Engine running lean, plugs burning out.. why? can solve?

[Sdfr]

--- hi guys... i'm reposting this thread from the delphi forums... hoping for a better suggestion/s here... thks!!! -------- err... the first poster that's me sdfr. ta!

 

 

hey dudes

need some help here. I've put in a cone filter with diy heat shield and a FSE PBV set to 3 bar, set of RPM jetracing cables and plats (that's all the mods in my engine bay). My plats are burnt out already after 13k km only. previously i had iridiums with FSE at 2.7bar, same thing 13k km all burnt out. (the car is a proton wira 1.5 manual). anyone got this problem with either the proton or the lancer? i hear this is due to too lean mix. The thing is I wanna know which mod is causing this -- the cone filter or the PBV? I'm guessing the cone filter but am not sure. Anyway the PBV have just been set up to 3.2 bar (and I changed to cheap plugs since i'm gonna be throwing them away after 8-10,000 km anyway!) since my car uses an OEM ECU, i can't tune the fueling or the timing unless i go the piggyback way (not something i'm seriously considering at the moment). I don't mind my changing the plugs more often, but i think it may be causing damage to the internal combustion chamber and pistons as well. any suggestions?

 

any help appreciated. thx!

 

 

 

 

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Edited 5/20/2002 5:51:34 AM ET by SDFR

 

From: LANCERCK May-20 6:59 pm

To: SDFR (2 of 20)

8478.2 in reply to 8478.1

 

Hi, me also have abt the same setup as u except I dun have the PBV. My iridium plugs' insulator broke down at abt 25k kms, so I have to change them all as the sparks created r flying all round inside the combustion chamber, causing power to drop, rougher engine. And I've also send my car for a tune up and also the diagnosis is that my engine is running lean. I'm using a plug that's 1 notch cooler than recommended (IW20 instead of IW16). Plug tip is still very good but the ceramic insulations got broken down. My guess is that lean burn produce a lot of heat, thereby causing the plugs to break down faster.

Chers

 

Cheers

 

 

 

From: SDFR May-20 8:41 pm

To: VTEC2295 (4 of 20)

8478.4 in reply to 8478.3

 

No no man. I think my problem is more serious than what you wrote. See, platinums should last at least 20K if taken care of. THe shop i took it to, the mechanic try his best to save my plats. He clean with the steel brush / scrub. But one or two is totally gone, have to change. remember, 13k km, the tip of the plug like kanna eaten by metal cockroach like dat. it's quite bad.

 

From: SDFR May-20 8:44 pm

To: LANCERCK (5 of 20)

8478.5 in reply to 8478.2

 

hi man thks for your input. since your idirium last quite long (25k sounds ok ) so it seems more likely the PBV liao, altho I really don't understand. since i put the pbv my consumption gone up a bit, so if i'm regularly using more petrol (due to the pbv) how come the engine run lean? btw wat cone filter u use?

 

 

From: EX6 May-21 12:42 am

To: SDFR (7 of 20)

8478.7 in reply to 8478.4

 

Hi,

Longlife platinum can last at least 100,000km. My OE platinum plugs in my car are 92,000km already and still going strong.

 

An aussie magazine conducted a dyno test for over ten brands of spark plugs. Ironically, the worst performance plug is the most expensive iridium and the cheapest Champhion copper plug is the best.

 

From: LANCERCK May-21 9:11 am

To: SDFR (9 of 20)

8478.9 in reply to 8478.5

 

Me oso not too sure how ur engine runs lean. As for my cone, I was using the RPM brand as bundled by Mcwell. Just changed to a K&N recently. Will monitor my new set of iridium.

Cheers

[Guyver]

Wah!! Chim... think it's best to change all back to original... then change one thing at a time.. so that u'll know what went wrong...

[Sky8807]

sdfr,

 

With hard driving, the plug life will be shorten, in our weather make it worse. A plug that last 15k is considered okay with hard driving in our climatic condition.

 

Plug run hot probably due to lean mixture. Lean mixture due to too wide a plug gap for the engine or the high tension cable supply too much voltage thus causing lean burn.

 

Cone filter is unlikely to be the cause whereas the increase fuel pressure could contribute but the amount of fuel into the c chamber is still dependent on the injector timing, higher pressure could mean a more positive supply and have little effect on jetting more fuel. If the iginition timing is too advance, could also result in burnt plug.

 

Incorrect valve timing (opening and closing duration) can also cause the problem.

Too small a valve clearance(intake) mean less air or mixture get into the c chamber for burning and may result in lean burn. The manufacturer recommendation is ideal or opening the valve clearance can help with a little louder valve tapping sound heard.

[Sdfr]

ooops reply to myself, snip snip

Edited May 28, 2002 by Sdfr

[Sdfr]

hi man

 

thanks for your reply.

I am currently ruling out vavle clearances / setting and ignition timing cos my car is only about 1 yr 2 months old and i've been sending it to the agent for resetting/ retune the ECU. ie valve problems probly due to age n wear and my car not reached that stage yet, mechanically, and the ignition is set by the ECU. Also valve timing mistimed due to timing chain and cam mechanical wear right? so i think my car still too new to have that problem. what do you tink? (i assume my car is ok from the agent). as for hard driving, unlikely cos i don't race.. once in a while i ram to >5000rpm and only for a while and that's it.

 

if yes to my assumption above i've narrowed it down based on forummers / mechanic help to the following:

 

1. filter

2. pbv (why? dunno).

3. my air flow sensor not functioning.

4. my rpm cables deliver too high voltage thus burning the plugs.

 

One thing for the wira, my air flow sensor is not the fancy type with an box adaptor. it's just a wire connect to the sensor which has a tip that protrudes into the air flow channel. maybe that was spoilt when the air filter piping was installed? would that be a cause of the problem? (if so, why doesn't my check engine light show up).

 

anyway appreciate your input. thaks!!

[Killer5010]

My guess, will be the jetracing cable. Replace wif stock and see how. Filter,pbv not possible. How many K had u run ? Had the engine overhaul once after the 100K ? Maybe u should do a proper tuning on your engine.

[Sdfr]

thks for your reply

yah dat's wat one of my colleagues said. ie. the jetracing cables are supplying too high current thus literally burning up the plugs. i thought shouldn't be cos so many ppl in Sg using those cables.

100k overhaul?? dude... my car only 33k km, 1 yr 2 months old dude! dat's why i'm ruling out a lot of mechanical wear and tear factors. plus i take care the car ok (well, except for the mods... heee).

btw, why did you say filter / pbv cannot be?

ohh, btw, about your theory, is it called over arcing? how else can i test for over arcing? (i mean other than putting back my stock cables and wait for 5 months to check the plugs again?? )

tks!

Edited May 28, 2002 by Sdfr