Avensis won't rev over 3,500 rpm when hot.

Avns1s

Hi all.

I have a 1999 Avensis 1.6 petrol 4AFE engine. 140,000 miles on the clock.

In the past few weeks, when running at normal operating temperature, the engine won't rev past about 3,500 rpm. I say "about" as sometimes it could max out at 3,000 rpm, sometimes at 4,000 rpm.

The engine runs normally up to the time it reaches normal operating temp. No problem red-lining it and no misfiring.

When hot, engine speed will increase without any problem up to the 3,500 rpm or so, but then stutters just like the rev limiter is reached. On occasion, the Engine Management Light will come on momentarily but no fault code is stored, so that's no help. There is no apparent loss of power or acceleration up to the 3,500 rpm. Acceleration is as smooth as would be expected.

The Spark plug leads and the O2 sensor were replaced about 30,000 miles ago. Car is in great shape besides and runs perfectly other than this fault.

Any ideas? Any help would be very much appreciated and Thanks in advance.

PADRAIC.M

Have come across two problems like this, first one was cat was blocked, first remove exhaust under manifold and see if it will rev then if it doesn't still, crankshaft sensor..

Ded_Zebra

come across a similar problem on an alfa... It was the air flow meter. Try disconnecting the air flow meter. It might run worse at idle (hunting) but should rev

Avns1s

Ded_Zebra wrote: »

come across a similar problem on an alfa... It was the air flow meter. Try disconnecting the air flow meter. It might run worse at idle (hunting) but should rev

Thanks for the reply. There is no air flow meter on the 1.6 lean burn engine AFAIK. If I am wrong, please feel free to correct me.

All indications are leaning toward the crank sensor. I would of course like to be sure before replacing it, as it's a relatively expensive piece.

Ded_Zebra

okey dokey. I don't know anything about Avensis'. It was just similar behavior to the alfa.

moodrater

Lambda sensor, get the genuine one.

Avns1s

moodrater wrote: »

Lambda sensor, get the genuine one.

Thanks for your reply but the Lambda sensor was replaced about 30,000 miles ago with a genuine one. I would hope it's not gone again given that they're over €300 a pop. I didn't get chance to get near it since but I am inclined to think its the crank sensor. I still have the old Lambda sensor, which didnt have the same symptoms when it went, and threw up a Engine Check Light and Code. I might stick it back in to rule it out. Thanks again for taking the time to comment.

Avns1s

An update for the benefit of anyone who might have the same problem. I picked up a new Crank Position Sensor today and just fitted it this evening. All sorted. Car is running perfectly again.

Thanks again guys for your replies and suggestions. Whether they turned out to be right or wrong, they are appreciated.

PADRAIC.M

Glad you got sorted!

Gaz2010

Did you check either of the sensors for resistance by any chance? Getting the same problem and threw in a new sensor but its still the same, ohm value was the same on both sensors. Think i could of gotten a bogey one out of the breakers :rolleyes:

Avns1s

Gaz2010 wrote: »

Did you check either of the sensors for resistance by any chance? Getting the same problem and threw in a new sensor but its still the same, ohm value was the same on both sensors. Think i could of gotten a bogey one out of the breakers :rolleyes:

I'd say you answered your own question.

I wouldn't bother using any sensor like this from a breakers yard, unless I was selling the car immediately, and even then......!

Are the symptoms exactly as per the opening post?

codod

My 2000 avensis is behaving exactly the same. Its fine when i start off in the morning, but when i get to the motor way it wont rev beyond 4000 RPM. Fortunately its not severe at i normally stay at the 120KPH. I worry though if i ever have to overtake and then this "limiter" kicks in then i'm in trouble! Will look into getting a replacement Crank Position Sensor. Avns1s How much did it cost you?

Mar4ix

also question , on top of all that about mine one, it is not driving smooth on high speeds, it jerking kind, like it have not enough power for second, than goes for full blast, and when idling, i think it is too low. 650 ish rpm.

Avns1s

codod wrote: »

My 2000 avensis is behaving exactly the same. Its fine when i start off in the morning, but when i get to the motor way it wont rev beyond 4000 RPM. Fortunately its not severe at i normally stay at the 120KPH. I worry though if i ever have to overtake and then this "limiter" kicks in then i'm in trouble! Will look into getting a replacement Crank Position Sensor. Avns1s How much did it cost you?

From memory, it was about €120-130. I will have a look for the invoice and repost if I can find it.

Avns1s

Mar4ix wrote: »

also question , on top of all that about mine one, it is not driving smooth on high speeds, it jerking kind, like it have not enough power for second, than goes for full blast, and when idling, i think it is too low. 650 ish rpm.

I would start by checking your plugs. If that doesn't sort it, check plug leads, and see where you go from there.

codod

Solved

Hi all just coming back on the diagnosis. The issue is with the inlet manifold flaps. The clip is broken therefore its not letting in enough oxygen for fuel burn at high revs. It is effectively "choking" the engine. New parts from dealer about EUR 500. Scrap part about EUR 50. Thanks for your input.