rpm issue

lincolnlocker

Well-known member
Joined
May 25, 2011
Messages
27,824
Reaction score
134
Location
Central Michigan
I have pm'd a couple guys about this issue I am having but thought I would post up. how or what would all of the sudden cause my truck to not go above 3500rpm? up untill my last couple pulls it would easily run 3800+rpm and now it stops at 3500 and kinda bounces 3450-3500 and spits and sputters like a gassers rev limiter... only oddball codes that has came up is a upshift selector wheel malfunction. I dont remember the exact code number and every now and then it will throw a speed sensor code.. used to throw a cps intermittent code but that hasnt happened since I shimmed it out far enough to stop hitting the tone ring.. sooooo, any ideas?

live life full throttle
 

Powerstroke Man 6.4

Active member
Joined
Jan 10, 2012
Messages
4,039
Reaction score
3
I have pm'd a couple guys about this issue I am having but thought I would post up. how or what would all of the sudden cause my truck to not go above 3500rpm? up untill my last couple pulls it would easily run 3800+rpm and now it stops at 3500 and kinda bounces 3450-3500 and spits and sputters like a gassers rev limiter... only oddball codes that has came up is a upshift selector wheel malfunction. I dont remember the exact code number and every now and then it will throw a speed sensor code.. used to throw a cps intermittent code but that hasnt happened since I shimmed it out far enough to stop hitting the tone ring.. sooooo, any ideas?

live life full throttle

Corrupted calibration on that certain position? Does it does it have the problem on all tuning positions? Chip seated tight? My 7.3 pulled all the way to 4500.
 

lincolnlocker

Well-known member
Joined
May 25, 2011
Messages
27,824
Reaction score
134
Location
Central Michigan
Corrupted calibration on that certain position? Does it does it have the problem on all tuning positions? Chip seated tight? My 7.3 pulled all the way to 4500.
guess I never tried switching tunes, but in the last 3 years I have never switched tunes off the hot setting... and yes the chip is tight. Jonathan put enough solder on it to where it almost takes pliers to get it out. and what I am saying is that it just up and started doing it.. I have done 4k+rpm burnouts and ran down the pullin track at 4100 before. now all of a sudden its like someone installed a rev limiter.
Think it might have anything to do with your cps issue?
well, thats what I thought all along but the code hasnt popped back up yet!

live life full throttle
 

pontiacross

New member
Joined
Jun 12, 2011
Messages
410
Reaction score
0
I would check to see if the cam is walking. Pull the sensor androll the engine a couple revolutions. Then mesure how far it is from the front cover then roll it over backward a couple times and recheck. The heilicle cut gears should push it to both extremes so you can check end play
 

lincolnlocker

Well-known member
Joined
May 25, 2011
Messages
27,824
Reaction score
134
Location
Central Michigan
I would check to see if the cam is walking. Pull the sensor androll the engine a couple revolutions. Then mesure how far it is from the front cover then roll it over backward a couple times and recheck. The heilicle cut gears should push it to both extremes so you can check end play
thanks Ross! I will do that. but how would that all of a sudden limit rpm?

when I had the heads off last Thursday I looked down at the lobes and they all looked uniform and not worn or shined up all the way across the lobe like it was walking... but I guess a few thousands wouldnt be seen with the naked eye.

live life full throttle
 

pontiacross

New member
Joined
Jun 12, 2011
Messages
410
Reaction score
0
thanks Ross! I will do that. but how would that all of a sudden limit rpm?

when I had the heads off last Thursday I looked down at the lobes and they all looked uniform and not worn or shined up all the way across the lobe like it was walking... but I guess a few thousands wouldnt be seen with the naked eye.

live life full throttle

My thinking is the cam gear may be getting a little to far from the sensor and it is having trouble picking up the signal at high rpms
 

lincolnlocker

Well-known member
Joined
May 25, 2011
Messages
27,824
Reaction score
134
Location
Central Michigan
My thinking is the cam gear may be getting a little to far from the sensor and it is having trouble picking up the signal at high rpms
yeah, I have been battling that issue too.. it started going through cps's then I put shims in it. it hasn't thrown any cps codes like it always has. thats where im lost cuz they havnt popped up since the shims where put in.. hell it used to throw hard codes all the time. soft codes where always present but the last couple pulls the codes never came up....

live life full throttle
 

Krause

New member
Joined
May 18, 2011
Messages
304
Reaction score
0
Location
BC Canada, and PA USA
Just had this issue about three weeks ago. On the highway, if I wanted to put the hammer down and go full throttle, it would sputter after a few seconds ana jerk/hesitate. Fuel pressure, ICP, all that good stuff was good and high. I had a spare CPS in the toolbox waiting, swapped it in and no problems since... Not sure this is the exact same issues but I'de say CPS is a solid guess.
 

lincolnlocker

Well-known member
Joined
May 25, 2011
Messages
27,824
Reaction score
134
Location
Central Michigan
Just had this issue about three weeks ago. On the highway, if I wanted to put the hammer down and go full throttle, it would sputter after a few seconds ana jerk/hesitate. Fuel pressure, ICP, all that good stuff was good and high. I had a spare CPS in the toolbox waiting, swapped it in and no problems since... Not sure this is the exact same issues but I'de say CPS is a solid guess.
I need to measure yet like mr.becker said but now im wondering if I just flat out shimmed it to far out to where it still has signal but not reading it fast enough...

here is my cps thread http://powerstrokearmy.com/forums/showthread.php?t=43949

live life full throttle
 

Chvyrkr

New member
Joined
May 18, 2011
Messages
2,197
Reaction score
0
thanks Ross! I will do that. but how would that all of a sudden limit rpm?

Timing is different when the cam gear walks out than it was when tuned. If the CPS isn't getting an accurate read due to gear walk as RPM's and force against the gear increase, I doubt your injections are close enough to the ever decreasing window to allow high RPM's.

Can you free rev over 3500?
 

lincolnlocker

Well-known member
Joined
May 25, 2011
Messages
27,824
Reaction score
134
Location
Central Michigan
Timing is different when the cam gear walks out than it was when tuned. If the CPS isn't getting an accurate read due to gear walk as RPM's and force against the gear increase, I doubt your injections are close enough to the ever decreasing window to allow high RPM's.

Can you free rev over 3500?
oh for ***s sake im a retard!!! duh!! it will not go above 3500 at all. ive hit over 4k on a free rev before.. on accident...

live life full throttle
 

TyCorr

New member
Joined
Jun 23, 2011
Messages
15,461
Reaction score
0
im not worried about the letting off part. im wanting it smooth at 4k rpm again...

live life full throttle

I understand. I was saying that like "what happens to the cam gear under acceleration?" Chvyrkr sorta hit on my point.
 

powerstrokenstang

New member
Joined
May 18, 2011
Messages
771
Reaction score
0
Location
Verona VA
Ive tried 3 diff cam sensors and even turned one down on a lathe to get it closer to the gear. Itll free rev to 4900 no prob but as soon as it goes full fuel it drops instantly. And wont turn over 3000-3100 going down track anymore. Use to turn 34-3600.
 

powerstrokenstang

New member
Joined
May 18, 2011
Messages
771
Reaction score
0
Location
Verona VA
Yea have also tried 2 other ecms, an idm, engine harness and all main sensors. Injectors are gettin sent out as soon as pullin slows down and allows the time.
 

Latest posts

Members online

Top