Post by DanD on Mar 21, 2006 16:59:44 GMT -5
Hey guy’s.
I just finish a good one here on a 2000 Ford Focus with the 2Lt single overhead cam. 38k showing. This engine is like the old Escorts engine.
This also goes to show you to always take 5 minutes to check for service bulletins.
Customers complaint was “the engine shakes sometimes”
Get in the car for a road test, start it up smooth a glass, go down the road lots/normal power, come to a stop with a dead misfire. Sit there for a minute in drive and you can feel the misfire slowly go away. Drive away it feels normal again, until you come to a stop and the same misfire. Get back to the shop and at first could not duplicate the problem until I raised the RPM above 2000 and held it there for at least 20 or 30 seconds.
Scan the thing and get a P0302, #2 cylinder misfire.
Me being cocky thinking it’s likely a plug; I fire in a new set, same misfire. Checked wires and they metered out ok. Switched #2 and #3 wires at the coil pack in the hope that the coil was shorting out on the secondary side for #2 same mis.
Check injector pulse during the high and low RPM and it was always consistent even during the misfire. The injectors also ohmed out ok.
Pull the fuel rail and switch #2and #3 injectors just to be sure, same thing again.
Ok now where do we go, compression test 165 psi across the four cylinders.
Take the shraider valve out of the compression tester and run the engine with the tester in #2 cylinder. At idle the needle is bouncing from 0 to 75 pounds take the RPM up to 2000 and the needle stays close to 0 but is twitching then suddenly it goes completely still at 0. Allow the engine to idle again the needle stays at 0 for about 20 seconds and then starts bouncing again up to 75psi.
OK I got you; it’s a lifter pumping up and holding a valve open after the high RPM. NOT change both lifters on #2 and the same misfire.
That’s when I finally went to the TSB’s and sure enough there’s one for an intermittent misfire at idle.
Their claim is that it’s carbon build on the exhaust valve stem between the head of the valve and the valve guide causing the valve to stick open at high RPM. Their fix is to replace the cylinder head along with installing revised guides and valves.
Try selling that to a customer with so little mileage on the engine. LOL What I ended up doing is running a couple of top end decarb’s which has seemed to cure the problem (for now anyway) and told the customer that if it returns we may have to rebuild the head.
Like I said I should have sat down for 5 minutes and read the TSB’s and saved myself all the grief of trying to figure this out let alone all the lost time I spent on this thing.
Dan.
I just finish a good one here on a 2000 Ford Focus with the 2Lt single overhead cam. 38k showing. This engine is like the old Escorts engine.
This also goes to show you to always take 5 minutes to check for service bulletins.
Customers complaint was “the engine shakes sometimes”
Get in the car for a road test, start it up smooth a glass, go down the road lots/normal power, come to a stop with a dead misfire. Sit there for a minute in drive and you can feel the misfire slowly go away. Drive away it feels normal again, until you come to a stop and the same misfire. Get back to the shop and at first could not duplicate the problem until I raised the RPM above 2000 and held it there for at least 20 or 30 seconds.
Scan the thing and get a P0302, #2 cylinder misfire.
Me being cocky thinking it’s likely a plug; I fire in a new set, same misfire. Checked wires and they metered out ok. Switched #2 and #3 wires at the coil pack in the hope that the coil was shorting out on the secondary side for #2 same mis.
Check injector pulse during the high and low RPM and it was always consistent even during the misfire. The injectors also ohmed out ok.
Pull the fuel rail and switch #2and #3 injectors just to be sure, same thing again.
Ok now where do we go, compression test 165 psi across the four cylinders.
Take the shraider valve out of the compression tester and run the engine with the tester in #2 cylinder. At idle the needle is bouncing from 0 to 75 pounds take the RPM up to 2000 and the needle stays close to 0 but is twitching then suddenly it goes completely still at 0. Allow the engine to idle again the needle stays at 0 for about 20 seconds and then starts bouncing again up to 75psi.
OK I got you; it’s a lifter pumping up and holding a valve open after the high RPM. NOT change both lifters on #2 and the same misfire.
That’s when I finally went to the TSB’s and sure enough there’s one for an intermittent misfire at idle.
Their claim is that it’s carbon build on the exhaust valve stem between the head of the valve and the valve guide causing the valve to stick open at high RPM. Their fix is to replace the cylinder head along with installing revised guides and valves.
Try selling that to a customer with so little mileage on the engine. LOL What I ended up doing is running a couple of top end decarb’s which has seemed to cure the problem (for now anyway) and told the customer that if it returns we may have to rebuild the head.
Like I said I should have sat down for 5 minutes and read the TSB’s and saved myself all the grief of trying to figure this out let alone all the lost time I spent on this thing.
Dan.
