Hi all,

I have a 2004 04 plate RX8 with really bad starting WHEN HOT issues and have been advised that it is a compression problem but really dont want to fork out for a new motor it has 82000 miles on it, serviced regular, i have replaced the coils, plugs, maf sensor and the air pump as it was making a really loud noise on cold start ups, could the air pump been broken for some time eventually worn my cat out?? and would a knackered cat affect hot starting?? i have not yet done a compression test as dont have a tester for rotarys and dont really want to pay dealer prices any help/info would be great.

Thanks in advance guys.

 

Hot start issues are almost always related to compression lost. The reason for this is that the metals expand when hot and gap seal tolerances a bit more, making it harder to make compression at low rotor speeds.


Trouble starting is never an issue with the cat, as cat issues are either just smell/noise related or causing a restriction to exhaust flow that robs top end power. The air flow (and exhaust flow) when starting it far too low for a clogged cat to cause issues with. (~5.5g/s vs ~200g/s top end)

 

If you haven't done a compression test, then you don't know for sure that it is "a compression problem" (although it could very well be.) No, a catalytic converter won't affect starting (unless it is incredibly bad, but then the car would be undrivable.)

Otherwise, everyone is going to tell you to search. There are dozens of threads regarding hot start issues.

 

sORRY, I HAVE ALSO FITTED AN UPRATED FUEL PUMP ASWELL.

 

have you had the starter checked?

 

I haven't had the starter checked but it is the upgraded starter which i fitted about a year back, it starts perfect when cold and cranks continuosly when hot until it eventually fires so was thinking if it was the starter it would have trouble wether hot or cold but i am probably wrong.

 

Fuel pump failures are usually due to heat, which fades while the car is off. The heat usually makes them stop working while you are driving, and it's a complete shutdown.


Thanks zoom, missed that one

 

I have also replaced the coils, plugs, done the seafoam thing, fitted an uprated fuel pump and a new air pump as the old one was making a loud noise on cold start up, all off the above have made no difference, i have been advised to do the ATF thing by pouring it into the leading plug holes and letting it sit to soak in etc to free off the seals, would this be of any benefit to me as it seems to have worked for a lot of people and does'nt cost much?

Thanks
Dan.

 

no do not do "the atf thing".

until you have had the fuel pump and starter properly checked there is nothing else anyone can tell you. go away. come back with results

 

Thought i was sensing 'Deja Vu' when I saw this thread


https://www.rx8club.com/showpost.php...5&postcount=23