C70 engine problem - pt 2

[Andrew]

Hi there,

I have a '99 C70 T5 Auto Convertible and today it's developed a fault
when accelerating hard.

I have no idea what might be causing it and I was wondering, if I
described the problem to the group, if someone might be able to point me
in the right direction so I can do some research (I like to be informed
before I get ripped off at the dealership

With my auto, there's a little kick-down facility where if I floor it,
there's a mechanism where I can push the accelerator slightly further to
the floor to cause the auto to change down a gear (or two).

This morning, with a semi warm engine, I press the accelerator to the
kick down point, it kicks down, accelerates hard until it reached about
4 1/2 krpm and then "topped out" - it appeared to lose power, and then
engine was revving but the car no longer accelerating, and not changing
up either.

It also sounded like something in the engine was not engaging but merely
spinning madly (not the turbo, but something else - I recognise the
turbo whine ya know

I don't know if it's related, but on Thursday I had to have the battery
replaced. The old one had gone completely flat - to the point of no
lights on the dash board - not even dim.

-----

Doh ! Accidentally posted the message before I'd finished !

Could it be the turbo ? The problem only seems to occur when the engine
revs get slightly inside the HP turbo band - I hear the turbo spin up
just before the problem occurs.

Otherwise the car drives completely normally - only under hard
acceleration does the problem manifest.

I'd be very interested to hear from anyone whose got any ideas or had a
similar problem.

Many thanks,

Andrew

 

[James Sweet]

Hi there,

I have a '99 C70 T5 Auto Convertible and today it's developed a fault
when accelerating hard.

I have no idea what might be causing it and I was wondering, if I
described the problem to the group, if someone might be able to point me
in the right direction so I can do some research (I like to be informed
before I get ripped off at the dealership

With my auto, there's a little kick-down facility where if I floor it,
there's a mechanism where I can push the accelerator slightly further to
the floor to cause the auto to change down a gear (or two).

This morning, with a semi warm engine, I press the accelerator to the
kick down point, it kicks down, accelerates hard until it reached about
4 1/2 krpm and then "topped out" - it appeared to lose power, and then
engine was revving but the car no longer accelerating, and not changing
up either.

It also sounded like something in the engine was not engaging but merely
spinning madly (not the turbo, but something else - I recognise the
turbo whine ya know

I don't know if it's related, but on Thursday I had to have the battery
replaced. The old one had gone completely flat - to the point of no
lights on the dash board - not even dim.

-----

Doh ! Accidentally posted the message before I'd finished !

Could it be the turbo ? The problem only seems to occur when the engine
revs get slightly inside the HP turbo band - I hear the turbo spin up
just before the problem occurs.

Otherwise the car drives completely normally - only under hard
acceleration does the problem manifest.

I'd be very interested to hear from anyone whose got any ideas or had a
similar problem.

Many thanks,

Andrew

That sounds very much like a transmission problem, your transmission is
slipping under the high torque during hard acceleration. Does the RPM rise
when it starts doing that or does it stay flat?

 

[Jeff Lesperance]

Andrew,

I think that you are hitting the fuel cutoff. I don't think that there is
anything wrong with the car, but sometimes the same thing happens if I floor
my C70 T5M.

 

[Andrew]

That sounds very much like a transmission problem, your transmission is
slipping under the high torque during hard acceleration. Does the RPM rise
when it starts doing that or does it stay flat?

Ack - that'd crossed my mind too. The RPM stays flat at 4 1/2 when it
happens.

What's the typical life on a torque converter, any idea ? The car's just
coming up to 47k miles...

 

[Andrew]

Andrew,

I think that you are hitting the fuel cutoff. I don't think that there is
anything wrong with the car, but sometimes the same thing happens if I floor
my C70 T5M.

That's interesting. Mine used to be fine until a few days ago, though,
what would cause the fuel cut off to happen so early ? It seems a bit
odd that it'd happen so low, since one then couldn't use the best bit of
the engine - the turbo :->