olleyjp

Hey guys, working on my neighbours RX8 and he has been having some starting problems.

So far we have;

1. Done a full ECU reset
2. Taken out fuel pump fuse
3. Removed and cleaned plugs
4. Connected to my diagnostic software and its not throwing up any error codes either!

Had to replace another plug as it had snapped

The car was running really rough and idling badly between 7 and 9ooo RPM.

Replaced broken plug removed the other 3 cleaned them up and put them back in the right places.

Started car, ran first time and beautifully, left it for 15 mins to warm up. Turned it off, left it again and then it refused to re start.

Left it for about half an hour and it started again but ran really rough.

What should i be looking for? Presumed it was the broken plug but obviously not that any more . . .

Will continue reading through threads but just trying to get it fixed ASAP.

Cheers for any help folks!

Mazurfer

Warm starts and rough running are a sign of low compression. You won't be able to fix that.

Car has an 8 year 100k warranty on the engine if they have good maintanance records AND you are in the US. Might need a compression check!

Possible clogged CAT. I only say this because you said no codes or I would lean towards coils and plugs. But ,if no CEL codes.......it could be the CAT as it takes awhile before it gets bad enough to throw a CEL.

Given what all you have said............I'm leaning towards telling you it needs a compression check!

How many miles does the car have?
Auto or manual?
How long since coils were changed........and "brand new plugs"?
It could also be a dirty MAF.

If it's an 04..............they were also known for weak starters, but since you say it starts but has a rough idle..........until you answer the rest of the questions, I would get "new" plugs, clean the MAF, and see how it goes with those first.


Anybody else?

olleyjp

Cheers for the info! Its got 40,000 miles on it, its a 2005 car.

Only the one plug has been changed, the other 3 were cleaned. the car is a manual. Where is the MAF on these? I will clean it as well.
As far as im aware the plugs and leads haven't been changed

Whats throwing me is as soon as the plugs were clean it was perfect started and ran perfectly. Then after it was off and on again it went back to what it was. . .

Mazurfer

Okay..............the MAF is located on that tube that runs from the accordion tube to the air box.
Two small screws hold it in. If you take out the screws to lift it out, be careful and be gentle with the MAF sensor itself. You can buy MAF cleaner at any autoparts store. Just spray it down real good and let it dry. Don't try and clean it any other way as they are fragile and have very small threads for wires in them, so don't stick anything in there. When you put the MAF back in, pay attention to the rubber grommet and make sure it is sealed properly against the tube and not pinched.

Having said all that................with 40k on the car, I'd really be tempted to get new coils and plugs and change them both out. Unfortunately the best way to not get screwed on price for these is to buy them online and have them shipped. This takes time, but will save a lot of money. Vendors on here sell them way cheaper than you can get them from Mazda or locally.
OEM coils are known to start giving issues at that mileage and if not done, lead to other issues down the road................such as the CAT mention previously. Hopefully it's not too late in that regard.

For the record..........even if if does turn out to be bad compression later on, Mazda usually will make the owner pay for new plugs and coils prior to running a compression check and determining of it needs a new motor..................whether under warranty or not.


Since you used the term "Cheers" to say nothing of the username, I'll still bet I was right and you aren't in the US?


Oh.................no matter what you do, after you perform the 20 brake pedal stomp(seems like you know what that is), it may take two complete drive cycles for the idle to settle down as the car re-learns the fuel trims. I'm an 05 manual as well and when I do the ECU reset, my car doesn't really want to idle coming to a stop for the first time or two. So....just be aware.

olleyjp

Ah cool, i must be loosing it as i swear i wrote that i was in Scotland haha. Im James (Or also known as Jim or Jimmy lol. )

I've got a few trade accounts with motorfactors here and got a not too bad price on the plugs i needed, so will see what i can get hold of and have a shop around.

I'll take it for a drive and see what happens after, but i think you might be right and it'll need plugs and leads!Hoping its not compression though, not sure what the UK warranty's are like, dealerships are pretty bloody stingy (grippy) at the best of times! Bit of a pain in the ****, but if it needs done, it needs done!