Have ''97 SW2, DOHC, auto, 204K miles. Rebuilt trans at 180K, new engine bearings and pistons/rings at 193K. Ran like a top, was getting 34-36 MPG, burned 1 qt of oil every tank until replaced pistons/rings. Replacing crank bearings brought oil press back to normal. Ex-aircraft engine mechanic, working on Fords since ''66, racing Fords since ''74. Enough history; let friend borrow car for 2 days, brought it back, engine idles rough, obvious miss fire, replaced plugs and ignition wires, no fix. Hooked up OBD reader and sure enough, Cyl 2 misfire. Drinking gas like a jumbo jet, plug #2 wet. So, replaced injectors, no fix. Dug into tech pubs, since cyl 2 & 3 fire both plugs at same time and injectors fire at same time, swapped injector leads => problem stayed at cyl 2; returned injector leads to normal, swapped ignition leads => problem stayed at cyl 2. So, I have eliminated the injector harness and the PCM by swapping injector leads, then eliminated coil pack by swapping ignition leads, my conclusion is that the problem is mechanical to that cylinder. No longer have access to boroscope, so next step is to use Cylinder Leakdown test and check rings/valves. Cranking compression doesn''t signify anything. If this engine had pushrods, I would bet that one was bent, exactly the way it acts. Has anyone had lifter problems with the DOHC engine? Engine smooths out above 1500 RPM, still idles rough, idles better when hot. Sticking valve guides are worse as engine is cold (could be problem), no oil on plug or in exhaust, so no valve guides leaking. Gas consumption and wet plug at #2 still suggest injector problem there. Swapped injectors from #1 and #2, problem still at #2.

Any other ideas? Really, really, really don''t want to take head off in winter (unheated garage), but looks like only option at this point.


Edited by: AztecDan

 

You did not mention it, but I assume you replaced the plugs again ...

OOOPS .. yes you did, sorry, missed that.


Edited by: OceanArcher

 

Are you getting a service engine light? If so, what is the exact code numnber? Im sorry for asking this, but are you sure its cylinder #2? Its the second one from the left correct? Have you tested the coil packs?

 

Update: ECT and IAT sensors check out, resistances good, no broken wires noted. No oil in spark plug wells, all new seals used when engine was apart this summer, still no leaks. In response to another question, all sensors are original factory. Just finished cylinder leakdown check: bad news, exhaust valves leaking on #2, no longer an option, head has to come off. Cylinder leakdown is a static compression test, air is supplied via the sparkplug hole with a set of guages and a measured orifice. Air is supplied at 80 psi and the pressure on the back side of the orifice indicates the condition of the cyclinder. pressure within 90% of the supply indicates a good cylinder, if only a faint hiss can be heard from the crankcase filler. If any hissing is noted from either intake or exhaust, you have a bad seal. A slight leak by the rings is normal, any more indicates worn rings, if you can''t get at least 50% of supply pressure, you have broken rings. All I could get was 35 psi on #2, and a loud hiss from the exhaust.The other cylinders were 73 to 75 psi. A word of caution; the cylinder being checked must be at TDC after compression stroke (when cylinder fires) and held in place securely, don''t trust the crank bolt, on large bore engines there is enough torque (from the air pressure) to back that bolt out. A flywheel tool is best. When doing this on aircraft engines, one or more guys were holding the propeller, if it gets more than 15 or 20 degrees off of top center, that prop will turn with enough force to hurt a person. Another response: Yes, the Service Engine light would blink and the code from the PCM was P0302, the only one I was getting. After cleaning the plug (or swapping the plugs) the code would go away for a few minutes before coming on again. Looks like I order all new valves, guides and seats, if one cylinder has failed, another isn''t too far behind. Might as well replace oil pump gears and timing chain and consider the engine overhauled.

 

I''m going to guess everyone that posted a reply knows how to do a compression test. Question is ... why would you start replacing parts if you had no idea what was wrong and before you did a compression test.

 

Parts replaced at 193K , there were definite reasons to replace them. Car now has 204.5K, that''s 11K miles where it was running great. And the standard cranking compression test failed to indicate the failure, all cylinders pumped between 100 and 120 psi. And approaching 60, (45 years of turning wrenches), it ain''t fun anymore to get out there in the cold.. [img]uploads/AztecDan/PICT0006A.jpg[/img]
The SW2 ride in question.

Since retirement, don''t like getting out in the cold.

Have a good one today, be safe.
DC

Edited by: AztecDan

 

Nice looking pictures there, Dan. Thank you for displaying them. I know garages can be cold and unforgiving this time of year, but do keep us informed on the malady/repair on the SW2 ...

 

Ordered rebuilt head assy from J and C Cylinder Exchange in Fairmont, WV. Sure hope they do good work.
Update: 01/10, am. Received overhauled head from J and C, head appears very well, new valves, lifters appear new, cams and head have been resurfaced. Very well packaged, with one exception, paperwork inside plastic bag with head and got soaked with the preservative oil, should''ve put papers inside separate baggie.
01/26 pm update: One of cyl#2 exhaust valves has broken face, picture coming, shiny reflection of oil in #1 looks worse in picture than really is, cannot detect scratches in cylinder walls (relief), old head received by shop via UPS (they provided return label, very good to deal with).

Does anyone have camshaft specs for valve opening, closing and lift numbers? Has anyone played with advancing/retarding one/both camshafts to see how performance changed? Without cam gears that have multiple keyways, the only way is one tooth at a time and at 19 degrees of crank rotation per tooth, any change would be radical, would prefer 4 and 8 degree intervals.

[img]uploads/AztecDan/PICT0173a.jpg[/img]

Edited by: AztecDan