Author Topic: One cylinder firing (Read 1318 times)

WideBoy04 · « **on:** Monday, September 17, 2012. 04:08:16 PM. »

2004 FLHT carb. Runs on one cylinder. Coil and wires test good.
Crank sensor? Ignition Module? I don't have the ability to test
either of these. I don't do electrical work much.

hogpipes1 · « **Reply #1 on:** Monday, September 17, 2012. 06:12:11 PM. »

try a new plug, or just pull the wire off the plug slide the boot back hold the wire a 1/4 " from plug . see if the cyl kicks in . still not working and new plug, i'd ck comp.on that cyl.

Jaycee1964 · « **Reply #2 on:** Monday, September 17, 2012. 06:32:32 PM. »

Compression test too may shed light

scoopfraser · « **Reply #3 on:** Monday, September 17, 2012. 07:45:04 PM. »

Under what conditions does it run on one cylinder (e.g. while idling, under load)?

bohnhead1 · « **Reply #4 on:** Monday, September 17, 2012. 09:03:06 PM. »

Try wiggling the wires at the connector that plugs into the coil. I've seen a bad pin connection there before.

WideBoy04 · « **Reply #5 on:** Tuesday, September 18, 2012. 02:47:07 AM. »

Quote from: scoopfraser on Monday, September 17, 2012. 07:45:04 PM.

Under what conditions does it run on one cylinder (e.g. while idling, under load)?

Both, already changed plugs. Going to clean the CPS tonight.

rbabos · « **Reply #6 on:** Tuesday, September 18, 2012. 11:42:15 AM. »

Quote from: WideBoy04 on Tuesday, September 18, 2012. 02:47:07 AM.

Quote from: scoopfraser on Monday, September 17, 2012. 07:45:04 PM.
Under what conditions does it run on one cylinder (e.g. while idling, under load)?

Both, already changed plugs. Going to clean the CPS tonight.

Probably nothing there to clean that would make a difference. Why not just unplug it and use a multimeter on it. I don't think it can effect once cyl only in either case.
Have you sprayed the intake with brake cleaner while running to see if the cyl starts to fire? Carbs are very touchy if there's an intake leak since it will starve that cyl for fuel.
Ron

Durwood · « **Reply #7 on:** Tuesday, September 18, 2012. 11:50:10 AM. »

Had one here a couple weeks ago doing the same thing,ended up being the ignition module..

WideBoy04 · « **Reply #8 on:** Wednesday, September 19, 2012. 03:36:35 PM. »

I have to go to the dealer to pick up a part, if I take the CPS and
the ignition module with me is there a test they can do on them?

Thanks, Jim

Garry in AZ · « **Reply #9 on:** Wednesday, September 19, 2012. 07:45:00 PM. »

I'm certainly no expert, but it seems to me if the crank position sensor was the problem, you would have a no spark situation on both cylinders, not just one. I'd start by swapping the coils around and see if the problem changes cylinders. If the coil is not the problem, disconnect the battery and check the resistance between the W/BK wire on the coil connector (middle wire I think) and the positive terminal of the battery. You must disconnect the battery to measure this. The resistance should be less than 1 ohm. If it is higher, the problem is in the harness. If the resistance is 1 ohm or lower, replace the ignition module.

Best of luck to you.

Garry

WideBoy04 · « **Reply #10 on:** Thursday, September 20, 2012. 03:30:17 PM. »

Front cylinder, no spark. Rear cylinder, weak spark.

WideBoy04 · « **Reply #11 on:** Thursday, September 20, 2012. 03:50:06 PM. »

Pulled error codes, all showed, none.

nibroc · « **Reply #12 on:** Friday, September 21, 2012. 05:48:21 AM. »

there's no error codes on my 59XLCH but it's still hard to start

WideBoy04 · « **Reply #13 on:** Saturday, September 22, 2012. 06:32:38 AM. »

This is my stepsons bike, my advice, send it to the dealer. He opted to put
on a Dynatech TC88A ignition module, now you are in territory I'm lost in.
What he has now, good spark to both cylinders, rear is firing front is dead.
Waiting on a friend to do a compression check this morning. With the
Dynatech it throws the code: P0373 Crank Sensor Intermediate Carb, and
U1016 Loss of ICM Serial Data Instrument. With the OE module, no codes.
I still say send it to the dealer.

WideBoy04 · « **Reply #14 on:** Saturday, September 22, 2012. 01:29:12 PM. »

Finally was able to get a compression check done. Front cylinder, 126. Rear 0.
Point me in the right direction, already started to get ready and pull the heads.
Checked the adjustable pushrods, tight. Valve springs look good. Broken ring,
piston hole, bent valve?

Thanks, Jim

ViennaHog · « **Reply #15 on:** Saturday, September 22, 2012. 01:59:44 PM. »

Take pushrod covers off and verify movement of both PR. Re-check the correct adjustment of PR. If that turns out OK, it smell like a stuck/bent valve or a hole in the piston.

WideBoy04 · « **Reply #16 on:** Saturday, September 22, 2012. 03:39:35 PM. »

Pushrods seem good. After very close inspection, it appears the
head gasket is blowed. will pull down tomorrow and hope thats it.

WideBoy04 · « **Reply #17 on:** Monday, September 24, 2012. 02:35:55 PM. »

Nice size hole in piston. About 1 1/2 x 3/4". Looks like a punched hole.
Spark plugs are fine. Don't know what a burnt hole looks like. Now to figure out what
caused it and where are those pieces

.

Durwood · « **Reply #18 on:** Monday, September 24, 2012. 04:19:45 PM. »

Quote from: WideBoy04 on Monday, September 24, 2012. 02:35:55 PM.

Nice size hole in piston. About 1 1/2 x 3/4". Looks like a punched hole.
Spark plugs are fine. Don't know what a burnt hole looks like. Now to figure out what
caused it and where are those pieces .

Look for signs of an intake leak on that head.

WideBoy04 · « **Reply #19 on:** Monday, September 24, 2012. 04:53:40 PM. »

Looks to be a leak around intake.

Durwood · « **Reply #20 on:** Monday, September 24, 2012. 05:42:47 PM. »

Hard to tell for sure but it looks like it could have been leaking next to the stud on the left side of the pic.

sfmichael · « **Reply #21 on:** Tuesday, September 25, 2012. 03:56:53 AM. »

Ouch. How many miles?

WideBoy04 · « **Reply #22 on:** Tuesday, September 25, 2012. 02:32:56 PM. »

70,000+ on bike, 40,000+ on build. If I remember right,
Keith Black cast 9.8:1 95" big bore kit. HeadQuarters 0034
cams, with 06 heads. Bike has run flawlessly. 2 months after
stepson buys it, it blows. Looks like we're going to split the
cases, weld and balance the crank, 98" w/forged pistons, and
some mild head work. Nice winter project.

rbabos · « **Reply #23 on:** Tuesday, September 25, 2012. 02:34:39 PM. »

Piston looks pretty black to be running lean.
Ron

Ajayrk · « **Reply #24 on:** Tuesday, September 25, 2012. 03:02:52 PM. »

If the light spots in the carbon is missing deposits I would suspect preignition (timing). Could be lugging the engine.

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Author Topic: One cylinder firing (Read 1318 times)