Idle problems

[Zachstrange]

Hello,
I'm a new rx8 owner and really need abit of help.
So i just bought a 2005 231 with 58000 miles that has just had a home rebuild and I'm having some problems with it idling. The problem is is turns on and warms up fine until the rev get to about 1100 rpm then it starts surge from 800 to 1300 a few times before it stalls but theres no problems when driving. It also has two error codes p0113 and p0103. It had new plugs and cat before the rebuild so I'm pretty sure there fine. Since buying it I put new coils, battery and maf on with know joy. I can't find any obvious vacuum leaks and the filter is clean but if I unplug the maf it runs fine just idles at about 1100 rpm so I'm pretty sure it's a air problem. Any help or advice would be greatly appreciated.

[warpc0il]

P0103 is the MAF sensor circuit and P0113 is the Intake Air Temp Sensor - which are both parts of the same module.
Either the module has been damaged, is saturated in oil or there's a problem with the wiring connector/loom.

Where did you buy the ignitions coils from?
There are lots of nasty fakes/clones out there that will kill your engine, even if their not responsible for your current problem.

[warpc0il]

Further reading
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[Zachstrange]

Thanks for the reply. Maybe the new maf I bought is faulty aswell as the old one? And the coils are haas ones from euro parts so not the best but adequate?

[SeeJay]

No,the ECP coils will not be adequate..think about replacing with genuine Mazda C coils,or upgrades such as D585 coils.

Was the new MAF sensor a genuine Mazda part or a pattern

[Zachstrange]

No it was off Ebay but seemed like a half decent one as it came with a year warranty.

[warpc0il]

The warranty is worthless. It's just to give the impression of quality.

You'd be much better fitting a known good used Mazda part, as they very rarely fail, unless mis-handled.

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[untakenname]

Could be a fueling issue, has similar idle issues couple of years back.
Try bypassing the fuel pump resistor so the pump runs normally when idling.

[Shagrington]

Hi and Zachstrange. My first stop for parts, especially the critical things like coils etc, has always been Mazda Rotary Parts or one of the rotary specialists (there is a list with contact details in the FAQ section).

Have a good read through whatever in the FAQ section you didn't already read and then (and just ignore me if you know all this already) here are my best tips for keeping it all running sweetly:

1. To start up turn the key to position 2, wait for most of the lights on the dash to go out (I watch the airbag light by the glove box), press the clutch to the floor (optional, but reduces drag), turn the key to start and do not touch the throttle until it has started. You can drive off straight away, just keep the revs down for a bit (see #4 below).

2. Never turn off the engine before it has reached at least somewhere towards normal operating temperature (should only take a minute or two, but best to go for a short drive if just swapping cars round on the drive etc). Switching off cold risks flooding, which is a real with a rotary engine. Mazda recommend rev to 4k and hold it for 8-10 seconds switching off while still revving if you have no option but to switch off cold (it is not necessary to do this in any other circumstance).

3. Check the oil level regularly (use the dipstick - the oil gauge tells you nothing other than that you have or don't have pressure) and top up if necessary with semi synthetic 5w30 (most people and specialists are advising to use 10w40 now though) ... small amounts at a time, no more than ½ a litre then check the level again before adding more as you don't want to overfill it.

4. Use all the revs once the engine is nice and warm (don't sit idling to warm up, start up and drive but keep it below about 4k until the needle on the water temperature gauge is pointing straight up, then give it another 10 minutes for the oil to warm up too before really thrashing it ) and hit the beep often. Best acceleration is from 4k revs up - to pull away you really need to rev to 2k - you can let the revs drop after lifting the clutch if you are in traffic, cruising steadily at 3½k revs and changing down to go up hills or accelerate gets you the best mpg ... which still won't be great.

5. Join the club for discounts on all sorts of things (you will very quickly get the cost of membership back - and then some), loads more info in the members only sections, local meets (or if you can't find one exactly local it is a good excuse for a drive if you come to one a bit further away), a sexy keyring just for joining and more.

[350matt]

if your scan tool can do monitoring take a look at what the lambda sensor is reading and what the LTFT ( long term fuel trim) figures are

as its possible you have 1 injector not firing so its stalling out once the cold start fuelling is used up

[GreySilver Beast]

Hi & to the RX-8OC


Please check out the EVENTS SECTION's - Events Team

[Zachstrange]

Hey guys, thanks for you replies and help. I thought I'd give you a update. I changed the front 02 sensor which has seemed to get rid of the codes and made he car idle with out stalling but still not perfect. It will still stall on take off and hunt abit but not as bad. I noticed the front engine mount is shot so I'm just waiting on a replacement set think I will check the plugs and leads next as it's slow to start and every thing I touch seems to have been butchered so I dont believe they are as new as the previous owner has said...

[ChrisHolmes]

If you know where it was rebuilt did they also fit the engine? Could be worth a trip to your nearest specialist to save a lot of time and expense on parts you may not require plus guidance what good parts and which are bad.

[acegeezer]

Suicidal ignition coils !!!!!!!!!!!!!.. they WILL kill your engine .. get genuine Mazda 'C' revision or uprated ones.. circa £300.
If you value the car, for gods sake don't buy off eBay they may well say genuine, but trust me they are far from it

[Essex2Visuvesi]

Did Someone say e-bay coils?

[warpc0il]

Mazda had to specify different front O2 sensors for the 231 and 192.

If you've replaced with anything other than the correct Mazda unit then it's the wrong spec.

Lot's of vendors list the wrong sensor for our car and it will put your engine at risk.

A good used original sensor would be a much better bet than a new non-original item.

If it says "oem" in the listing then that's usually the clue that it's wrong.

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