2nd Gen Non-Engine/Transmission -Wanted '98 12V auto ECM to dissect

[budnate]

any of you guys have a Auto 12V '98 ECM around you dont want, I want to crack one open and figure out how to correct the +5 drift we have on the signal to the trans, I have been playing with old vintage 80's arcades the last couple of years and have connected with some really sharp guys that keep these games going, I want to open one of these up with the group and see what we can come up with.



also wondering if anyone has seen good schematics of the ECM around?









Peace, B.

 

[Cosmo]

+5 drift?
10

 

[n7gxz]

Are you talking about a PCM? The 12V engines do not have an ECM.

Kevin

 

[budnate]

I meant PCM,

B.

 

[DRAG DIESEL]

I cracked one of mine open last night to chase down an intermittent issue. I was shocked to find a flexible printed circuit board. I was hoping to float all the solder joints to see if i could make the problem go away, but that's not going to happen on this style of board.

 

[budnate]

well crap... . is it still out?, I would like to see a picture of one... . there has to be some kind of rectifier circuit dropping the +12 down to the +5.....

 

[fest3er]

Or a DC-DC converter... .

 

[budnate]

Or a DC-DC converter... .

yes that also but they take up room on a board to do it that way, more so than a single component, defiantly has me very curious on how they did it, if it is a single printed board that is probably how they did it.

 

[HHhuntitall]

Can I get it back?

 

[budnate]

Hi, after Drag diesels post it sounds like a guy is not going to chase components on the board, I am hesitant to take something you will want back, you know how it goes sometimes stuff is wrecked during the inspection of figuring out how things work, I may go look on ebay and see if anything looks interesting.


B.

 

[DRAG DIESEL]

well crap... . is it still out?, I would like to see a picture of one... . there has to be some kind of rectifier circuit dropping the +12 down to the +5.....

No, I put it back. I only have the one in my truck right now (95's computer is different)

However, taking it apart seems to have fixed my tach speedo warning lights alt and ac all shutting off.

Prior to this I was getting some burping in the FM side of my radio. When the dash died, the burping went away.

Headed out on 1200 mile run, thinking about having a spare shipped to the hotel.

I will do my best t describe what it looked like inside because I didn't think to take a picture.

Imagine a standard sheet of paper mounted to a thin sheet of aluminum. then they bend the sheet in half and it wrapped around the computer chassis. Then epoxy, epoxy, epoxy. good luck just pulling it apart!

 

[budnate]

Long story short, bought a rebuild off of one of the ebay pimps, 2 vendors on there selling pcm's rebuilt... both claim they are doing them right, both had decent feedback,



one didnt know about the common problems on the diesel, or at least the guy answering emails didnt, second place knew all about the problem spot and said it would be solid when he was done with it... ... . hit the buy it now for $420... ... guess we will see what he ships me in a couple days.



B.

 

[HHhuntitall]

Keep us posted, I'm always interested... ...

Also, what pimp are you using that seemed so knowledgable? I'm always needing..... parts... .

Got a 99 right now that blew the ECM out. I put my spare on it, which has the long crank issue, but I gotta get it back, and gotta get this one fixed.....

 

[budnate]

hit ebay and surf, there are a bunch of 24V pcm's for sale... ... the ebay rebuild shops... one wants 250, the other 399... . I went the 399 route as he sounded like he knew what he was doing... ... hopefully its not the crap shoot people talk about with rebuilds... .



I will pm you the shop, I think I got in trouble adding links awhile back.





B.

 

[budnate]

well round one didn't go well... ..... rebuilt pcm showed up last night, installed it and NO worky..... throwing codes p1694 no bus read, and p0122 tps sensor low input.

so doing the ship it back and he will find another I guess, still trading emails on what the next move is,

crazy guy wants me to ship him mine to fix my plus 5 circuit, terrified to do it, if he kills this one the truck is dead in the water and I need it all the time... cant bring myself to send it to him no matter what he says.

-question for you guys... ... how does it work if you buy a used one with a diff vin flashed in it, truck will run fine right?

 

[HHhuntitall]

Yeah, truck will run if VIN num doesn't match on 98-2002. I got two fixed this week. The ECM off the 99 ended up just being scrambled, somehow. Larry (Cummins Southern Plains) said it looked like someone plugged in a programmer and had a failed program attempt, and all the parameters were screwed..... Not sure, but owner said nothing like that has ever been done to it, but I do know they jumped it off 3-4 times in a short period, so I think that may have done it. It's also a welding rig, sooooo... .

For $55 they purchased the flash code used per Eng. Num. from Cummins and reflashed it and it tested fine. They didn't charge me the flash service, as I ordered a reman'd one for my '98, as I had to have it, and it used the same code as the '99, despite being a '98 auto engine... I'm guessing the differences lay in the year and HP program..... BUT, I'm getting out with two ECMs for $1600 and the ECM code if I need it for any future ECMs that need the same code... . I'll just have to pay the flash cost of $180... ..... Now, if they'll all be that easy.....

 

[cerberusiam]

While you are at it why don't you get them to flash the 98 ECM with the 400 HP marine tune.

 

[HHhuntitall]

What's the engine number?!?!?! :foamatmouth:

There is a really nice tune for early 2000's industrial engines, too, so I've heard. Supposedly going to trade some INsight programming knowledge and access for some EFI Live programming and access in the near future..... That may be fruitful, as well!!!

One thing I failed to mention is the HO option on the engines. The engines will run with the non-spec ECM, but you won't like it... . The tow truck will run faster with it on the back... . The HO engines use a different Spec program, as do the engines with crank sensors in the block behind the starter. Not sure what all the differences are, but it seems the 98-early 2000 trucks all run the basic "J. code" program, found on the superceded ECM part number... ... I'm not sure if the part number is 3942336 or if that is the old number..... have to check, but that's the part number on the ECM in the 99 24v truck I put together the other day.....