1989 AUTO WONT REV

[mow/uk]

my 1989 auto wont rev when kickdown is used. if throttle is released & pushed down normally the car runs fine,car starts & runs fine. just before tis problem started there was a engine backfire. as i live in the uk there are no gm dealerships willing to look at the car anywere local to me. can anyone help please..confused:confused

 

[vetteoz]

More info needed
Will the car rev out correctly from a standing start?
Is it actually "kicking down"; as in , does gearbox actually drop a gear?
Trying to determine if gearbox or engine problem.

 

[mow/uk]

More info needed
Will the car rev out correctly from a standing start?
Is it actually "kicking down"; as in , does gearbox actually drop a gear?
Trying to determine if gearbox or engine problem.

thats exactly my problem. the car starts runs goes through the box ok. its only on kickdown all revs die. makes me think its a torque converter problem, but the engine back fire makes me think fuel. maybe a mass air meter fault ?????

 

[vetteoz]

its only on kickdown all revs die.

Dies . like dead not just flat spot?
Does the trans actually shift down?
What happens if you manually downshift?

 

[mow/uk]

Dies . like dead not just flat spot?
Does the trans actually shift down?
What happens if you manually downshift?

the car almost stalls when floored so no gear change, driven normaly it goes up & down box fine. i never change manually so cant answer your last ? :confused :confused

 

[vetteoz]

Thoughts
TV cable out of adjustment so gearbox doesn't kick down? Should drop down on cable alone irrespective of what engine is doing.not vac operated like earlier GM trans

TCC not unlocking ; but that would give same effect as accel in top gear with manual gearbox , slow but not dead

 

[mow/uk]

thanks for your help i will look into these points at the weekend

 

[vetteoz]

First up you need to determine if a engine problem.
Get to speed where you would normally kick it down and manually shift down ,accel.
If it still has the same problem then it is engine related

What worries me is you say if you release the throttle and reapply it works fine which would indicate throttle related;
TPS not showing opened throttle or as you suggest MAF
Have you tried pulling the codes to see if anything is in fault?

 

[mow/uk]

i do have a pal with an auto shop + rolling road access, who can pull codes for me. but as its easter this weekend every thing closes downd till mid next week. good friday is first of the big shows, wheels day just south of london around 3000+ us cars of all types & years,,,,,,,,,,,,,

 

[vetteoz]

Can pull them yourself with a paperclip
How to
Pulling Codes on your Corvette without a code reader
C4 Corvette Diagnostic Code Recovery Techniques
Recovering the C4 ECM Codes - www.c4vettes.com


Codes definitions here
Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical
A code is for a fault in the whole system , not just the sensor so it could also be bad / loose connector , broken wiring , bad earth.

 

[mow/uk]

thanks will give it ago this weekend