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well, its almost tune up time for me. new dizzy cap/rotor/wires and plugs (all densco stuff, NGK plugs, of course)

is there any advantage to running colder plugs in it? if so, how do you step NGK plugs colder? i dont really know how to read them...
 
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horrible idea... seriously screwed up my honda when i did that,. i got 15 miles to the gallon instead of 35.... The guy at advance told me to only run colder plugs if im spraying or have forced induction.
 

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^^you must have REALLY gotten colder plugs lol.... im talkin like 1 or 2 steps colder.

what if i plan to advance the timing?
 
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i got 28's or something like that,... i dont remember,. i was still in high school and very stupid. i thought it would make me have more hp................... anyways yea i got like the coldest plug i could find.

edit: maybe it was 82,.... i honestly cant remember that was almost 2 and a half years ago..
 

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Dijital357 said:
so should i run those? or go colder? is there any advantage to doing this?
I think you try to run colder plugs if you are suffering from (trace) detonation when your engine is up to temperature. If you are not having any detonation problems now, there should be no real advantage to running colder plugs. Since increasing CR or running (more) boost tends to increase detonation, then running colder plugs will help.

If the plugs are starting to get fouled (too wet from fuel, possibly allowing carbon buildup to eventually form), then your plugs may be too cold. If this happens then you try to run slightly hotter plugs. This will then improve low rpm driving.
 

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if you're going to advance the timing and don't have a knock sensor, just run 89 octane or 91 octane.

i ran my 5SFE with the timing at 13BTDC on 91 for 2 years with no problems on stock heat range plugs.

-Mike
 

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Discussion Starter #9
rupes said:
I think you try to run colder plugs if you are suffering from (trace) detonation when your engine is up to temperature. If you are not having any detonation problems now, there should be no real advantage to running colder plugs. Since increasing CR or running (more) boost tends to increase detonation, then running colder plugs will help.

If the plugs are starting to get fouled (too wet from fuel, possibly allowing carbon buildup to eventually form), then your plugs may be too cold. If this happens then you try to run slightly hotter plugs. This will then improve low rpm driving.
well, im having annoying detonation problems now, mainly cuz of bad carbon build up that i cannot seem to remedy (thus increasing CR), even running high test fuel. i think im gonna try the colder plugs. how many steps colder should i go to make a difference? should the one step colder of 93 be enough, or should i go more?

again, i dont know how to read NGK plugs, so i dont know how exactly to go colder, except buying 93 plugs.
 

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Discussion Starter #10
fawker said:
if you're going to advance the timing and don't have a knock sensor, just run 89 octane or 91 octane.

i ran my 5SFE with the timing at 13BTDC on 91 for 2 years with no problems on stock heat range plugs.

-Mike
im running 91 octane right now and still knocking pretty bad cuz of carbon build up increasing my CR. ive tried everything.... its annoying as hell.
 

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Dijital357, where is this carbon buildup happening? On the plugs, or pistons? I think it would have to be alot of buildup to increase your CR to the point of causing 'annoying' detonation.
 

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rupes said:
Dijital357, where is this carbon buildup happening? On the plugs, or pistons? I think it would have to be alot of buildup to increase your CR to the point of causing 'annoying' detonation.

its on the head itself. my teacher at school explained it to me this way: several of toyota's engines (including the 5sfe) use a "pent-roof" combustion chamber, and they are notorious for carbon build up. i have done compression tests on my car and hit 200 PSI!!! it seems the carbon build up has pushed my CR high enough to cause detonation...
 

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Some loose information tht may help based on spark plug conditions (as opposed to what you've seen in your cylinder head):

Carbon deposits: Dry sooty deposits indicate a rich mixture OR weak ignition. Causes misfiring, hard starting and hesitation. Check plug heat range, problem in fuel system or engine management system, or ignition system problems.

Ash deposits: If excessive deposits accumulate over a shorttime, replace valveguide seals to prevent oil seepage into combustion chambers.

Oil deposits: Oil leaking past worn valve guide seals, or piston rings into combustion chamber.

Seeing that you are replacing most of the electrical components...
new dizzy cap/rotor/wires and plugs (all densco stuff, NGK plugs, of course)
...I think you are on the right track. If the problem persists, then look into your oil control. Remember, high CR should give you more power, otherwise you dont want it. Right?
 

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Dijital357 said:
well, im having annoying detonation problems now, mainly cuz of bad carbon build up that i cannot seem to remedy (thus increasing CR), even running high test fuel. i think im gonna try the colder plugs. .
If you have excessive engine deposits, a colder plug is NOT a good idea.

It will probably NOT help your problem, but it will foul more quickly.

If you have excessive engine deposits, you need to fix the problem.

bill
 

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alright, thanks everyone for your responses. i'll investigate these things and see what i can come up with. grr this is frustrating me! i hate running high test fuel cuz its so expensive, but its the only thing that keeps it from knocking like crazy. if i run 87 its almost constant.
 

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Dijital357 said:
alright, thanks everyone for your responses. i'll investigate these things and see what i can come up with. grr this is frustrating me! i hate running high test fuel cuz its so expensive, but its the only thing that keeps it from knocking like crazy. if i run 87 its almost constant.
Have you checked your timing?

bill
 

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Discussion Starter #18
billwot said:
Have you checked your timing?

bill
uhh....weeeeellll....... sort of ;)


ive bridged the diagnostic connections and moved the distributor a little bit to the advanced position, driven it, moved it to the retarded position, driven it and seen no change.

i havent officially checked it with a timing light cuz its a PITA.... i knew you were going to bring this up :smile:
 

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Forgive me pls (i'm new to the forum - only 35 posts at this time), what does "PITA" mean?

Also, what about your cam timing Dijital357? Get that checked out too.
 
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