push down the drive way with my Expedition so that I could get out of the garage.

The truck has become a pig to start in the mornings, but is fine for the rest of the day. The search continues.

Gerald

To add to this mess. Last night I began unplugging vacuum lines (EGR, one behind the intake, and then the ones attached to the fuel pump relay? It had two vacuum lines attached. One green and one red.) Anyway my check engine light never came on even after giving the truck gas. I'm beginning to wondering if the main computer is wonky.

 

Garage repaired the starter again. Truck ran fine last night. This morning while cranking strong the engine began catching and then everything went dead. No dash lights, headlights, etc. I have a feeling that my battery has a serious short.

Gerald

 

Truck is running once more. The starter was shorting out after the garage replaced the bendix. They replaced battery cable ends etc. before finally pulling the starter apart.

Finally.