Cat starting to die??? Or something else?

[RemarkLima]

Hey all,

New problem The car run OK at lower revs and fine at low throttle... But when giving it WOT it now sounds different, and not quite as much power, but almost sounds "fluffy" if that makes sense and not as smooth a sound, a bit louder so maybe an exhaust leak?

I *need* to get rid of the cat TBH, so I guess I do need an power fc...

Any ideas would be appreciated!

Cheers,
Mark

[banned advertiser]

could it be a boost leak, check larger pipes intercooler pipes for splits etc

[RemarkLima]

Will, do, also I double check but I think I could still make full boost.

And definately sounds more like the exhaust area I think... But it\'s always hard to tell when in motion!

[Wombat-007]

Hey all,
 
New problem The car run OK at lower revs and fine at low throttle... But when giving it WOT it now sounds different, and not quite as much power, but almost sounds "fluffy" if that makes sense and not as smooth a sound, a bit louder so maybe an exhaust leak?
 
I *need* to get rid of the cat TBH, so I guess I do need an power fc...
 
Any ideas would be appreciated!
 
Cheers,
Mark

Hey Mark, do you have a power loss all the time or just when the car is fully warm?
 I have what sounds to be the same problem, especially when fully warmed up.
I took the car down to REWORX (excellent guy\'s) thinking there was a boost/fuel issue as the car ran great on warm up, after 10 mins had the same symptoms you\'re experiencing.
Once on the rollers it showed good power on initial runs, then left to idle for about 10 mins and was then found to have a slight loss of power from low revs (I hadn\'t noticed a difference), and a big drop when the second turbo kicked in (around 70bhp).
Turbo\'s were found to be boosting fine and at correct revs, fuel mixture was also fine.
The Cat was suspected to be causing the issue as all other engine perameters were fine (bearing in mind when I bought the car the fuse for the air pump had been removed as the pump was shot, replacement pump was fitted and maybe the cat has finally had enough as there was no pump to properly warm it before I bought the car).
Am waiting to fit a full exhaust system with de-cat from Martin at Speedline Imports (another top guy) so am afraid I cannot confirm at the moment that it\'s definately the cat, but seems most likely.
Let us know how you get on, will post once I get my system fitted with the results.
 
Good Luck
 
Phil

[RemarkLima]

Cheers Phil, does kind of sound like that... Obviously I don\'t really give it any or very little boost when warming up so can\'t comment on the power loss but may have lost some power low down but it\'s hard to tell.

But yeah, when the 2nd turbo kicks in it\'s definately strained and the exhaust just doesn\'t sound quite right!

Also, when I come home tonight when I turned off I heard quite a loud pop from the exhaust about 10 seconds after the engine shut down... So like a backfire basically, so a load of fuel trapped in the exhaust, maybe from the cat??? Or maybe the O2 sensor\'s gone duff and it\'s ovefuelling???

[Wombat-007]

Yep, I\'ve had a similar pop when switching off sometimes. Sounds like we have the same or similar problem.
I can only confirm in my case that the fuelling was spot on and am hoping it\'s the cat causing the problems.
Also, what I meant with the warm up was only giving the car full boost once the temp gauge first reached normal opperating temp (wouldn\'t dare trying it before as I gather that can kill the water seals and god knows what else).
It\'s only after about 10 mins or more that I seem to lose power and get the same symptoms you have. I\'m assuming this is when the cat has reached normal opperating temp as starts causing problems.
Would be interesting to see if you suffer the same problem, i.e  good power straight after initial warm up, then losing power soon after.
 
Hope someone who has experienced the same problem before could shed some light on the matter. These cars are great but a PITA when playing up :2Mad

[RemarkLima]

That\'s good news (in a way!), I\'ve got a silenced decat waiting to go on, just need to get an ECU really.

I\'ll try and get an APEXi (if I can track one down!) and then get the cat swapped over and see!

I\'ll try seeing how it runs as it warms up and let you know.

[Wombat-007]

Guess the race of who can get their exhaust/ECU fitted is on.
There always seems to be plenty of Apexi\'s on e-bay (new) so may be worth a look.
Also try dropping Martin at Speedline Imports a line and see what he has in stock. I got my HKS F-CON V PRO ECU and getting my entire exhaust system from trust downpipe to Racing Beat back box second hand but in great condition from him at excellent prices. Def worth a chat before you shed out on new parts.
 
Look forward to hearing your problem is sorted.

[RemarkLima]

Good call about Martin, have just dropped him a line!

[RemarkLima]

Hey Phil, looks like it could be the cat after all, just swapped mine for a silenced decat and a new back box (both in Ti! Mmmmmm).

Still on standard software but had to do a bit of a journey tomorrow so thought I\'d rather have no cat and just take it easy on the throttle and not go mental with the revs, rather than the cat blocking up and bursting into flames! LOL!

My cat did look blocked at the inlet end so hopefully it\'s the same case with you! Defo gonna get my a PFC pronto and mapped to 95 RON me thinks!

[Wombat-007]

Sounds good Mark, take it really easy until you get your pfc, would be a disaster to kill the motor before you really get going.
Might be worth popping down to your nearest rx7 specialist and have your fueling checked just in case the swap is leaning the motor out too much over the whole rev range. I\'ve heard these engines are really fussy with their mixture.
Let me know how it drives, will have finger crossed your problem is sorted.
Regards
Phil

[adib]

does the exhaust sound louder when your been on wot and you lose power as if turbos not kicking in

[RemarkLima]

Hey Phil, will be taking it very easy! And making sure it\'s filled with super at all times until the PFC arrives... I\'ve also heard that det is bad for these, very bad! But pretty sure now that the the cat is the cause of the problem.

Adib, yeah, sounds quite a bit louder, almost like the exhaust is blowing, but not quite, and definately more on boost! When it\'s crusiing it\'s not that much different.

I was going to change them myself but then a much friend done it in about 40 minutes so well worth it IMHO

[Wombat-007]

Good to hear, looking forward to hearing the results when you get your PFC hooked up. Am dying to get mine sorted, just waiting for the exhaust to arrive from Japan and I\'ll be joining you with the de-cat and hopefully a decent hike in power.
Regards
Phil

[RemarkLima]

Hey Phil,

Got my Power FC fitted tonight (brrrr! Very chilly!), leant the idle fine (didn\'t seem to need much TBH) and I was good to go!

Obviously I need to get it properly mapped but the difference is astounding! It\'s back to how it should have always been and I was always getting random boost on the 2nd turbo, sometimes it would, sometimes it would just hold at .4 bar, sometime just creep up from .4 bar.

Now it\'s just that momentary blip and all hell breaking loose (along with all traction at the rear!).

So mine was definately a blocked cat, nothing major, just looked a little gammed up on the inlet side, but clearly has big consequences