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Discussion Starter · #1 ·
Hi all newbie here first post hoping to get some advice,
I have a r53 mcs running 220bhp
Well I did before my head gasket went ? sadly since replacement car is very underpowered estimate around 10% + down.
Only symptoms are engine pinging and every now and again the revs bog at idle then catch. I am thinking the mechanic has skipped a timing tooth. But looking for advice.
 

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pinging or pinking, maybe anti knock sensor has not been plugged back it sits on front of block behind the super charger, if tooth out the idle would be bad plug it in with scanner i done one last week top end rebuild with a high lift cam shaft, that when first started and driven was a like that, so i plugged it in with autocom cdp plus and that allows me to reset the adaptation on the gen 1 cooper s cars after it behaved fine again, it going on rollers next week see what can be got from it
 
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Discussion Starter · #3 ·
It was just the head gasket that was changed so knock sensor wouldn't have been removed, and I'm sure it would throw a code. Don't see how I can loose about 20 hp and lbs unless the mechanic has done something wrong the only thing I can think of is timing. Thanks for reply
 

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the timing chains on gen 1 mini is very easy to set up cant see how anyone could get it wrong,, you have 3 links coloured and two side by side arrow marks on bottom sprocket and one mark on top sprocket really is a no brainer ant tech would totally not get that wrong its so in your face as such, unlike the gen 2 r56 princes engine they are easy to get wrong, the knock sensor multi plug is bolted to one of the bolts around inlet and ss i know i always unplug them to avoid damage,, but would deffo give a code if not connected,,
its common after head gasket failure for the 02 sensor to get damaged also the cat as well, its also common the badly running engine before the ecu learns the setting of the adaptations and good idea to reset them like said before how to, i done one last week and fitted a high lift newman camshaft in it and until i reset the ecu it ran all lumpy and would not pick up right, after reset then a hour long run through the rev band its back better than right again,
 

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Discussion Starter · #5 ·
I am aware how easy it is to set the timing, which is why I am thinking it might have somehow skipped a tooth by accident.
I have found a fair amount of what seems to be dirt in the bottom of the fuel pump casing today and am wondering if maybe the fuel injectors have got clogged? I did have access to a spare pump and O2 sensor so I have tried with these but no change. I also have a set of standard mcs fuel injectors that I can check incase but if its not that then I am going to have to leave it back with the mechanic.
 

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the 02 sensor will take a few runs to work right with ecu ie reset adaptions or maybe 4 times hot to cold and use all rev band as such,
its not easy to skip a tooth as oil pump/timing cover has a lip on it for bottom sprocket unless its been worn away from past use with tensioner fault maybe.
 

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Discussion Starter · #7 ·
Yes I have been told that as long as the oil pump isn't disconnected it can't skip. Maybe they haven't fitted the gasket correctly incorrect lbs setting maybe I have on occasion heard a gasp of air escaping when I switch the engine off. But if gasket wasn't sealed right wouldn't it be either pressuring the coolant or mixing with oil?
 

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if head gasket was wrong you would have all kinds of water cooling and oil issues etc, if water level stays right and oil dont turn chocolate colour its prob fine, could do a compression test see if any are low if get two next to each other its poss that could leak between,, the head bolts on them are stretch bolts 20nm then 40nm then plus 90 degrees. maybe divertor valve playing up above the throttle body,, worth doing live data run see if 02 sensor when hot runs around the 0.45v mark
 

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I did have a faulty bypass valve but replacement upgrade from 132* min* and wouldn't explain pre det. Will leave back to mechanic and find out I guess.
i would get him when its cold reset all adaptions for throttle control valve and 02 sensor etc then start from cold leave on idle until around 80c then take for a drive at 2000 revs then after a few miles increase it to 3k then 4 k then a couple to the top so ecu can work out where it need to be with learnings then park it up let go cold then repeat this will give it a controlled level to work it self out see what you have at end of it, has car been mapped when smaller pulley fitted was it on rolling road if so if might need another un to tweak it,
 

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Yes 14% , cat back, stealth cai, 380cc injections, ngk iridium 7, big intercooler. I have reset adaptions made no difference.
Leaving it back with him on Friday
its common for if car had head gasket issues to destroy the 02 sensor, its also common if valve seals were gone that oil does same trick, just done a 52 reg one stem seals were so bad and head gasket failed including throwing oil in the water now back together its got a feeling like its holding back when really pushed so decat next job and 02 sensor, anti freeze kills the 02 sensors for a past time, and oil will as well.
 

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now uses no oil we also think that the lack of extra oil to burn off can lower the out put a tad on top
 

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Discussion Starter · #16 ·
Always run on super. This lack of performance,idle drop and pre det has only occurred since head gasket went. I am trying to find out what could have caused these symptoms from a head gasket change
 

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Thanks all but no codes both o2 sensors and catalyst issues throw fault codes but I have changed o2 to be sure, No coolant in oil and no oil in coolant also not burning any oil.
done one a while ago it was at 100k burning oil like hell due to exhaust valve stem seals worn out after this was all done and no longer burning oil,, little tip when anyone fits new valve stem seals fit them with a light film of seal link below is thin stuff can beat it for this sort of job,
after doing that coat the valves and the new rubber seals with a mixture of engine oil and wyns engine treatment ie this leaks a stick coating on all engine parts when go back together
so after rebuilding it we found it had partially blocked the cat also found when cold the car would go very well as soon ad got to near 80c was holding back feeling,, decat'd it mapped it out car goes well again, this car had traces of block weld or rad weld over the years could tell it had not had antifreeze in it for a long time as the insides of block were rusty,, i treated this with rust cure solution and when back together was flushed out and then a strong does of antifreeze added, they all seem to do the stem seals and use oil and the age is not on their side, makers of the cats and 02 sensor say 60-120k miles but gen one cars now are getting very old and rubber parts like stem seals leak and cause all kinds n the exhaust
 

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Discussion Starter · #19 ·
What was the old head gasket OE or aftermarket?

Did you replace like for like i.e OE for OE/upgraded aftermarket with upgraded aftermarket?
Kit was from 132* full gasket kit so both manifolds and thermostat +head gasket+arp bolts. Doubt the issue is with gasket as it is not leaking into coolant or oil. And all 4 cylinders seem to be burning the same. Car almost died at the round about again today. As far as I am aware the only thing that could cause pre det and power loss during a head gasket change is if the timing was off.
 

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All 4 cylinders seem to be burning the same. Car almost died at the round about again today. As far as I am aware the only thing that could cause pre det and power loss during a head gasket change is if the timing was off.
Would a reason for pre-det, pinking, be that it is running too weak a mixture? If so, why following a head gasket replacement would it be running lean? But you saying the plug colours look OK?
Worth doing a compression test?
The 220bhp - that is a dyno figure presumably? Worth doing another dyno run but with an AFR read at the same time? See what the AFRs are doing? And what bhp you are actually getting?
 
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