RE: RE: misfire/backfire 02 Dakota 3.9

From: Bernd D. Ratsch (bernd@dodgetrucks.org)
Date: Mon Dec 21 2009 - 06:35:08 EST


Possible burnt valve. You'll need to do a vacuum check and compression test.

-----Original Message-----
From: ttroidl@bluefrog.com [mailto:ttroidl@bluefrog.com]
Sent: Sunday, December 20, 2009 11:38 PM
To: dakota-truck@dakota-truck.net
Subject: RE: DML: RE: misfire/backfire 02 Dakota 3.9

Ok,

I even swapped the injector with #3...

tonight it started acting up so we pulled over, I pulled the wire to the #1 injector and again #1 was the dead Cyl.

then pulled the plug wire and confirmed good constant spark.

was not even trying to fire, running flat on 5.

then for shits and giggles I pulled a vac hose to see if there was any noticable lack of it, seems like plenty BUT... when I reconnected it the engine rpm dropped way low reacting to the vaccume. and #1 started to fire and idled smoothly?

This makes me think the idea of the valve guide not it?

also, I just noticed a bit of oil on the lower side of the bank 1 valve cover dripping onto the exh. man. that was new?!? seemed to be coming from the rear of the engine? couldn't see too well in the dark.

Any ideas?
Blew a gasket from popping? OR is why it's popping????

Thanks much!
Tony.

--- bernd@dodgetrucks.org wrote:

From: "Bernd D. Ratsch" <bernd@dodgetrucks.org>
To: <dakota-truck@dakota-truck.net>
Subject: RE: DML: RE: misfire/backfire 02 Dakota 3.9
Date: Tue, 8 Dec 2009 05:25:00 -0600

Swap out the #1 and #3 plugs - see if the popping follows....next, swap the plug wires, again...check for the popping. Narrow it down as much as you can before spending any large amounts of money. Compression sounds ok. I'd be curious on the vacuum though when it's popping.

- Bernd

-----Original Message-----
From: ttroidl@bluefrog.com [mailto:ttroidl@bluefrog.com]
Sent: Monday, December 07, 2009 10:01 PM
To: dakota-truck@dakota-truck.net
Subject: Re: DML: RE: misfire/backfire 02 Dakota 3.9

Ok, tested Compression, cranking I got around 160/165

Running I got around 90/100.

I wasn't able to get vac as I dunno where my vac guage disapeared to!

I disconnected #1 injector, measured around 13 ohms (engine was hot) and compared it to the other 2 on bank 1 and all were about the same.

With it unhooked I got no popping, so it's cyl #1 for sure...

Plug (new 1 week old) was very white confirming lean cond.

Ideas???

was told it could possibly be a valve guide came loose?

have to have to spend $$$ to have that torn down :( I just don't have time to be pulling heads rite now.

Thanks
Tony.

--- bernd@dodgetrucks.org wrote:

From: "Bernd D. Ratsch" <bernd@dodgetrucks.org>
To: <dakota-truck@dakota-truck.net>
Subject: DML: RE: misfire/backfire 02 Dakota 3.9
Date: Mon, 7 Dec 2009 05:18:51 -0600

P0172: Fuel Trim System Rich Bank 1 (Driver-Side)
P0301: Cylinder #1 Misfire (not necessarily an injector)

Definitely sounds like something is wrong with #1....i'd be checking compression and actual engine vacuum before replacing anything else. Compression, running compression, and vacuum will give you the direction to go.

- Bernd

-----Original Message-----
From: ttroidl@bluefrog.com [mailto:ttroidl@bluefrog.com]
Sent: Sunday, December 06, 2009 11:48 PM
To: dakota-truck@dakota-truck.net
Subject: DML: misfire/backfire 02 Dakota 3.9

Well, after replacing cap rotor, plugs, wires. it still pops thru the intake under load at low rpms, (sometimes) and for the 1st time the eng light came on!

Got po172
po301

misfire only cyl 1, new plug & changed out wire again still no go.

I did look down the TB for oil, pretty clean, very very little oil or anything.

I'm looking at injector next????

when it's popping in OD if I step on it hard it goes like a bat outta hell...

$72 for an injector, figured I'd post my findings befor I spend $$$ if it's not gonna help!

thanks much!

Tony.



This archive was generated by hypermail 2b29 : Fri Jan 01 2010 - 02:54:40 EST