1997 HMC4 Stock with Brains

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1997 HMC4 Stock with Brains

Postby Greenmeanie » Tue Oct 20, 2009 6:10 pm

I bought my 1997 HMC4 in 2000. At the time it was the only green 4 door hardtop available in Canada in that vintage. Initially there were piles of problems the previous owner had ignored so over the years i have been fixing those problems one by one and deriving much pleasure from the expierience. The list is long and ongoing and i see it more as a rescue as oppossed to a build. Over time i ended up with a good truck that now has 110,000 miles. I have some mods in mind but i want to keep the truck stock for the most part so im not going to be cutting up anything. The things I have done are mosly maintanance related to include:
Find out that i have a new motor #h296 (extremly good news) no cylinder 8 problem here.
New rear spindle and half shaft
New starter(rebuilt prestolite)
Transfer case cooling loop (dealer did this one)
Rebuilt DS4 pump to 5288 standards (dealer did the timing)
Idler and piman arms
Replace Batteries
Replace Glowplugs (that was stupid cause they were all good and the dealer broke the#1 off)
Replace vacum pump
Replace vacum switch
New Mickey Thomson Tires (never again)
Bypass ACME heater core front unit.
Replace oil cooler
New rotors x1 pads x2
Transmission filter & hoses.

So now thats all done and really only a few things left to include
Rebuild Turbo and Intake manifold (mostly gaskets)
New intermediate pipes
Figure out a custom exhaust solution
Solve rear window and rear passenger door rust issues
Little bits of body work and paint
Last edited by Greenmeanie on Tue Oct 20, 2009 6:53 pm, edited 1 time in total.
1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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Re: 1997 HMC4 Stock with Brains

Postby Greenmeanie » Tue Oct 20, 2009 6:40 pm

Most of the above remaining items are near completion so now i am planing my first set of mods to this truck. This will include a centre roof console to house all my add ons and controls. Some bolt holes need to be tapped in the roll bar and centre window trim must be rebuilt to accomadate wires and the wire hole that goes out to the front roof markers will have to be enlarged. Extra wirng to the side view mirrors to run camera actuators. Also the rear panel of the truck which is rusted out will be replaced and a speaker/ amp wall installed which involves some alterations to the window trim. The new roof rack system i am designing will carry off road lights on the front and back and a pan til zoom night vision camera. In addition the roof rack will provide some winshield protection and replace the stock exterior window trim with somthing more similar to an uparmoured Hmmvee.
I have been taking lots of pics, far to many to upload here so here is a link to my pics. In time i will organize this for better viewing but it all takes time. (UPDATED) http://www.greenmeanh1.com
Attachments
Roof Console.jpg
Rough fit and fab
Roof Console.jpg (86.55 KiB) Viewed 5956 times
a5.jpg
Where we are today
a5.jpg (90.26 KiB) Viewed 5956 times
Fuse Panel outside.jpg
where we are today 2
Fuse Panel outside.jpg (81.83 KiB) Viewed 5957 times
Last edited by Greenmeanie on Thu May 24, 2012 6:56 pm, edited 1 time in total.
1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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Re: 1997 HMC4 Stock with Brains

Postby Bellvis » Tue Oct 20, 2009 6:56 pm

Wow!
Gorgeous!
Miss you Rich! Thank's for all the memories!
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Re: 1997 HMC4 Stock with Brains

Postby Mark » Wed Oct 21, 2009 7:09 am

Very nice 8)
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Re: 1997 HMC4 Stock with Brains

Postby Greenmeanie » Thu Oct 22, 2009 10:42 pm

Heres one i have been trying to figure out for a while. I have long suspected that there is a fault by design in our PMDs. I have been trying to figure out the curcuit and there are some complications and findings i would like to share.
1.All faulty units i have tested have intact MJ15004g power transistors leading me to believe heat sinking of the transistor is not the problem.
2. All faulty units showed some minor signs of water intrusion on the edges of the PCB.
3. Sensitve logic electronics and load resistor curcuits are encased in epoxy and will overheat enevitably.This process i believe is to protect intellectual rights on the curcuit.
4.There appear to be several logic curcuits that tie into the turbo wastgate, optical sensor and fuel metering control through the PCM. These are a pain in the to figure out.
5.Switching resolution on the 15004gs can potentialy be as high as 7200 rpm (of couse youd be picking up your heads several blocks back)
What i need to do is figure out all resistor values in this curcuit and after busting open a bunch i realize that there must be a better way to get these things out of the epoxy. All the componets tend to break off with the epoxy. Some i can read with a microscope and i have managed to retrieve the info on about 50% of the curcuit. The logic chips are impossible to read.
Does anyone have any ideas on how to remove epoxy via some chemical or acid?

The back side of the board handles the high current switching of the main transistors that sends trigger voltage to your fuel solinoid driver. Its very interesting to see how the #1-#9 resistors that we stick in the end of the plug affect the curcuit.(maybe some depleted uranium head bolts are in order here). You can see all the transfer pins that connect to the top side of the board.
PMD Backa.jpg
PMD Backa.jpg (31.19 KiB) Viewed 5874 times

The top side shows the several logic curcuits involved in calculating the math on pulse widths and so forth. One of the OP amps is almost intact and you can plainly see the 14 pin if, then, else curcuit. Several resistor networks are shown as well. It makes me wonder. Do the military turbo trucks use the same PMD we do? Clearly there are some ways to fuel up these things allthough the motor would need to get the heads buttoned up better with new pistons and some way of cooling and the list goes on.
PMD Fronta.jpg
PMD Fronta.jpg (39.61 KiB) Viewed 5871 times


--------------------------------------------------------------------------------
Here are the first traces of the curcuit board for those of you who might find this interesting. I have figured out about 30% of the curcuit which is the simple stuff. A lot of the resistor values were readable under magnification. I have a idea how this thing works sort of. To know more i will have to take a detailed look at a PCM under operational condition in the truck while monitoring saw tooth variables on an scope. I will also need a Tech 2 programmer to disable sensors so i can trace the logic funtions down in relation to the PMDs operation. I guess my biggest problem is I am an idiot. I had the opportunity to learn this stuff in high school and i didnt so now im getting stuck on ohms law equations and having to look stuff up. What i iniatally thought would take a couple weeks will take much longer i think but i will do it.

On the front board there are still several areas i have not been able to map so if you look close under Op amp and chips you can see the incomplete traces. traces are in yellow, board jumpers are the red dots( a few mistakes on photo) chips are blue, grey is major solder connections. The items in white boxes are resistors, capacitors and diodes about 30%determined. There are also a few small transistors whether PNP or NPN i dont know yet.
PMD front plot-1.JPG
PMD front plot-1.JPG (163.01 KiB) Viewed 5871 times


The rear of the board is basic. Only 4 componets attach on this side and they would be 2-1ohm 5 watt resistors and 2- MJ15004g power transistors. All traces are in red.
PMD rear plot-1.JPG
PMD rear plot-1.JPG (103.94 KiB) Viewed 5872 times




My initial summary on all this is vague because i just dont know enoegh yet to blap my mouth off. Clearly to recreate one of these is some work but more important is how to go about making some improvements in the design and function. That is the battle. First off i think its gotta be bigger in size so people can work, fix or modify them to fit there needs. I invision somthing half the size of a laptop in side the truck. TD offset and resistor change should be able to happen on the fly. I would seriously beef up the high current side (solinoid voltage) with bigger wire and isolate it from the logic side perhaps even 2 curcuit boards. Also a 20 second warp switch (5400rpm) on a timer to bypass the govenor curcuit( with propane inj) so you can pass on the highway and last but not least a simple computer fan to cool the transistors and the 2- 5 watt resitors curcuit board. As far as doing an epoxy casing---- i will save stuff that for the body work, Its strong stuff!!!!
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1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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Re: 1997 HMC4 Stock with Brains

Postby Mark » Fri Oct 23, 2009 8:27 am

Looks like you have spent a lot of time on this. Those incomplete traces on the top of the PCB, do they look burn/broken or do they just not go anywhere by design. Doesn't look like there should be but are their vias there to go to another layer on the board? Any idea how many layers the board is? I am guessing it's probably only a 2 layer board. If you really wanted to get into it I know of a couple of places you could send the bare board to get it scanned and in return you get complete gerber files for the board.

We have several products that we encapsulate in epoxy due to proprietary information and if they fail they are toast, no way to get to the components. I think it would depend on what epoxy is used but I have one of my equipment vendors coming by shortly and will ask if he has any ideas on how to remove it without destroying the components.
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Re: 1997 HMC4 Stock with Brains

Postby Greenmeanie » Fri Oct 23, 2009 4:11 pm

Thanks for the info. Clearly i will need some help with this. It is a 2 sided board. The main problem is the op amps are in the way so i cant see underneath to trace the curcuit. Im going to remove all the parts that are left to get a clean surface and hopefully i will be able to complete the diagram. There are also 2 componets that i cant identify. They have 4 solder points (3on one side 1 on the other). As well there appears to be 5 or 6 transistos that broke off with the epoxy so i have no idea at this point if they are pnp or npn. The rest can be sorted out over time. Each unit i take apart gives a little more info.
The next step for me is to create tranpararent films of the 2 sides and lay them over top of each other. This will complete the picture of what is going on. I will probably re scan the boards or shoot a high res stat photo to get a clearer image to blow up. All of the vias through the board are traced allthough there are some mistakes on the top of the board.
I apprieciate your thoughts and info on this. Once i finish my homework i would be interested in going over it with someone in detail. I would be really cool to find a way to disolve the epoxy, if you find anything on that let me know.
1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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Re: 1997 HMC4 Stock with Brains

Postby Mark » Fri Oct 23, 2009 9:57 pm

The two components you can't identify could be voltage regulators. Do they look like this?

LDOReg.jpg
LDOReg.jpg (72 KiB) Viewed 5826 times


Talked to my equipment vendor and assuming it's anything like the 2 part epoxy we use he didn't have any suggestions.
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Re: 1997 HMC4 Stock with Brains

Postby ronb » Sat Oct 24, 2009 1:44 am

Mike Sabaresse (Hummech) has always told me that pmd failure is due to vibration and breakdown of the epoxy rather than the heat. Interesting finding...one of the main weaknesses of the 6.5 td
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Re: 1997 HMC4 Stock with Brains

Postby Greenmeanie » Sat Oct 24, 2009 2:37 pm

Voltage regs? I had thought of that but i wasnt sure. The VRs im familiar with only have 3 pins ie 7800 or 7900. I suppose the forth solder joint on the top could be the heat sinking for the back plane of the regulator. Once i figure out the 8m and 14m chips that will give me a better idea of the current specs. It appears that the 14m's only use 2 of the 5 inputs unless im looking at them backwards. These chips are programable via software. Seen as the ones on the board have been destroyed ill have to work my way back though the curcuit. I guess the dumb way to do this would be to etch out several boards and use sockets for the chips so i can swap out the preprogramed chips until i get the right combination. I am using PICAXE software to program the chips so i guess there would be about 15-20 different variations of programing based on the number of inputs used. I can probably narrow this down a bit by determining the location of the 22k and 10k resistors in the curcuit.
1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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Re: 1997 HMC4 Stock with Brains

Postby dailydriver » Tue Oct 27, 2009 2:20 pm

ronb wrote:Mike Sabaresse (Hummech) has always told me that pmd failure is due to vibration and breakdown of the epoxy rather than the heat. Interesting finding...one of the main weaknesses of the 6.5 td


Interesting, I wounder if we mounted the PMD to a cooler and the cooler to anti vibration pads (not like the headlight or CTIS compressor mounts, more like what a CD player would use) if that would prolong the life of a PMD.
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Re: 1997 HMC4 Stock with Brains

Postby Greenmeanie » Thu Oct 29, 2009 11:17 pm

Bit by bit the picture is getting clearer. Im really starting to think the box is to small to support the amperage and capacitance needed to supply steady output over long periods. I think you have to get the big Power transistors (MJ15004gs) and the 2 5watt resistors away from the logic curcuit on a separate board with traces that will support the necessary amperage. This will make the package bigger and thats probably why the designers didnt do it that way. The voltage regulation in this curcuit is primitive at best and will be the first priority in the curcuit re design.

In the meantime im still sorting out the existing curcuit. I have logged about 80% of the parts involved in the curcuit and am just finishing the high res overlays. My wife looked at it and thinks it would make a nice picture to blow up and hang on the wall. It is kinda pretty even though by design it is flawed.
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PMDARTsmall.jpg
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1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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Re: 1997 HMC4 Stock with Brains

Postby Greenmeanie » Thu May 24, 2012 6:33 pm

I haven't posted here in quite a while and almost forgot i even started this thread. The majority of the build details are on the HML and early stuff on Flash Off Road.
I though i should bring this up to date.
Anyway truck has been done for a while now and i have put almost 10k on it since its been out of the shop last October and is running great. There are a few minor details left to do here and there but all the bugs are out and all issues fixed. I did so much stuff i can't remember it all and its a good thing i took pics of the process. I won't repeat myself here on all of that other than to leave a few links to photos.
I split the build into two sections Part one and Part 2 on the top menu bar. Unfortunatly i don't have a dialog and they are just pics split into several sub catagories but you can see what i have done.
The truck with original at risk engine just recently past the 120k mile mark.
http://www.greenmeanh1.com/
http://greenmeanh1-com.webs.com/hummerbuildpartone.htm
http://greenmeanh1-com.webs.com/apps/photos/
1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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Re: 1997 HMC4 Stock with Brains

Postby Mark » Fri May 25, 2012 3:45 pm

Congratulations on getting it done. Was actually wondering a couple of months ago what happened with it.
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Re: 1997 HMC4 Stock with Brains

Postby Greenmeanie » Fri Oct 19, 2012 11:48 pm

1997 HMC4 G10 green, 110k no cracks yet, original H296 engine UPDATED MILEAGE 120,168
http://www.greenmeanh1.com
http://www.amusikzone.com
Custom: Roof Rack, Brush Guard, Rear Bumper, Overhead Console, Doghouse, Rear Stereo Wall, Battery/Aux Buss
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