NL lack of power

[Ian Sharpe]

Guys,

Paj started up one day with rough idle & really low power in the low rev ranges, seems OK when you give it the boot, though.

OK I thought it might be injectors or fuel filter as I dont get to use the Paj much these days maybe every couple of weekends or so. It has been sitting a bit .


Took it to the local Mitsu dealer , who do the following under my instructions:

replace fuel filter
replaced plugs & leads
carried out off car injector service
checked compression , Ok all cyclinder 160-165 psi (seems pretty high to me)

Checked air flow meter, OK
Checked code (no codes present)

Both problems are still apparant.


They say it could be a slipping timing belt at crank shaft gear.

The vehicle is coming up to 200k, so would be just about due for a new belt.

They say they can have a good look when they pull it down.

Should I be worried here?? or just hope that a new belt will do the trick.

[NJV6]

HI Ian

Without reading all of your post I would have said air flow meter but you had that checked.

I had recently been doing all those checks chasing my problem, as you know, my outcome was not as good as yours.

160 - 165 is down a little - my 'good' ones were 185 but if they are all even that that is great for 200k.

I don't see how the timing belt can cause that issue, unless it has jumped teeth but if it did that it wouldn't be running so well! When you say rough at low RPM, is it a regular or irregular roughness? Maybe the cambelt did skip a toth and put the timing out - remember cars with really tweaked timing don't run at low RPM so well.......

If it is like the DOHC, it is eay enough to check the timing - I take one cam belt cover off the top off th left hand bank and line the bottom pully up with TDC mark on the timing cover (easiest with the radiator out but should still be possible.....Famous last words... ) and the marks on the cam pullys.

[-Scott-]

160 - 165 is down a little - my 'good' ones were 185 but if they are all even that that is great for 200k.

I'm hoping those numbers are with the throttle closed. Throttle open, I would prefer to see 180 plus.

I'd be leaning towards air flow meter too - how easy is the Paj meter to check? Anywhere you can go for a (reliable) second opinion? Anybody you can do a temporary swap with?

Good luck,

Scott

[Ian Sharpe]

thanks guys,

They reckoned that they did check the airflow meter, dont know how though. I could always source one from a wrecker, but you never know what your getting. last time a newie was around $800. I'd pay that if I knew it was the problem. But you could spend a fortune on this trial & error crap.

[-Scott-]

thanks guys,

They reckoned that they did check the airflow meter, dont know how though. I could always source one from a wrecker, but you never know what your getting. last time a newie was around $800. I'd pay that if I knew it was the problem. But you could spend a fortune on this trial & error crap.

You don't know anybody nearby with the same model? In the 3.0, the airflow meter is pretty simple to swap over - open air filter housing, undo hose clamp from throttle body, unclip the electrical plug. Shouldn't take more than 10 minutes to swap between vehicles and see if the problem follows the AFM.

[eddy 76]

dont want to alarm you ian but that is what my nk 3.5 was doing and the problem was a couple of butterflies in the plenum chamber had worked loose and were getting jammed . I had it looked at but was told all was ok but in the end it cost me a new motor when they sucked through and into head. Apparently it is a common failure so just check for it.

cheers eddy

[NJV6]

Could be worth taking the plenum off for a look - they are not to bad to take off.

I can't see how it would affect power and make it rough very much though becasuse all they do is lengthen & shorten the intake depending on vacuum/acceleration. (unless the damage was already done but I doubt it)

I'd be trying what Scott said and see if you can borrow an air flow...

[Dexter]

My NL is doing the same thing, I dont have any roughness but I get some hesitation in the lower rev ranges(stuttering), but pulls fine up higher. Mine has 260,xxx kms so I just ignore it at the moment. My thought is it could be the Exhaust sensor being dead so its getting too much fuel down low.

[Ian Sharpe]

Unfortunately I dont know anyone with the same model, so I cant swap air flow meters.

& yes I have head about the butterflies working loose, however I thought that was confined to the DOHC motors.

[scooby_74]

I've seen the front crank pully come loose and flog the gear and or the plate that the crank sensor reads on.
Just been through a problem vehicle that the injectors were serviced out of the vehicle aswell but were still the problem had them recleaned an another place and fixed the problem.
My 3 ltr was laging down low and yes that was timing belt but that had done over 150k on the one belt and is now just over 320k

[NLShorty]

Hi Ian, not sure if you have found the problem or not but my paj did a similar thing before i stuck a diesel in it, If it run's fine at full throttle and above 3,500 rpm and hesitates below this than i would suspect its the o2 sensor. Its at about this point/throttle setting where the computer switches to a closed loop map and cuts the o2 sensor out of the picture.

I also happen to have an airflow meter for your model you can try if you still need it?

[Ian Sharpe]

HI mate,

I replaced the 02 sensor last year, I bought a new one by NGK.

If you have an air sensor I would love to borrow it, so I can at least eliminate that possibility.

I went to the South Coast over the hols, coming up the Clyde was a major disaster, absolutley no power until about 2500 revs.

This has turned the Paj from being a delight to drive to a dog.

Where are you these days, I thought you were in Wagga for a while.?

Is it possible for you to post the air sensor to me , I will cover postage costs of course.

You could send it to my folks place in Canberra:

26 Dethridge Street
Higgins ACT 2615

and for the 4.90 diffs.

I did this swap when I had a 3.5l DOHC NK. I really didnt think it a worthwhile swap.

I sourced my diffs from All Spares in Revesby, Sydney Ph; 02 97724429. they have heaps of pajero stuff.

cheers mate & hope to hear fom you.

[NJV6]

Ian,

I was talking with someone recently about my motor and testing the air flow meter came up in the conversation. He said the wire ones such as we have are very difficult to test as they give a wide variety if random numbers.

Worth another check?

[Ian Sharpe]

Ian,

I was talking with someone recently about my motor and testing the air flow meter came up in the conversation. He said the wire ones such as we have are very difficult to test as they give a wide variety if random numbers.

Worth another check?

yeah thanks, hopefully NL Shorty can lend me one to try

[Ian Sharpe]

well guys, finally found out the culprit, the Paj dropped the harmonic balancer today in down town Braidwood!!. Luckily it was turned off straight away & rolled down the street to the local mechanic.

I am just hoping that there is no damage done to the crank, as the mechanic said "throw away the motor " if it has.

Will know in the next couple of days when he pulls it down.

Wonder how much $$$ a second hand or new motor costs??

[NJV6]

Ah bugger!

So what is the harmonic balancer? I have heard about it but never come across it..

$ for a 6G74 - well $ basically as this is what I ahve been through recently. I ended up going the rebuild road as a replcememnt would have been almost the same cost and i wouldn't know the history.

I found one motor over here that was $4300 + GST + Freight. GST = 12.5%

[Ian Sharpe]

yeah, real bugger.

The balancer is keyed to the crank (sometimes its called the crank pu;lley) & held on by a big washer & bolt, anyway it is meant to relieve stress on the crank & it also runs ancillary stuff like water pumps, ac & power steering.

If it has come off , then it has probably caused some damage to the crank, I am just hoping I stopped the car earlier enough to avoid major damage, I'll know by the end of the week.

I can see big $$$ signs here unfortunatley.

cheers

[Ian Sharpe]

Well I cant believe my luck here.!!

My mechanic called & said the crank is Ok, I just need another pulley & bolt. I am getting him to do the timing belt as well . If it had of happened when I was on the hway at 100kph , it would have been goodbye motor.

I think I will buy a lottery ticket today.

[Dexter]

Do you reckon that was what was causing your hesitation? I have had hesitation for about a year now, but I dont drive it day to day so have not had a good look into it, mine has 260,000kms on it. I think the first thing I should check is the Oxy sensor as she is averaging about 17L/100KM with no 4WDing. I seem to remember slightly better consumption than that back in the early days.

[psycronic]

had the same thing happen to mine, but mine took out the keyway in the crank


supposedly a common thing with mitsu's. Was telling a mate about it and he said the same thing happened to his mirage

[Ian Sharpe]

Do you reckon that was what was causing your hesitation? I have had hesitation for about a year now, but I dont drive it day to day so have not had a good look into it, mine has 260,000kms on it. I think the first thing I should check is the Oxy sensor as she is averaging about 17L/100KM with no 4WDing. I seem to remember slightly better consumption than that back in the early days.

Dexter, yes this guy says that the lack of low down power was probably caused by the failing or moving pulley. In fact the guys in Canberra did identify that this could be the cause(after I paid for such things as new plugs & leads & an on & off car injector service) & that I should bring it back so they can tear it down & look at the pulley, gear & key.

Thing is they should have warned me that I use it at my own risk & that if the pulley goes & flogs out the crank, then I am basically stuffed.

This local guys says he would have never let me take it under those conditions. So mate, if your has low down hesitation & especially no low down power, please get it checked out & hopefully save you some big bucks when you least want it. Not to mention the inconvenience of it all, Man I am so lucky mine happened at low speed & right in town, I stopped it straight away & rolled it to the mechanic. Just to think a week earlier I was flogging it up the Clyde mountain, that would have been mighty inconveninet if it let go then!!!!!!!!!!!!

In short , get iot checked out , real quick.

[Dexter]

Do you reckon that was what was causing your hesitation? I have had hesitation for about a year now, but I dont drive it day to day so have not had a good look into it, mine has 260,000kms on it. I think the first thing I should check is the Oxy sensor as she is averaging about 17L/100KM with no 4WDing. I seem to remember slightly better consumption than that back in the early days.

Dexter, yes this guy says that the lack of low down power was probably caused by the failing or moving pulley. In fact the guys in Canberra did identify that this could be the cause(after I paid for such things as new plugs & leads & an on & off car injector service) & that I should bring it back so they can tear it down & look at the pulley, gear & key.

Thing is they should have warned me that I use it at my own risk & that if the pulley goes & flogs out the crank, then I am basically stuffed.

This local guys says he would have never let me take it under those conditions. So mate, if your has low down hesitation & especially no low down power, please get it checked out & hopefully save you some big bucks when you least want it. Not to mention the inconvenience of it all, Man I am so lucky mine happened at low speed & right in town, I stopped it straight away & rolled it to the mechanic. Just to think a week earlier I was flogging it up the Clyde mountain, that would have been mighty inconveninet if it let go then!!!!!!!!!!!!

In short , get iot checked out , real quick.

Sweet I think I will book it in next week, its my second car so I can put off driving it till then.

[NJV6]

What great news!

Have a beer tonight!

[Ian Sharpe]

What great news!

Have a beer tonight!

Definately

[NLShorty]

Sorry for the late reply Ian, have been away, just sent you a pm and now reading your post.. great to hear you got it sorted!

[Ian Sharpe]

Sorry for the late reply Ian, have been away, just sent you a pm and now reading your post.. great to hear you got it sorted!

thanks Ben,

do you hear from the guy who bought your supercharger, did he get it installed OK??

cheers

[Dexter]

Did this fix all your issues Ian?

[Ian Sharpe]

Did this fix all your issues Ian?

Yep, certainly did, Paj is great now, back to its usual fanstastic self!!!

[t_e_z_a]

just curious why did it only affect the car at low revs?

was it rattling around on the key at idle but under load or revs the key pushed evenly on the pulley/balanced giving an even reading on the crank sensor? wouldnt it evenly push under load going up a range? Where abouts is the crank position sensor? on the pulley?

I just cant get my head around why a loose/spinning/missing harmonic balancer would really affect performance (other than the leaking oil, no fan, power steering, a/c, alternator, etc) oh and the crank shattering due to bad harmonics

[Ian Sharpe]

dont know mate, all I can recall is that it was a dog under about about 3k revs, after that it seemed oK.