Car holding revs back

ninty9er

I was on a few weeks back asking if dirty fuel might have been the problem but it's still there periodically

Basically, from cold it sometimes holds revs at 3500 rpm (redline is 6500) even in neutral when foot is to the floor. (1.0 12v Opel ECOtec 90k miles serviced at 87k)

I'm not in the business of making money (I'm a student) and I've been at the doctor a few times the last few weeks so i'm not in the position to have a mechanic check it over.

It's lost power and I've had to pull in a few times.

What could it be and and how much is it going to cost for each of the possible problems

milltown

ninty9er wrote:

I was on a few weeks back asking if dirty fuel might have been the problem but it's still there periodically

Basically, from cold it sometimes holds revs at 3500 rpm (redline is 6500) even in neutral when foot is to the floor. (1.0 12v Opel ECOtec 90k miles serviced at 87k)

I'm not in the business of making money (I'm a student) and I've been at the doctor a few times the last few weeks so i'm not in the position to have a mechanic check it over.

It's lost power and I've had to pull in a few times.

What could it be and and how much is it going to cost for each of the possible problems

Possibly a problem with the vacuum advance for the ignition? As the rpms increase, the spark needs to arrive a bit earlier to ensure the fuel/air mix burns fully to make an efficient power stroke. In the olden days this was done by means of a vacuum tube from the inlet manifold to the distributor. As the revs rose and the vacuum in the manifold increased, the spark was sent to the plugs earlier. I'm not sure how it's managed now in these times of transistorised ignition and engine management but Opel were never really at the forefront of innovation so I would not be surprised to find such a vacuum tube on a Corsa. Look for kinks, breaks or blockages.

I am presuming from your post that the car runs fine most of the time and even up to 3.5k when it's acting up.

ninty9er

Cheers for that. I'll have a poke around under the bonnet later on in the week. I'm just anxious not to cause damage by driving it as is. My dad's using it for commuting this week so it'll get a good run that might sort it out if its a soft blockage somewhere

smash

some cars hold revs back when cold so you don't blow the engine... Celica T-Sport redlines at 9k but 6 when cold

JHMEG

steve06 wrote:

some cars hold revs back when cold so you don't blow the engine... Celica T-Sport redlines at 9k but 6 when cold

Can 2nd that. My Integra bounces off about 6.5k when cold, gradually increasing to about 8.4k when warm.

(PS That celica redlines at 8.2k)

smash

JHMEG wrote:

Can 2nd that. My Integra bounces off about 6.5k when cold, gradually increasing to about 8.4k when warm.

(PS That celica redlines at 8.2k)

well the redlines start at 8.2 and finish at 9

JHMEG

steve06 wrote:

well the redlines start at 8.2 and finish at 9

It could finish at 20, but the rev limiter cuts in at 8.2

Fey!

Is there an mass airflow sensor on the corsa? It sounds similar to a problem I had last year, and that was the problem.

Didn't you only buy the corsa recently? If you bought off a garage, it may be under warranty.

crosstownk

I'd second Fey!'s suggestion of a mass airflow sensor - or some other sensor - ie crankshaft sensor. TBH, I don't think the Corsa would have the cold rev limiter that a Celica has. The only real solution is a diagnostic check.

ninty9er

crosstownk wrote:

The only real solution is a diagnostic check.

Sounds expensive, I've heard of sensor trouble of different types on the Corsa alright. Bought it in Feb but it's been back to the garage already to sort emissions for NCT so I assume they would have had to "once-over" the engine when doing this. I'll get back on.

Would it have to be an Opel Garage for diagnostics???