Got it in car, having trouble

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Originally Posted by dcb

Can you rig up some alligator clips or test leads and and watch the voltage on b10 as the car rolls slowly?

P.S. the ECU will ground out the other side of the injector, you want to be tapped into the injector line that leads to the ECU, not the one that leads to the resistor.

sure I can do that, but I can tell you according to the manual that it will pulse 0v and 12v.

On the injectors, the way I see it, power comes from the relay, passes through the resistor, then to the injectors, which are ground out by the ecu, is that right?

And I've soldered the connections about an inch from the ecu plugs, so I didn't run any into the engine bay. I want to use the shortest wires possible to hopefully avoid the mass of electrical interference that passes through a car. I also twisted the wire pair, and they lead to the guino using cat5

[dcb]

Ok, well see if you can get it to stop on 12 volts with the ignition on by rolling the car back and forth by foot a little, then test it at every point on down the line till you dont see any voltage. I.e. test where the vss wire goes into your board, test one side of the vss 100k resistor, test the other side of the vss resistor, then test pin 14 (analog 0). analog 0 shouldn't be more than 5 ish, if it is less and b10 is at 12 then it is a wiring/build oops of some sort.

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Can do, and will do, thanks for the help

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Ok, while I was getting it set back up today, I pulled on the vss resistor and it came loose so I figured there was a shoddy solder on the point. Re-soldered it, good this time, and I get a more consistent signal.

I put the wheel in the air, and turned it until it gave me battery voltage.

Measuring from my wire which leads to the ecu, I get 11.37v, measuring at pin 0 gives me .58v

I also checked the Injector readings, and I get 11.87 at my wire, and .56 at pins 2/3

However I still don't get readings on the guino. I took it for a drive around the block, about 1/4 mile, about 4 minutes. Instant readings still all read 000.00, and I never got anything but 0's. I scrolled through the other screens, but they all read 0.

Status showed -
4 minutes
C% 52.16
Free Mem- 602.00

I also probed an injector and found that both leads provide 12v

So stuck again

[dcb]

Are your zeners put in the right direction?

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That could be it, the black band points away from the incoming signal (vss/INJ) and towards the black ground

This looks wrong according to your schematic but when I assembled the board they had the black band going opposite of the way I thought it should go and therefore I felt I was backwards. Perhaps that is also why my board doesn't use the power plug it came with. I'll flip them round

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I have good news! The diode flip fixed it!

Bad news is it worked while I drove to work for the first time but when I got off work it only came up with a lit LCD, no characters displayed.

While it was working the readings were pretty far out, I have to fiddle and adjust.

I just got home and I resent the code and it's working now, don't know why it quit before.

Also while I was trying to extract and flip the diode on my board I pulled one of it's legs off

So I may need to get a new diode if I can't save this one.

But I have some questions.

1. Is it safe to use VIN and ground on the board instead of the power plug lead on the board? Is it the same?

2. I have some numbers that I know are correct when it comes to the car. Can you guys help me translate that for the code?

-The manual states that the vss spins 1026/min at 60 mph
-My injectors flow at 235 cc/min

So I figure I have to convert cc/min to Gal/uS, so I figured 3,784 ml to a gallon 3,784/236=16.1021
60,000,000uS per minute
60,000,000x16.1021=966,126,000uS

Now I tried 4104 for my VSS and it was approximately twice as fast as actual, so I figured lower it to 2052. I'm gonna try that tomorrow.

But my injector rate sounds much higher than the saturn number of 404409714, that's less than half on a car that is somewhat similiar..

Also, a question related to the mpguino function/design..

How can we get it to turn off but retain its numbers, so it doesn't start fresh each time? Leaving it on all the time isn't really an option for me.

[dcb]

Very good

re: LCD watch how you hook up the power, make sure you are connected to battery power, not ignition, also be very deliberate when connecting it as it can get amnesia if the initial power hookup (or ignition switch bouncing) is too jittery. Auto turn off is in the works, I just have to decide on a solution I like. Use the middle button to turn off the LED backlight for now if you are worried about the drain.

re: vss, I've seen it listed as 4102 pulses per mile, but I think we are counting the rising edge and falling edge of the pulse I think so you need to try 8204. (more = slower)

re: injector, higher microsecondsPerGallon means better displayed fuel efficiency. Once you get the speed/distance dialed in take a look at your mpg readings and modify microsecondsPerGallon by the percentage you think it is off for an initial setup. Eventually (we are still bleeding edge here remember) we will get to a point where you can run a whole tank through and see how close your guess is.

re: vin vs ground, put your ohm meter leads on them and see if there is 0 ohms between them. If so then they be the same.

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I forgot about the lcd brightness, that seems reasonable for now.

Ok, I'll double the vss instead of halve

Luckily I was able to ghetto rig my on-board diode into working so I'll see how long it lasts, but now I can run off the on-board power plug

I'm using a constant 12v power source in the car, there are three extras available in the drivers side under-dash fuse box. One provides 12v only with the accesories, one provides 12v when the headlights are on, and one provides a constant 12v.

I just need to solder the points instead of using twisted wire connections like I was before (since it was going in and out of the car)

I hope to get some better readings tomorrow

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I'm gonna be away from my car for a while, and I won't be able to make any advancements for a couple weeks.

I did get a chance to fiddle around today. Speed and distance is pretty spot on at around 40-50 mph, but it gets worse at lower speeds. At 20 it will think you're doing 28. So I'm not quite sure what to make of that.

Fuel efficiency I couldn't get going though. Instant was always reading 99999, or 0 (stopped)

current climbed, starting at around 11 which was already wrong, but it continued to climb as I drove, after about 8 minutes it thought I was doing 800 mpg I assume it's simply because my injector rate was way off. I kept cutting it down, first in half, then by 5.5, then by 100, but I never escaped the all 9's. More time is needed.