[sameerg001]

Hello guys, need your help on this one

I have a Hyundai Accent 1.5 petrol with 81k clicks on ODO. From last few days, a strange issue has cropped up, the car doesn't go above 3k rpm with AC on.

However, with AC of the car revvs freely to the redline mark, and even on standstill the car revvs freely till redline, irrespective of the fact that AC is on or not.

What could be the issue, showed it to a nearby mechanic, he said that there's something wrong with silencer and told me get it cleaned, however the problem still persists.

Today went to Hyundai A.S.S, they scanned the car and corrected some codes and told me that, it'll work fine now but on the back same problem was there, will take the car back to them in the evening.

What could the issue behind this, searched throughout the forum but was not able to find out anything relevant ??

Please help, Thanks in advance.

Cheers,
Sameer

[rohannr]

Hello Sameer... It could be something to do with the a/c wiring because of which the ecm is not allowing the engine to rev beyond 3k rpm...please have that checked.

[sameerg001]

Originally Posted by rohannr

Hello Sameer... It could be something to do with the a/c wiring because of which the ecm is not allowing the engine to rev beyond 3k rpm...please have that checked.

But on idle, it's revving freely till redline mark.

If there's something to do with AC wiring, it shouldn't rev on idle as well, ain't it like this or is it other way out ?

Cheers,
Sameer

[Catalyst_delhi]

Originally Posted by sameerg001

But on idle, it's revving freely till redline mark.

If there's something to do with AC wiring, it shouldn't rev on idle as well, ain't it like this or is it other way out ?

Cheers,
Sameer

I think it is a problem with your VSS wiring , please check that

[sameerg001]

Originally Posted by Catalyst_delhi

I think it is a problem with your VSS wiring , please check that

What is VSS wiring, never heard of it before. Can you please explain it a bit ?

Thanks!
Sameer

[rohannr]

@ sameer: in the sense that the compressor could be zapping excessive power when running due to some wiring issue, hence as a safety precaution the ecm is preventing the rpm from going too high when moving with load to prevent damage to sensitive components.

As slight relation could also be to the knock sensors triggering due to load & preventing the engine knocking at higher revs when moving.

But i'll still advice to get the car checked by a Hyundai a.s.s or a competent professional thoroughly.

Kind Regards,
Rohan.

[aaggoswami]

Originally Posted by sameerg001

What is VSS wiring, never heard of it before. Can you please explain it a bit ?

Thanks!
Sameer

Its Vehicle Speed Sensor. There is something wrong with either wiring or sensor/s. The fact that with AC the car revs freely means mechanically the engine is sound. Reset the ECU first and see what happens.

[esteem_lover]

Have you replaced your clutch before. I suspect it could be the clutch. But that should not stop the engine from revving. Get it checked by A.S.S and tell us their findings.

[sameerg001]

Originally Posted by rohannr

@ sameer: in the sense that the compressor could be zapping excessive power when running due to some wiring issue, hence as a safety precaution the ecm is preventing the rpm from going too high when moving with load to prevent damage to sensitive components.

As slight relation could also be to the knock sensors triggering due to load & preventing the engine knocking at higher revs when moving.

But i'll still advice to get the car checked by a Hyundai a.s.s or a competent professional thoroughly.

Kind Regards,
Rohan.

Thanks alot for the help, will be taking it to Hyundai A.S.S over the weekend.

Originally Posted by aaggoswami

Its Vehicle Speed Sensor. There is something wrong with either wiring or sensor/s. The fact that with AC the car revs freely means mechanically the engine is sound. Reset the ECU first and see what happens.

OK, will reset the ECU tomorrow and will let you know the result for same.

Originally Posted by esteem_lover

Have you replaced your clutch before. I suspect it could be the clutch. But that should not stop the engine from revving. Get it checked by A.S.S and tell us their findings.

No, the car is running on stock clutch, i changed the clutch cylinder 2 days back, but this problem persist from last 5-6 days.

I'll reset the ECU tomorrow, if it doesn't solves the problem, I'll be taking her A.S.S over the weekend.

Thanks alot guys, appreciate your help

Cheers,
Sameer

[knob]

ac bearings? i don't this it is anything related to the ecu but to the a\c mechanical. check it out

[esteem_lover]

Originally Posted by sameerg001

No, the car is running on stock clutch

Which is why I thought it could be the problem.

[Catalyst_delhi]

Originally Posted by sameerg001

No, the car is running on stock clutch, i changed the clutch cylinder 2 days back, but this problem persist from last 5-6 days.

Cheers,
Sameer

There might be a switch or sensor the mechanics could have forgotten to connect. It is the clutch sensor switch.

[sameerg001]

Originally Posted by Catalyst_delhi

There might be a switch or sensor the mechanics could have forgotten to connect. It is the clutch sensor switch.

That's connected, got it checked.

____________________________________________

Got the car inspected, they suggested me to get the car scanned, and on scanned the car and we got following errors :

1- Oxygen sensor

2- fuel pump

3- alternator

Among the above mentioned error codes, I got the alternator issue fixed. Oxygen sensor, I'll be replacing tomorrow.

In the mean time, the RPM sensor was not working properly, got that replaced too.

Now my question is, Can the Oxygen sensor be the culprit behind this issue ?


Cheers
Sameer

[rohannr]

Yes definitely. Any sensor if it gives out an error can send the car into a protective mode, so that vital components such as the engine internals, catalytic converter etc don't get damaged because of excessive revving.

What exactly did they say about the fuel pump? are you experiencing any jerking, power loss, missing as well?

Originally Posted by sameerg001

That's connected, got it checked.

____________________________________________

Got the car inspected, they suggested me to get the car scanned, and on scanned the car and we got following errors :

1- Oxygen sensor

2- fuel pump

3- alternator

Among the above mentioned error codes, I got the alternator issue fixed. Oxygen sensor, I'll be replacing tomorrow.

In the mean time, the RPM sensor was not working properly, got that replaced too.

Now my question is, Can the Oxygen sensor be the culprit behind this issue ?


Cheers
Sameer

[sameerg001]

Originally Posted by rohannr

Yes definitely. Any sensor if it gives out an error can send the car into a protective mode, so that vital components such as the engine internals, catalytic converter etc don't get damaged because of excessive revving.

What exactly did they say about the fuel pump? are you experiencing any jerking, power loss, missing as well?

They suggested me to, first get the oxygen sensor replaced, then we'll again scan, as the fuel pump error can also be due to faulty oxygen sensor.

Got the sensor today for 1600/- will be replacing tomorrow, Hope it sort out my problem.

And ya, No jerking or power loss as such, just it's that the car, didn't rev above 2.7k with AC on, On neutral and without AC, it works flawlessly.

Cheers,
Sameer