plugs fouling repeatedly (4agte)

[l1ttle_d3vil]

the plugs on my 4agte keep fouling every 2 or 3 weeks. haven't worked out if its after its been sitting for a week or two without running or after repeated cold starts. sometimes if its starting to miss at idle i'll take it for a thrash (before it gets worst and won't idle) and it seems to clear itself up.

it'll eventually start missing and running on 3 cylinders, 2, then 1. when i take the plugs out they're quite dirty and wet but doesn't seem to be fuel - more like oil. i'll give them a spray with some cleaner and then it'll go perfectly fine. is it possible they're getting condensation or any sort of similar buildup after sitting for a while?

or is it more likely to be the tune being too rich on cold start up/warm up? it was a semi-rushed tune and the tuner didn't have it overnight to set the coldstart up 100%. is there any way I can easily alter the map to see if it corrects the problem, without causing more issues?

cheers
-matt

[Bazda]

its most likely your tune, far too rich at low revs.
Or your rings are shot and leaking oil past into the cylinder.

[l1ttle_d3vil]

cheers, is there any way I can check to see if it is the rings? if they're that stuffed would it show up in a compression test?

the engine seems to be in pretty good condition, very clean under the rocker covers etc, and the tuner never heard a sound from the bottom end during tuning - but in saying that its never been stripped down and inspected since ive had it.

[evil_si]

a cylinder leak down test will show ring and valve seat condition,

compression test will also give a good idea

my pick is the tune,
who tuned it?
saying they rushed it isnt a good sign at all,
personally id be going back to them and getting them to sort the overfuelling as it simply isnt right

[Paulio]

yes, yes.

interesting.

[l1ttle_d3vil]

i'll do a compression check on it next then, and a leak down test.
it was sort of my fault regarding the tune, as I had to get back to work.
should've left it there overnight so it could be setup correctly but I didn't it was really just the cold start which isn't setup 100%, not the overall tune.

[l1ttle_d3vil]

not_paul, whats that supposed to mean. got anything you want to share?

have so far done a compression test, don't have access to a leak down tester yet. tested it cold too just out of curiosity and it was 130psi on all 4 cylinders. warmed it up and retested it, and was 90psi on all 4.

seems a bit low doesn't it? im not sure on the ze blocks (im running the 8.0 low c/r bigport mr2 block) but bluetops should be around 170psi hot, how much would the ze differ?
edit - and i also had one spark plug out at a time while testing, and the throttle was closed - didn't read that bit til afterwards. is that likely to effect it much?


also something else i noticed the link manual says the map pressure should be 100kpa at sea level with the engine running. mine is 102kpa when switched off and 40 - 45kpa when the engine is running. what is likely to cause that?

[Paulio]

Sorry dude yeah i did but was thinking about it for too long and had to take off.

My 4age turbo was around 180psi on 8.9:1 pistons. Maybe there is something wrong with your test.

102kpa is normal because you are above sea level. 100kpa is 0 psi, when it goes below that, the engine is sucking air in, when it goes above that then something is forcing air in to the engine, e.g turbo.

Paulio

[Py7h0n]

Compression does seem rather low...

Test again with Throttle wide open and all plugs taken out.

[escortman]

in my car i didnt have a cold start setup and never had this problem but iv got a stinger ecu

[l1ttle_d3vil]

102kpa is normal because you are above sea level. 100kpa is 0 psi, when it goes below that, the engine is sucking air in, when it goes above that then something is forcing air in to the engine, e.g turbo.

yeah theres no leaks or anything like that, but the link manual definitely says 100kpa while running.

had a compression test re-done using a different tester and came back with 150psi on all four, so looks like the tune may need a tweak...

[79rolla]

also are they old plugs? they shuldint be fouling up that fast but new plugs wont foul up as fast as old plugs that have been cleaned. is it blowing smoke? stupid question. i know.

have you tryed unplugging the cold start injector?

[l1ttle_d3vil]

plugs were put in when it was tuned, so they've had about 3 hours on the dyno and done about 200km on the road probably. been cleaned numerous times during that period though!

not running a coldstart injector because thats all part of the link.
it blows a bit of smoke but I think its more cos of the turbo than running rich. i'll get it back to the tuner some time anyway, probably when I put a bigger turbo on

[l1ttle_d3vil]

just had an afterthought - is it likely to be anything to do with old fuel?

[mr30%jr]

yes, and are what blowby are you using?

[l1ttle_d3vil]

aaah, might try putting some fresh gas in it them. I can't actually remember putting any more in since I had it tuned which was in September

both rocker covers have a vent on them running to a catch can.

[tsoob]

check you water temp sensor

[l1ttle_d3vil]

finally got round to checking the temp sensor.
what would the ambient water temp be roughly, after the car has been sitting in a warm shed all day? ecu was saying 29º before I started it.

or if the sensor is stuffed, is that going to give the wrong reading at the ecu too? thats the only way to get a specific temp to check the ohmes against. i was getting the temp from the ecu thru pclink, and it was:

29º - 1.82ohmes
42º - 1.05ohmes
62º - 0.70ohmes

i have a printout of what it should be just nothing I can upload - but the ohmes seem near enough for those temps. also, when using the factory sensor should "Standard Bosch NTC" be selected in PCLink? guessing the tuner would've altered it if required, but just double checking.

[tsoob]

finally got round to checking the temp sensor.
what would the ambient water temp be roughly, after the car has been sitting in a warm shed all day? ecu was saying 29º before I started it.

or if the sensor is stuffed, is that going to give the wrong reading at the ecu too? thats the only way to get a specific temp to check the ohmes against. i was getting the temp from the ecu thru pclink, and it was:

29º - 1.82ohmes
42º - 1.05ohmes
62º - 0.70ohmes

i have a printout of what it should be just nothing I can upload - but the ohmes seem near enough for those temps. also, when using the factory sensor should "Standard Bosch NTC" be selected in PCLink? guessing the tuner would've altered it if required, but just double checking.

that sounds right to me, ususally if its stuffed you will get a negative reading i.e. -18 when it should read say +60, do you know what heat range your plugs are?

I find with a lot of the cars we have on race tunes they really foul up plugs when they are not driven often (the plus dont get hot enuf) failing that u need to look at removing some fuel from the map (contact your tuner)

[l1ttle_d3vil]

sweet, plugs im using are BKR7E, which is what the tuner recommended.
Does that sound about right? What do other people use? It is consistently only when run cold, if its warm I can run it for hours without fouling.