Hi People, I am hoping someone here will be able to help. I have a k reg 850 glt that had a leaking exhaust manifold. Have a limited budget and most tools I decided to change the gasket myself. When the job was completed I decided to give the engine a bit of a clean (water and degrease). When I got round to starting the car it started first time but the exhaust was leaking (sounded like a boy racer mobile J ). Anyway I decided to let it run until it warmed up so the water could dry off. Ten minutes latter it stalled and now it won’t start.

When I turn the key the engine turns fine but it’s like it stops DEAD upon the first fire. It will eventually start if I violently pump the accelerator peddle, whilst started the only way I can keep it running is by keeping the revs above 3000 once I remove my foot from the peddle it stalls. After that it might start, one thing I noticed is that the first fire really drains the momentum in the engine…one minute it turns fine the next minute it almost stops dead.

My thoughts are that it’s an electrical problem, the fact that I had it running for 10minutes with the exhaust really leaking maybe all the sensors have lost there settings???? Any help/suggestions would be most appreciated. Oh yeh the diagnostic tool flashes 1-1-1, the plugs are ok, there is fuel in the tank, it was running fine for 10 mins or so.

 

On your air filter box there is a mass flow sensor where the fresh air hose comes out.Unplug the plug then try to start and see if it runs any better.The computer goes into a special limp home mode.Also have you checked the plugs since you washed it?Usualy when you wash it the water will make its way into the cylinders and flood out the plug wires causing it to missfire.Check those 2 things and let me know.

 

Hi tech,

Thanks for that, unfortunately I can only work on the car during weekends, since it’s parked at my parents place. Can I just assume a few outcomes:

What if I disconnect the sensor and 1. there is no difference, 2. there is a difference, what next?

No I did not check the plugs after the wash, but assuming the plugs are ok, what next?

Sorry to be like this but I want to try as much as possible this weekend since I will only have to wait another week if nothing works.

Thank you for your help.

 

If you unplug the sensor and the car runs better the sensor is bad.I would try to look at the plug wires if you can because that will cause the problem too.It might be dry and run normal by the time you get back to it if it had water in it but you will see marks on the wires.Give that a try and let me know.Do you have access to a computer by your parents?If so and you need more help post again ill be watching.Good luck

 

Hi Tech,

Thanks for your help. It turns out that he exhaust manifold was blowing so violently that the oxygen sensor input to the ecu was totally out. As a result the car thought the oxygen sensor was faulty and would not allow the car to start. Just a word of caution to everyone out there thinking of replacing the exhaust manifold gasket on their 850, don’t make the same mistake I made, the gasket will only seal if put on the right way round J. I now have a sheared stud that needs replacing and hopefully the oxygen sensor will start to work again after which all should be good. Do you have any idea how to get the manifold out of between the engine and bulkhead. The manual says turn it 90 degrees and Walla! But I can’t turn it 90 degrees????

 

You might have to remove the right side axle to remove the manifold.Its a little easier than it looks.I would try to install the gasket correctly then tighten every thing up and see if it seals.You might not have to replace the stud it might seal without that one.Hopefully its not an end one.Good luck if you need any more help im here.