Peak and hold injector driver board

[deluded]

still waiting on digikey. not sure what their hold up is... nothing was on backorder. we are leaving for speedweek at the bonneville salt flats on saturday, and i'd like to post some feedback before then.

[JET]

deluded - Any luck with changing the sense resistors for the bosch 160# injectors?
I'm about to do a similar setup.

Another curious cat, planning to use a pair of bosch 160# injectors with the V2.0 external board....cheers

[RicerX1]

Another curious cat, planning to use a pair of bosch 160# injectors with the V2.0 external board....cheers

haha Yes it actually inspired me buy an oscilloscope, and a bench power supply, and to build another megasquirt for the work bench. Once everything comes in hopefully I will be able to contribute something.

[myk777]

Not sure if you guys looked back around page 12 of this thread but I had a similar issues with my setup, I solved it by changing the resistor in the timer circuit to ensure it transitioned to the hold mode prior to the injector closing event at my smallest PW's and also made sure it fully opened under the lowest batt conditions. Worked out to be a good compromise and gave nice consistent injector closing times.

Mike

[deluded]

the issue with the 5 ohm injectors is that the peak to hold trigger is never reached... it always relys on the time out to drop to hold current. also, the hold current is more than the bosch 160# injector requires so the purpose of the p&h driver is lost; you may as well have a resistor in line with a low z driver.

we did well at bonneville with a new production supercharged 2.0 liter record at 216 mph! that increased our own record by 13 mph while in low boost (29 psi) which is surprising since we dynoed 860whp at 48 psi.

anyway, i'm back, the new board is assembled, and testing with waveform data is scheduled for sunday. so i'll have some info to share then. if it works i'll share my schematic mods and parts list for those who want to use these injectors specifically. this is a great discussion forum.

[racingmini_mtl]

Obviously, 4A will never be reached with a 5 Ohm injector. Have you tried simply using a 0.2 Ohm sense resistor. That should be a good starting point.

Jean

[deluded]

that is part of the changes that were made to test. the question then becomes Will the .5Amp hold current be sufficient to keep the injector open?... obviously

[racingmini_mtl]

Obviously

And congratulation on the new record at Bonneville. How much speed do you think you'd be able to get with the full 48 psi? And more importantly, would the engine last the full run on it?

[deluded]

i think another 5-8mph is likely, but not much more given the aerodynamics of the car. we've learned alot about land speed engine building/tuning in the last 5 years with world records in two different classes (we also did the engine/turbo/tuning for a 3 liter GT class record in a Z32 at about 224mph). the mitsu engine is pretty solid anyway, and with proper lubrication and valve train mods we've have zero engine failures in the last two years (knock on wood). one of the things that really helps is the 4wd... we get to top speed by the first timing point at the two mile mark so that we only have to run to the third mile. this greatly lessens the potenital for damage that other cars endure when running to the end of the 5 mile course. our entire run lasts just over a minute, and only 2/3rds of that is under full load. on the other hand, it takes 30 seconds to accelerate from 8000rpm to 9200rpm in 5th gear a real pucker-factor for the driver! keeping the egts in check is the number one worry followed closely by intake temps. the people you meet at Bonneville make it the most enjoyable form of racing i've ever been involved with: a truly generous and good-natured group of competitors.

[undesiredshoe]

Not exactly. The V1.1A board doesn't connect in between the ECU and the injectors in the way you mean. The 4 connections at the bottom of the picture above need to have 5V pulse when the injectors are injecting. So it needs to be connected somewhere inside your ECU. (I can't exactly say where and how in your case) The signal outside the ECU is a grounding signal which will not work with this board.

If you want to just replace a resistor pack, you need the V2.0 board (for 4 injectors or the V2.1 board for 8 injectors). With the V2.0 board, you will connect 4 wires to the injectors and 4 wires to the ECU (like you would the resistor pack). In addition, you will need to connect 4 wires to ground for the injector grounds (which is no longer done at the ECU) and a 12V and ground wire to power the board.

The V2.0 fit in it's own box independent from the ECU. You can look at my post from Feb. 10 (on page 10) on this thread to have an idea of what it looks like and also at this: http://jbperf.com/p&h_board/v2_0.html. This is what the finished box looks like (without the connector):


If you're interested in getting a board, you can contact me by PM or by email (boards at jbperf.com).

Jean

Sorry to bring up an old post but on the V2 board's BOM, it says ill need a LM2937 if im not using the megasquit 5v. Is this regulator regulating 12v or 5v since this diagram says i can use a 12v input.

[racingmini_mtl]

This is to regulate the 12V input. If you have a regulated 5V, you don't need the voltage regulator (and the associated power supply components identified in the BOM). Also, if using a 5V input, you will need to connect it to the correct pad which is just a bit above the 12V pad. It is quite obvious on the board as it is indicated on the silk screen.

Jean

[wild_eye]

Hello,
I would like to use this on my honda civic and replace the resistor box I am currently using (with dsm injectors). I read here on page 12 that v2 must be used for that application. When I checked it says that v2 is no longer available. Where can I get one?

[racingmini_mtl]

The only board I still carry is the V1.1 board (the current revision is the V1.1B) either as a bare board or as a kit. The V2 (V2.0 and V2.1) board is no longer available. It may become available later as a complete box but when, where and how much is not known at this point. I'll continue to support those who already bought a V2.0 or V2.1 board if needed.

Jean

[UnaClocker]

Heh, and I'd never even heard of a v2.0.. Seems like a good enough idea. Was it just not selling well enough?

[johnboy426]

I have a short in my P&H board! This is my first attempt with MS and it's getting a bit frustrating because I thought I was finished. The quality and thought put into all parts of the MS system is truly amazing for DIY. I installed D4 and D5 reversed. I corrected this issue with new pieces of the same P/N and still found the 5V shorted to ground. Transistor pads have 5M ohms or more to ground.

John

[racingmini_mtl]

John,

Have you tried to run the engine with D4 and D5 reversed? And if so, did it run for a while? I ask because if the injectors were fired with D4 and D5 reversed, that means there wasn't any flyback protection on the 2 transistors Q4, Q5 so they may have been damaged. If the injectors were never fired then there is no problem with Q4 and Q5.

The 5V shorted to ground is not related to the diodes. It might be a defect in the board itself. Can you take pictures of the bottom of the board and post them? I want to see if there is a connection between the 5V pads and the ground plane due to some copper that shouldn't be there. If it's the case, it is possible to cut this using a knife or a blade. Or I could send you another board but the problem would be with the components.

If you can't take pictures and/or want to check by yourself, the components to check are: R3, R5, R7, R9 the top pad (towards the transistors), U1, U2, U3, U4 pin 7 (second from the bottom on the left side) and the 5V pad at the bottom of the board (where you connect the 5V supply). If you look carefully at the bottom of the board, all those pads should have a clear circle around them and not connected to the ground plane. If there is some copper flash (due to an error during board manufacturing) then you can cut this with a knife and the short should be removed. There is also one 5V trace on the bottom of the board that goes from the input 5V pad to pin 7 of U3. Again, there should be clearance between this trace and the ground plane. If you see any connection between the trace and the ground plane then this is a defect and needs to be corrected.

Jean

[johnboy426]

Jean,

The engine never ran with the diodes reversed. MS powers the P&H board so, nothing would power up.

I visually checked the board and found three potential area to check. Tonight I will unsolder these areas and for a better view. If I understand correctly, I could have put too much solder on an area and caused this because power and ground are on the same plane of the board.

John

[racingmini_mtl]

It should not be caused by too much solder if the board is OK. Normally, there is some distance between the solder pad and the ground plane and the ground plane is completely covered by the solder mask (the green layer that covers the whole board except the solder pads).

So the only way excess solder would cause a problem is if the solder mask is incomplete and there is some ground plane exposed (you'd see exposed copper) and you used a lot of solder that joined the solder pad and the exposed ground plane. And solder will not stick to the solder mask so normally you should be able to see the clear ring around the solder pads because the solder will only be on the pad and the component lead. If it's no the case and there is solder that prevent you from seeing a clear ring then it may be due to a copper bridge between the pad and the ground plane.

Jean

[johnboy426]

Jean,

Thanks so much for your direction, although it was not needed. I checked the board in the areas you specified and there was no issue. I checked the board and there was no short out of the case. The five volt pin on U3 was shorting to the screw of my COP board heat sink! ARRRGGHHHH. The setup and tuning have begun.

John

[racingmini_mtl]

John,

Troubleshooting is always full of surprises!

I'm glad you found your problem and that, even though it's annoying to have had this issue, it turned out to be simple to fix.

Cheers,
Jean