Ignition Coil Problem?

[russellb]

My 2005 RXT has not been running like it should. When changing out the spark plugs today I found that one of the coils looks pretty bad. The plastic is cracked and there seems to be some rust inside. Anyone else ever have any coil problems? Maybe I have been running on 2 cylinders?

 

[Sportster-2001-951C-Stock]

It's probably cracked due to the expansion of rusting. Honestly, I'm surprised it still fires the plug but hard to say if this is the root cause of rough running. Yep, I'd replace and see if it does run better.

BTW, How many hours do you have on that thing?

 

[russellb]

It only has around 85 or 86 hours. Are the replacement coils a decent quality? I can buy a set for what one OEM coil costs.

 

[Sportster-2001-951C-Stock]

I've used aftermarket coils many times on a variety of engines and had good experiences, not sure about this particular application. Other people have reported in the case of turbo engines or supercharged, aftermarket coils occasionally don't produce the voltage necessary to reliably fire the plugs under full throttle conditions. I believe there's some truth to this.

So in case your ski is supercharged, I'd probably go OEM and not take the risk.

 

[russellb]

I ordered a set of aftermarket coils a few minutes ago. I wanted to try replacing the entire set and see what happens. $108 for 3 aftermarket vs. $112 each for factory coils. They would have been about $375 with shipping. I hope they work. They come with a 90 day warranty and the store I ordered from is close enough I can drive by one day before work if I'm not happy with them. They're coming from Yorktown, VA.

 

[Sportster-2001-951C-Stock]

$112 each and they rust.... Might be worth giving the aftermarkets a go. I think I know the shop, I buy stuff from them too and have been happy (no return attempts though).

I bet those work fine.

 

[russellb]

I definitely hope the coil is my problem but I thought there was supposed to be a fault code for a bad coil. I don't have any codes as far as I can tell.

 

[Sportster-2001-951C-Stock]

Generally that would be the expectation, most newer systems are pretty sensitive towards detecting an ignition miss. But not always if the miss is slight enough. Not sure how sensitive the 4-tec is. Typically when a coil stops firing due to a bad coil it's very noticeable and tends to worsen as the coil comes up to temp. One of my favorite tests is to hit the coil with a spray mist of water to identify insulation issues.

 

[russellb]

I just got the new ignition coils in. I ran the RXT for a few minutes on the trailer (with hose) and the throttle seems a little more responsive and I'm not noticing the hesitation anymore. Unfortunately I don't have time to put it in the water today because I have to go to work. I'll try to get a test run in tomorrow.

 

[devonte007]

If indeed the new aftermarket coils perform without problem, please post the manufacturer/model number. Would be good information to have on hand if any of us ever need replacements. Sure would save a few bucks from the OEM ones.

Thanks!

 

[russellb]

I think the aftermarket coils are fine. My RXT may run a little better but the coils did not fix the problem. The supercharger was just rebuilt by PWC Muscle on 5/15. I have double checked and retightened my supercharger hose and that was not the problem. I don't think it is bad gas because the tank was probably only about 1/4 full and I refilled with fresh premium gas. Today I ran almost the entire tank out hoping that it may have just been bad gas but I think I would have had a few moments where I would have got some boost. Was only able to do between 43 and 45 mph and reach 6400-6500 rpm.

 

[russellb]

Here's the link to where I purchased the coils if anyone wants to take a look. Actual store is in Yorktown, VA. Close enough for me that I could have driven there but it was free priority shipping.

http://www.ebay.com/itm/3-NEW-IGNIT...TEC-/191200031162?hash=item2c8468f1ba&vxp=mtr

 

[Sportster-2001-951C-Stock]

I certainly would expect you were into boost at WOT. I dunno, do those have a boost gauge? Maybe 10psi or so?

 

[russellb]

I have heard that the supercharged 4-tecs don't start to make boost until around 5000 rpm and they should rev to around 8500 rpm give or take a little. It may have been making boost but not too much most likely. I believe stock superchargers make about 7 pounds or so. Maybe one day soon I'll have all the bugs worked out.

 

[Sportster-2001-951C-Stock]

If there's a miss it might not rev out. Otherwise, I'm thinking throttle cable adjustment might not be opening throttle body butterflies or there's probably some throttle position sensor position or switch that signals the engine controller to advance the ignition (retarded ignition won't rev.).

Good luck.

 

[russellb]

The ignition coils seem to be working fine. My problem was mainly caused by one almost completely clogged fuel injector. Seems like a different machine. Coils seem to be doing as good of a job as could be expected.

 

[Sportster-2001-951C-Stock]

Glad you found the issue. Dead-headed fuel rails are known for clogged injectors more often than those that have the regulator on the rail and return line to tank, the debris has to go through the injector and the last one on the rail is the one that catches most of it seems like..