EFI For Big Blue

[ArdWrknTrk]

Of course I'm going to throw my monkey wrench into the works and I apologize in advance for my technobabble.

The IVR in the early Ford trucks up to 1986 is not really a 5 volt regulator. It would be more accurately described as a pulse width power regulator. More simply, it is a flasher. It runs at approximately 1hz rate with about a 30 to 40% duty cycle. If you care to do a power calculation, 5 VDC contains about 42% of the power that 12VDC contains. The gauges are a movement that move the needle proportional to the current pulses flowing through the gauge. They react quite slowly, so you do not see the 1hz pulses on the needle.

So, the gauge sender presents a variable current sink ranging from 70 ohms empty to 10 ohms full. The meter movement itself represents about 13 ohms by my measurement. When you do the math, the current through the meter becomes about 150 ma for empty to 500 ma for full. It is quite difficult to measure with an ammeter because of the pulsing supply voltage, (which has a peak voltage = to battery voltage). The later Ford FDM's have a resistance range from 16 ohms empty to 165 ohms full.

I did a napkin sketch of what I feel would be a simple solution. Basically, I figured on using an NPN transistor as a current sink for the gauge. A 10 ohm resistor provides a limit to the current sink equal to the original 10 ohm reading from the 86 down sender. A 0.1 mf capacitor filters any noise out of the transistor. The 92 and up FDM sender is used as a variable voltage divider which will range from about 1V empty to about 5 volts full. This signal is applied to a resistor which drives the transistor B/E junction. The transistor will increase C/E current proportional to B/E current and I will assume a gain of 1000. This value may change depending on the actual gain of the transistor and must be of a value that allows the transistor to work in it's linear range. I figure 25K will be close, but I have not yet built a prototype. The best method to pick the value would be to select it for an accurate reading at "Full".

An Arduino would be an interesting solution, but I think a single transistor would be far simpler.

So, sorry if I bored anyone to tears, but this is what I used to do back in the previous millenium.

You say it is 42% of 12V, but 12V is well below the 12.6V of a six cell LA battery at rest, and even farther below the 14.35V my regulator puts out with the engine running.

But I really like your analog solution using discreet components.

Newark is another handy source.

[Gary Lewis]

You say it is 42% of 12V, but 12V is well below the 12.6V of a six cell LA battery at rest, and even farther below the 14.35V my regulator puts out with the engine running.

But I really like your analog solution using discreet components.

Newark is another handy source.

Ok folks, the Arduino approach works. I've documented everything in my Bricknose Sender To Bullnose Gauge Interface project. To test it I downloaded an Arduino simulator and tried the concept - and it worked well.

However, along the way I did find a bust in my spreadsheet, which caused me to recalculate the "m" and "b" values in the equation to y=.27x+.02. And, I found a minor omission in the sketch/program - both of which I've changed in the previous posts to ensure posterity doesn't try to replicate this with dodgy data.

You can see from the screenshots of the simulator that the results are extremely close to what we need, and can easily be dialed in via the m and b parameters. In fact, they could be dialed in for every combo of senders and gauges, so it would be easy to use Bullnose senders and Bricknose gauges.

Now to figure out other things to have the Arduino do in its spare time - and it will have a lot of it.

 

[NotEnoughTrucks]

Ok folks, the Arduino approach works. I've documented everything in my Bricknose Sender To Bullnose Gauge Interface project. To test it I downloaded an Arduino simulator and tried the concept - and it worked well.

However, along the way I did find a bust in my spreadsheet, which caused me to recalculate the "m" and "b" values in the equation to y=.27x+.02. And, I found a minor omission in the sketch/program - both of which I've changed in the previous posts to ensure posterity doesn't try to replicate this with dodgy data.

You can see from the screenshots of the simulator that the results are extremely close to what we need, and can easily be dialed in via the m and b parameters. In fact, they could be dialed in for every combo of senders and gauges, so it would be easy to use Bullnose senders and Bricknose gauges.

Now to figure out other things to have the Arduino do in its spare time - and it will have a lot of it.

Just a thought here on driving the bullnose gauges.

Are you going to use the OEM IVR, (flasher type), or operate the gauge from a regulated 5V source? It may make a difference in that you could need a level shift or some sort of driver for the Arduino?

[Gary Lewis]

Just a thought here on driving the bullnose gauges.

Are you going to use the OEM IVR, (flasher type), or operate the gauge from a regulated 5V source? It may make a difference in that you could need a level shift or some sort of driver for the Arduino?

I don't usually leave a flasher in. As shown in the drawing, I'll replace it with one of the regulated supplies like shown here: Electrical/ICVR. That way all the gauges will have a stable supply.

But, the Arduino will run off of the vehicle battery voltage and create its own power - as well as the 5v reference I'll feed to the tank senders.

As for a level shift, I can do that with the "b" value in the equation. But if that equation doesn't do it for another application I could go quadratic if needed to give a curve. Lots and lots of flexibility.

[Gary Lewis]

I don't usually leave a flasher in. As shown in the drawing, I'll replace it with one of the regulated supplies like shown here: Electrical/ICVR. That way all the gauges will have a stable supply.

But, the Arduino will run off of the vehicle battery voltage and create its own power - as well as the 5v reference I'll feed to the tank senders.

As for a level shift, I can do that with the "b" value in the equation. But if that equation doesn't do it for another application I could go quadratic if needed to give a curve. Lots and lots of flexibility.

Doing some thinking about the path forward on the engine and wanted to bounce a few ideas/thoughts off you guys. But, before I ask, let me state how I'll use the truck - casually. Driving in town and on the highway, overlanding but nothing serious, and very little towing since I have the 2015 truck that is a tow monster.

But I've been reading a number of opinions, most notably those of Scott, The Mad Porters, and he recommends:

• Heads: Porting the intake side of the F3TE's, which apparently are slightly better than the earlier E7 EFI heads. However, according to Scott the exhaust ports are decent but the intake ports need some work. Is it worth it for my use?

• Lower Plenum: It is recommended that the head flange be ported to match the heads.

• Cam: I have the Edelbrock Performer, which Scott called "pooh" and "little more than stock". He recommends a VooDoo cam with more lift and dwell. Should I change?

• Exhaust: Scott also recommends headers and large pipes. But I don't see the need.

Also, I was looking at the EGR port on the upper plenum today, and realized that the boss where the EGR valve bolts on is both ugly and at an angle. So I'm thinking of milling the boss off where the red line is, below. And then tap the hole 3/8 NPT and plug it as the one on the rear is plugged. Thoughts?

[ArdWrknTrk]

Doing some thinking about the path forward on the engine and wanted to bounce a few ideas/thoughts off you guys. But, before I ask, let me state how I'll use the truck - casually. Driving in town and on the highway, overlanding but nothing serious, and very little towing since I have the 2015 truck that is a tow monster.

But I've been reading a number of opinions, most notably those of Scott, The Mad Porters, and he recommends:

• Heads: Porting the intake side of the F3TE's, which apparently are slightly better than the earlier E7 EFI heads. However, according to Scott the exhaust ports are decent but the intake ports need some work. Is it worth it for my use?

• Lower Plenum: It is recommended that the head flange be ported to match the heads.

• Cam: I have the Edelbrock Performer, which Scott called "pooh" and "little more than stock". He recommends a VooDoo cam with more lift and dwell. Should I change?

• Exhaust: Scott also recommends headers and large pipes. But I don't see the need.

Also, I was looking at the EGR port on the upper plenum today, and realized that the boss where the EGR valve bolts on is both ugly and at an angle. So I'm thinking of milling the boss off where the red line is, below. And then tap the hole 3/8 NPT and plug it as the one on the rear is plugged. Thoughts?

Scott is very forthright with his knowledge and not trying to hardsell his work.

Try to contact him and get answers.

I would guess he knows at least as much about 385's as Tim knows about 335's.

Aggree with him on the cam.

I do not know about the internals of the 7.5l uppers, but I do know you have another....

So, why not work on the 'spare'?

[Gary Lewis]

Scott is very forthright with his knowledge and not trying to hardsell his work.

Try to contact him and get answers.

I would guess he knows at least as much about 385's as Tim knows about 335's.

Aggree with him on the cam.

I do not know about the internals of the 7.5l uppers, but I do know you have another....

So, why not work on the 'spare'?

Yes, the plan is to work on the "spare", but it is stored away and this one is up on the stand, so is much easier to see. But, you agree with the approach?

As for the cam, it obviously needs to be part of a "package". So the question to Scott really has to start with what that package should be. I'll email him.

[85lebaront2]

Yes, the plan is to work on the "spare", but it is stored away and this one is up on the stand, so is much easier to see. But, you agree with the approach?

As for the cam, it obviously needs to be part of a "package". So the question to Scott really has to start with what that package should be. I'll email him.

Gary, if the threads in that plenum are good, I will trade you one with a broken off bolt in the EGR pad. Then I will have a spare good one. My thought, remove the plug on the back and make a new one that will go in far enough to be flush with the inner passage. Or you can use it as an extra vacuum port (not that you will really need it).

[NotEnoughTrucks]

Doing some thinking about the path forward on the engine and wanted to bounce a few ideas/thoughts off you guys. But, before I ask, let me state how I'll use the truck - casually. Driving in town and on the highway, overlanding but nothing serious, and very little towing since I have the 2015 truck that is a tow monster.

But I've been reading a number of opinions, most notably those of Scott, The Mad Porters, and he recommends:

• Heads: Porting the intake side of the F3TE's, which apparently are slightly better than the earlier E7 EFI heads. However, according to Scott the exhaust ports are decent but the intake ports need some work. Is it worth it for my use?

• Lower Plenum: It is recommended that the head flange be ported to match the heads.

• Cam: I have the Edelbrock Performer, which Scott called "pooh" and "little more than stock". He recommends a VooDoo cam with more lift and dwell. Should I change?

• Exhaust: Scott also recommends headers and large pipes. But I don't see the need.

Also, I was looking at the EGR port on the upper plenum today, and realized that the boss where the EGR valve bolts on is both ugly and at an angle. So I'm thinking of milling the boss off where the red line is, below. And then tap the hole 3/8 NPT and plug it as the one on the rear is plugged. Thoughts?

Probably a really dumb question, but why is a drill bit sticking out of that EGR port?

[Gary Lewis]

Gary, if the threads in that plenum are good, I will trade you one with a broken off bolt in the EGR pad. Then I will have a spare good one. My thought, remove the plug on the back and make a new one that will go in far enough to be flush with the inner passage. Or you can use it as an extra vacuum port (not that you will really need it).

Bill - I'll check tomorrow, but I'm pretty sure I have two good plenums. So let's swap and I'll mill the stripped one down.

And, you are suggesting that I use the rear plug to seal off the side passage - right? I understand, but I think that will beg the question of why there's a hole on the side of the plenum. So why not just plug it?

Ray - That 5/8" bit is there to show both the diameter as well as the angle of that passage. See how the face of the EGR mount is not perpendicular to the bit? For some reason the EGR valve sits partially facing forward rather that completely to the side. I was initially planning to make a block-off plate to seal that passage, but came to the conclusion that the whole boss is ugly and needs to go.