84 Alfa Romeo Spider. Ignition ECU & vacuum sensor

[@MalcolmEllul-b9p]

Do you know from which website i can buy one. It is gone on my S3 and i cannot get hold of one.

[@dawodchatha]

You seem really knowledgeable about these spiders, do you know any fix for a gas gauge that reads in reverse? Before i start it its at 0 but when i start it goes the opposite direction only a little bit cause it cant mechanically go further.

[@albagr01]

Sounds to me like the float or the sender in your gas tank has failed. Mine moves around a little bit when I brake and when I'm going up hill or down hill... and when I go around corners, but it always goes back to where it was when I am flat again and going at a fairly constant speed. When I replaced my gas tank, I saw a small amount of liquid in the float, so it will never be perfectly accurate until I replace it, but it isn't bad enough to bother me. If your float is full of gas though, then I suppose that might do what you're describing. There are some videos that were posted by international auto before it merged with centerline. The ones that deal with fixing the gas smell deal with accessing it at some point, I think there are three videos. (Link to their page below) You can also try and see if it's bad electrical connection and it's reading wrong. I would try that first as it's the easiest. You have to disconnect the battery. Access the top part of the fuel sending unit (screwed into the gas tank, which is in the floor of the trunk, drivers side, under the carpet, if you look at the videos I mentioned, you should be able to figure it out). then, again with battery disconnected, you can carefully separate the spade connectors from their contacts, and clean them up. I used things like a dremel tool with wire brush, tiny wire pipe cleaning brushes, sand paper, and/or contact cleaning spray. I did all those contacts and then did the ground, which if I remember right, is connected on the drivers side all the way near the tail light. There should be a bolt with a few of black wires with eye connectors under it. that one is easy, unscrew it, clean the contacts, and then screw it back on tight, but don't over tighten it. You can buy some star washers if you want to give them a little more bite. I watched a video from what was called "flash drive films" I think about his old fiat spider, but the concept is the same. It could also be the gauge itself, I have never tried to touch the gauges as pulling them out of this model involves a lot of work that I just don't want to needlessly do. I imagine it's a little easier in spiders from 86 and on when they changed the setup, but I don't know for sure. Hope that helps. kzbin.info/door/cyNYdkFkjPUdfvGYGhStCQ

[@albagr01]

Or... maybe the connectors are in the wrong place on the gauge. That sounds realistic if the positive and negative connected to the gauge itself are mixed up, I've never gotten inside there to mess with those wires though, so I'm not sure what it looks like.

[@davelee7572]

where does that hose you replaces go to? from the rear ecu to where? thanks (ECU & vacuum sensor)

[@albagr01]

there is a small clear tube in the background coming out of the floor, you see me poke it at 4:09. The hose connects the VPS with that little tube.

[@davelee7572]

@@albagr01 thanks, but where does that hose connect to? where does it go? from the ecu sensor to where?

[@albagr01]

@@davelee7572 there are two possibilities, I don't remember which off the top of my head. Could be the black canister in the trunk, which connects to the gas tank and the intake plenum. Or it could be the charcoal canister behind the front passenger wheel. It all involves vacuum and emissions. I never got too knowledge about that stuff. In this case was just replacing old degraded hoses and cleaning up electrical contacts.

[@dawodchatha]

Did any of the electrical cleaning help start your car? Im particularly interested if this second ecu cleaning helped

[@albagr01]

Most of the electrical cleaning that I did was more preventative maintenance and cheap insurance. My car didn't have trouble starting at the time and the times that is has after that were unrelated to that computer (I believe it's called the Ignition Control Module)

[@davidvanzanten4385]

Greg, what does this vacuum pressure sensor do?

[@albagr01]

I'm not 100% certain. It has something to do with the fuel recover, I believe relating to emissions. It connects via tube to the vapor canister in back of the front passenger side wheel and either the vapor canister in the trunk or the fuel tank, I don't recall which. My understanding of it is that when it goes, you hear a high pitched whistle and it affects your fuel efficiency. I'd have to dig a little further to know for sure, but alfabb.com has a lot of information, probably with this question answered.

[@stevewaclo167]

Greg A Proper name is Vacuum Sensor Device (VSD) and it provides vacuum advance 411 to the ignition module. It is a variable inductor and when it fails, fuel economy drops about 10%. They are no longer available.