Lack of power after 5000 RPM

Anonymous · March 3, 2004, 11:04

When I say stops pulling, its like its reached a flat spot which it fails to get through, if that makes any sense. You get a sudden jerk as you pass the 5000 limit it continues to acellarate but it takes a much longer time to get from 5000 to 6000 and it is not smoothe at all. When I drive I have to change gear before I reach 5000 to avoid embarrasement.

Anonymous · March 3, 2004, 11:11

when you say stops pulling, do you mean it slows at 5000 or its more like hitting a brick wall or limiter of some sort and it simply wont go above that?

aaronjb · March 3, 2004, 11:11

Not a lot of info to go on there, but..

When you say 'stops accellerating', do you mean it stops dead and will literally rev no further, or that it really struggles to rev further?

The next things on my list to check for that one would be fuel filter, fuel pump, fuel leaks & injectors (fuelling, at any rate).

Not sure on the soft-top side of things, though (not put mine up yet!), I'm sure someone else will have an idea..

[edit: d'oh, beaten to it by Kris!]

SteveJ · March 3, 2004, 11:33

Sounds distinctly like the problem Rogue had with his MR-S after some thieving little scum nicked it and thrashed the nuts off it.

Does you car display a CEL if you do this more than once or twice on a run? If so Rogue located a garage in the Coventry area that can read the OBD-II codes from an MR-S (Normal Mr-T's can't)

Good luck and keep us posted with the result.

Anonymous · March 3, 2004, 11:35

I'd check the oil as well just to make sure, the CAT problem seems to be different for us all.

EDIT - I'm not saying this to worry you, just saying it would be wise to check the oil just to make sure.

GSB · March 3, 2004, 11:56

Cant help you with the power problem, although I would advise keeping a close eye on your oil consumption, and a quick inspection of your precats as well. In fact, as you have a J-spec car and its not subject to the warranty restriction placed upon the rest of us, you may as well gut the precats, both for your own piece of mind and for better breathing.

SteveJ · March 3, 2004, 12:16

Quote from: "GSB"Cant help you with the power problem, although I would advise keeping a close eye on your oil consumption, and a quick inspection of your precats as well. In fact, as you have a J-spec car and its not subject to the warranty restriction placed upon the rest of us, you may as well gut the precats, both for your own piece of mind and for better breathing.

If you gut the pre-cats, don't forget to sleave them too, cause otherwise you will have this lovely resonance chamber sitting just outside the engine - I dread to think what will happen to the gas flow as a result s:shock: :shock: s:shock:

<self admin note> Topic drifting - let's get back on track please </self admin note>

GSB · March 3, 2004, 12:51

Just to continue the drift slightly... Sleeving the pre-cat chambers is not the work of a moment. I'd say you'need to be very handy with a welder, and have some experience in fabrication as well. I was going to have a go myself, but I dont think its worth it.

Having looked at it in detail, I'd say it really wasnt worth the bother, as the welding of 'Y' shaped tubes inside the cat chambers will be extremely time consuming, and I believe the gains from doing so negligable, as the manifold design is inherently flawed anyway. The unequal length branches are designed for compactness, not power.

You would be better of just gutting the chambers and leaving them alone (after all - the lump of cat material that you just removed surely had a far more detrimental effect on gas flow than the 2 empty chambers you just created). Or you could could cut the precat chambers out entirely, and replace them with fabricated tubes of the appropriate diameter. Both would be far easier, and have very similar results.

So... Back on Topic please... If anyone wants to discuss the removal of precats any further, then start a new topic and we can all waste several hours of our employers tiime by discussing it for the rest of the day. s:wink: :wink: s:wink:

Anonymous · March 4, 2004, 04:18

Had the pre-cats removed without damaging sensors, did not have it sleeved. Since I'm in Sri Lanka advice about going to the local dealer is out of the question as they do not import this model. Is there any limiter on an MRS? how well do all other MRS's accellerate after 5000 RPM? I have extremely good accelleration between 3000 to 5000 then it feels like a big flat spot where you can actually feel the car jerk back as you pass the 5000 mark.

Tem · March 4, 2004, 06:36

"Is there any limiter on an MRS?"

Yes, a rev limiter around 7000rpm and J-spec probably has a speed limiter at 180kmh. Neither should affect this.

"how well do all other MRS's accellerate after 5000 RPM?"

Just fine s8)

s8)

Can you run the car without exhaust..? Just leave the muffler on and remove the midpipe. It's noisy as hell, but a good way to check if your exhaust somehow got stuck. Kinda sounds like it wouldn't be able to breath freely, which starts to bother after some rpm when too much gas tries to get out.

The above mentioned fueling issues are another good guess...

Anonymous · March 15, 2004, 03:41

Thanks for all the replies. Just to keep everyone upto date I hade a faulty airflow sensor this has been replaced and all my problems are cured. Just out of interest I was reading the other threads on the Uni chip. Is it possible for a good mechanic to set this up without a dyno? Are there any pre-programmed chips that are easy to install?

mph · March 15, 2004, 08:04

Quote from: "kalinda"Just out of interest I was reading the other threads on the Uni chip. Is it possible for a good mechanic to set this up without a dyno? Are there any pre-programmed chips that are easy to install?

No.

I think so. Yes, depending on your definition of easy.

Preset chips are no more easy nor difficult than any other chip to install. Personally I really wouldn't bother with preset chips.