[john rotonda]

I drive a mechanically sound 86 graduate. During a recent drive a screeching noise erupted from behind the passenger seat. I pulled up the back panel and found the 6' X 6" X 2" black box was the source of the noise. I replaced the altitude sensor but it didn't have an effect on the noise. No help from local (west Michigan) mechanics so far. Any ideas??

 

[86spider]

That 6x6x2 inch black box is the L-Jetronic fuel injection controller. I am not aware of anything inside which should cause a screeching noise. But there is a vacuum sensor in the passenger's side wall behind the carpet next to where you found the black jetronic controller. I have heard of that making a screeching sound which changes with engine load (vacuum).

http://www.alfabb.com/bb/forums/spider-1966-up/5660-screaming-squealing-noise-idle.html

good luck,

wayne

 

[ghnl]

I think I recall someone here describing one of the relays (located next to the FI computer) making a screeching sound.

 

[Tifosi]

The drive relay can make some pretty horrific noises like described when it's on its way out.

Might be worth a harder look at the main fuel pump too, as while it's outside the car, it's pretty much directly under the ECU area.

It's not impossible that the ECU itself could make such sounds, (it controls the ground circut for the injectors, so could be creating noise from there), but I'd have to imagine it would be acting pretty uppity beforehand and may not even run the engine.

 

[Dekuiper]

Location

Hey John,
Where in West Michigan are you? I'm in Fremont and I know another person on the board here is from Big Rapids.