My TJ model 1.5 (series 2 engine 4 spd auto :cry:) appears to pull hard in 1st gear in that great 3500 to 5500rpm magna 3.5 power range, one time it will push you into the seat and pull hard with a seamless feed of gentle power (it's not a dragster) and then next time it will rev out but seem to go nowhere but it's not a transmission problem it's just that it does not seem to pull hard. I don't drive it like that all the time, but my mate at work went for a ride in it today (he has a VT) and when I put the foot down in 1st gear it did not feel powerful at all and he said his VT feels much more powerful off the mark.

Then when I drove it a bit later it pulled hard again and took off like a rocket, does anyone else experience this "moody" performance variations with their TJ's?

Could it be the computer changing states of tune? I also wish I could get it to kick down to 1st gear above 40 kph (preferably 50-55kph) but it won't kick down above 40 kph leaving me with an enormous flat spot between 40 and 80kph for overtaking.

I've heard that a "piggy back" computer can rectify a lot of issues like this, has anyone found a piggy back to give some gains? I'm also thinking of putting in a K&N filter to improve intake air flow.

My TJ model 1.5 (series 2 engine 4 spd auto :cry:) appears to pull hard in 1st gear in that great 3500 to 5500rpm magna 3.5 power range, one time it will push you into the seat and pull hard with a seamless feed of gentle power (it's not a dragster) and then next time it will rev out but seem to go nowhere but it's not a transmission problem it's just that it does not seem to pull hard. I don't drive it like that all the time, but my mate at work went for a ride in it today (he has a VT) and when I put the foot down in 1st gear it did not feel powerful at all and he said his VT feels much more powerful off the mark.

Then when I drove it a bit later it pulled hard again and took off like a rocket, does anyone else experience this "moody" performance variations with their TJ's?

Could it be the computer changing states of tune? I also wish I could get it to kick down to 1st gear above 40 kph (preferably 50-55kph) but it won't kick down above 40 kph leaving me with an enormous flat spot between 40 and 80kph for overtaking.

I've heard that a "piggy back" computer can rectify a lot of issues like this, has anyone found a piggy back to give some gains? I'm also thinking of putting in a K&N filter to improve intake air flow.

Man I have the exact issue in m KJ, sometimes youll be cruising at 60 and plant it and she will drop to first and launch, but other times she will just bog down and slowly accelerate around the car im overtaking. Sorry Im no help, but at least you know you arent the only one.

Series 2... Should have Tiptronic, just use that :)

Was that aimed at me?

KJ Series 1 has tippy aswell, I do use it but WOT should force it to first IMO

Mine has series 2 engine but series 1 gearbox (no tippy) I would not have thought that the tiptronic would make a difference, if it won't pick up 1st gear at 50 kph in mine surely it won't in a tippy? Or is the tippy programed to kick down manually even if you are going too fast (ie pick up 1st gear above 45 kph)

Gas_Hed even at WOT I don't think it would pick up 1st gear if you are going too fast, I think the computer is set to only pick up 1st gear if at or below 45 kph or something tippy or not, but I'd love to know if it can be re-calibrated, If I could pick up 1st gear at 50-55 kph by simply booting it hard it would fill that dead flat 2nd gear spot especially up hills, even if 1st only lasted a second or so it would offer a similar effect as "feathering" the clutch in a manual.

1st and 2nd gears are insanely tall, yet 3rd seems quite short, I wish mine was a manual but I still like it.

Ahh disregard that then. 1st will only engage under 40km/h.

Ahh disregard that then. 1st will only engage under 40km/h.

Thats the first design flaw, IMO it should still be in first at 40km/h.

I get that too. I think it comes down to weather a bit... if it's a nice cool day my car goes hard, if it's hot and dry it kinda feels like it's dragging itself along.

Yeah you can shift down to first @ 40kmh, floor it at 35kmh, shift down to 1st and you'll see your car go nuts.

Maybe the reason your car sometimes goes hard and sometimes doesn't is coz it stays in 2nd gear through while you flat stick... like stated above, try use the tippy more.

I've heard that a "piggy back" computer can rectify a lot of issues like this, has anyone found a piggy back to give some gains? I'm also thinking of putting in a K&N filter to improve intake air flow.

It'll improve air flow, lower you fuel consumption (a tiny bit) but i highly doubt you'll notice any difference in power. I've got a K&N in mine, i didn't really notice much

Be sure to clean it regularly using the K&N cleaning filters and stuff

It'll improve air flow, lower you fuel consumption (a tiny bit) but i highly doubt you'll notice any difference in power. I've got a K&N in mine, i didn't really notice much

Be sure to clean it regularly using the K&N cleaning filters and stuff

put barrys gaskets and fuel rail kit in as well and the fuel consumption will go down a lot more + runs better :badgrin:

i don't have any problems being sluggish, he he but mines a manual :D

Thats the first design flaw, IMO it should still be in first at 40km/h.
A bit annoying really, it'll hold first till it's bouncing off the limiter at like 60/70km/h but you can't slip it in first while travelling... Stupid car, what I do with my auto box is my business :P

A bit annoying really, it'll hold first till it's bouncing off the limiter at like 60/70km/h but you can't slip it in first while travelling... Stupid car, what I do with my auto box is my business :P
Actually in a 4spd auto its more like 80-90 :P.
While I see your point guys, I feel guilty pulling back to 1st even @ 35, the car feels like it's been pulled forward by a 13 year old boy who's just hit puberty, it feels very awkward (not to mention the torque steer :P).

I wouldn't say it's a design flaw, more of a design safety mechanism.

As for the OP, never had this problem unless the engine is cold.

Then when I drove it a bit later it pulled hard again and took off like a rocket, does anyone else experience this "moody" performance variations with their TJ's?

Could it be the computer changing states of tune?


I had this same issue with my 380 even with a bigger intake, K&N etc. Especially dependant on temperature. On cold days it went well, usually.

Once I had it chipped, it completely removed this neurotic trait. Everyday I drive it, it feels like every KW is available.

Unfortunately it comes at a fairly hefty price tho, but worth it for me.

So I believe it's the ECU intereferring in the timing. It senses not just temp but also barometric pressure (not sure for the TJ series, prob for the TL) etc and it all influences the ECU's map

Actually in a 4spd auto its more like 80-90 .

As for the OP, never had this problem unless the engine is cold.





M4DDOG What is the 'OP'?

Perry, you got a manual, lucky devil......that's cheating lol

Interesting problem. I have tippy 3litre TF and find that it always goes hard. And if anything I would say it was a bit too willing to kickdown from second and grab 1st.

M4DDOG What is the 'OP'?


Ive always assumed OP meant "Original Post" or "Original Poster" depending in which context it is used in.

Willing to be corrected however.

EDIT: Damn Im Good (http://forums.whirlpool.net.au/index.cfm?a=wiki&tag=OP)

M4DDOG What is the 'OP'?

Perry, you got a manual, lucky devil......that's cheating lol

yea i know, its hard to find them :badgrin:

yea i know, its hard to find them :badgrin:


just go manual all there is to it lol

just go manual all there is to it lol
dont think the op had manual in mind
but back on track my tj2 feels that way at times (auto4trippy)
think its just how you expect it to go
people in it and you think its slow
as for your commadoore mate well mine is stock
and i have NEVER been beaten in a leagle ;) race yet against a 6
have not tried the new model as yet

Mine use to do the same But i gutted the cat and WHOOOOSH off it goes, hard and Fast all the time. My Temp just sit 3 bars under half now not like b4 always spot on, I ve been using premo fuel now. My Auto wont shift into first unless it below 40km/h its a tippy as well, Me have no complaints about the way it goes at all.

Well, having just sold my VT and having driven both from day to day it feels as though my Magna would absolutely slaughter the VT (or my previous VX) but only in the illegal (lose license kill someone speed range above 90 kph) And my car is speed limited to 100 kph by my right foot. The commodores did feel more powerful straight off idle just putting your foot down at the lights (no stalling it up tricks) but only in 1st gear, in 2nd gear all my commodores would be seeing is Magna tail lights. I am only talking about my TJ though, I once drove a stock 4 spd auto TH which was awesome in 1st gear with wheel spinning idle step off acceleration which would beat heaps of other cars off the mark.

It was interesting getting out of the Magna and into the Commodore, the commodore felt very unwilling to rev above 3000 rpm compared to the Magna which is so unrestrained, it seemed that everything seemed to happen below 3000 rpm in the Commodores but in the Magna the party starts at 3,500 rpm, I think it's called refinement, but the VT had more go under 3000 rpm. 0-80 Commodore 0-400m Magna

I wish mine was tip-tronic but I guess you can still hold the gears down manually just not as easily, maybe a Hi-Flow cat would help, there is definately quite a lot of restriction there, you can feel it and that never ending 1st gear is ridiculous.

Easy. Yes the weather etc makes a small difference, but the real reason the is the gradient of the road you are on.

sometimes roads seem flat when they actually aren't, e.g a long a straight bit of road with a constant gradient can often seem level when you are on it.

So at times you are actually booting it up a hill without being aware of it, and it will feel slow.

Yes there are many variables, road gradient and weather making some difference.

The piece of road where I often give it a bit is a straight length of level highway 100 kph zone on the way to work, it is along this same stretch where I can test it's 1st gear performance as well as it's 2nd gear pulling power as it hits 100 kph before backing off and along this same stretch it is sometimes fast and sometimes gutless (revs out but seems to go nowhere) or pushes you back into the seat and torque steers even in 2nd gear.

just a quick - left of feild question here

noticed in your profile, your car is factory dual fuel lpg system...

on the 'not so powerful' accel tests... is the car in LPG mode?
as im sure you know... when running dual fuel instead of dedicated either way the timings / mixtures etc have to be set for both fuels...
so same car that you do a flog it test in lpg it seems to make lotsa noise but doesnt go anywhere at the topend of its rev range... but in fuel itl pull hard...

Sorry I should have mentioned the Dual fuel thing but it's performance is off and on with either fuel, unlike some LPG cars it seems to go as hard on LPG as Petrol, it will still pull strongly to the redline on Gas yet gives me between 15-17 L/100 km on LPG depending on how I drive it (Mitsubishi/Impco Factory system) I've just had the front lowered to eyebrow height of 370 mm (down from 400+) so I'm busy too watching for spoon drains and cops etc to worry about it's sporodic performance, but with the cooler weather after that ******* heatwave it is running a bit better.