Wet morning start engine problem - Page 2

fdxforester · 07-24-2008, 01:24 PM

Quote:

Originally Posted by Tau137

Bad wet start is almost always an electrical issue. Anything ignition-related should be checked first - spark plug wires, coil, igniter and connections throughout. Check the sparkplugs, too - while not the problem, they may contribute due to incorrect gap or whatnot.

Then it might be some other electrical gremlin, having to do with failing sensors or not so good wiring from them (TPS, cam & crank position, knock, MAF). Check, clean (use dielectric grease on connectors where needed), reinstall.

Finally, weak alternator and/or battery may also be contributing to the problem.

Agreed, the engine shaking tells me at least one cylinder is not firing. When it happens again, pull the plug wires off one at a time. You'll know when you have the right cylinder because the rpms won't drop or the engine wont quit when you pull the wire off the plug that not's firing.

bbottomley · 07-24-2008, 01:43 PM

That can be a recipe for a nasty shock if indeed one of the wires is leaking. I'd tend to do the disconnecting with the engine off. I realize that you don't get the benefit of observing an immediate change in RPM that way, but you still ought to be able to see a difference.

Do the disconnect at the coil pack, not at the plug. Easier and faster there. Those plug connectors are in pretty darn tight.

2006F0717 · 07-24-2008, 02:12 PM

It's not easy to test. As I said - it should be a wet morning and cold engine.
Now everything looks dry.
Next morning should be wet again, will look then.

BTW
If a moisture is a problem then it should be a problem until engine got warm. Right?
Why the problem is only on low < 1.0 RPM?
On1.5 RPM no misfire!

neolynne · 07-24-2008, 05:00 PM

Same thing happened to me. Took 3 dealers to figure out it was a cracked coil. $150 later and it ran fine.

bbottomley · 07-24-2008, 05:26 PM

On a dark and very dry night you might be able to see sparks somewhere. But it hasn't been like that in NH for a while!

If everything seems to be OK while you're doing this, then start wiggling things.

2006F0717 · 07-28-2008, 02:52 PM

Thanks neolynne.
So, is it possible they cracked it during the “60k miles” service?
Thanks

lfdal · 07-29-2008, 04:34 AM

If it is still mounted on top of the engine on the 06's, it was a real popular place to lean on, especially if you were messing around the air filter and PCV valve. I think there's a TSB or maybe just a caution notice about not placing any weight on the coil pack since you can crack it that way.

07-24-2008, 01:43 PM	#17 (permalink)
bbottomley Engineer Contributing Member Join Date: Jan 2006 Location: New London, NH Posts: 4,124 Gallery: 0 iTrader: 1 / 100%	That can be a recipe for a nasty shock if indeed one of the wires is leaking. I'd tend to do the disconnecting with the engine off. I realize that you don't get the benefit of observing an immediate change in RPM that way, but you still ought to be able to see a difference. Do the disconnect at the coil pack, not at the plug. Easier and faster there. Those plug connectors are in pretty darn tight. __________________ 2003 XS Premium MT - 2005 Impreza 2.5 RS MT

07-24-2008, 05:26 PM	#20 (permalink)
bbottomley Engineer Contributing Member Join Date: Jan 2006 Location: New London, NH Posts: 4,124 Gallery: 0 iTrader: 1 / 100%	On a dark and very dry night you might be able to see sparks somewhere. But it hasn't been like that in NH for a while! If everything seems to be OK while you're doing this, then start wiggling things. __________________ 2003 XS Premium MT - 2005 Impreza 2.5 RS MT

07-29-2008, 04:34 AM	#22 (permalink)
lfdal Contributing Member Join Date: Jan 2006 Location: Metro Boston Posts: 471 Gallery: 0 iTrader: 6 / 100%	If it is still mounted on top of the engine on the 06's, it was a real popular place to lean on, especially if you were messing around the air filter and PCV valve. I think there's a TSB or maybe just a caution notice about not placing any weight on the coil pack since you can crack it that way. __________________ Larry D 08 OBW Ltd, Missing my 04 FXT 4EAT

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

07-24-2008, 02:12 PM	#18 (permalink)
2006F0717 Join Date: Jul 2008 Location: Nashua, NH, USA Posts: 5 Gallery: 0 iTrader: 0 / 0%	It's not easy to test. As I said - it should be a wet morning and cold engine. Now everything looks dry. Next morning should be wet again, will look then. BTW If a moisture is a problem then it should be a problem until engine got warm. Right? Why the problem is only on low < 1.0 RPM? On1.5 RPM no misfire!

07-24-2008, 05:00 PM	#19 (permalink)
neolynne Join Date: Aug 2006 Location: Westerville, Ohio Posts: 56 Gallery: 0 iTrader: 0 / 0%	Same thing happened to me. Took 3 dealers to figure out it was a cracked coil. $150 later and it ran fine.

07-28-2008, 02:52 PM	#21 (permalink)
2006F0717 Join Date: Jul 2008 Location: Nashua, NH, USA Posts: 5 Gallery: 0 iTrader: 0 / 0%	Thanks neolynne. So, is it possible they cracked it during the “60k miles” service? Thanks