2004 8.1L trying to go back to stock ? new guy to this

[terry735001]

so i am working on my RV and hoping some 1 can give me a hand to keep me from making any really bad errs

a few years back i did a mail order PCM for a motor swap that got me going and put 30K on the RV but its never ran just right at idle
along story short i am not sure if this tune cost me a motor from running slight rich
after trying to get it to run right and after 3K of new parts i was left with the PCM tune

right now i have a very rough idle and seems low idle RPM seems to start the misfires and then the misfire plays with my fuel trims
get the RPMs up to 750 to 800s and the misfires go away
the tune was set for better fuel economy and i would like to go more stock . the stock 2005 tune file on the HP website does show some differences
i am not sure if its ok to add the stock file here
i am not sure if my tune was made from a 2003 tune
i know there are some differences in the 2002 2003 then 2004 year 8.1L motors and sensors they used

i have 2 credits and MPIV2 and want to do this right the first time

keep in mind when looking at my scan file that
oneway valve in fuel line is bad so fuel flows back after some time of setting so misfires at start of scan is mostly air in 40 feet of line
motor and all sensors are new with just a few hrs of run time and 30 miles drive time

setup is a full stock 2004.5 8.1L allison 5 speed 1000 MH

8.1l 12.09.2018.hpt18-12-09 11-55-19.hpl

[DGS]

Here is the information about the vehicle from your files. Refer to the screen prints. Hopefully the VIN number matches. Shows it's a 2004 GMC Kodiak top kick. I got it from the VCM Editor under Calibration Details (4th. icon over on top of screen). Hover mouse over icons and they will show what they are. You must first address the misfire issue. You cannot tune a vehicle that has any mechanical issues/low compression/valve seats, ignition/plugs/coils, injectors, fuel quality, low fuel pressure , intake vacuum leaks, etc. that may be causing the misfires. No tune will fix any of these issues. If the vehicle is mechanically sound (assuming swapped engine is sound), I would find a stock tune in the repository (if it exists) and compare it to what you have. Save what you have first in several places and name it stock tune or a name that makes sense to you. You can always return to that tune. Rename the tune something like First New Tune or whatever you want to call it and save any changes under that same name. I would put it back to stock with the known good comparison file or a complete stock tune file. Then you can go from there. Watching your cold start to full operating temp, your idle is where it is supposed to be for the Target Idle vs. Coolant Temp table. Refer to screen shot. I don't know if this is correct for a stock tune for your application. I would look at fuel pressure. I've seen water in fuel cause this. You have misfires on all cylinders. Compression could be low, but would have to be across all cylinders. Intake gasket leaks. You could even have a pressure regulator leaking inside intake causing misfires, but I don't really see that by the fuel trims. Evap purge solenoid leak. Injectors slightly plugged. The misses are on all cylinders, so it's something that would affect all cylinders. Do you have any codes or a check engine light? Lots to look at , but hard to do by looking at just data without other information by actually working on it. Did not see map/baro with key on and not running to see if they are accurate. First relearn the crank position sensor and idle learn. That would not be possible on a mail order pcm. Has to be performed on running vehicle. I know I'm rambling on, but hope this helps. More info on the 3k of parts replaced. New engine, used engine, short block. long block, sensors, etc?

[terry735001]

thank you so much for taking the time and YES rambling on as much as you want . all info is good info when trying to track down bugs

so this is going to be a long story
the vin number you see is a donor vin for the motor/trans swap . i tried to find a vin with my setup and GVWR
this was if i had to guess 5 years ago and the RV has ran like a top for many years
6 months ago on a trip on the way home i starting to get a tapping / knocking sound in the motor why under load at low RPM
it was like a spark knock with no codes
when trying to fix this i started with fuel and i found a ground wire for fuel injector 2 going to ground some times . this would dump fuel into cylinder 2
if the ground wire some how back feed power it could have hurt the fuel injector driver but a auto scope showed it ok
next new fuel filter and fuel pressure is at 60 psi pulled fuel injectors and cleaned them and in the end installed new stock 1s so fuel system is good
next was new knock sensors . i have 2 of them
then stopped by a junk yard and picked up 2 used MAFS and swapped them around still no fix so we know MAFS is ok
LTFT where all ways showing - 5 to 10 at times so i was thinking unseen air so i looked at all gaskets for a leaks and did not find any really
did a cylinder Compression test and all showed in the 180s and new spark plugs /wires / coils as well
pulled oil pan intake and valve covers to try to find the tapping sound and no luck
put every thing back and pulled drive belt to make sure it was not a accessories and giving its a RV and hard to get to some things just installed a new water pump and power steering pump new belt and some pulleys
sound was still there so i pulled the motor out and looked at flywheel . pulled the motor apart and gave it to the shop to find it . they did not find any thing wrong cleaned up the motor and gave it back . i did go back with alot of new parts
but it was not bored over but i did get a full reman kit .now they did rework the cam some but i do not know how much they cut off the cam but its still the same stock cam .
in the end in be leave it was a hydraulic lifter and the sound was no longer there but it did take a full reman to get the sound to go away

i have all ways never had a very good idle O forgot to add that there are 2 new O2 sensors as well
so the only old parts left on this motor is the throttle body MAFS cam and crank sensor
when you add up the cost of all that work tools parts and now the cost of the HPt i am now over 3K and i am doing all this work in a friends drive way so when i go back on the road you can see i want to have this right
as i am a full time RVer and this thing is my home so i have alot ridding on this

i have never done a relearn for the crank position . this was some thing that came up in my mind some time back . my motor does roll over a few more times then it should at start up so i was not sure if i needed to do that

IS there any other tests i can do with HPt scan to help pick out if any thing else is wrong or if some thing could be wrong with the PCM or the tune
thank you again so much for your time .

[DGS]

Anytime you change computers, programs, sensors, or mechanical parts related to crank or cam, you need to do a crankshaft position learn.

[DGS]

Do you have any DTC's?

[DGS]

Did you clean the MAF?

[terry735001]

i well do a crankshaft position relearn today
with a stander obd2 scanner i show no DTCs but HPt is showing high low volt on oil sending unit . removed it and it comes right back . was going to look into that today
i have 2 oil sending units as 1 is for the motor and 1 for my dash cluster so if the 1 for the motor is being funny i would have never seen it
yes cleaned MAF and throttle body and intake when it was off . 1 note to add my throttle body is from a 2003 i think its a old unit and does have some play in the gear box but no codes for it and works fine
this is a setup with 40 feet of fly by wire and this is a gas pusher setup

things i forgot to add in last post
i do not have EGR on this setup . it was not installed on my year and was removed from most stock setups
i did install a new map sensor
2ed i have a air pump on this motor for the air brake system . it takes time to pump up to 175 psi before cutout so this can show some HP pull at start up on log files

again thanks so much for working with me . all the shops around me that do tuning well not look at some thing so big . what guys i do get that well say well help drop off and stop talking as soon as they see what i am working on
its come down to having to fix this my self

[terry735001]

here is my setup and what i am working on


20181115_191831.jpg

[10_SS]

I had a 2002 8.1L Fiesta 31H motorhome, ran great, I modified the shift points and locked the converter up below 50mph and helped with MPG. Also increased based running airflow just a bit to keep it from stalling after would gas it a lot like climbing over a curb when not moving then letting off gas, sometimes it would stall.

I left PE alone since it was basically towing all the time, noticed stock setup would delay PE for awhile under heavy or full load, still left that alone, figured that is helping with mpg, not hurting.

Tune and log Attached

RV08 from Traverse City GAS WOT.hpl
2002 8.1 Fiesta 31H RV08.hpt

[terry735001]

[QUOTE=10_SS;551935]I had a 2002 8.1L Fiesta 31H motorhome, ran great, I modified the shift points and locked the converter up below 50mph and helped with MPG. Also increased based running airflow just a bit to keep it from stalling after would gas it a lot like climbing over a curb when not moving then letting off gas, sometimes it would stall.

I left PE alone since it was basically towing all the time, noticed stock setup would delay PE for awhile under heavy or full load, still left that alone, figured that is helping with mpg, not hurting.

thanks for the tune files .
i know we had 3 def timing chines from 02 03 and then that last at 04 and some other things so i am trying to stay with a tune 2004 or higher

i am sure i do not have any mechanical issues but i am not 100% sure of this and trying to find what tests i can do before i can say its the tune and work with it
i did find a 2005 8.1l allison stick tune for the repository and it does show alot of my fuel and air and volts tabs are not the same .
part of me just wants to swap every thing over on the motor side of things but i am new to this and as they say i know enough to be dangers

my motor would never stall . just a hard idle . yeah PE i am not sure if it would help me . i am all most at max load for trans so i all so think it would hurt MPG

[terry735001]

just got dune playing with it

i did a crank relearn and could tell right off the bat it sounded better but when i tuned the key off and back on i am not sure it kept it and the app ever told me if it worked?
played with the oil sending unit and its maxed out at 130 psi so i guess the unit is bad so i well get a new 1

i do not under stand the misfires at all . if it stayed on 1 cylinder then i could work on that but it jumps cylinders at low idle
i set the app to keep the motor at 720 RPMs and the misfires all most stop but each time i let the PCM pull the rpm back it seems to pick a few cylinders and they misfire alot
each time it does this its not the same cylinders

IS my idle air/fuel off at idle in the tune

[10_SS]

you mentioned it cranks more than it should and idles rough. This is common for the crank or cam sensor not working right.. have you changed those? I know I have this problem just from a low battery in my 2010 camaro, sometimes it causes the cam signal to drop and I startup on crank only, doesn't run right. Are you sure you have the right cam gear/sensor combo for that ECU? and the sensors are good?

Missfires are showing up in your o2 values at idle. Good example is 12:53:09 area, Bank 1 looks much worse than Bank 2. You could always try a timing light on a few cyl Bank 1 just to see if the spark is consistent and not skipping randomly.

[terry735001]

That is a very good thing to ask .. right cam gear/sensor combo for that ECU?

The motor came from a Schwan's delivery truck that was setup to run off propane so i had to swap the engine back over to gas
I was told it was a new motor install and had low miles on it . when really it had alot of miles on it . but the timing chain cover had the new year 2004 cover and sensor and chain
That made me think that the crank sensor was all so 04 as i think both has to be the same
The PMC i think was a ???2002??? pics show 12200411 / 12216121 and the plugs where the wrong color it all so had the really old 2 plug throttle body on it
When i got the motor i just started making my wiring order the pcm and TCM and off i went . its all ways had a rich smell at idle but ran like a top with lots of power

I used a auto scope every way i could to see if i could find some thing wrong with the wiring or drivers in the pcm . i used my auto / digital multimeter to see rpms if they where jumping and nothing is skipping . all waveforms look good
Its in a RV so there is a power converter that keeps the 12v up and the only thing i could find with the scope shows a 2volts drop when the coils are firing on the driver side / that was on the old coils . i have not redone that test with the new coils

When doing the reman i did install a new timing chain as it came in the kit but i am still running on the old sensors / i did not scope any of the cam or crank sensor / no codes for them but they maybe turned off in PCM .
How can i use the HPt scan tool to see if some thing is wrong here ? if there a add channel for that

[terry735001]

did some digging and there is not much info out there on the 8.1L

if i see this right the 24x reluctor wheel was used in 8.1L from 01 to 07 still looking to see on the sensor its self if its the some over the years

i used this website before on the cam and timing chain and it looks like i have this right
http://www.raylarengineering.com/vor...aft-gears.html


20180922_113827.jpg20180924_153412.jpg

[10_SS]

propane has a different optimal AFR than gas, is the ecu from propane setup being used? Not sure how they calibrate an ECU for gasoline to propane. Mayne you explained that somewhere.

You should he able to log cam sensor counts and crank sensor counts, if no numbers are imcrenting for each then you may have a problem.

[terry735001]

to run the newer 2004.5 allison trans i had to move to a newer PCM and that dumped the LP tune
that all so helped me get away from the fuel pressure regulator on the fuel rail and move to a inline all in 1 fuel filter /pressure regulator setup

i well add them into the log and try again tomorrow

[10_SS]

is yer fuel pressure the same as what is called out in the tune? I know they had problems with the earlier cam sensors, not reliable and then the aftermarket supply weren't avail, so people convert to the newer cam sensor setup which you probably have.

Where is the tune? I dont see it.

[terry735001]

the fuel pressure i am seeing at all times is 60 psi and it really does not move
the 8.1l calls for 52 to 56psi i think and i am not sure what it is in the tune
pressure regulator is inside the fuel filter so any time i change it its can move some
the fuel tank has 35 feet on line so when i did the install i put the fuel pump and pressure regulator 50% down the line
so fuel looks good even at wot
thats why i did a 2004 swap as there where many bugs that where worked out by then Allison trans as well

the tune file is in first post at the very top . i am very afraid to edit any thing in the tune intell i get to know more about what i am doing or get a hand with it . i have been spamming YouTube videos but i am still just a newbie

[DGS]

In the photo your fuel pressure regulator (left side by cyl. 5/third one back) has no manifold vacuum to it. Looks like it's plugged with a rubber cap or kinked line. Can't see where it should be attached to manifold vacuum. No vacuum, no fuel pressure regulation. It's going to run full pressure with no vacuum. Which would explain constant 60 psi. That is unless my view is obstructed. This is the vacuum line I mentioned earlier that can leak fuel and dump raw fuel into intake. Remove vacuum line while running and make sure no fuel is coming out of the vacuum port. It may only leak with vacuum applied. Typically will be wet with fuel when you remove vacuum line. You can pull vacuum on it with at tool and clear hose to check for fuel leak. Also make sure it's attached to manifold vacuum when you done checking it out. You stated your regulator is 1/2 way between tank and engine? The tank pump supplies the max. pressure and flow and dumps extra fuel back to tank via filter. The regulator on the rail controls the pressure at the injectors. You want instant ramp of pressure at injector rail when throttle opens to offset loss of intake vacuum that helps draw fuel thru injectors. Combined rail pressure and vacuum at the injector tip inside intake control fuel flow thru injector. If regulator vacuum port is plugged off, plugged, or has no vacuum to it, it would over-fuel the injectors with no pressure control at idle. This appears to be a return-less fuel system meaning the fuel is returned to the tank from the filter in the back / 50% back to the tank that you mentioned. This keeps fuel cooler instead of flowing it to hot engine compartment and back to tank. Let us know what you find.

[10_SS]

I looked through just a couple tables in your tune, there are so many different tables compared to the stock file. For example your WOT Main Spark table is asking for 30 degrees of Timing! WOW. Stock is around 15-18 degrees.

I would suggest taking all of the tables in mine, and pasting to yours just see how it fires up. I would guess your getting so much knock retard that your running mostly in the Low Octane timing table, if that is even enabled still, then the Low Octane table only has 2 degrees less. Not Good. Seeing that much timing in the High Octane table tells me the other tuner didn't really know what he was doing or maybe it's still setup for Propane, I don't know. The changes made seem like "In Theory more timing and less fuel will increase MPG", but in reality you can't run like that. Those values look like something you would run on 115 Octane.

Your Spark Dwell Settings are also 20-30% different.

All of your Idle/RPM/Proportional settings are much different also, like 500% different.

Desired IAC Area Max, huge difference. 2000 vs 226.

MAF Airflow table isnt that far off, a good sign that the overall setup is the same.

Injector Flow Rate vs Manifold pressure also very close to the same but I don't see Injector Flow Rate vs Fuel Pressure.. strange.

Fuel Prime Pulses are 0'd on your tune.

02 sensor Rich/Lean values are lower on yours.


LTFT Min Learn is 200% on mine, 6% on yours.

Closed loop Proportional is Disabled on mine with 0 in my tables, yours enabled and set to 14g/sec.

There's a lot changed, I would try to revert back to stock, sounds to me like Fuel Correction is limited and not showing you the real problems your having.

A big problem I see is with Open Loop F/A vs Coolant Temp vs MAP. Yours is basically set to 1.00, which isnt adding any fuel cold. Set this back to stock from my table.

PE Enrichment, your tune has that running very lean, so very lean with 30deg of timing, not good. Put back to stock (mine).

Transient Fueling is disabled in yours.

Missfire detection, this is disabled around 400-500rpm on yours, likely why your not getting codes.

So many things that arent good in yours, I would take most of my tables and import into yours. You should see big changes.