2006 Sportster LE DI Runs rough

[despower]

My 2006 Sportster has been running rough all of this season. The best I can describe it is that the engine runs in spits and spurts, definitely not smooth - however, it runs good enough for it to get up to 6000-7000 RPM and plane fine. The engine also runs better after 15-20 minutes, but it never becomes a smooth sound. At full throttle, it never goes past 7000 RPM and mostly sits at 6000 RPM. I know there's a lot of things to check so I'd like some of the experts to give me a list of things to try. It sounds like a fuel supply problem, but I'm not sure how to check for that. A couple of observations:

1) The boat is now 16 years old and I note that the in-line fuel filter (part number 204560290) has never been replaced. It's an item that should be replaced every 250 hours according to the maintenance chart and I might be well over that number by now (I don't get many hours in per year because of the weather). Are there any other fuel related items I should be replacing?

2) The engine sounds fine at low RPM. The spits and spurts only seems to happen at higher RPM at maybe 4000 and higher, when I get the boat up to plane.

3) I replace my plugs every year and I only run the boat for 4 months while it's warm here in these parts. I noticed a few times when I inspected the plugs that there appears to be condensation and even some green corrosion at the contacts. Otherwise, when the plugs are cleaned, they look fine. I plan to replace them shortly since this is an easy fix. However they were replaced at the season start.

4) My bilge pump failed last year and the engine compartment flooded. I cleaned everything out, but the condensation from (3) might be due to that. But that's only a guess.

5) Cylinder compression is fine. That's one thing I know how to test.

If anyone has any thoughts about the above, I'd appreciate it.

Best Regards

Des

 

[POPPS]

Fuel pump could be failing?. Connect an external gauge to see what your ”running” pressure is.

 

[despower]

Thanks. I can try that. Where is it best to hook up the gauge? Never did it before so I figured it's best to ask.

 

[despower]

I think I found the test procedures. There's a static test (inserting DESS key) and a dynamic test (cranking the engine). I'll try both. The manual says to release the fuel pressure using the VCK. I don't have one of these so is this necessary?

 

[despower]

There's also a fuel pump output pressure test. Looks like a have a few tests to try. I'll do these and report back when I'm done.

 

[Raven888]

Did you replace the fuel filter? Cheap and easy. It's likely clogged.

 

[despower]

Do you mean the fuel filter contained within the fuel pump? Or the external fuel filter? The external one is about 300 bucks but the internal one is real cheap. I'm going to do the pressure tests this weekend and I'll see how both filters are looking.

 

[Raven888]

$300 for a fuel filter? Are they friggin' insane!

 

[despower]

That's why I reluctant to buy without doing a pressure test first. It's a 2006 model so many of the parts are discontinued. The fuel pump is almost 1100 bucks (Canadian) so I'm hoping it isn't that. The internal filter isn't available to purchase, but I might be able to service it if I remove it. Yeah, sounds like a bad deal, doesn't it.

 

[Raven888]

Here's one for $20 USD. fuel filter If it's the right one.

 

[despower]

It's a reasonable facsimile. Different connectors but I can just use oetiker clamps instead of the quick disconnect fuel connectors. Thanks for the tip.

 

[Raven888]

They have fuel pumps also and the strainer/filter for the fuel pump. They even have a fuel pressure gauge.
other stuff

 

[despower]

Wow. There's a direct replacement for the fuel pump at a fifth of the price. That's awesome.

 

[despower]

In actual fact, I can get the pump and the external filter for $109, whereas if I had to buy the OEM versions, it would cost me almost $1500 from my usual Canadian site. And it's a match to the OEM part numbers. This is excellent - thanks.

 

[wayneh]

Please let us know how it turns out.

On the last outing, my 2001 Challenger behaved very oddly and a little similar to what you described. It started and idled fine but had trouble reaching and holding rpms over 4,0000. Both engines were affected, but not at the same time except randomly. They'd run fine for a bit and then lose rpm, from 5k down to 3k for instance, and then come surging back. I had just put in gas, but only 8 gallons in the over-20 gal tank. It's easy to think it was the gas but I'm not convinced. I replaced my fuel filter a couple years ago and I was thinking that could be it.

The oddest part is that after running for maybe a half hour, then sitting (at a dock concert) for a couple hours, it came back to normal and smooth operation. It's like something got hot and dried out. I've had the boat for 10 years and never had this happen.

 

[despower]

First update - I purchased a new fuel pump and filter from Quantum Fuel. I decided to replace the filter before doing any pressure tests. Looks like the fuel filter isn't the problem because the old one wasn't clogged. It isn't as freely flowing as the new one, but there shouldn't have been any fuel flow issues through it. I had to order fittings for the fuel pressure test - and these came today so I'll do the fuel pump test in a few days.

The 1/2" hose clamps that were shipped with the filter weren't the right size. Fortunately, I had the next size up already (18.5mm) so it was relatively easy to install. I had to cut the old filter off (it's a complete unit with hose assembly). I was still able to mount the filter in the usual spot - I had just enough hose left for the length that runs to the pump.

If I have to replace the pump, that's going to be an off season job because I have to remove the seats before pulling the pump and it's a little more work than expected.

 

[despower]

Second update - with the new fuel filter installed, and the right fittings to do pressure testing, I performed the static and dynamic fuel pressure test as prescribed in the service manual.

1) The static pressure test measures the pressure at the air fuel rail along the hose that feeds from the pump to the injectors (the line with the fuel filter). That's supposed to be 27+/- 2 psi when the lanyard is inserted. I measure about 30 PSI. I don't consider that to be out of spec because I have no idea of the accuracy of my pressure gauge. There is also no pressure drop (rapid or slow) with the key inserted, so I interpret that there is no leakage in the system anywhere.

2) The dynamic pressure test performs the test on the same line while cranking or running the engine. That's supposed to be 107+/- 2 psi. I measure between 106 and 110psi (the needle wiggles back and forth between those two numbers with the engine running). I also interpret this to be within spec, unless someone can tell me if the 4 psi variance is an issue.

My next test is a fuel pump output pressure test, which measures the pressure between the outlet and return lines of the fuel pump. That is supposed to be 105 psi. I haven't done this yet, but I might do this on the weekend. I also need to take the boat out for a spin, since I haven't done that since installing the new filter.

Anyone see any issues?

Note that the fuel pump pressure test is supposed to be done, according to the manual, with a pressure relief valve so that there's no damage to the air compressor. This sounds strange to me because the compressor isn't in the loop involving the fuel pump outlet or return lines. Can anyone explain what the manual is trying to say?

 

[Raven888]

I'm glad I was able to help. I've added Quantum Fuel to my favourites list for future use.

 

[despower]

I finally did a closed loop fuel pump test today - weather has been crappy all week and I have the boat outside. In any case, I connected the Tee Adapter between the outlet hose from the fuel pump (to the external fuel filter) and return hose to the fuel pump (the one that comes directly from the fuel/air rail). The shop manual says that this should read 105 PSI after I connect the safety lanyard (note that it does not say to crank the engine). It reads nothing. I disconnected the lanyard several times and reconnected it to see if that would change. All I get is a little jump from the needle and it goes back to zero. So, am I doing something wrong or is my fuel pump truly toasted? I feel as if I'm doing this loopback test incorrectly or I'm reading the shop manual wrong. Any thoughts???

 

[despower]

No answer to the previous post, so I decided to go ahead and swap the fuel pump. Removing the centre seat cushion wasn't good enough to get at the fuel pump module because it looks like the gas tank has shifted forward a bit so that the fuel pump and the access panel aren't perfectly aligned. See photo. I removed all the seats and managed to wiggle the fuel pump up and out after some patient jiggling. Question - should the fuel pump module and the seat access be perfectly aligned or is what is shown in the photo the way it's supposed to be? I am wondering if I should try too move the gas tank back a bit so it's easier to get that the fuel pump in the future.

 

[despower]

After removing the module, I was able to disassemble the pump and remove the internal fuel filters. As you can see in the photos, they are pretty filthy. Can't say if they are 'blocked' but they are certainly dirty enough that replacement is warranted. It would be nice if BRP designed these things to be accessed more easily.

 

[Raven888]

Those are grungy. I hope the pump cures your issues.

 

[despower]

So, now I'm at the point of swapping the fuel pump and unfortunately, the wiring harness on the pump from Quantum Fuel Systems isn't an exact replacement. I'll have to cut the wires off the leads from the new pump and crimp new pins on so that I can use the connector from the old pump, which also includes the two wires for the fuel level float (black and green wires in the photo). Unfortunately, when I pulled the connector off the main housing, the two leads from the fuel pump were pulled from the connector. I didn't take a photo beforehand so I'm not sure about the correct polarity of the connector. So, two questions:

1) Can anyone tell me what sides the red and black wires from the fuel pump belong on (i.e., red left, black right)?

2) Does anyone know the make and model of these pins for the connector? I'd like to get new pins for the new fuel pump, since swapping over the old pins is almost impossible without damaging the pins. I am pretty sure I could get replacement pins from Digikey if I knew the make and model (i.e., is the connector a molex)?

 

[HumbleRestorer]

No answer to the previous post, so I decided to go ahead and swap the fuel pump. Removing the centre seat cushion wasn't good enough to get at the fuel pump module because it looks like the gas tank has shifted forward a bit so that the fuel pump and the access panel aren't perfectly aligned. See photo. I removed all the seats and managed to wiggle the fuel pump up and out after some patient jiggling. Question - should the fuel pump module and the seat access be perfectly aligned or is what is shown in the photo the way it's supposed to be? I am wondering if I should try too move the gas tank back a bit so it's easier to get that the fuel pump in the future.

Hey, they are not perfectly aligned from the factory! I've also researched Quantum and it seems they are the best aftermarket alternative to the OEM fuel pump on these 951 DIs. Following your thread