xladyzstarx

Hi Boys,

We've a 05 6speed manual (about 150Km done) with the same issue of having a power loss upon hitting 7krpm thereabouts as did many of the dudes here, but ours kind of mucks up differently. There are no CELs and other signs, save for the loss of power and the sputtering hesitation. I don't recall hearing rocks in the engine and before we brought it to the garage, we had plugged up a sensor to see if the valves were opening at 4k rpm and thereafter but the poor thing died on us before we could continue the testing. We were fiddling around with the AP but no codes were thrown out. The garage and ourselves kind of feel that it shouldn't be a rebuild case as yet, but we just want to be doubly sure.

At the garage, the FIs were checked but there didn't seem to be anything wrong with it. Our cat is you could say, is a some what de-cat one (it wasn't fully de-cat - I can't remember the term for it at the mo) and it's a relatively new one. No muck in the MAF, and now our garage is thinking to swop the O2 sensor.

According to them there was no loss of power after resetting but after an intial warm up and drive around, the car would start sputtering again. The guy who owns the place is a Japanese and he's also starting to wonder what it can be.

I'm also curious. If the 8 requires a rebuild, would the engine still start up and idle like a normal vehicle? And if it does require a rebuild, would it be able to still drive around normally? I'm from Singapore and one of the garages here would definately deem it a rebuild case, but I'm skeptical, as based on our analysis (my fiance's the one who DIYs on the car), should there be a moderation done on your compression test as the coils may be different between the various specs of the 8? Would the wankel behave normally even requiring a rebuild, allowing the car to function as it should?

I'm not a tech expert myself, but after surfing through the various forums overseas etc, I've a little given up on the information I see in the Singapore forums (cos they usually deem it a rebuild case) so I've decided to ask you guys here if there's any suggestions?

I can't find the thread in the UK with regard to this issue and hope you guys may be able to help.

This is excruciating. If it really needs a rebuild (as they say here in Singapore "up car"), I'm going to die of a heart attack. We'll just need to sell off the poor baby as a half cut case. And I won't bear to do it!

xladyzstarx

Oh yea, other things we do religiously: We redline, we use our 2T and we use higher octane fuel. We've changed the coils and we've checked most of the problem possibility areas. I'm just wondering if there is anything else that can be done, other than the compression test we took quite some time ago.

Would a Dyno test work too?

VOODOO8

You note you have already changed coils (recently I hope) so that begs the question whether the spark plugs and ignition wires between the coils and the spark plugs were done at the same time. If not, that is your best first place to start. Sounds like you have a catalytic converter that has been modified in some manner, can't really say I understand what that mod may have been. Good test that is easy to do is to go out one evening at sunset or dark and warm up the vehicle gradually until engine is at normal operating temperature. Then run it hard under load for around 15 minutes (hill climbs at high revs are good for this), stop the car, lay on the ground next to the passenger's door, look under the car at the catalytic converter and see if it is glowing red at all.

Post back when you can. If these steps don't get you anywhere then we can talk about other things such as decarboning the engine, and finally a proper compression test if it gets to that.

xladyzstarx

Hi Bro,

We've did a switch on coils yesterday just to be sure and it didn't work. Still the same.
Our Cat has been cleared to a straight pipe. But this time, the engine seems confused. After a reset, we've found that the sputtering occurs randomly throughout the 4k rpm range and beyond. We can work the car but not redline it constantly, and after it warms up considerably, the sputtering and random slight lurches (like we've released clutch in first gear at low speed) seems more eminent.

We had a fuel pump problem previously that was changed about 4 months thereabouts ago. We had a loose fuel tank seal previously as well that had been changed. We suspect that the fuel pump may be the culprit again as the sputtering seems to attribute to some fault with the fuel injection to the engine chambers (or some sort as my fiance explained).

We were wondering if it could be a possiblity with the fact that after the reset, could the default fuel trims (I understand that there should be a long term FT map and a short term one) be unable to deal with the fact that we've been revving it to test if the power loss is still present? We're of the opinion that the car needs to learn the driving pattern and adjust the FT to the necessary before it's able to communicate rationally with the rest of the vehicle. Right now, could it be a case that the fuel is running too thin?

I'm not sure what the heck I'm talking about right now, but I only know that the warm up of the vehicle after the initial drive off and rev seems to have balked the engine and confused it. The sputter occurs randomly through and it can be driven but not long distance. We've noted there are no rocks in the engine.

The compression test we did in the last few days was balanced according to our resident Jap boss at the garage and their more or less convinced it isn't a case of poor compression. I clarify that we have power now but the sputter now seems to be hindering the allowance of acceleration, which in the end makes us tap the accelerator more and more gingerly. I have no idea why!

I hope you guys get what I'm trying to say. =)

We'll be running another set of tests today as well as a dyno and removing the fuel pump as well. Will update!

Thanks!

Vulcan

Yes the engine does have to re-learn a load of stuff when the ECU is re-set, I'd recomend re-setting it again, and then just letting it idle by itself for around 10 minutes, you'll noticed that the revs will go up and down as the engine relearns its idle position. If that doesn't work, as VOODOO8 says, check the leads and sparks, these could be the source of your splutter, Magnecore leads are the best if you do want to change em!

bse50

Are all of the intake solenoids working properly? Vdi, ssv, apv etc.

xladyzstarx

Well, turns out it was the Fuel Pump problem. Our mech broke one of the solenoids while testing. If you guys are keen I'll load up the pictures of our Dyno test and the graphs. Our fuel turned up 2 bars off instead of the original 4 bars. Although we've had it changed recently, my fiance's suspicion was right. We've overtaxed the Fuel pump as he always has this bad habit on running on almost empty as he's always late to somewhere (tsk tsk).

As I've said before, there's nothing wrong with the leads and sparks. We had the mech as well as ourselves go thru them not once, not twice but many times (he's quite annoyed with us...)

The sputter is due to the drop in the fuel bars when warmed up. This causes the fuel to trickle instead of atomize and thus causes the loss in the ability to accelerate. At the first instance of restart/reset, the vehicle seems to "think" he's able to run it, but the fuel pump pressure after heat up causes it to deteriorate.

Phew. We had a totally great scare there.

The baby runs like new again. And we got a new cat to boot (we met a friend who had a spare hi-flow cat and loaned it to us) - and we're modding another one to fit so we can return this to him.

Thanks for all the suggestions. I'll know where to turn to when the baby acts up. =D

Perhaps the dudes who have this unresolved problem may want to check their fuel pump pressures as well... Seems like wear and tear does bonk out the pressure!

Cheers!

P/s let me know if you boys are keen to see the Dyno test and the graph.

Oh yea @bse50: We had already checked all the Valves and ports for any defect on the first day the car was brought in and had attached multimeters ourselves to check too (I think I wasn't clear about it in my first post) and our car in general is healthy =)