Mystery Trouble

[rsx84]

i have this issue with the car at the moment,

last week i spat the cat out the exhaust, got the car home, just, as it was stalling, got it started the next day drove it round the block, seemed fine, then it just stopped.

didn't get it started again. towed it home and thats where it has stayed for the last week.

what i have now is it will fire for a second or so every once and awhile, i swapped out the fuel filter and plugs today, it fired up for about 30 seconds than just stopped.

i've had the ecu go before which gave similar simptoms (turning over but not firing) but this time it will fire every once and a while. i've looked at the turbo and its fine, i've checked the wiring and earths seem ok.

i have disconnected the exhaust from the front pipe so there is no blockage from the dead cat.

a mate is lending me his ECU and ignitor tuesday night to see if that fixes it but wanted to know if anyone would have a clue as to what is going on??

the engine is an rb25det S1 (i think) matching r33 auto box, this has been fitted in my r31 for the last month, was in my other r31 for 18 months before this.

i have had the fuel pump replaced at the same time the engine went in.

cheers, Matt

[MBS206]

CAS okay? Is it loose? Pull it out, make sure the little teeth inside aren't all chewed out. (Be aware, when you put this back in, you'll need to reset the timing.)

[rsx84]

the CAS seems fine but i might check the timing belt to see if it may have jumped a tooth when the cat got spat out (pressure build up??)

[MBS206]

Did you pull the cas out and actually check it?

It's very unlikely the cat fouling will make it skip a tooth.

Have you replaced the actual fouled cat yet?

[rsx84]

the exhaust was blocked enough to push out a kiwi fruit sized bit of cat..

i havn't taken out the CAS to look but i will tomorrow.

i've removed the cat so that all that is left is just the front pipe.

trying to narrow down the could be's

[MBS206]

What do you mean pushed out a kiwi size?

Whered it push it out? Pics?

[rsx84]

this came out the back of the exhaust..

[MBS206]

Okay.

Go and compression check the engine... That's f**ked...

[R31Nismoid]

lol holy shit that's a fair collapsed/melted cat!

Is it a stock-ish setup? Could have been running a bit hot etc.

Have you checked you've got signal etc going to injectors and ignitor, i'd have a look there being its turning but not firing, sounds intermittent around the spark area (id also have said check CAS too)

[rsx84]

yeah it was a shock, whats more that is from the back half of the cat, the front is fine not even scorched.

engine runs stock boost, i have a full 3" exhaust, FMIC, 040 fuel pump, pod, i also run a nismo thermostat and larger engine oil cooler to keep temp down.

i haven't even over rev'd it, peek rpm is showing as 7100rpm.

i even had a thought about the fuel pressure reg, with the new pump, my have given up??

[R31Nismoid]

doubt thats it.

should still fire

[MBS206]

Pull the CAS and check it. And do a compression check whist you're there.