I recently replaced my 6.5 in my truck with a used hummer one. I had my injector pump rebuilt by a reputable rebuilder as well as my injectors. I have about 3000 miles on it now and have an issue i cant figure out. Going down the road at any speed it will surge and take off like crazy for a couple seconds, then go back to normal. It accelerates way faster than it ever has when it does it itll bark the tires at 40mph in 4th gear then slow down to normal. sometimes it will lope at idle then smooth out. It has no codes at all. Sorry this is longwinded, just trying to accurately describe this cuz it blows my mind!! Any suggestions would be appreciated.
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Possessed I.P. or electrical issues?? Need input!
- Thread starter Redneck
- Start date
JMJNet
Recruit
Welcome!!!
Does it have any SES or code?
Does it have any SES or code?
buddy
Active Member
Where is your PMD located and how old is it?
Do you have access to a scanner to get some data points?
Do you have access to a scanner to get some data points?
bison
Well-Known Member
What is your Fuel pressure at idle cruise and WOT.
Like said,PMD? What brand?
Like said,PMD? What brand?
Thanks for the welcome. The pmd is from ss diesel and is only a year old. i have it mounted on top of the intake. It has no codes at all. At first it was like my elec throttle was messed up because it would surge from time to time. But now its started missing at idle only for a few seconds then it'll rev up on its own, sometimes wide open! As far as fuel pressure i dont have a gauge in my pillar yet but i replaced the lift pump when i put the engine in last month. The only scanner i have access to is an older snap on. Ive rechecked all my grounds and made sure i didn't pinch any wires. Thanks for the replies i could use the help!!!
ak diesel driver
6.5 driver
Sounds like an IP prob to me
buddy
Active Member
When you installed the engine did you properly time the IP electronically? Also, PMDs on the intake have been known to fail and PMD can cause this. I would try a known good PMD first.
IP itself can also cause this, but you should always have a spare PMD anyway. Do you use lubrication additives in the fuel, and do you know how to check fuel pressure out the water drain for the fuel filter?
If you have the Snap On scanner and 6.5 module, I would look at what your warm idle fuel rate is. Desired timing, actual timing, TDCO value.
IP itself can also cause this, but you should always have a spare PMD anyway. Do you use lubrication additives in the fuel, and do you know how to check fuel pressure out the water drain for the fuel filter?
If you have the Snap On scanner and 6.5 module, I would look at what your warm idle fuel rate is. Desired timing, actual timing, TDCO value.
bison
Well-Known Member
I am more inclined to blame the PMD or the ECM.The IP itself commands nothing,it just carries out orders.
Thanks guys. I probably wont have access to the scanner until monday night but i will check it out. I have always run additive in my fuel. As far as fuel pressure i will check it from the water drain later on today. I was bored with it this morning so for giggles i did the KOKO to it and now it runs like complete crap ,smokes a lot of white and doesnt idle so hot. But no ses light. Guess i should have left it alone til i plugged into it!! I did try a different pmd from my buddies daily driver 6.5 with no luck. Also last night it seemed that if i got on it from 2500rpm up it sounded like a popcorn tin in my crosspipe.
buddy
Active Member
Sounds like your IP is not timed correctly. You must not have timed it when swapping engines. So you will have to get the scanner and see what it is. Clear the codes and reposition the IP accordingly. Is the SES light coming on, giving you codes?
JMJNet
Recruit
x2 on the intake PMD location. They are bad despite Walt swore by it, everybody else swore the other direction. LOL!!!
There is a batch of PMD that cause bad surges. On the rebadged Dtech (SSD) PMD, it surges when it goes bad instead of stalling.
There is another thread about it.
The PMD you put in, needs to be sure they are good and new.
The reason I ask about the code is if the IP is bad, then there is codes. APPs bad caused codes.
But bad PMD may not cause any code.
There is a batch of PMD that cause bad surges. On the rebadged Dtech (SSD) PMD, it surges when it goes bad instead of stalling.
There is another thread about it.
The PMD you put in, needs to be sure they are good and new.
The reason I ask about the code is if the IP is bad, then there is codes. APPs bad caused codes.
But bad PMD may not cause any code.
Funny thing about the pmd is its the second one i got from walt because the first one went bad after 8 months and was causing it to stall out. When he sent my new one i noticed it was different looking. I will try to find the thread on the bad PMDs. I never did plug it in to the scanner when i swapped motors because it never threw a code yet. I figured i would scan it when it was available to me to fine tune it. If the intake is a bad place for the PMD, where is the ideal place? This is my first 6.5 so its kinda new to me, ive been a gasser guy and can deal with custom gas fuel injection systems and read the computer but im def lacking experience on this!
ak diesel driver
6.5 driver
behind the front bumper in the airflow
buddy
Active Member
check out pmdcable.com for an extension cable. The computer doesnt know youre not in the location you last set it, so it just runs like crap and theres no code for that until it gets bad enough for an imbalance code. Or the IP is so far turned that it cant go low enough or the stepper motor comes unlatched.
great white
Well-Known Member
If it runs like complete crap after the KOKO procedure, the timing is outside of spec. It may or may not set a code depending on how "out of whack" it is.
For now, you can try setting the pump straight up and run the KOKO procedure again to get it running at least reasonably.
Then, have TDCO set properly.
I use a program called "car code". If you shop around and/or watch ebay, you can get it for around 60-70 bucks.
The pump is a biotch to adjust on an OBDII truck with the dual thermostat housing and air conditioning. I built a couple special tools to make my life easier:
You could also by a flex head gear wrench instead of the tool I built. Here's one on the "Lowes hardware" site:
http://www.lowes.com/pd_141623-8749..._prd_lis_ord_nbr|0||p_product_quantity_sold|1
I picked one up off ebay for 10 bucks and it works just a well as the one I built.
You can also buy a stock tool to turn the pump, but it's hard to find and not usually very cheap. Before I built my tools, I used to just grab the pump and turn it or use a block of wood on the body to nudge it. DO NOT TURN IT BY THE SOLENOID OR OPTICAL SENSOR!
Cheers
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