Hmm, you cruise higher than I do, I guess I've got a 2.97 ratio then. But OD seems to kick in unusually late for you, with your shorter gearing, if anything, it'* supposed to go into OD sooner than a non-GX3 equipped car. OD can come at 60-65km/h (about 40mph) for me.

BTW... I'm getting horrible gas milage.... 350km per tank.
(And no it'* not ALL my heavy foot)
Tank I suspect is 50-60L.

Cruising on the highway @ 110kph @ 2400rpm kills gas fast, espically when you just tap the pedal at that point you're up over 2500rpm before you reach 120kph.

Any ideas what could be going on here folks?

Stock tires - 3.33 axle - lockup o/d = 2200 rpm @ 70 mph . Is the 2400 reading from your Tach or a scan tool ?

Lockup in the 45-50 mph range sounds right, is MPH & gear related, not rpm.

BTW I usually fill ours at 300-340 miles (less if wife driving around town).

When did you replace the O2 sensor last ?

The OD speed is right, because its supposed to kick in at 45mph, so that'* good. But the RPM seems WAAAY too high for OD, especailly at 45mph. There must be something up with you TCC. I can dig up what my FSM says to test if your OD and TCC is functioning properly, if you'd like.


-justin

Tach reading

That'* miles... my # is in KMs. 350km = 217miles

Probably last year.

ack, this still could mean I have the GX3, hah


i really should check my RPO codes

my 1989 SSE has a 1987 2.84 tranny i believe and i do 1400RPM at 50mph and 1550 at 60mph...at 2,000 im at 78-82mph

i get better mileage

Let me give you a hand with this, I forgot about the chart, thanks for reminding me!

Which model tranny do you have, I have several listed here with the 3.33 drive axle.

*9AAH, 9ABH, 9AFH
*9ANH, 9ATH
*9BJH
*9BWH
*9CDH, 9CLH, 9CZH
*9CPH, 9CYH
*9PAH
*9VXH

* equals different catagory, models separated by comma'* are different transmissions, but in the same catagory.


-justin

Service manual gives reanges so broad that you really cannot tell much.

To tell what transmission you have, you rally need the letter code. For exmple in 1987 the Bonnevile shows a 2.97 (AFJH - F79) and a 2.73 (AFKH - FP3). 2000 at 78-82 sounds like a 2.73 with a couple of mph error.

For example my 1988 has a code F79 (three digit code is on the option sticker, four digit code is on transmission) which means it has a 2.97 and 70 mph is 2000 rpm actual but the tach shows 2100 (scan tool will give rpm to 25 rpm granularity and MPH directly)

Other codes for 1990 are F17 for 2.84 and GX3 for 3.33 (numerous foulr digit codes) so if the original trans, the code sticker is the best place to look.

That said, both RPM (from ISC) and MPH (from transmission at 4000 pulses per mile) are pulsed digital signals fed to the ECM. These are translated into analog signals for the instruments so what the scan tool says is closer to reality than the guages.

How can I find the 4 digital code for my transmission?

Here'* a link to my buildsheet, if that helps...
http://rubix.ca/Bonnie/91sse/91sse_buildsheet.jpg

Sidenote.... what does ME9 "Man 5 SPD Eaton FSO-2305A 4" mean?