HedgehogSandwich adi Posted January 24, 2002 Share Posted January 24, 2002 Got the results of my dodgy running due to optimax, burnt out 3 plugs in cylinders 3,4 and 5 ! Least i didnt do anything else but still not good, they were toyota platinums only 1 month old !! They had to replace the whole set. Damn optimax, strange how it worked fine on my old 3.0t, with virtually the same spec plugs. adi 2.5tt Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted January 24, 2002 Share Posted January 24, 2002 Did you have the fuelling checked as well ? Quote Link to comment Share on other sites More sharing options...
HedgehogSandwich adi Posted January 24, 2002 Author Share Posted January 24, 2002 Didn't have the fuelling checked, no..could that be a problem as well then? I've actually still got some optimax still in the tank, heavy diluted by now i hope. Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted January 24, 2002 Share Posted January 24, 2002 Well burn't out plugs could be a number of other things other than just the type of fuel you are using. How do you know your car is not running lean ? For example i have a Mondeo that has been running rich for a long time due to a faulty thermostat and i know that the plugs need replacing because they are shagged. How do you know your timing is not out ? Quote Link to comment Share on other sites More sharing options...
HedgehogSandwich adi Posted January 24, 2002 Author Share Posted January 24, 2002 Well, im assuming it was optimax, as the problem started after about 50 miles of filling it up with the stuff (after a half and half mix earlier in the week). AFAIK the fuelling is okay, Toyota had it in for a full check up when i bought it (diagnostic, not a service) and the fuelling wasn't mentioned. But doesnt that necessarily mean they checked it i guess. I'll keep an eye on the plugs over the next few weeks. Runs like a dream again now :cheesy: adi 2.5tt Quote Link to comment Share on other sites More sharing options...
Doughie Posted January 24, 2002 Share Posted January 24, 2002 keep us all informed on this one please. i.e. change nothing (except the fuel) and then after a month get someone to take a look at the plugs and then report back. If the only thing you've changed is the fuel and all is well now, then this could be serious cause for concern about mk4 owners using optimax. Formula Shell all over again ?? Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted January 24, 2002 Share Posted January 24, 2002 Has anyone, running on Optimax for some time, had a look at their plugs lately? (Edited by Phil Wall at 11:16 pm on Jan. 24, 2002) Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 25, 2002 Share Posted January 25, 2002 This could be interesting indeed - I'm glad I buy all my fuel at one petrol station on one debit card. I can prove that all I bought was Optimax for a period of time leading upto an engine failure, should it be apparent that Optimax in fact causes trouble... Keep us informed. -Ian Quote Link to comment Share on other sites More sharing options...
mrboost Posted January 25, 2002 Share Posted January 25, 2002 quality web page! a very nice start!!! good work m8y Quote Link to comment Share on other sites More sharing options...
HedgehogSandwich adi Posted January 25, 2002 Author Share Posted January 25, 2002 I think if you've got the right plugs (ie colder plugs) then optimax will not foul them up. The problem i think is caused by the combustion temp being too hot and the plugs not being able to cope, thus they burn out. Mine are standard toyota plugs, so not sure about the rating. Yet on my old 3.0t they were also standard and this problem didn't happen. I'll let everyone know in a month or so. I'm just glad it wasn't a burnt valve, which was always a possibility. Cheers for the website comments ! Although i'm cheating a bit as i design websites as part of my job, and though it was about time i had my own !! Still thin on content though. Quote Link to comment Share on other sites More sharing options...
Alex Posted January 25, 2002 Share Posted January 25, 2002 What about with the colder NGK or HKS plugs? I'm taking mine down to the garage tomorrow, my HKS plugs have been in since May so I'll see what they are like. Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 25, 2002 Share Posted January 25, 2002 My MkIII suffered from low rev hesitation and was scorching the stock plugs because I was running higher boost. Moving to a colder grade cured the problem totally. Could it have been simply running a higher boost caused the stocker plugs to melt? -Ian Quote Link to comment Share on other sites More sharing options...
HedgehogSandwich adi Posted January 25, 2002 Author Share Posted January 25, 2002 More likely a combination of factors (fuelling) caused by the higher boost rather than the boost itself. Quote Link to comment Share on other sites More sharing options...
Alex Posted January 26, 2002 Share Posted January 26, 2002 I've just checked plugs 1&2 - both needed to have the gapping adjusted down - but they seem to be healthy (if my reading of the MKIV.com explanation of plug condition is correct) They are brown in colour but the electrode is clean and sharp. But the gapping was incorrect so I'll have to pull them all out check that. I think they were erring on the too hot side of ok so I think its not worth pushing the engine any harder than the 1.1bar I'm running now. More worrying was the fact that the cambelt has chips off of the edges missing!! Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted January 26, 2002 Share Posted January 26, 2002 Any signs of damage, change it. Much cheaper than an engine rebuild. Quote Link to comment Share on other sites More sharing options...
Alex Posted January 26, 2002 Share Posted January 26, 2002 You're not wrong there! I shall call the parts dept on Monday. Out of interest, are there different types of cambelt? Is there an uprated one for big power high revving engines? I doubt this but its worth a question Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted January 26, 2002 Share Posted January 26, 2002 As far as I know you will only get a stock belt from Toyota. Chris W may know of other options. The biggest increase in pressure on the belt may be caused by uprated springs. Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted January 26, 2002 Share Posted January 26, 2002 May want to renew the tensioner as well. Not sure if the TRSM advises replacing this at the same time as well. Phil ? Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 26, 2002 Share Posted January 26, 2002 Does the cambelt change require the crank pulley to come off? From pulling my old engine apart, it seemed like you couldn't get the water pump or lower plastic cambelt cover off until the pulley was out of the way. If you do need to take it off, rather you than me And that's with a MkIII head gasket and MkIV sequential turbo swap under my belt! My MkIII had it's cambelt changed by a garage... I give them all the shit jobs I tried to get the pulley off my old engine - heavy housemate on the engine block, one foot braced on it, both hands on a long breaker bar, heeeaaaaave, eyes bulge, face purple, and the socket split clean in half. I launch backwards across the garage. Fairly good quality socket as well -Ian Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted January 26, 2002 Share Posted January 26, 2002 Yes the crank pulley does need to come off to do a cam belt change. The easiest way is to use a long breaker bar on the nut wedged against the ground and then turn the starter over. Make sure you have disabled the ignition though and that you have the breaker bar wedged the right way!!!!!!!!!!!!!!!!!!!!!! Then you will need a puller to get the pulley off. Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted January 26, 2002 Share Posted January 26, 2002 Quote: from Martin F on 7:14 pm on Jan. 26, 2002[br] May want to renew the tensioner as well. Not sure if the TRSM advises replacing this at the same time as well. Phil ? Do you mean the drive belt tensioner? Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted January 27, 2002 Share Posted January 27, 2002 Well i guess the question is both then, the cam belt one and the drive belt one. Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted January 27, 2002 Share Posted January 27, 2002 Sorry I was looking at the wrong diagram. For both, it is a matter of change if necessary after inspection, not an automatic change with belt. The timing belt tensioner assembly does need checking the guide wheel surface should be checked, if suspect, it should be changed. In Alex's case something has caused belt damage, the guide wheel on the tensioner assembly would be the first thing to check, also check the lower timing cover plate for any obvious damage or signs of chafing. Quote Link to comment Share on other sites More sharing options...
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