[Mk2 NA] 1k..2k..3k..4k...5k......6k.........Where's the pow

[DotNetter]

Okay, I have an automatic G-Limited - let's just clear that up.

now, I've noticed that when in overdrive (4th) and I hit the kick down, the revs jump as expected and the autobox drops to 2nd but as the revs approach 6k, the engine just seems to rev and rev for ages before finally reaching the 7k mark.

It's like the car reaches 6k revs and then it just runs out of power and struggles to reach the change point?

Anyone any idea what could be causing this?

I've not noticed it in 1st - such as when pulling away from a stand still (although to be totally honest I've not paid much attention)

Can anyone suggest any tests to confirm their suggestions aswel please.

I've check the fault codes and there are none for either ECU or the autobox (for those not in the know, the autobox also gives off error codes in the same blinking-icon image on the dash as the ECU).

Cheers


Wayne

[DotNetter]

Just an update (and some potential causes which I'd like opinions on).

I've now driven the car for the last few days taking every oporunity to red line it so that I can get an idea of when it's losing it's power.

As i said before, it's fine in first gear:

1k...2k...3k...4k...5k..6k.7k

The real problem (and typically where u need it most) is in 2nd gear

1k..2k...3k...4k...5k...6k.......7k

It's basically fine until it hits 6k and then it's just revving and revving and revving until it finnaly get's to 7k

Now, I have a K&N filter and a mnogoose zorst with de-cat so I'd expect the power to be exactly here and if lost anywhere it would be be in the first gear?

Also, I'm getting an intermittent "belt slipping sound" at low revs...could it be that I'm losing power due to excessive belt slip?!?!

Any ideas guys?

No problems with the car other than this.

Cheers


Wayne

[jonb-]

If a belt slipping is causing you to loose power i'd be seriously worried

How's your TVIS (or eq) kicking in around 5? You get the usual thump of power and the change in exhaust note?

[blue2]

Whats the mileage of your car as I really wouldnt be redlining it all the time if I were you, take it to 5500 -6k tops. You could seriously screw your engine and gearbox doing this. I have a manual NA and have never needed to take mine above 5500k, the same should apply for the auto. You should feel the most pull at this rpm as this is were the most power is on an NA, anything after this is poor and can do damage. Plus the cost of fixing a screwed autobox is very high. Hope this helps!

[DotNetter]

Whats the mileage of your car as I really wouldnt be redlining it all the time if I were you, take it to 5500 -6k tops. You could seriously screw your engine and gearbox doing this. I have a manual NA and have never needed to take mine above 5500k, the same should apply for the auto. You should feel the most pull at this rpm as this is were the most power is on an NA, anything after this is poor and can do damage. Plus the cost of fixing a screwed autobox is very high. Hope this helps!

okay, just to clarify things a bit here. When I say I'm "red lining" it what I mean is I'm put the auto box into sports mode (little button next to selector) and then florring it. This allows the car to rev right up to about 6900rmp before shifting. In normal mode the change occurs earlier (around 5500rpm from memory?).

I'm assuming Toyota wouldn't build this function into the autobox if it was going to kill the car!?

If Sports mode is "officially" only supposed to be used occassionally then can someone let me know (although sounds odd if that's the case?)

Not sure that the rev1 NA has a TVIS...not sure what it is (although I think I heard someone saying you get that on the 3SFE engines and rev3 3SGE engines???

Cheers


Wayne

[Hurstie1981]

I used to have a rev 2 auto but to be honest i only used sports mode occasionally or when i felt the need to overtake something.
Mine did change up at 6900 but im sure max power is below 6k so youre not going to gain anything after that....and i didnt want to kill my car. As you say, you have a rev 1 which now must be approaching 15 years old, take it easy on the old fella, if its your main car!

[waelwulfas]

Daft question but have you checked the gearbox oil level.Unlike a manual box this is critical, low oil causes loss of pressure in the valving and gearchanges go u/s particularly on ECU controlled boxes.
another thought is that the brake band inside the box needs adjusting, the guys that play with my auto boxes reckon Toyotas are bomb proof so don't panic!

[ldavies83]

Dont worry about the "redlining issue", your right, MrT would not give you the option of sports mode, should it damage the car irreperably (spelling!), its obviously more easier to do damage in a manual because your in charge . I'd go oil route myself aswell in this case.

Check it out, see whether that is the problem.

[blue2]

Im pretty sure that most auto boxes arent designed to be constantly overeved (unless its an aston/ferrari). Not sure how the toyota auto box was designed but most have torque converters that act as the clutch system and these are suprisingly easy to damage (I have broken 2) if your hoofing the revs up frequently.

[DotNetter]

I've previously checked the fluid level and when hot it seems fine (I followed the Toyota specified checking routine of shifting through each of the gears etc).

The oil didn't smell at all burnt either.

I may consider changing the fluid in the not-too-distant future as it's a relatively easy job and I can do it while I'm chaning my oil (if the damn ebay ordered TRD filter ever turns up! )

Anyhow...I digress

Not sure about getting the autobox checked/tweeked - I don't want to take it to the half-wits at Mr T and most garages won't touch an autobox with a barge poll due to the "technical" nature of them

I'll try swapping the fluid first and see if that helps any.

As for constantly red-lining it...I don't believe it would do any harm. The MR2 is a sports car...the auto version has a Sports mode...the car never actually goes into the red, it just holds the revs a few hundred longer to optimise on the loss of power when changing between gears at lower revs.

Cheers


Wayne

[DotNetter]

Anyone know what's best fluid for an autobox?

What's that Redline stuff (ironically named...or just my mind playing tricks again!)

Cheers


Wayne

[waelwulfas]

If I recall it's Dexron II, someone'll be along soon with a manual. I think Redline is only appropriate for manuals. As for garages, you need an auto transmission specialist, try yellow pages or see where the indys sub-contract their work; very few garages work on boxes direct. (My VW VR6 local dealer subcontracts even under warranty).

[twistywizard]

I believe Redline do an Auto box replacement as well though

Couldnt tell you what though. See if they have a website

[jonb-]

Dexron 3 is Dexron 2 compatible and you can get it dirt cheap at pretty much any halfrauds.

[BenF]

Whats the mileage of your car as I really wouldnt be redlining it all the time if I were you, take it to 5500 -6k tops. You could seriously screw your engine and gearbox doing this. I have a manual NA and have never needed to take mine above 5500k, the same should apply for the auto. You should feel the most pull at this rpm as this is were the most power is on an NA, anything after this is poor and can do damage. Plus the cost of fixing a screwed autobox is very high. Hope this helps!

Blue, the 3S and 4A series engines LOVE revs. There's no problem holding the car at 6-7krpms providing you top up with oil as needed.

I've got a trackday MK1 NA and I've been thrashing the nuts off it around circuits for the last year and a half. Its done 118k miles, and other than needing a little sip of oil (not surprising as she's 21 now!) its a good as gold.

If you Decat a Turbo (and probably a NA) you'll find the engine really will run well all the way to the rev limiter ..

[BenF]

Before you go off down the route of the Autobox ... have you checked your HT stuff?

If its original (year of manufacture should be on MrT HT leads) then replace it, the dizzy cap, rotor arm and put new plugs in.

On a back to back rolling road test on my turbo I gained 20bhp by doing this, much more than I thought. Cars with forced induction see more of a gain, but you probably would see a redline approach more rapidly in 2nd after that.

Another tangent - does yours have a cat? If it does, I'd be tempted to pull it out and check it hasn't melted or clogged at all.. .?

Ben

[DotNetter]

Before you go off down the route of the Autobox ... have you checked your HT stuff?

If its original (year of manufacture should be on MrT HT leads) then replace it, the dizzy cap, rotor arm and put new plugs in.

On a back to back rolling road test on my turbo I gained 20bhp by doing this, much more than I thought. Cars with forced induction see more of a gain, but you probably would see a redline approach more rapidly in 2nd after that.

Another tangent - does yours have a cat? If it does, I'd be tempted to pull it out and check it hasn't melted or clogged at all.. .?

Ben

Hi Ben (and others).

Before I start replacing all my ignition system, I want to make sure this is going to have an impact. Surely if the revs are find in 1st gear this suggests theres no problem with the ignition - if there were I would have assumed that 1st gear would have the same problem? - or are you saying that the ignition system is under greater load in 2nd?

The car has already been de-catted mate so this is a no-no.

Cheers


Wayne

[DotNetter]

Hi all

Just an update. I've been using cheapo fuel of late (trying to reduce me running costs) and a guy I work with from the GT4OC suggested I go back to using Optimax.

I'm half way through the new tank after an ECU reset and it's deffinately improved so hopefully this was the reason.

Got to admit that I never realised cheaper petrol would cause such a noticable performance decrease.

I'm trying to sell the car but I'll update if things get worse...if not then we can be sure it was the petrol!

Cheers


Wayne

[US_SMG_MK1]

I have a slush box '86 NA with "sport mode" It's been driven hard for years in Seattle, WA traffic and it's still going strong. I never take it out of sport mode.

I've owned many 4A's and I have first hand knowledge with 3 and 5S's. the 4A's will sit at 6900 RPM for three hours and never think about it (I did this to prove a point with a AE92 4AGE red top)

The 5S just flat runs out of power after 5500 RPM. It falls on it's face, thats why it takes for ever to shift it

[BenF]

Hi Ben (and others).

Before I start replacing all my ignition system, I want to make sure this is going to have an impact. Surely if the revs are find in 1st gear this suggests theres no problem with the ignition - if there were I would have assumed that 1st gear would have the same problem? - or are you saying that the ignition system is under greater load in 2nd?

The car has already been de-catted mate so this is a no-no.

Not really - 1st gear doesn't put that much load on the engine and won't tell you much about the state of the HT stuff.

The taller gears move you more slowly through the rev range and on wide open throttle will reveal flatspots.

A cheap'n'cheerfull alternative would be to swap parts from someone else's car here to yours and see if it makes a difference- If that improves things, that would be the way to go. It may be worth getting a passenger ride in a Manual G-Limited or Uk NA to get a reference point to compare yours to.

However, I'm certain that if the leads are original for your car you'd benefit from replacing them. If they're original MrT leads, they should have their year of manufacture printed on them. Anything older than 5-8 years I'd replace.