Ferrari Forums banner
1 - 14 of 14 Posts

Discussion Starter · #1 ·
Hello JRV and others....I'

Hello JRV and others....I'm new to the forum here, but it's great to see familiar names. You have provided a very nice and useful forum, JRV -- thank you for sharing your expertise with the owners and enthusiasts! I regret that my first post here is of a technical nature, but here goes...

Recently purchased an '85 Euro TR, and am still "getting familiar" with the car. Last night, I encountered my first "glitch" -- a humming noise coming from what appears to be the warm up / control pressure regulators on either side of the engine, while the engine / ignition is off.

This only occured recently according to the gentleman who I've hired to fully detail the car. He did give the engine a thorough wash / rinse / cleaning with the garden hose, and mentioned that he heard the buzzing noise on occasion (would come on for a while and then stop for a while). He figured it was normal.

As of last night it was buzzing again, and I couldn't shut it off so I disconnected the battery. Just went and checked it out again...

First I blew the engine compartment out with compressed air, especially around the wiring and regulators. Then reconnected the battery -- the humming started instantly, but then quit. So...I cranked it up and let it fully warm up for about 5 - 10 minutes. The engine did start to hesitate slightly after a while, and then finally "choke down" and quit.

Unfortunately, I'm not familiar with the K-Jetronic systems. Any ideas what might be the problem, or was it simply wet wires? Should I be concerned with driving the car under these conditions? Wasn't sure if the car needed to be driven at speed (say 45mph), long enough for the ECM to reset?

Any help would be greatly appreciated -- thanks in advance!

Discussion Starter · #2 ·

Hi, welcome to Ferrar


Hi, welcome to Ferrari-Talk...and sorry you're having a problem.

I'm not so sure you are describing what I would call a warm up insure we are all on the same page can you post a photo or tech diagram of exactly what is "humming". The reason I request the pic, is because I can't think of any way that what I call a warm up regulator can make noise at all.

Thanks, JRV

Discussion Starter · #3 ·
Thanks for the quick reply, JR

Thanks for the quick reply, JRV...

Here's a couple of pics showing the two parts that were buzzing / humming:

This first illustration is from the owners manual, and shows the two warm up and control pressure regulators and additional air valves (parts "B" and "D")...

The following image shows these same two parts circled in yellow...

There is also another electrical part on the drivers side just adjacent to and inboard of the regulator that I think was buzzing as well. It was hard to tell which one was the culprit -- as both regulators, both air valves, the inboard electrical "part", and all assorted hoses / wires directly connected to them were vibrating.

I pulled all the related fuel pump fuses / relays, but this had no affect. Disconnecting the negative cable on the battery did

I'm not certain as to what the inboard electrical part is, but it is pictured in both of the above attachments (the shorter "tube" left of the longer "tube" on the drivers side attached to the top of the engine / bellhousing.

The buzzing almost seemed like an "open loop" condition. I did not feel or hear any vibrations from any other locations on the engine or fuel distributors.

Discussion Starter · #4 ·
Oops, don't know what happ

Oops, don't know what happened but the second pic didn't upload correctly...

Trying it again:


Discussion Starter · #5 ·
Wow...must be doing something

Wow...must be doing something wrong here. Image size is 640 x 252.

Trying once more...


Discussion Starter · #6 ·
Hmmmmmm...those are the warm-u

Hmmmmmm...those are the warm-up regulators .

Is there any possibility it was actually the starter humming?

Discussion Starter · #7 ·
Hello Eric,

JR is probably

Hello Eric,

JR is probably busy, but I'm sure he'll be here to the rescue shortly.

I think what's buzzing are your fuel pumps. I was gonna say earlier (either fuel pumps or Freq. valve/lambda valve) but since your's is a Euro, you may not even have Lambda (O2 sensors and frequency valves).

I think what you're feeling is pulsations of fuel running through the system because the Fuel Pumps are on. The items you circled don't buzz (nuthin in them to buzz, so my mind is blown there).

Try locating and disconnecting the leads on your fuel pumps and 'then' see if you hear the buzzing with the negative reconnected.
Being that you disconnected the fuel pump relays (which also blows my mind), you may have a short somewhere causing the F.P.'s to stay on, or, your car has had some 'rewiring' done to it.

My thoughts anyways
while we wait for JR.

Discussion Starter · #8 ·
Thanks, Joe & JRV, for the

Thanks, Joe & JRV, for the replies!

That's a very good point you brought up about the fuel pumps / valves pulsating. This may very well be the case here. I did not realize that the regulators did not buzz, as I thought that perhaps they were some sort of electrical metering devices.

Not sure if it was the starter either. Is the starter the large black cylindrical device mounted on top of the engine / bellhousing next to the drivers side regulator? Most of the vibration was coming from the regulators / hoses / wires themselves.

I'll try your recommendation this evening (at the office right now) -- and see if disconnecting the leads on the pumps make any difference. It is quite possible that some rewiring may have been done. Until then, I'm wide open for ideas....

Discussion Starter · #9 ·
Any news Eric?

Do you have

Any news Eric?

Do you have an aftermarket Alarm installed?

I'm still pondering how the Fuel Pumps could run with the key turned off...and how/why washing the engine would have this effect?

Discussion Starter · #10 ·
So far so good....since reconn

So far so good....since reconnecting the battery yesterday AM, I haven't heard any more buzzing / humming. I still am not certain whether it was the auxilary air valves or the fuel pumps. What is odd is that both my detail guy and I felt and heard the source of the buzzing / humming from the regulators / air valves.

To my knowledge, there is no aftermarket alarm installed -- only power locks activated by a key fob.

I did a little further investigating around the regulator on the driver's side, and found a black plastic relay (?) with four wires connected that seem to trace to the regulators, etc. Perhaps some re-wiring was done at some point?

What's odd is that I cranked the engine and let her run for a good 5 to 10 minutes, and the idle hunted just a tad at around 1k. Then it started choking down, and eventually stalled on its own. I haven't cranked it up since yesterday (detail guy has been working on the car all day to day).

Perhaps I need to take the car for a good spin once he's done, and see how things go.

With regards to the pumps running with ignition off....the key was left in the ignition by the detailer, but was in the off position...when I noticed the humming.

Discussion Starter · #11 ·
Well...I thought the problem w

Well...I thought the problem went away, but unfortunately not.

Just swung by the house to throw out some fertilizer on the lawn before this tropical depression hits town; and, out of the clear blue, I hear that buzzing / humming noise again coming from the engine compartment of the TR! So, apparently it is happening off and on either during the day or late evening. This is the first time I've heard the noise since my last post over two weeks ago.

Did some digging around, and have narrowed it down to these two "air valves" (?) -- part "D" in the above diagram -- one is located on each side of the air cleaner next to the warm-up regulators. They both have a wiring connector plugged into them that branch out of a wiring harness -- so they are electrically charged, hence the electrical buzzing noise and vibration upon touch.

I have no idea why these would be buzzing on their own like this when the car is just sitting in the garage without having been driven for a while. Perhaps it's related to the ambient temperature or pressure in the hot afternoon?

This one has me stumped. Any ideas as to what might be the culprit, or what to check out? I felt all the fuel related items, and did not notice anything out of the ordinary. It all seems point to these two inline valves.

Not sure how important these are to the operation of the car. Nearest F-car mechanic is over an hour away, so was hoping to figure it out before having to resort to bringing the car down.

Any further help would be greatly appreciated. Thanks again!

Discussion Starter · #12 ·
Eric, what is this "stump

Eric, what is this "stump the experts" ?

The two valves are the auxilary air valves for cold they could humm or vibrate is beyond me. But if any part of the system which includes the AAV's is on with the key off then I can only think of 2 possibilities...either the FI relays are bad or there is some type of short in the ignition switch or circuit board, that allows the FI system to power up when the key is off.

I would suggest you first have a look at all the plug in connectors on the circuit board, by unplugging, inspecting for any burning, melting, shorting of any type and if nothing is discovered replace the relays for the engine fuel pump & fuel injection circuits.

Try those checks first and let us know if it helps.

Regards, JRV

Discussion Starter · #13 ·
Thank you, JRV, for the quick

Thank you, JRV, for the quick reply and suggestions! I will certainly check these items out this evening, locate new related relays as well, and let you all know what transpires.

BTW, where would be the best source for replacement relays? There's a large NAPA down the street, plus PepBoys, etc.

Discussion Starter · #14 ·
Eric, anywhere that sells Bosc

Eric, anywhere that sells Bosch relays should have the ones you need, if necc. pull one call both places and give them the Bosch part # off the housing.

Regards, JRV
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.