Can't rev when running

[madduck]

The engine can rev properly in idle.
Can't rev past 1800 RPM kapag paakyat ang road. Hindi tuloy makahatak.
Can't rev at all kapag naka ON ang aircon.
RPM drops kapag bumabagal.

Pleas help. Car is Sentra, GA16DNE.

[siopaonatoasted]

Fuel filter.

[madduck]

Changed my fuel filter last April.

[vinj]

Perhaps it could be MAF (Mass Air Flow) sensor issue. Try having your throttle body opened and cleaned along with the MAF sensor. A diagnostic engine scan should help.

[madduck]

I've cleaned the throttle body, last month, pero nilinis ko lang ng nakakabit pa. I'll clean MAF, thanks sir!

[oj88]

Sounds like it could be on limp mode. Is the CEL on? Have the engine computer checked for DTCs.

[jick.cejoco]

The engine can rev properly in idle.
Can't rev past 1800 RPM kapag paakyat ang road. Hindi tuloy makahatak.
Can't rev at all kapag naka ON ang aircon.
RPM drops kapag bumabagal.

Pleas help. Car is Sentra, GA16DNE.

what year is your car? how many miles? what was the last thing done to it? did the symptoms start after you refueled? is the exhaust system clogged? do you have throttle by wire? what is the engine vacuum measured at the intake manifold at idle speed?

[madduck]

it is when turning the key ON but it turns off after starting.
Where can I have the computer checked? Sa casa lang po ba available yan?

[lowslowbenz]

Sounds like it could be on limp mode. Is the CEL on? Have the engine computer checked for DTCs.

Yup, I'd agree on this one.

TS: Have your car scanned for trouble codes. Or try a hard reset, disconnect your negative cable from the battery for a few minutes, then reconnect. Then tell us what happened.

[jick.cejoco]

if the car is OBD II compliant, disconnecting the battery does nor erase the codes. it will be in the memory as history code. the only way to reset this kind of situation is to repair the cause of the problem and reset using the clear code function of the scan tool not a code reader alone

[madduck]

what year is your car? how many miles? what was the last thing done to it? did the symptoms start after you refueled? is the exhaust system clogged? do you have throttle by wire? what is the engine vacuum measured at the intake manifold at idle speed?

year 2000
last thing done, replaced distributor o-ring
no, not after refuel.
don't know if the exhaust is clogged.
not sure what is throttle body by wire.
I don't know the engine vacuum

[madduck]

Yup, I'd agree on this one.

TS: Have your car scanned for trouble codes. Or try a hard reset, disconnect your negative cable from the battery for a few minutes, then reconnect. Then tell us what happened.

I'll try the hard reset. if it doesn't solve it, i'll have it scanned. Thank you sir.

[jick.cejoco]

year 2000
last thing done, replaced distributor o-ring
no, not after refuel.
don't know if the exhaust is clogged.
not sure what is throttle body by wire.
I don't know the engine vacuum

have the ignition timing checked and maybe adjusted.



chances are the ignition timing is late and should display lower than 18 inches of mercury vacuum at the intake manifold at idle speed

[madduck]

have the ignition timing checked and maybe adjusted.



chances are the ignition timing is late and should display lower than 18 inches of mercury vacuum at the intake manifold at idle speed

how would i know if the ignition is adjusted correctly? Thank you.

[jick.cejoco]

how would i know if the ignition is adjusted correctly? Thank you.

you can have this done in different ways:

1-using a scan tool with the engine running and go to engine parameters

2-using a stroboscopic timing light aimed at the timing marks after all the prerequisites are satisfied

3-if the two above are unavailable, you can use an inexpensive engine vacuum gauge connected to a non ported vacuum source on the intake manifold

4-if the shop you have been going to is incompetent or has incompetent "mechanics", go to another shop with equipped, trained and experienced technicians

[mina_nuka]

how can you rev the engine when you're running?

[dr. d]

advancer mechanism is out..?

[jick.cejoco]

ga16e, ga16de, ga16dne all have electronic spark advance system. no centrifugal advancer, no vacuum advancer

[madduck]

Update

1. MAF Sensor cleaning - wasn't able to do this over the weekend, I can't find a MAF Sensor cleaner. I have a CRC Throttle Body cleaner, can I use it instead?
2. Battery disconnect - I have disconnected the battery over the weekend.
3. Ignition timing - the shop where I regularly goes to doesn't do this. I've read the stock position should be somewhere in the middle, I checked my distributor and it is in the most reversed (delayed) position. I turned the distributor forward to be approximately in middle position. I'll try to have my ignition timed properly next time.

The car ran smoothly. The problems mentioned earlier seems to be gone.
I'd still like to clean the MAF sensor and the IACV as well, if I can just figure out how to remove that IACV hehe.

Thank you for everyone's help.

[siopaonatoasted]

You can use Mr. Mckenic Fast Dry Contact cleaner.