Neighbor has an '08 Street Glide.

It will backfire, then he has no power, it will run, but that's about it.

Had a Cobra fi2000 unit on it, we took that off, thinking it may be the culprit, and it happened to him again Saturday.

Rinehart TD's and mufflers, and a Heavy Breather.

We started, based on his description, by changing the fuel filter, regulator and filter housing.

After that he started telling me about the backfire first....

I think I need to get a good look at his air filter.

Any ideas?

 

Have you checked the color of the spark plugs? Should be a nice tan color

 

Check for an intake air leak. Spray a short blast of brake cleaner on the Y manifold. If the engine dies, you have a leak. Be careful to not let it get into the air cleaner, that will give you a false positive.

Don't use propane, unless you are the type who says "Hold my beer, and watch this". I have a friend who has no eyebrows who did that.

 

Did you check to see if the plug on the vacuum line on top of the throttle body got blown off? That's the usual culprit.

2010 Limited with some stuff!!

 

The first thing I would do is check the DTC's. I would also double check the plug on the side of the throttle body, make sure there is no corrosion on the pins and the plug is seated properly.

 

Backfire through the intake or exhaust? Any codes?

 

I'll check his codes when he brings it down...

It runs fine until it pops, the way he describes it, sounds like an intake backfire. Then it has no power. Sometimes he shuts it down and 10 minutes later it's fine, and sometimes it's not until it sits overnight.

I'm going to try to get my hands on it tonight to get a better look.

 

Sounds similar to my carb'd softail. It ended up being a flooded situation (my fault). It would have to sit for 10 mins, then it would fire right up and run like a champ

 

I would think that you want to find the root cause of the backfire and not no power after it happens. Fuel problems are generally the cause of backfires though the intake. Other's have said it but here's my list:

1. Trouble codes
2. Bad gas?
3. Gas tank QD o-ring
4. Dirty injectors
5. Intake leak - Use a map or propane torch - unlit of course.
6. Tune modifications
7. Air filter clean
8. Rubber cap installed by injectors
9. Spark plugs
10. Cam timing - off a tooth
10. Valve train problems

 

From my experience, (which is limited, LOL) backfires are usually caused by a fuel flow problem. The first thing I would check is your fuel line quick connect. Pull it off and put it back on, make sure you have a good connection, and flow.

If this just started after the fuel filter change, it could also be that the o ring that seats the fuel filter is bunched up stopping good flow. (This happened to me, and it took disassembling 3 times before I found it).

Hope this helps, and good luck.