MAP sensor discussion.

[raygreenwood]

. You know...that rubbing alcohol can make you blind!...Oh...harry palms already....you might already blind! Ray

[Adriel Rowley]

[blues90]

Lot's of info here.

I do agree , electical connections are for the most part a very common cause of drivability issues as well as all issues that relate to anything in a car becoming inoperable ,

The reason I say this is because my main focus working mainly for ford dealerships as well as some shops on many models and makes since 1969 was electical diagnosis.

I could diag a car or electical system issue on a car or truck by looking at the wiring diagrams and determine the most likey source of the problem and grounds are usually the issue if the car has not been tampered with . Connectors came in second place.

I found MOST techs know little to nothing about electrical systems and and change parts until they just might by accident fix a bad connection. I have seen techs remove and entire interior looking for short when all along the problem with the power locks cycling was a ice chest sitting in the rear power lock switch located in the cargo compartment of a ford explorer.

On my 73 SB FI auto trans which still has the original wiring and connectors I find little issue at this point and this is an old car . I cleaned the terminals when I got the car in 1985 and I got a few books to understand the FI system and did the basic resistence test at the ECU from each component and did what ford calls a wiggle test , move the wires and connectors which checking resistence and really found nothing that I felt needed attention.

Any connector made of metal will expand under heat and all will corrode over time if exposed to damp elements and condensation.

Over all yes these things need to be checked if there is an issue before anything else is done .

But to actually know just how and engine is running at all speeds and conditions is far beyond the owner without a dyno and all sorts of assorted test equipment.

MOst aften if there is a drivabilty issue especially on a 4 cylinder engine you are going to feel it and if you keep track of gas milage you can determine too rich or too lean if you know what the car did in good condition and look at the exhaust pipe .

My 73 will get 38.5 MPG on the freeway and after close to 40,000 miles after a re-build it still does.

On no car whether FI or carb are you going to have perfection at all speeds and load conditions an internal combustion engine is not and will never be what is called efficient by a long shot.

[raygreenwood]

The D-jet is a different issue. Theconnectors were found to be defective....sub-par....for the application. They were an un-engineered off the shelf product that was modified. They have never again been used in a fuel injected vehicle by any manufacturer.

Yes...and terminal expands...but ...D-jet has no extrenal spring system to take up that expansion. All modern injection used a spring loaded dual cantilever terminal that can instantaneously adapt for huge expansion with no change to connectivity save for the rise in resistance with temperature.

D-jet terminals change the way you tune. Because you ahve no on-board diagnostics....you have no way of ever finding out if and when D-jet changes tunability, running and efficiency.
Ford used L-jet terminals (which are the original dual cantilever replacement terminals for D-jet).....in the beginning of their fuel injection production. They bought and/or produced them under license.

In short time they created valid variatiosn of thsoe terminals and patented them.

They were able to do this because they got into the game early enough right after L-jet came out. AMP had not yet covered every angle with blanket patents.
GM got in too late. With 35,000 patents or more on the books for variants of dual cantilever terminals by 1999 alone.....there was not a lot more they could do.

You can tuen D-jet a lot tighter and with better efficiency and output than factory....but you can only tune as far as the connection system will allow you to. Ray