Please help! Car can't run over 4000rpm.

[Bom]

I clean my engine 2 weeks ago (valve cover of left bank) and water got into 1 sparkplug. I didn't remove the plug and dry it because I thought when I run a car, engine will hot and will get rid of that water naturally. But it was mistake. Water was dried but the car ran terribly. It seems that ECU limit the rev at 4000 rpm. When kick down, engine was cut off and car seem to be stop by engine brake. So last Sunday I removed all plugs and check the condition of them. They look nearly dead to my eyes but I have no time to get new set of sparkplugs so I just clean it and reinstalled. Problem still exist so I remove ECU plug for about 3 hours and test my car again. Car ran better but for another 2 days this problem came back again. I am wondering whether the ECU have the safe mode to protect engine or have have function to memory fault code so engine can't be rev? How can I reset the ECU? Or should it be other reasons rather than the ECU? I will get new plugs this Saturday.

thank you in advance for all helps,

 

[samsdad]

Diagnostic plug on the engine by the left had cylinder bank, Connect TE1 to E1 and turn the key on, Check engine lamp on the dash will flash. report the number of flashes

 

[louie661]

mine does the same thing. you floor it and it wont pass 4k rpm. is that normal? please help.

 

[sideshow]

yes ive seen it many times
water in the spark plug holes does not evaperate quickly with heat of motor
does it rev ok to 4k
maybe u dropped 4 cylinders by having faulty coil or coil lead

 

[MUDGUTS]

Hi,

I have a similar problem with my LS 400. The whole saga is at http://www.lexusownersclub.co.uk/forum/index.php?showtopic=73960&st=0

It's well worth a read and I am very open to suggestions. It looks to be an issue with the MAF sensor or readings from it.

 

[sideshow]

fk mudguts must be costing u a fortune sending it to all those different shops
anyway did u know some 1uzs have a 4000 rpm rev limit when in park and neutral
but ok in drive
so does your car have a 4000 rev limit when driving it
i had a similar problem on an sc400 right after the customer changed the motor
so im not sure what might have gone wrong
i changed maf and ecu and checked over afew other things but an hour later still coul dnot fix it and since customer was not going to spend money i said take yr heap of shit
and shive it up yr asss heheheheeheh
problems like this can take months to solve
but u havnt tried an ecu so far
can u borrow one of another car
unplug the maf and see if it does the same thing
the problem is its very very hard to tell if a maf is faulty just by reading the data on the scanner
i garantee 99% of mechanics will not know what the specs should be when driving in different loads so most of use have to sometimes guess what the problem is
when people say go thru it logically tell them u come and fix my fking car and see what they say
sometimes u go thru all the basics and get nowhere
goto a local car yard and ask to road test a similar car to yours
quickly drive it round corner to where your car is and swap over afew parts and test
u really need to just test the engine ecu and the maf
hopefully yr car doesnt have security

 

[MUDGUTS]

fk mudguts must be costing u a fortune sending it to all those different shops
anyway did u know some 1uzs have a 4000 rpm rev limit when in park and neutral
but ok in drive
so does your car have a 4000 rev limit when driving it
i had a similar problem on an sc400 right after the customer changed the motor
so im not sure what might have gone wrong
i changed maf and ecu and checked over afew other things but an hour later still coul dnot fix it and since customer was not going to spend money i said take yr heap of shit
and shive it up yr asss heheheheeheh
problems like this can take months to solve
but u havnt tried an ecu so far
can u borrow one of another car
unplug the maf and see if it does the same thing
the problem is its very very hard to tell if a maf is faulty just by reading the data on the scanner
i garantee 99% of mechanics will not know what the specs should be when driving in different loads so most of use have to sometimes guess what the problem is
when people say go thru it logically tell them u come and fix my fking car and see what they say
sometimes u go thru all the basics and get nowhere
goto a local car yard and ask to road test a similar car to yours
quickly drive it round corner to where your car is and swap over afew parts and test
u really need to just test the engine ecu and the maf
hopefully yr car doesnt have security

Hi sideshow, thanks for the advice.

The following things have been done:

Exhaust & Catalytic Converters checked
Valve timing checked
EGR valve cleaned & checked
Throttle Body & Plenum Chamber cleaned
Distributor Caps, Rotor Arms & HT Leads replaced (Old Spark plugs were not suspect so replaced after new ones tried)
Engine sensor connections checked

If you build up the revs gently it seems to get to the redline now and blipping the throttle achieves the same but (and here is the symptom that hopefully will enlighten someone): If you floor the throttle the revs immediately drop to 4000 RPM for as long as you hold your foot to the floor. If you then release it the revs will rise right up again.

Also if you play about with the throttle the engine sort of surges...

I have located a local racing ECU remap specialists for the 1UZ-FE so when I get a chance it will be going to them.

In answer to your question its the same in N or P or D.

I'll try disconnecting the MAF tomorrow.

Will keep you posted.

 

[MUDGUTS]

Re the MAF Sensor I unpugged it: Check engine light is on, engine runs rough and won't rev up much

 

[sideshow]

that shows the Maf is atleast doing something
someone had issues with wrong ignitors causing 4000 rev limit
I also know smetimes in park and neutral they have a factory
rev limit at 4000
so maybe issue with something there

 

[gloverman]

What road speed are you doing when it hits the RPM limit? Does it have a hydraulic fan or viscious fan? Does it have a factory immobiliser? Cheers

 

[XR8tt]

Could it be fuel supply as in restrictive fuel filter ??

 

[MUDGUTS]

What road speed are you doing when it hits the RPM limit? Does it have a hydraulic fan or viscious fan? Does it have a factory immobiliser? Cheers

Regarding the speed, it doesn't matter. It has a factory immobiliser and I'll check about the hydrualic or viscous fan (How can I tell BTW)

Thanks guys.

 

[MUDGUTS]

Could it be fuel supply as in restrictive fuel filter ??

I'm not sure, the fuel filter at the rear has been changed but it goes really well on the motorway and I'm pretty sure that at that speed even at 3000 RPM it would be sucking more fuel through than 4000 RPM at idle.

 

[Bushwhacker]

Throttle Position Sensor OK?

 

[gloverman]

So it does fault when driving down the road? and not just when stationary?

 

[MUDGUTS]

Throttle Position Sensor OK?

The first Garage did check this but I think it may have to be re-visited...

So it does fault when driving down the road? and not just when stationary?

Yes, it will kick down into a lower gear then just sit there at 4000, it you take your foot off the throttle, it will change up...

 

[MUDGUTS]

What road speed are you doing when it hits the RPM limit? Does it have a hydraulic fan or viscious fan? Does it have a factory immobiliser? Cheers

I'm pretty sure it has a vicous fan (have done a bit of checking).

 

[XR8tt]

Maybe broken catalytic converter blocking exhaust ???
Overheated when plugs failed with water on leads etc ??
If it isn't an ECU safety setting ?...
Head gaskets or any coolant passagers on intake etc not leaking coolant into engine ??
Try closing plug gaps ?? This will indicate a bad / weak coil if it cures the issue..

 

[sideshow]

if the engine is stopping at exactly at 4000 revs its most prob in limp mode
same as what i went thru
but i checked every diaganostics on the sc400 i looked at and could nto find anything
i even had live data and drove it for few minutes but could not find anything

sometimes if the auto wires or signals are faulty i have had similar symptoms
but problems like these always takes ages and half the time never get solved
or if they do its usually a fluke

one way to test if its sensors liek tps or coolant temp etc etc
is to unplug them then go for a drive
the car should perform abit differently so can mean the sensor is working

 

[MUDGUTS]

if the engine is stopping at exactly at 4000 revs its most prob in limp mode
same as what i went thru
but i checked every diaganostics on the sc400 i looked at and could nto find anything
i even had live data and drove it for few minutes but could not find anything

sometimes if the auto wires or signals are faulty i have had similar symptoms
but problems like these always takes ages and half the time never get solved
or if they do its usually a fluke

one way to test if its sensors liek tps or coolant temp etc etc
is to unplug them then go for a drive
the car should perform abit differently so can mean the sensor is working

...Well its with a 1UZ-FE specialist now, so far they have dsicovered a host of fault codes, most seem to have been related to stuff previous techs have been touching, these have all been cleared but one required the fitting of another O2 sensor. This hasn't made any difference. Should know more tomorrow.