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Surging in Reverse! Holy Cow!!!!

mfgguru

mfgguru

Makin' it better!
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Location
Winkler, MB, Canada
Well, a few of us have discussed this in other places at other times, but I have some interesting results. I have had my truck surge while reversing several times in the past. I was convinced by myself and others that my FSD was failing. Well, I bought a brand new D-Tech module and not 3 days after installing it behind the grill on my custom setup, it surged, real hard. I 'bout s..t my pants! So, what could it be? IP(original), ECM(stock) anything else? Help me out hear guys, I don't want to back into someone "involuntarily".
 
It was great meeting you today Mike. Lets hope some 6.5 gu-rus can get your surging problem fixed for ya.
Does it only happen in reverse? Could it be a gas (diesel) pedal issue maybe? Just throwing ideas out there.:hat:
 
Does it ONLY happen in reversE?

Does it happen always?

Does it happen instantly when Reverse is selected?

What does the B&M Shift enhacer do exactly?

Seems very tranny related.

Did it do this before your tranny rebuild?

Did it do this shortly after the rebuild?
 
Matt Bachand said:
Does it ONLY happen in reversE?

Does it happen always?

Does it happen instantly when Reverse is selected?

What does the B&M Shift enhacer do exactly?

Seems very tranny related.

Did it do this before your tranny rebuild?

Did it do this shortly after the rebuild?
Click to expand...

It happens only in reverse.

No, it happens spuraticaly (correct spelling?)

It happens any time after reverse is selected, not imediately.

The B&M firms up shift points and ups the line pressure to help hold TCC lock up longer. I can select perf mod, mid range and stock shifting. Really like it.

It did this prior to the new tranny.

Gerald,
It was great to meet you too. Hope our paths cross again soon. Have a great week end.
Mike
 
Mine was PMD, guys... after I changed it out, it never came back. Good thing, too; that surge-in-reverse thing is too hard on the shorts when you're in a parking lot full of Cadillacs and other expensive but fragile vehicles...

Others have reported that they cured theirs by changing ECMs. One guy by changing IP (armature shaft).

Another theory is, the idle system runs on a feedback loop; the computer senses the rpm and gives the command for more/less fuel to keep it where it wants it to be. If the IP starts to run out of fuel, the RPMs will drop and the computer should compensate by calling for more fuel. If the IP suddenly GETS more fuel, you got yourself a surge. If there's enough of a gap between the rpms dropping and the IP getting more fuel, you get a surge. If you push a steady-state system out of balance, it pushes back. If the initial push was hard (ie: almost stalls), the pushback will also be hard. That's why PMD failures cause surging at idle. They seem most obvious in reverse because of the line pressure and gearing... reverse is pretty direct-drive.

In other words, check the fuel filter, lift pump, OPS... look for something that interrupts the fuel flow.

And, I'm pretty sure I know somebody who will tell you it's air in the lines. :)

I could buy that if it happened on a regular basis. If it just happens sporadically, look for something more systemic than leaky lines.

Sorry I'm not more help. I even went and searched/read a pile of threads in the old place... nothing conclusive.
 
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I had it in my '95 and now my '99 has done it once. Only in reverse. I have searched several sites for answers but nothing conclusive. I talked to the pump guy at BD Diesel a number of years back and he said "Optic Sensor" WTF?
 
Does it surge in reverse at idle, or only after the truck starts moving?
Could be the fuel moving to the front of the tank while in motion causing something in the tank (loose baffle?) to block the flow briefly... Going fwd would cause the whatever to move toward the rear of the tank, so then everything's OK again.
Just throwing out an idea.
 
Mine reverse surge went away when I remote mounted a Heath FSD and replaced the filter harness on the pump.

Not even sure a '99 has the filter harness, but that's what I attribute my "cure" to. And yes, I know, you supposedly can run without one....
 
When you relocated the PMD did you remove the ground wire from the IP? If so, put it back. This can cause problems like this. After I had my truck worked on for some reason the mechanic removed the ground wire from the PMD harness that is grounded onto the pump and put it on another screw off the pump. I was sitting at a stop sign and suddenly my truck did a big surge and sputter with a big puff of smoke. I quickly put it in neutral and it kept running. I put the ground wire back on the pump and it hasn't done it since. I can't say for sure that was the problem but maybe. That wire is supposed to be there for a reason.

If you didn't move yours then forget about everything I just typed.:biggrin5:

Dave
 
Come to think of it, when I changed my harness, I grounded it to the cooler, not the pump. I think we have our solution! I will try it and see if that fixes the problem.:gnorsi: Does anyone see an issue with grounding to both the pump and the fsd cooler?
2 minds are better than one, but all of you make the 6.5 world go round!
Blessings be upon you all!:grouphug:
 
mfgguru said:
Come to think of it, when I changed my harness, I grounded it to the cooler, not the pump. I think we have our solution! I will try it and see if that fixes the problem.:gnorsi: Does anyone see an issue with grounding to both the pump and the fsd cooler?
2 minds are better than one, but all of you make the 6.5 world go round!
Blessings be upon you all!:grouphug:
Click to expand...

I have mine grounded to the head bolt that my Driver side battery grounds to. I have had no problems for 2 years with this setup (only moved it after dealing with SSDiesels stupid waste iof money heatsync)...

When I upgraded SSDiesels stupid waste of money heatsync and PMD that only lasted for 4 months, to Heaths (which BTW am stall free since, 1.5 years and counting), I put the ground wire to said bolt. GMCTD told me to do so as getting to the screw on the IP is extremely difficult

Geeze... I really wish i had the 500 bux that I wasted buying SSDIESEL"S stupid waste of money heatsync and PMD... Guages... heath's triple pack with pod... Maybe next week...\

Anyone want to buy a used/failed/garbage Stupid waste of money heatsync and PMD that I bought from SSDIESEL?....

You get the point. :banghead:
 
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:iagree:Was that a rant? I think it was a rant! I hear ya Matt. I wonder how many people get sucked into that BS. Unfortunately we all sometimes learn the hard way, which ends up costing us $$$$$$$. School of hard knocks, sometimes feels like a kick in nuts!:willynilly:
 
mfgguru said:
:iagree:Was that a rant? I think it was a rant! I hear ya Matt. I wonder how many people get sucked into that BS. Unfortunately we all sometimes learn the hard way, which ends up costing us $$$$$$$. School of hard knocks, sometimes feels like a kick in nuts!:willynilly:
Click to expand...

LOL, yep, was a rant :)... I feel better now thank you.
 
Well, you guys can correct me if I'm wrong, but I grounded the FSD to the intake manifold bolt. Is this a no no? If so, where to specifically?
Now, after I did all this, I started the truck and it sputtered and coughed a bit. Gray smoke was present and unburnt fuel was smelt. I have never had this before. I went away after it warmed up, but I took it for a drive and a WOT it smokes black pretty good. Runs fine and smoke subsides when I reach desired speed. I checked the WG solenoid and it is closed under idle, but how much pressure should it take to release it? If I push on it with a screw driver, it takes very little pressure to release it. The pump is pumping, I can feel it on my finger is I take the line off. Any thoughts?
 
You should BARELY be able to move the wastegate at idle... if you can move it that easy, you got vacuum issues.

Get yourself a vac gauge, mfguru... you should have about 25" at the pump, same just before the wastegate solenoid. You might lose a little, and have 20" after the solenoid, and at the wastegate actuator.

If you have less than that, you got issues. If the pump is OK, then start following vac. hoses. If the pump is shot, I recommend a turbomaster. If you're sold on vacuum pumps, I know a guy who has one for sale cheap. (Dave12)

Let us know how the diagnostics go; been there, done that.
 
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