Help! Big engine problem!

[Mark Emerson]

Hey guys, if anyone here is mechanically minded, please help...

I was wondering if you had any thoughts on this one… I had my rocker cover and plenum re-powder coated, and I refitted them today with new spark plug gaskets and cam cover gaskets. As far as I know, I fitted them properly. Anyway, put it all back together and then when I started the car it idled really rough and was hunting. Then after about 10 or 15 seconds I noticed smoke (or steam?) coming out of the engine! (not really sure where it was coming out) it sounded quite mechanical as well, a kind of metallic clanging. I just can’t think of anything I have done that could make this happen, the only thing I did notice is that the bin bag that I had over the cam cover had some water on it and some water might have got into the engine oil/engine? Do you think that would explain it? There is no milkiness in the dipstick or in the oil filter, or on the filler cap, so I can’t believe they would be that much water in there to cause this... I then thought about the electrical connections, there was a plug onto the air plenum (sensor), another electric plug on the top of the air filter, and there was plugs onto the spark plug coils, but they were all put back in order properly, so I really don’t know... I’m completely baffled! Dare not start it again as sounds horrendous! I did top up the oil, which went a little over the max mark, would this cause an issue?

 

[Eddie Zedder]

Hi Mark, I would recheck all your electrical connections & pipes and any others in the area that may have become dislodged accidentally, especially cam sensors and vanos connectors. Also put a code reader on to see if there were any errors thrown up.

I would have said that the smoke maybe a bit of burn off from the powder coating but I don't think you have run the engine long enough for it to be that.

Any ideas @t-tony?

 

[BMBabe]

@Lee maybe able to make a suggestion

 

[Mark Emerson]

Hi Mark, I would recheck all your electrical connections & pipes and any others in the area that may have become dislodged accidentally, especially cam sensors and vanos connectors. Also put a code reader on to see if there were any errors thrown up.

I would have said that the smoke maybe a bit of burn off from the powder coating but I don't think you have run the engine long enough for it to be that.

Any ideas @t-tony?

Thanks Eddie, that’s helpful. I have done this today and reassembled. Nothing untoward found. Still running a very lumpy idle and occasionally hunting. BUT I noticed this time a milky patch on the oil cap so suspect maybe more water that I thought got in there. Smoke seems to be from oil on the exhaust manifold. I’m now thinking the lump idle is water in the oil affecting oil pressure and powertrain lubrication. I’m going to flush the oil and refill to see if that helps... sound sensible/plausible to you?

 

[t-tony]

A good idea to change the oil and filter regardless of how much water may have got on there but I doubt that is the reason for rough/lumpy idling assuming it was ok before. Is this 1 9?

Tony.

 

[Eddie Zedder]

A good idea to change the oil and filter regardless of how much water may have got on there but I doubt that is the reason for rough/lumpy idling assuming it was ok before. Is this 1 9?

Tony.

Z3M I think Tony.

 

[Eddie Zedder]

Thanks Eddie, that’s helpful. I have done this today and reassembled. Nothing untoward found. Still running a very lumpy idle and occasionally hunting. BUT I noticed this time a milky patch on the oil cap so suspect maybe more water that I thought got in there. Smoke seems to be from oil on the exhaust manifold. I’m now thinking the lump idle is water in the oil affecting oil pressure and powertrain lubrication. I’m going to flush the oil and refill to see if that helps... sound sensible/plausible to you?

As Tony says, water in oil wouldn't cause combustion issues unless you have a head gasket issue.

 

[Fender2004]

What about checking the rubber hoses on the air intake side, these might have dislodged a crack in the pipe that was already there. Lumpy running can be caused by a leak in the air intake hoses.

 

[t-tony]

Why I was wanting to know which engine it was. Many different issues.

Tony.

 

[Mark Emerson]

Hi, thank you for the reply, it’s appreciated, it’s the 3.2L S50 engine from the 1999 M-Roadster. (UK car) there is always the possibility that something has gone wrong with the van off, but it seems a bit sudden for that to go.

 

[t-tony]

The suddeness makes me think its something you did/didnt do while changing the rocker cover etc. Also a rubber induction part disturbed split left off maybe.

Tony.

 

[BMBabe]

@Mnbrennan

 

[Mark Emerson]

The suddeness makes me think its something you did/didnt do while changing the rocker cover etc. Also a rubber induction part disturbed split left off maybe.

Tony.

Thanks, yes I’m inclined to agree with you but really can’t see/find anything, maybe I’ll completely go over this again just to doublecheck .

 

[t-tony]

Good luck getting to the bottom of it Mark and please keep us in the loop.

Tony.

 

[Lazzzydog]

The mechanical racket was possibly pre-ignition or just a misfire. If the car has been standing over winter it could just be degraded fuel. It’s unikely to be anything too serious unless you have been very unlucky.

 

[gookah]

did you rescue every bit of gasket, if there are some old brittle bits left in place, and the rocker cover is not sealed down properly because of it, it will lose pressure and run rough. It's like taking the filler cap off,. Also did any old bits fall into the valve tappets and get under the shims?

 

[Mark Emerson]

Thanks guys, all good points! I’ve still not got to the bottom of this but appreciate the input!

 

[NJBoyce]

Try spraying brake cleaner around inlet pipework with engine running, if revs pick up you have got a leak on inlet system