Misfire M35a2

[mark m35a2]

Was running fine last week, now its misfiring , changed fuel filters were not dirty anyway , lift pump working , if i crack each injector it has the same effect, really smoking black if you drive it, it has also peeled the paint of the top of the exhaust ? high exhaust temp .... no water in oil , no oil in water ......anyone have any ideas ?

 

[DaneGer21]

Stuck open or leaky injector maybe?

 

[mark m35a2]

That was my initial thoughts but when I crack each injector pipe it seams to have the same effect on all 6 cylinders.......

 

[Floridianson]

Is your flame heater deleted? That will put a lot of extra fuel into the system if it was malfunctioning.

 

[mark m35a2]

Mmmm now I fitted a reversing camera and picked up a live under the dash ... have I earthed the heater and made it on permanent... ill disconnect... fingers crossed and thanks

 

[ToddJK]

When you said you cracked the injectors, that mean you visually checked the spray pattern? If yours has the flame heater, I'd highly encourage to delete it unless it's something you really need,otherwise those usually lead to more issues than problems that part is there to solve.

 

[DaneGer21]

Mmmm now I fitted a reversing camera and picked up a live under the dash ... have I earthed the heater and made it on permanent... ill disconnect... fingers crossed and thanks

I would think an electrical issue wouldnt mess with this type of mechanical engine.

If that’s the case, and you think its an electrical issue, maybe it’s messing with the lift pump???

 

[mark m35a2]

When you said you cracked the injectors, that mean you visually checked the spray pattern? If yours has the flame heater, I'd highly encourage to delete it unless it's something you really need,otherwise those usually lead to more issues than problems that part is there to solve.

no just slightly opened each injector feed pipe and each on had pressure but could be the injector itself

 

[DJGerry]

I would believe more of an injector issue. But you say the change is the same on each cylinder when you crack the injector line open?

 

[ToddJK]

You'll want to pull the injectors and have a buddy crank the engine and watch the spray pattern. If they stream or sputter, that can be the issue, each one should put out a nice mist spray. If the spray patterns look okay, you could test each injector to make sure it pops at the proper psi as specified in the tech manual, I don't remember the exact psi, but there are plenty of threads on here where it's discussed and others sharing their methods to test the injector. If an injector has a poor spray pattern, it could be dirty and just needs to be disassembled and cleaned or could be worn and needs rebuilt or replaced. Being a mechanical engine, I find it unlikely any power source can cause a misfire. Only other possibility is that the misfire was misdiagnosed as a surge due to dirty fuel filters, which I can see that being a possibility as surges can sometimes feel like a misfire, but being you changed the filters amd really black smoke is a big indicator of unburnt fuel, I believe it to an injector issue.

 

[mark m35a2]

thanks for the input guys , its rocker cover off day to check valve openings and compression test to see if we have suspect anywhere ..... with the very distinct pop sound on each revolution we are thinking more a stuck exhaust valve or head gasket

 

[ToddJK]

thanks for the input guys , its rocker cover off day to check valve openings and compression test to see if we have suspect anywhere ..... with the very distinct pop sound on each revolution we are thinking more a stuck exhaust valve or head gasket

Keep us updated, many threads end with no solution which isn't any help to those with similar issues. I hope you find the issue and get the beast back to running in top condition.

 

[mark m35a2]

so update so far , pressurised the water system and no loss of pressure , low compression on cylinder 5 with signs of oil dripping from head gasket , removed injector and spray pattern is good , all 12 valves seating correctly , so heads coming off , ordering a head gasket set which is looking like the issue ....... hopefully

 

[ToddJK]

so update so far , pressurised the water system and no loss of pressure , low compression on cylinder 5 with signs of oil dripping from head gasket , removed injector and spray pattern is good , all 12 valves seating correctly , so heads coming off , ordering a head gasket set which is looking like the issue ....... hopefully

Exterior oil leaks from the head gasket is typically normal. The old style has tabs that allow for seepage. If you're ordering a new gasket, check out SECO for the set, I bought a set earlier this year at $60/EA which was much cheaper than anyone else, just took about week or so with shipping. Hopefully that is the issue, perhaps the gasket was allowing for oil to dump in the cylinder and maybe that's why it was getting so hot, but that makes me think the steel ring gave out.

 

[mark m35a2]

ahh ok , as there is a weep from Cyl 2 area so that may be normal .. ok , im in the UK so am trying Maltrax initially for a gasket set , else ill get it from across the pond at SECO

 

[ToddJK]

ahh ok , as there is a weep from Cyl 2 area so that may be normal .. ok , im in the UK so am trying Maltrax initially for a gasket set , else ill get it from across the pond at SECO

My bad, I didn't check to see where you were, lol.

 

[mark m35a2]

Huston we found the problem , HG gone between Cyl 2&3 , all else looks ok , hopefully back together next week and back running like a watch

 

[mark m35a2]

COMMUNITY HELP !

so the heads were skimmed by 7thou , all new gaskets inc head gasket ( obviously ) , all back together and torqued down, bled the fuel through to injectors and hey presto fired up first time running like a watch ! BUT oil leaking out between head and block and a bit of coolant also its leaking on both heads and both sides , its as if the heads havent seated correctly ... fire rings must be seated as its running perfectly , the replacement head gasket was the gasket and separate fire rings (same as i removed) , anyone any suggestions??

could the dowels that locate the gasket and head be bottoming out ? but its only had a 7thou skim ?

its as if the fire rings have not compressed enough .... picture of old head gasket and fire rings below

should i have gone for the new head gasket with integral fire rings ?

 

[Welder1]

COMMUNITY HELP !

so the heads were skimmed by 7thou , all new gaskets inc head gasket ( obviously ) , all back together and torqued down, bled the fuel through to injectors and hey presto fired up first time running like a watch ! BUT oil leaking out between head and block and a bit of coolant also its leaking on both heads and both sides , its as if the heads havent seated correctly ... fire rings must be seated as its running perfectly , the replacement head gasket was the gasket and separate fire rings (same as i removed) , anyone any suggestions??

could the dowels that locate the gasket and head be bottoming out ? but its only had a 7thou skim ?

its as if the fire rings have not compressed enough .... picture of old head gasket and fire rings below

should i have gone for the new head gasket with integral fire rings ?

The gaskets you used are the old style with separate fire rings. They tend to give problems and were upgraded to the new style ones. For the TD block (thick deck) you should have torqued the head nuts to 157FtLbs.

 

[gringeltaube]

Too bad you didn't get the new-style gaskets from Seco...

I don't think that the dowels are the culprit.
If I had no other choice as to use the early OEM gaskets, I would at least anneal the rings (450-500°C = barely red) to get them nice and ductile.
Also make sure that the torque wrench is accurate.