buzzing sound...

[86RangerDrew]

I own an '86 Ford Ranger 2wd 2.9 cyl. FI...Whenever I shut the engine off,I hear a strange buzzing sound from the passenger side firewall...It sometimes varies in tempo,but always remains...Help!...Is it the solenoid?...The truck starts fine and runs well,but this problem remains...

 

[AllanD]

I'm thinking the vacuum reservoir under the air cleaner box is leaking down.

Either that or it is an AC system noise.

AD

 

[Natedog]

I'm thinking the vacuum reservoir under the air cleaner box is leaking down.

AD

I have this same problem and was thinking this may be. Shouldn't it hold vacuum for at least several minutes? So it could be the vacuum solenoid on the passenger fender, the vacuum reservoir and/or the vacuum lines?

 

[CRASHJT]

I had a similar problem turned out to be the fuel pump relay....its the green one

 

[Natedog]

I had a similar problem turned out to be the fuel pump relay....its the green one

So you replaced the relay and it went away or? Did you have any other problems associated with this?

 

[CRASHJT]

I replaced the relay and that was it I some how got it filled with water if its that you can feel it vibrate and it will get hot too

 

[Natedog]

Thanks Crashjt.

 

[AllanD]

I have this same problem and was thinking this may be. Shouldn't it hold vacuum for at least several minutes? So it could be the vacuum solenoid on the passenger fender, the vacuum reservoir and/or the vacuum lines?

I had several vacuum reservoirs that developed leaks.
Usually the seam.

MY truck now doesn't have one at all.

the Last EGR 2.9 I had is several years in the past,
the Non-EGR 2.9's I had only had vacuum lines
between the FPR and the intake manifold
and between the manifold and brake power booster.

And since switching to a 4.0 I actually added a vacuum line...
To the air intake vacuum pot for the air preheat
(TB icing can be a real bitch)

and since I have an '87 cab all of the HVAC controls are mechanical
(cables), so I don't have a blend door vacuum actuator like a gen2
either.

How loud is this buzzing?

AD

 

[Natedog]

My 87 HVAC controls are all cables. Have you ever eliminated this box on an EGR truck like mine? Enough vacuum there without it? Still should pass smog on the tailpipe part.

The noise can be heard inside the cab with windows open or closed after turning the key to off and engine stopping. Not loud, but easily heard if you are paying attention.

 

[86RangerDrew]

I replaced the fuel relay switch...Not it...I replaced the starter relay(solenoid?)...It still buzzes sometimes...But not every time I shut the truck off...Better than it was...Thanks!!!

 

[Natedog]

The buzzing is exactly what AllanD said!!! Now that I have all 1988 emissions on my 1987, I don't have this vacuum reservoir and no more buzzing noise after shutting the engine off.