- Nov 16, 2013
- 59
Morning,09 Trailblazer with the 4.2....when doing approx. 60MPH the RPM's sit around 2000...is that about right?...seems a bit high...can anyone advise?....Thanks
Morning,09 Trailblazer with the 4.2....when doing approx. 60MPH the RPM's sit around 2000...is that about right?...seems a bit high...can anyone advise?....Thanks
Morning,09 Trailblazer with the 4.2....when doing approx. 60MPH the RPM's sit around 2000...is that about right?...seems a bit high...can anyone advise?....Thanks
I have the 4:10 axle and I'm right at 2000 RPM @ 60 MPH with the converter locked.
Stock.
245/65/17
TJ,I looked at the codes on the glove box sticker and no GT4,might you be able to advise the RPO code for the other 2 gearing ratiosWhat is your gear ratio?? (See the glovebox sticker for the rpo code)
Edit: 60 mph at around 2000 engine rpm sounds close to mine with rpo GT4, 3.73 gearing. Maybe a tad high on the engine rpm though.
Just checked and my 2002 with 3.73 gears is 65 mph at 1965 rpm +/- a fuzz.
Blazer,I was having problems with the stepper motor at first,but after taking apart the dash and a good cleaning it seemed to be working fine....thanks for the input!Sounds a little high depending on gear ratio. But could very well be a stepper motor not reading correct.
TJ,I looked at the codes on the glove box sticker and no GT4,might you be able to advise the RPO code for the other 2 gearing ratios
Winner,winner...chicken dinner!!....GU6!...Thanks Matt!!You can find them using the search forums feature, it's a hand device. Here they are anyway:
G80 Differential, locking, heavy-duty, rear
GT4 Rear axle, 3.73 ratio
GT5 Rear axle, 4.10 ratio
GU6 Rear axle, 3.42 ratio
Blazer,I was having problems with the stepper motor at first,but after taking apart the dash and a good cleaning it seemed to be working fine....thanks for the input!
Cman,I never removed the needle,just gave the contacts a good cleaning and at hot idle,a/c off 650rpm's is the magic number.This is where your problem could be.
Are you sure you replaced the tachometer dial back in the correct position?
Can you take a pic of where it rests when the key is off?
Also, take a pic of the tach when the engine is at a hot idle, AC off.
Should be right at 600 RPM.
Moose,I bought the vehicle a few months ago from the son of the original owner,who is no longer among the living and the son wasn't much help with repair records. I don't know...Getting a Bluetooth OBD adapter and the Torque app will tell all. Maybe your speedo is off so check with a GPS. Torque also can display the read vehicle speed and GPS speed to compare. Has the PCM ever been replaced?
I'm going to get on it this weekend if the weather complies,I don't have a garage,I work in the driveway and its been coooold here in NYCOK but have you tried any of the other suggestions?
Morning,did the comparison reading from the speedometer and GPS as you suggested...did it at 30,50,and 70mph and according to the GPS the vehicle is traveling at 1mph slower than what the speedometer says. Moose for a 13 year old vehicle I don't think that's bad....Thoughts?I'm going to get on it this weekend if the weather complies,I don't have a garage,I work in the driveway and its been coooold here in NYC
It's farking good. My brand new 22 Sportage is slightly out compared to GPS speed.Morning,did the comparison reading from the speedometer and GPS as you suggested...did it at 30,50,and 70mph and according to the GPS the vehicle is traveling at 1mph slower than what the speedometer says. Moose for a 13 year old vehicle I don't think that's bad....Thoughts?
LOL...thanks!It's farking good. My brand new 22 Sportage is slightly out compared to GPS speed.
Moose,I don't have an OBD adapter...I'll try the speed/brake method....thanks!Yep, pretty good accuracy so something with the PCM is not in question.
Possibly the torque converter isn't locking. If you have an OBD adapter and torque, you could verify the RPM being reported by the cluster and also if the torque converter is locking. A quick way to verify this is to hold the speed at 60mph with the right foot for a while and with the left, lightly tap the brake. You should see the RPM jump up.
With 3.42 gears, using the same calculator, at 60mph, you should have an RPM of 1680. Check to see what RPM you also get in 3rd gear. There, you should have an RPM of about 2400.
It is possible that your gears were changed at some point in its life. Might have to verify what gearing you actually have using a manual method.
Moose,I tried the speed/brake method and the RPM's didn't flinch...as someone else suggested,even though there is no code it might be a blockage in the Cat. converter...I looked at some youtube videos and am going to borrow a temp gun and check it next. Thanks!Moose,I don't have an OBD adapter...I'll try the speed/brake method....thanks!
AHH!!....Okay,I had it backwards...I read where the TCC is located inside the trans pan,is the solenoid located there as well...?.....Power?....dude,she runs circles around most newer vehicles on the road!!If the rpm isn't changing while cruising at maybe 60 mph, then this indicates that the torque converter isn't locking, which would explain the higher rpm. Either the solenoid for it isn't working or the torque converter ckutch is defective.
Cat clogging would manifest itself with low power. A poorly performing cat would trigger a CEL and the lower output temperature. A clogged cat could still be working and still show a higher output temp but not necessarily trigger a CEL.
Moose,I have had that problem since day 1...the vehicle won't trigger codes,but if a tire is low on pressure,THEN the dash lights up like a X-mas tree...go figure...I'm going to retry the speed/brake method...maybe I didn'r let the trans get hot enough...as always...Thanks!!The TCC is in the torque converter, hence the name torque converter clutch. The solenoid that controls it is located in the valve body accessible from the pan.
Surprising it didn't trigger a code for the slippage.
I doubt very much the cat is at issue here.
Thanks for the input...I'm going to retry the speed/brake method moose mention again,this time I'll run it longer,get the temp on the trans upKeep in mind you have to check the converter lock up when the trans is hot. Not sure of the exact temp but if you drive it away cold, the trans won't lockup right away.
The converter also locks in 3rd, try that also.
If the converter is not locking, you will need to address that sooner than later to prolong the life of the trans.