Installing a MPGuino to help save fuel on my E320
 

I am ready to install a MPGuino unit see MPGuino - EcoModder. One of the requirements is to input the VSS/mile into the MPGuino. I also need to know where to connect into the VSS and also into one of the injectors to get a pulse signal. I need to know which wire has the 0 voltage. Or, is there an output connector with all these signals available (my car has a 16pin connector above the battery can this be used?). Also how do I get form the engine bay through the firewall into the cabin with the cable to connect the MPGuino unit. I believe the injectors for this car are Bosch 0 280 155 209 units with 197.6cc/min is this correct?

Vehicle
E320 1995

Whats the point? Why not just pay attention to the economy gauge?

I got a ScanGaugeII and I am very happy. My coworker bought one also and he likes it very much. It plugs in super easy, into the OBDII connector. That is what I would recommend.

However, the injector signal will be available from the ECU which I think is inside the firewall, but I am not positive.

grommets through firewall
 

I don't have the electrical answer, but there are three or more rubber grommets through the firewall into the interior with unused holes that you just cut off the tip to use.

"What's the point?" More feedback to save gas and reduce his carbon footprint.

"I got a ScanGaugeII and I am very happy. My coworker bought one also and he likes it very much. It plugs in super easy, into the OBDII connector." A 95 E320 does not have OBDII??

95 = obdi not obdii

Get a subscription to alldatadiy.com and you will have more data & wiring diagrams than you will ever need.

But seriously, does your built-in mileage gauge not work?

My '95 E320 SE doesn't have a mileage gauge like my old '87 300E did. Perhaps his doesn't either?

The ECu is in that area behind the battery. I think there's a plastic cover above it.

The '87 300E had a vacuum gauge, not a mileage gauge.

My E320 does not have a Vacuum guage or a mileage guage. OBDII only came out in 1996 for North American cars from what I have read. Part of the reason I bought the MPGuino kit was for interest and economy. I learnt much from building the kit supplied by Fundamental Logic. The theory behind the electronis board and the components are explained extermely well in lecture notes supplied by SparkFun Electronics - News

Using MPGuino in a old Mercedes (pre 1996).
 

Dear Terry,

I have a Mercedes 300E and a MPGuino, which I want to install on it.

To get the VSS signal is rather easy, but not the injection signal. We have the same problem. Let us share our experience to beat this difficulty.

My car has a "economy" gauge, which provides an idea of economy based on the admission vaccum generated by the engine. However, this variable isn´t always a sign of efficiency or ineficiency, something you car read in an article in Auto Speed of Australia. They explain that very clear.

Second, even if that gauge may work sometimes, the visual info it gives is too course, one cannot assess the impact of a single mod on fuel yield in the car based on this gauge. We need more precise information over some, say, 100 km to be sure.

Then comes MPGuino to solve it.

Then, we need to spot a signal on the ignition system of our cars to be used in the MPGuino device.

Do you have any ideas?

I have the circuits but they are difficult to me to understand, first because english is not my first language, and second, because mechanics and electronics are not my first profession either. I am a forester.

Shall we continue? What have you discovered so far?

Looking forward to hear you,

OldBeaver

Note: Can you tell me what is a "trackback"?

Hey OldBeaver, this thread is really old, 2009. Terry may not even be around any more. If Terry doesn't get back to you, you can send me a PM, and I might be able to give you a hand. I'd suggest tying in to the tach signal, since there's nothing electronic on the injector pump. I'm not sure that will get you much in the way of economy information though.