Melted plugs HELP!!!

[Bumpkin]

Just started having a running problem where the car would misfire badly at anything over 1/4 throttle. Felt HT related so checked the plugs (Denso Iridium) to find 1 was OK, 3 had the inner ceramic all but missing and one had the outer electrode melted away :shock: :shock: :shock: :shock:

Hoping I had no holes in pistons valves etc, I fitted some standard Denso's and hey presto, OK again........I thought. 10 miles down the road at highish speed (120ish), loads of misfire all of a sudden and the problem is back. I don't know if I've knacked the plugs again yet (will check tomorrow).

Has anyone had a similar thing ? What could cause the plugs to get that hot ? I assume lean mixture etc. Is there a get you home mode on the GTIR ? and iif so does this advance the ignition ? if it does I may have had some detonation perhaps.

Bit lost on this one guys. I have just had the engine out to re-new the clutch so anyone got any bright ideas what could have been damaged/crimped/fitted incorrectly ? pretty sure it all went together OK but you never know for sure......



cheers
JB

 

[geetee]

Sounds like it's detonating. Caused by weak mixture, over advanced ignition, crap fuel.

Has it been standing for a whikle and have you put fresh fuel in it?

What fuel are you using?

Double check ur ignition timing.

What boost are running and how's it set up? i.e. bleed valve, EBC etc

If ur running high boost, have you got any add on fuel controller / piggy back ECU etc?

May be an idea to get it to a decent tuner for a quick check up, they will very quickly be able to tell you if it's running weak or detting.

And in answer to ur question.....

The R has a Safe mode and a Limp Home mode

Safe mode is triggered when detonation is detected by the DET sensor. This basically stops the ignition advancing at all and keeps boost to a minimum (provided u still have the original boost solenoid connected!). Once the detonation goes away the car automatically comes back out of Safe Mode. Makes the car feel like it is holding back a lot but will still rev out eventually. Will not show up on an ECU fault code check.

Limp Home - when the ECU detects a complete failure of one of the critical sensors. i.e. it detects that it is not connected / there is a short on a circuit to a sensor / the sensor is feeding back totally out of range readings. Limits rpm to about 3000 plus all the above in Safe Mode!


Hope that helps.

Cheers
GeeTee 8)

 

[jonee]

r

m8 the denso plugs are not true iridium plugs and i have had this problem before with these plugs.

just try a different make of plug and see if the problem is cured.




jonee

 

[Bumpkin]

Thanks for the replies guys, just took out the plugs and sure enough No1 is melted.....bugger, definitely detting. I'm running a SAFC which was set up by Interpro but wonder if having the battery disconnected for 2 days whilst the clutch was changed would cause it to lose its values ?

Having said that, in default state (before it was set up) it was rich everywhere so I can't see that as the problem. I think I'll check the onbourd mixture sensor and see what it says to be sure.

BTW I'm running a Blitz BC at 1.2 BAR, Mongoose straight through and a K&N. Just replaced the knackered plug so I can use it and I'll back off the boost to 1 BAR to be safe methinks......

will keep you updated....

 

[MarkTurbo]

I'll back off the boost to 1 BAR to be safe methinks......

If it was mine i wouldnt even be running 1 bar :shock: I'd be back on standard boost, actually i probably wouldnt drive it until i'd found the problem

 

[Anonymous]

same probs

hi mate i have got a similar prob 2 u. when my probs started off the plug tips kept burnin off in 1 and 3. kept gettin new plugs but didnt sort it. now i got a cam rocker prob wher a rocker keeps coming off causing my R to smoke its bag off! now as a result i got a scratched cam but that dunna matter cus i got a nice couple of piper cams to go in!!! If you sort the problem out can u get in touch with me and tell me wot u did??? im currently saving money to have it all sorted but bit skint at the mo!!!! my email add is gtirjaymz85@hotmail.co.uk or jus PM me!! if u wan chat bout the prob or give me more details get bak in touch.
Jaymz. p.s dont drive the car till fixed as will f**k up!!