TripMinder Data Sources

[lairdt]

I'm working on a replacement Tripminder project. I know that the gas gauge delivers an analog voltage.

Does anyone know what kind of signals each of these items provides to the Tripminder unit?

1) Speed sensor (I assume it's a pulse generator, right?)
2) Pin34 from the ECU (digital data stream? pulse?)

If there are any references someone can point me at for these items it would help a lot.

[Elemino]

If there are any references someone can point me at for these items it would help a lot.It's called an Oscilliscope. LOL... sorry, no real advice though.

[Tman70]

This might help...
Tripminder Pinout
Pin 3 is Ignition power (hot in run)
Pin 4 is the dimmer from fuse panel & instr. illumination
Pin 5 is KeepAlive power from fuse panel ( bat.+)
Pin 6 is Fuel Flow data stream from pin 34 of EEC Module
Pin 7 & 9 are grounds
Pin 8 is the speed input from the VSS to pins 3 & 6 of the Speed control ECA.

[lairdt]

This might help...
Tripminder Pinout
Pin 3 is Ignition power (hot in run)
Pin 4 is the dimmer from fuse panel & instr. illumination
Pin 5 is KeepAlive power from fuse panel ( bat.+)
Pin 6 is Fuel Flow data stream from pin 34 of EEC Module
Pin 7 & 9 are grounds
Pin 8 is the speed input from the VSS to pins 3 & 6 of the Speed control ECA.

Already had that part of things, but thanks for trying to help.

And no, I don't have a scope to read the data lines. Have a couple counters and function generators, plus logic probes, but never had the need to justify the $$ for a scope.

[pro-five-oh]

1) Speed sensor (I assume it's a pulse generator, right?)
2) Pin34 from the ECU (digital data stream? pulse?)


1) Whatever kind of sensor the Vehicle speed sensor is. I think its cog driven. (you can tell I donno what I'm talking about)

2) Correct: it reads the fuel injector pulse width, or duty cycle.

[gadget73]

VSS should be a pulse generator, higher frequency = higher speed. This might be of some small use

http://fordfuelinjection.com/index.php?p=33

[lairdt]

VSS should be a pulse generator, higher frequency = higher speed. This might be of some small use

http://fordfuelinjection.com/index.php?p=33

That's perfect!

I hope the PIN34 stuff is also a pulse generator, I guess it would be the easiest thing to have implemented so that's probably what it is, but I'd like to find something similar on it still.

[gadget73]

Unfortunately, probably short of finding some internal documentation with the specfic data output pattern for each terminal on the ECM, your best bet is to use an occiliscope to check it directly. I imagine its also probably a data pulse arrangement.

[pro-five-oh]

I think it just reads when the EEC computer turns the injectors on/off and then uses the flow rate (15lb-hr in this case) programmed into the EEC to determine fuel consumed.

[gadget73]

14 lb/hr actually. It also would make assumptions based on stock fuel pressure levels, since the amount of fuel per a given injector cycle would differ if you changed the pressure.

[pro-five-oh]

That's right, 14lb-hr. I don't think the EEC can determine fuel pressure, all it knows is the on/off position of the injector and the injector's flow rating.

[Red91SiT]

That's right, 14lb-hr. I don't think the EEC can determine fuel pressure, all it knows is the on/off position of the injector and the injector's flow rating.

It seems like it shoudl be like that, but looking at a pin out diagram, fuel injectors are 12, 13, 14, 15, 40, 52, 58, and 59. I can't find anything that says what Pin 34 actually is?

I'd love to hear more about this, i really want a Fuel economy gauge in my car :(

[lairdt]

Still working on this project. Started collecting the components last week (new stuff to me), and hope to make it into Ford this week to get a printout of all of the dashboard components to make things easier. Then I'll be able to fab up something and see what the signals actually are and write the software to run everything.

Pin 34 isn't documented very well at all, but it's there even on cars without a tripminder.

[pro-five-oh]

Yes, its mentioned in Mark VII wiring diagrams and many (all?) EEC processors have it.

I put a Mustang computer and Crown Vic Tripminder into my Cougar and Pin 34 worked.

Just do it. :)

[gadget73]

I have a Mark VII ECM and a Crown Vic tripminder in my Townie, and it functions. HO swaps in Crown Vics usually use a Mark VII or Mustang ECM and they retain working tripminder function too. Not sure what exactly 34 is other than fuel flow, but I don't believe anything but the tripminder taps into it.

[rainhopper]

can you keep me updated on this project? I'd like to update my analog display to a digital display with the trip minder setup. =) pm me plz!

[MichiganTeddyBear]

wow, late for me comming into this thread... but, just a thought here.

the pin 34 signal may be a pulse (coinciding with the injector pulse width), or it may be much more complicated.

My conti (also EEC-IV) (and most 88-94's) have had (or have) problems with the 'DCL' which is the Data Communications Link from the EEC to the Dash. I dont know off the top of my head if this is the same pin, but when the DCL craps on the conti's, all info that requires fuel input goes with it. I *think* this may be more than a simple pulse train, but an actual communications signal with more than just injector pulse width.

It would make sense to me to have the EEC just output (at various intervals) the current fuel flow info to the Tripminder (or dash in case of the Conti's) since it already has calculated that info out for its own use. Why have the other device figure it out as well? Again, this is total speculation on my part, but seems to make sense to me.

While I have an O-scope avail to me, its at my dad's house, 150 miles away, so not avail at a moments notice. I could however, given enough notice, have it at my disposal relatively easily, as I make trips to his house fairly regularly.

Another thought came to mind to me. if your just looking for the amount of fuel delivered by the injectors to the engine, how about this:

assume a set flow/hr.. 14lbs has been mentioned as the stock value.
actually measure the pulse width of a single injector (any one will work, as they all will be very close to the same width) real time, and calculate it on the fly? requires a little more electronics, and another hookup into the wiring harness, but definatly do-able, as long as you make the proper assumptions on the max delivery rate of the injector.

[lairdt]

Still working on the project!

Have the electronics underdevelopment to include a bunch of things I've always wanted to have that didn't exist on the stock unit.

I don't have a scope (yet) but I'm seriously thinking about getting one just to solve this question on pin34 data. I really do figure it's a pulse width, the duration of which indicates avg open injector time for all 8 injectors (or similar value with a pulse duration indicated). I'm already allowing for different gears/tires and injector sizes to adjust for changes if needed but still don't know yet what this value really is. If it's a data stream, no problem. Pulse, no problem. Just won't know until I get to a point where I can crack things open in the car and hook things up. Winter isn't my time for working outside... so, I'm working on adding/determining features for it, while nailing down the specifics for which pin on this does what, etc.

If you have the time & desire to check out what info pin34 does, great. Would save a little grief, but isn't required.

[MichiganTeddyBear]

Kinda like you, winter and working on cars dont go well together where I am at (NW Michigan, with no garage).

if I get a chance to check out pin 34, will let ya know what I find out.

I should be able to get a signal off my Conti's EEC fairly easily (will tap it at the back of the dash), because I have a big hole in the dash right next to the I/P. which just happens to be DIN sized where the non-existant radio used to live. LOL

[OVERKILL]

From the GFUB:

The Data Output Link (DOL) provides a communication line between the EEC and the vehicle dashboard computer, Tripminder, for the transfer of its fuel consumption information. The fuel flow information sent by the EEC is used for computation of instantaneous and average fuel economy, which is then displayed to the driver.

The Tripminder requires an appropriate integer number of pulses within 100 msec period. Therefore, within each background loop or each 100 msec period, whichever is shorter, the EEC sums the fuel flow through the injectors output since the summing period started, converts this sum into DOL pulses, and outputs these pulses at a maximum frequency of 500Hz during the following summation period.

The fuel flow is converted into DOL pulses according to the following equation:

DOL_COUNT = INTEGER {FUEL_SUM * 7804.19 * INJOUT} + DOL_COUNT

The FUEL_SUM is then reduced by the amount converted into DOL_COUNTS {One DOL_COUNT = 1.282E-4 lbm}.

where,

DOL_COUNT = Number of pulses to be output beginning in the next summation period. One DOL_COUNT = 1.282E-4 lbm.

FUEL_SUM = Sum of fuel flow per injector, which was initiated since the last summation period. It is updated during the Fuel PW output routine.

7804.19 = {48000 pulses/gal} / 6.15 lbm/gal, pulses/lmb.

INJOUT = Number of injectors per output port. {See fuel strategy}

[gadget73]

Another thought came to mind to me. if your just looking for the amount of fuel delivered by the injectors to the engine, how about this:

assume a set flow/hr.. 14lbs has been mentioned as the stock value.
actually measure the pulse width of a single injector (any one will work, as they all will be very close to the same width) real time, and calculate it on the fly? requires a little more electronics, and another hookup into the wiring harness, but definatly do-able, as long as you make the proper assumptions on the max delivery rate of the injector.

This would mostly work but readings at WOT or high load would be somewhat off as the fuel pressure regulator is vacuum controlled. Lower vacuum = more pressure, and more pressure with a given pulse width will deliver more fuel than the low load pressure that is present when the engine is operating with high manifold vacuum. It may not be significant however if you wanted it to be dead on accurate, thats another thing to calculate. On a related note, the stock ECM can't make up for changes in fuel pressure either. It assumes a given stock pressure and amount of variance and changes to it affect fuel economy in ways the fuel flow wire and tripminder can't compensate for. I would assume that it can calculate what the fuel pressure ought to be based on MAP sensor input and some built-in table to match MAP signal to fuel pressure, which would then be crossed with the injector pulse width to determine the actual amount of flow.

[MichiganTeddyBear]

This would mostly work but readings at WOT or high load would be somewhat off as the fuel pressure regulator is vacuum controlled. Lower vacuum = more pressure, and more pressure with a given pulse width will deliver more fuel than the low load pressure that is present when the engine is operating with high manifold vacuum. It may not be significant however if you wanted it to be dead on accurate, thats another thing to calculate. On a related note, the stock ECM can't make up for changes in fuel pressure either. It assumes a given stock pressure and amount of variance and changes to it affect fuel economy in ways the fuel flow wire and tripminder can't compensate for. I would assume that it can calculate what the fuel pressure ought to be based on MAP sensor input and some built-in table to match MAP signal to fuel pressure, which would then be crossed with the injector pulse width to determine the actual amount of flow.

Yes, the fuel pressure changes depending on vacuum on the regulator, and therefore the amount of fuel delivered per injector pulse changes. but the pressure dont change from (pulling #'s out of the air) 20 psi to 100 psi. the pumps only put out 40-50 typically, and if the pressure drops below 30 or so most injectors just dont spray properly. I agree with you, but the changes in fuel delivered b y the injector based soley on pressure are not that great. the main metering method for fuel delivery is the pulse duration. the EEC monitors MAF, as well as all the other sensors in the system and uses that to control the fuel amount.

[Tony T]

Some are assuming the EEC is doing all the calculations. The EEC simply adds up the on times of the injectors and sends it (flow) to the message center. The message center knows the speed, gas on board and does the math. The fuel pressure will have little to do with it, Higher pressure will result in higher speed or maybe lower speed if pulling a hill. If 1 or 2 injectors are completely stopped up you still have their pulsewidth figured in but all the injector pulsewidths will have to be longer to maintain speed so MPG will go DOWN. It's not perfect but pretty close. A more accurate method would be to have a flow meter in the fuel line to messure flow and one in the return line to subtract fuel not used. (This used to be available from whitneys and others, don't know if it still is.)

[OVERKILL]

Some are assuming the EEC is doing all the calculations. The EEC simply adds up the on times of the injectors and sends it (flow) to the message center. The message center knows the speed, gas on board and does the math. The fuel pressure will have little to do with it, Higher pressure will result in higher speed or maybe lower speed if pulling a hill. If 1 or 2 injectors are completely stopped up you still have their pulsewidth figured in but all the injector pulsewidths will have to be longer to maintain speed so MPH will go DOWN. It's not perfect but pretty close. A more accurate method would be to have a flow meter in the fuel line to messure flow and one in the return line to subtract fuel not used. (This used to be available from whitneys and others, don't know if it still is.)

Tony: Direct from Ford, the info I posted above, its right out of the GFUB and pretty much backs up what you are saying.

[lairdt]

Some are assuming the EEC is doing all the calculations. The EEC simply adds up the on times of the injectors and sends it (flow) to the message center. The message center knows the speed, gas on board and does the math. The fuel pressure will have little to do with it, Higher pressure will result in higher speed or maybe lower speed if pulling a hill. If 1 or 2 injectors are completely stopped up you still have their pulsewidth figured in but all the injector pulsewidths will have to be longer to maintain speed so MPH will go DOWN. It's not perfect but pretty close. A more accurate method would be to have a flow meter in the fuel line to messure flow and one in the return line to subtract fuel not used. (This used to be available from whitneys and others, don't know if it still is.)

Sounds good to me... makes the interface simpler/cheaper.

[pro-five-oh]

A more accurate method would be to have a flow meter in the fuel line to messure flow and one in the return line to subtract fuel not used. (This used to be available from whitneys and others, don't know if it still is.)

Those were used on carb'd Lincolns from 1978-1982. I don't think they work on EFI applications because of the higher pressure fuel. :confused:

The EEC does a good job, it definitely "caught on" to the better fuel mileage when I put new injectors on my 190,000 motor.

[lairdt]

Tony: Direct from Ford, the info I posted above, its right out of the GFUB and pretty much backs up what you are saying.

The last line that breaks explains the value of 7804.19, is that last section supposed to be pulses/lbm? And I assume all values here are based upon using 14lb injectors.

[OVERKILL]

The last line that breaks explains the value of 7804.19, is that last section supposed to be pulses/lbm? And I assume all values here are based upon using 14lb injectors.

That info is all for the A9L, so no, it would be for 19lb/hr injectors if the size of the injector plays a role or not. The actual document says lmb............ don't know if its a typo or not :)

[pro-five-oh]

That info is all for the A9L, so no, it would be for 19lb/hr injectors if the size of the injector plays a role or not. The actual document says lmb............ don't know if its a typo or not :)

The injector size is included. Found that out after getting a twEECer for an A9L. Changing the injector size means nothing on a Mustang (no Tripminder) but its a good idea for Lincolns. :)

[gadget73]

Those were used on carb'd Lincolns from 1978-1982. I don't think they work on EFI applications because of the higher pressure fuel. :confused:


They also used it on early Crown Vics with carbs and a tripminder. It mounts right on the side of the carb. It actually wouldn't work for our return system unless you installed two of them and calculated the fuel by subtracting the flow on the return line from the flow on the pressure line. Just installing one on the pressure line would show vast amounts of fuel burn.

[OVERKILL]

The injector size is included. Found that out after getting a twEECer for an A9L. Changing the injector size means nothing on a Mustang (no Tripminder) but its a good idea for Lincolns. :)

But I mean, if you are running an LSC ECM (like I am) the ECM thinks 19lb/hr injectors (which I'm running) SO, does the Tripminder know the injector size or is the ECM's output relative to injector size, I guess I could see if that's mentioned in the GFUB.

I'm getting my TWEECER in a month or so, but they aren't ECM specific, IE, you can use it on any EEC-IV ECM.........

[lairdt]

I guess I could see if that's mentioned in the GFUB.

What's GFUB - Giant Ford Utility Belt ?? Can't find any reference to it elsewhere here.

[ekooke]

The older Mark VII (1984?) and other Ford-made cars with CFI had a vane type fuel flow meter in the fuel line to give fuel flow rate to the TM. I also had one of those JCW car computers installed on a ’76 AMC Hornet wagon; it was fairly accurate for giving fuel mileage numbers on the highway, but I depended more on the factory installed vacuum gauge to keep my mpg numbers up.

[OVERKILL]

What's GFUB - Giant Ford Utility Belt ?? Can't find any reference to it elsewhere here.


The GFUB is a (leaked?) internal Ford document, its well over 500 pages, and details how the EEC-IV system functions and the like. Its quite the read.

[pro-five-oh]

But I mean, if you are running an LSC ECM (like I am) the ECM thinks 19lb/hr injectors (which I'm running) SO, does the Tripminder know the injector size or is the ECM's output relative to injector size, I guess I could see if that's mentioned in the GFUB.

The tripminder doesn't know injector size, that bit of info is only needed to calculate fuel flow. The Tripminder takes the fuel flow information from the ECM and converts it into MPG.


I'm getting my TWEECER in a month or so, but they aren't ECM specific, IE, you can use it on any EEC-IV ECM.........

The twEECer isn't universal, they make one for each ECM. Luckily they do make one for the LSC's computer.

The older Mark VII (1984?) and other Ford-made cars with CFI had a vane type fuel flow meter in the fuel line to give fuel flow rate to the TM.

The CFI ones had the information in the ECM, just like the SEFI models. Only the pre-1983 Lincolns with 2bbl carbs had the fuel flow meter. I searched up and down for a fuel flow meter on my 1983 Continental until I got my EVTM manual. :)

[pro-five-oh]

I just realized how many stupid acronyms we Lincoln folk have to deal with. :rofl:

[OVERKILL]

The tripminder doesn't know injector size, that bit of info is only needed to calculate fuel flow. The Tripminder takes the fuel flow information from the ECM and converts it into MPG.




The twEECer isn't universal, they make one for each ECM. Luckily they do make one for the LSC's computer.



The CFI ones had the information in the ECM, just like the SEFI models. Only the pre-1983 Lincolns with 2bbl carbs had the fuel flow meter. I searched up and down for a fuel flow meter on my 1983 Continental until I got my EVTM manual. :)

They only make two TWEECERS.

http://www.tweecer.com/tweecer_rt.htm

That's the RT, which has datalogging.

They are compatible with ALMOST ANY EEC-IV ECM. I have the software here and the BIN files for a pile of different ECM's. If its EEC-IV and has a J3 port, in theory, you can use a TWEECER on it.

What I was implying with the fuel flow info was whether the output by the EEC RE injector pulse-width is relative to injector size (which it sounds like it is) or if its simply a direct output of injector pulses, regardless of injector size, which would mean the tripminder would have to know injector size to calculate consumption correctly. See what I'm getting at?

The TripMinder formula I mentioned earlier is from an A9L, but I wonder if there is a variance in the formula for a 14lb/hr-based ECM...........

[Dereck]

Hi Laidt

Have you seen This PDF on Ford EEC (http://lincoln.superstitiongold.com/video/Ford%20EEC.pdf)? Might find what you are looking for in there.

Regards

Dereck

[OVERKILL]

Here's a list of compatible EEC-IV ECM's listed by one of the TWEECER resellers.

Note that SOME of them aren't compatible with the RT, but are with the non-RT model.

http://www.v8mustang.com/products.php#TwEECer

[OVERKILL]

Here's a link to the twEECer downloads page, where they have the GUFB and a few other useful links/documents.

http://www.tweecer.com/downloads.htm

[pro-five-oh]

Whoops, I see what you mean about the twEECer. The units are universal, but you have to get the right software for your application.


What I was implying with the fuel flow info was whether the output by the EEC RE injector pulse-width is relative to injector size (which it sounds like it is) or if its simply a direct output of injector pulses, regardless of injector size, which would mean the tripminder would have to know injector size to calculate consumption correctly. See what I'm getting at?

Yes but I can't say for sure. I am saying this because I converted my 1988 Cougar (14lb injectors) to HO (A9L, stock injectors, stock everything) and the tripminder (from a 14lb-hr car) still reads correctly even after the conversion.

That is why I say the EEC only needs the correct injector size to do the calculation. The Tripminder only divides speed information by EEC's fuel flow to make fuel economy.

[OVERKILL]

Whoops, I see what you mean about the twEECer. The units are universal, but you have to get the right software for your application.



Yes but I can't say for sure. I am saying this because I converted my 1988 Cougar (14lb injectors) to HO (A9L, stock injectors, stock everything) and the tripminder (from a 14lb-hr car) still reads correctly even after the conversion.

That is why I say the EEC only needs the correct injector size to do the calculation. The Tripminder only divides speed information by EEC's fuel flow to make fuel economy.

Correct, and the tripminder in my TC works fine as well with the 19lb injectors.

[lairdt]

Here's a link to the twEECer downloads page, where they have the GUFB and a few other useful links/documents.

http://www.tweecer.com/downloads.htm

I'll have to pick this up once I feel like dealing with the stupidness of having to go through Yahoo.

[OVERKILL]

Which are you talking about? I can e-mail you any of it, let me know via PM.

-Chris

[lairdt]

I got them - just had to spend the time to get yahoo login and such. The documents will help out some for sure.