Classic FSD Failure

[gwaidman]

Well, I'm officialy part of the club now...Feels great. Just brought home my 20' travel trailer and the mean machine up and died! Too bad, as I JUST finished my Heath exaust install and wanted to make some noise. So, cruising back from the sani-dump, through town, doing say 40mph, and its like someone turned the key off. Execept every light on the dash is lit. Fight it over to the side of the road, and try to restart. Nothing. Walked back to the service station and grabbed a bag of ice, but I though I would try it one more time before I applied the cold to the PMD. Well, she fired up and I was on my way, for a block. Died again, so I iced up the PMD and applied a cold pack with a doggie bag and my future wifes hair tie. Fired up again, but this time I took it slow, like 20 mph with my foot barely on the pedal. Lucky I only had 5 miles to go to get home.
No SES light, except when it was in the process of stalling. This is the PMD failure, correct? I have had no trouble prior to this, and this was my first time towing. Maybe 4000lb trailer. Looks like Bill will be getting more of my buisness, but he is a fantastic guy to deal with. Can someone offer comments on my situation? Also, when I do relocate the PMD, where is the best place? That should spark some comments! Thanks guys. :rolleyes:

[a5150nut]

Just for grins, pull the FSD and check the back side. Two round whatever they are recessed into back. Held in place with 4 small nuts. If they are loose, tighten them and try it again. Mine was tripping SES lite, did this and its been fine for two weeks.....fingers crossed!

Its a pain to remove while on Injection pump. But I hear it can be done if you get a little creative with tools.

I have a cooler on mine mounted on the intake. Been looking at moving it between left battery on back of radiator bulkhead. Some say behind bumper or inside cab.

[eracers999]

Extension harness and a heat sink, move that thing out in good air behind the bumper. I used the cut out to the left of the licence plate and it always has ambient air going across it, even sitting still the engine fan does a good job of bringing air across it. In the cab sounded like a good idea but i like the heater on my feet not blowing heat on the FSD.
There's 2 cents for ya.
Kent

[gwaidman]

Thanks guys, I will be pulling the old unit to see if I can tighten up the nuts, maybe make a good spare out of it. It wont be going back on the pump, thats for sure! Is the connector required to make an extention harness a parts store item, or must it be ordered from GM?

[MTTwister]

You can get them pre-made from Kennedy or Heath. Bill has a 6' extension with his plate and FSD module mounted. Kennedy has a 4' and he can supply longer ones, I believe.

Or, you can splice into the harness and mak your own ( kinda scary, and hard to get to the original harness unless you pull the intake, I bet..
there are options out there.

[eracers999]

The 4 wire harness just unplugs, 4 at one end and 6 at the other. 2 of them break out and go to the fuel solonoid. Cut the 2 wires to the solonoid cut the 4 wire harness in the middle, add your length of wire. Solder and heat shrink.
Its not a big deal to make one longer and you can save some $. Or just order one from one of the fine DP supporters.
Good luck to you.
Kent

[Marty Lau]

You have a couple of suggestions on where to mount an FSD/PMD, I not sure it make a lot of differience other than out of the engine compartment where it can stay cool. Heath has two different mounts for his set up, for 4x4's behind the front skid plate, and 4x2's behind the front bumper. I mounted mine on top of the frame cross member under the seat area. All I had to do was drill 2 holes in the cross member flange.
Tighening the loose nuts on the PMD may help for awhile, but I think once you start having failures it's a down hill slide. My personal opinion is either spring for a remote mount or get a new PMD and put it back on the pump. I did the Beta cooler on the intake and the FSD/PMD went 30,000 miles before getting fried. The one that it replaced on the pump went 100,000 miles. I'm not the ony guy this has happened too. Again go the remote mount I think it's the best choice we now have.
There had been some disscussions around that some folks where trying to make a "Better PMD" I haven't seen anything for a long time on that.

[spra01]

Kent

What gauge wire did you splice in for your extension harness, or what gauge are the extentions on the market, I'm planning on splicing a 6' extension on mine, but the existing wire gauge seems to light to add 6' when the fsd is a such a high draw?

[morgan]

Has anybody determined if a conductive fluid under the transistor nuts might help? Dielectric grease?

Or will reflowing an internal solder joint will help refreshen a problematic PMD? (kinda like the itermitent windshield wiper problem on our trucks)

What about tightening the nuts lightly, then putting a lock nut behind each one?

We've been talking about PMD's ever since the DP and the Forum were established, and we haven't found a solution YET? Come on! Do the military Humvee's have this problem? Does GM sell them PMD's by the carton, at cost?

[ucdavis]

Hint on special tool to remove FSD from pump:
Buy a 1/4" drive T-15 bit & grind about 1/4" off the hex end.
Buy or otherwise obtain a piece of flat bar, 1/8 x 1 or so. Drill a 1/4" hole near one end of an 8" piece of it. Set the hole over the open jaws of your vise, & drive the T-15 into the hole.
You now have a PMD wrench to get that last damn torx screw out w/out messing w/the pump or manifold.

[Bobbie Martin]

We've been talking about PMD's ever since the DP and the Forum were established, and we haven't found a solution YET? Come on! Do the military Humvee's have this problem? Does GM sell them PMD's by the carton, at cost?
Military Hummers use mechanical FI pumps. Which is what you can do when you get tired with playing with failing DS pumps....

[eracers999]

SPRA01;
I used 14 ga wire and you could also use 12, i have used the 14ga with no trouble.
The heat sink that i used was out of a yamaha stereo, it is 3 times the size of the FSD and has big tall fins on it. I havent been able to detect the FSD having any temp to it at all.
Hope this helps you.
Kent

[moondoggie]

Massive amounts of FSD/PMD information was summarized in FSD, PMD, PMD, FSD -or- It's 10 pm - where is your FSD? (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=005199#000000) (Click on the colored text.) This topic was preceded directly by FSD\PMD - BFD (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=005013#000003) (Click on the colored text.) & two other long topics, which was preceded by years of trying to figure these things out.

Blessings!

Brian Johnson, #5044

[FarmerDale]

Add me to the list, even though the new FSD only was installed for 10 days. Fails only on colds starts. Tightened up the transistors, adn it worked well for a couple starts, then failed again. Unplugged FSD, then reconnected & it has worked well for 2 trips, except for a brief hiccup this morning. Dealer says they will replace this one on GM also!

[Beedee]

You guys are starting to scare the S@#T out of me with all of these horror stories. I only have 95000 kilometers (that around 55000 miles) on mine. Haven't gotten around to putting a cooler on or remote mounting, but I think that is going to be next on my list after I do the engine oil cooler lines.
Having said that, I still love my truck, love the power, love the economy, love the rattle and the smoke. :D
Just had to say that ;)

[Marty Lau]

Originally posted by Beedee:
You guys are starting to scare the S@#T out of me with all of these horror stories. I only have 95000 kilometers (that around 55000 miles) on mine. Haven't gotten around to putting a cooler on or remote mounting, but I think that is going to be next on my list after I do the engine oil cooler lines.
Having said that, I still love my truck, love the power, love the economy, love the rattle and the smoke. :D
Just had to say that ;) BeeDee;
Don't sweet it until it craps out or at least be ready for WHEN it does, I got 100,000 miles out of the one on the pump. Wish the Beat cooler on the intake did half as well. When you do it do it right.

[S\W Off Road]

Originally posted by Bobbie Martin:
[QUOTE] Military Hummers use mechanical FI pumps. Which is what you can do when you get tired with playing with failing DS pumps.... I have been waiting for you to tell us how to work it with an automatic transmission. Is it going to be sometime soon?

[Bobbie Martin]

Should be soon. There was a problem with 4WDs, but its now worked out. I finishing up the article now - should be getting it ti Jim before too long.

[gwaidman]

Beedee, 16ga is giving good advice hear. Be prepared. My truck now has 296,000km on it, pump and injectors done 60k ago. I love everything about my truck, and kind of thought I was 'immune' to the FSD bug. Out of know where, it hit. Earlier that day when I had my trailer out, I thought to myself, seems a little pokey today... That night it died. But hey, the second it happend, I knew what is was, and was already going to order a fresh FSD and cooler. Not a big deal. Chances are its going to happen at some point. Spend a few hundred now, or maybe be caught out somewhere where its going to cost you that few hundred buck to get towed back to where you can replace it. Dont fret, its a good truck. They just need a little special TLC once in a while! Cheers. :cool:

[S\W Off Road]

Originally posted by Bobbie Martin:
Should be soon. There was a problem with 4WDs, but its now worked out. I finishing up the article now - should be getting it ti Jim before too long. Great! I like the fact that you say there WAS a problem with 4WD. I hope it comes out soon because I have had it with these pump problems.


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