Not Revving Past 4K

[Dave1971]

Has anybody got any ideas what is causing this, it has recently started to do this. I haven`t altered or changed any think, took it to the garage and there are no fault codes stored.

It is only doing it while am driving, help

[paul2508]

if it feels like its pulling i had similar problem, changed the plugs and it was sorted, could be a possibility

[Dave1971]

if it feels like its pulling i had similar problem, changed the plugs and it was sorted, could be a possibility

It pulls up until 4k, then bounces around the 4k mark or until it changes gear then the revs drop below 4k then again when it reaches 4k again.

[optical illusion]

Not doing this when cold no?

[Dave1971]

I haven't tried when cold will have a go tonight

[Dave1971]

Nope still the same when cold

[Bernard]

Was it a big garage you went to?
Not all places would have the equipment (not that you need any) to check for error codes...

If I were you I'd do a diagnostic myself to check, it only takes a couple of minutes.

[Dave1971]

Was it a big garage you went to?
Not all places would have the equipment (not that you need any) to check for error codes...

If I were you I'd do a diagnostic myself to check, it only takes a couple of minutes.

The garage who carried out the diagnostics, used a jap style reader which did read a code which was a throttle position sensor. After he cleared it i went for a run and come back, he then plugged the machine in and no further codes where on there. I have to go back tomorrow to see again if any codes are stored on there if there arn`t any i don`t know what am going to do maybe put it on the cryton tuning machine to see if that finds any think wrong.

You said you can diagnose it yourself ?, I have already rigged up a ecu read and the only thing that happen is the N flashes quite quickly..

[karlf]

Not sure if there is a fault code for it but when I had a similar problem it was because of a coil pack not being refitted properly after being off. As soon as it was fitted correctly it was back to normal. Didn't check it at the time for any fault codes so cant help ya there, but you could check them and atleast rule it out.

[Dave1971]

Not sure if there is a fault code for it but when I had a similar problem it was because of a coil pack not being refitted properly after being off. As soon as it was fitted correctly it was back to normal. Didn't check it at the time for any fault codes so cant help ya there, but you could check them and atleast rule it out.

I have had the coil packs off to check the plugs to see if they were okay, of which they were. I will however check them again just in case as i am at a total loss to find a cure to this.

Please keep your suggestions coming as its much appreciated.

[Mustang]

Is it a mivec?

[Dave1971]

No GR model

[Mustang]

I'm not sure if this applies to non mivec cars -I think Optical illusion is hinting at this suggestion as well. As I understand it the rev range is limited by the engine temperature. That is to say that the engine will not rev past a particular set point until the engine is up to running temperature. I am not sure which temperature sender is used (the thermostat for the coolant, the air intake temperature sensor (unlikely), or is there a sepraste sensor for the oil temperature?). If this temperature sender or the associated circuit is compromised then the incorrect signal will be received by the ECU, limiting the revs.
Perhaps someone more knowledgeable than me can fill in the gaps.

[Mustang]

I suggest you run a diagnostic. thissounds like a similar problem (not the exact same though)

[Dave1971]

I suggest you run a diagnostic. thissounds like a similar problem (not the exact same though)

Thanks once again for the update, do you know where about the crank sensor fits to so i can check to see if it is loose.

[ultrakupra]

Have you checked all the spark plugs?

[Dave1971]

Have you checked all the spark plugs?

Yes the front ones, but not the rears.

[Sebastian]

is the alternator charging propperly ?

[Dave1971]

is the alternator charging propperly ?

Yes changed it recently, charging okay.

[Dave1971]

Anybody else, this is doing my head in.

When things happen like this, i feel like getting rid of it.

[jayod12b]

Hi Dave

When you say you changed the alternator recently do you mean you purchased a new one or got your old one reconditioned?
What model fto do you have (mivec)?

Did the problem of not passing 4k occur after you changed the alternator?

[Dave1971]

Hi Dave

When you say you changed the alternator recently do you mean you purchased a new one or got your old one reconditioned?
What model fto do you have (mivec)?

Did the problem of not passing 4k occur after you changed the alternator?

Hi Fella,

My motor is a GR model,i don`t recal since changing the second hand one that i purchased caused the problem as far as i know.

[jayod12b]

Im not sure so

I know i had a similar problem with my gpx model a year or so ago

It wouldnt pass 5k just bounce at that point through each gear

Turned out it was the alternator that i had replaced with a secondhand reconditioned one which was stopping this,
Theres a special diode pack inside that allows the mivec to activate
Even though the alternator was charging 100% it needed this pack inside to allow the revs to pass 5k

But yours been a gr , the gr has a 2pin alternator tats right?

[Dave1971]

Im not sure so

I know i had a similar problem with my gpx model a year or so ago

It wouldnt pass 5k just bounce at that point through each gear

Turned out it was the alternator that i had replaced with a secondhand reconditioned one which was stopping this,
Theres a special diode pack inside that allows the mivec to activate
Even though the alternator was charging 100% it needed this pack inside to allow the revs to pass 5k

But yours been a gr , the gr has a 2pin alternator tats right?

Yes 2 pins, to rule the alternator out. Can i just disconnect it ? to rule out the revving problem.

[jayod12b]

No

Mine charged perfectly just wouldnt pass that point because of the pack inside