PDA

View Full Version : saxo missfire / idle problem.

andyrew_69
29th November 2009, 17:36
car ticks over lumpy, from say 900rpm to 500rpm, then when revved it misses around 2k/3k and then if you take foot off throttle it just cuts out. when accelerating from stand still misses like mad till like 4k then revs fine. changed coil pack, fitted new lambda sensor, and ngk iridium plugs, still does it, 2 of old plugs sooted up, 2 perfect, any ideas?! thanks
Lew_C
29th November 2009, 17:37
HT leads mate?
andyrew_69
29th November 2009, 17:43
sorry forgot to mention its a saxo vts mate, coil pack straight onto engine, doesnt have any leads. cheers
LeeM
29th November 2009, 17:55
exactly what mine does, i suspect some kind of vacuum leak
Lew_C
29th November 2009, 18:06
oh sorry, didnt know the car was an S.. Idle control valve? Crankshaft position sensor?
andyrew_69
29th November 2009, 18:14
ive changed idle control valve...and the sensor, what happens if i havent reset ecu when changing lambda sensor etc, would fault clear itself? injector?!
AndySAXO
29th November 2009, 20:29
check to make sure that it not an injector, as the ilde could be down to the car firing on 3 cyl, so if oyu changed the coil pack and sprak plugs, then that two of the three things to make a fire inside the cyl as to speak,

so check that all the injectors are working next before getting a ICV as a ICV will not make it mis fire!!!!

and if it mis firing it will make the car idle lower normal!

ANDY
AndySAXO
29th November 2009, 20:31
the ECU will sort itself out!

maybe you should of got the car pluged in so see if you have any fualt codes first as it would of been cheap maybe instead of changing everything, butr check the injectors, as the ICV will not make it mis fire!

andy
tomsmith5
29th November 2009, 22:02
i had the same problem on my Mk1 VTS, and it was found to be a crack in the fuel pump, which was letting too much air into the system...good news was my fuel lasted Agggeeeeess... :)
RustySkull
29th November 2009, 23:00
i had the same problem on my Mk1 VTS, and it was found to be a crack in the fuel pump, which was letting too much air into the system...good news was my fuel lasted Agggeeeeess... :)

That's what I was thinking, are you sure it's missing and not just lacking fuel?
AndySAXO
30th November 2009, 13:18
well if it was lack of fuel it be bad al lthe way though the rev range, but he say it revs ok after 4k!

but it could be alot of different thing hard to say without seeing it.

andy
RustySkull
30th November 2009, 17:32
well if it was lack of fuel it be bad al lthe way though the rev range, but he say it revs ok after 4k!

but it could be alot of different thing hard to say without seeing it.

andy

Very true!