'07 M8 Terrible lean bog, running on one cylinder etc etc

[mutti_wilson]

First ride this year, get onto the trail and get a bog when i hit the gas. Figured it was just cold so i cruise along a bit and hit the gas again. This time it acts like the tether was pulled. I am standing up and nearly went over the bars. I stop, and swap the plugs, same story. So I nursed it back to the trailer by pumping the throttle non stop, would only run at idle or 8k. The problem happens on decel when you hit the gas again, there is a huge bog and then it wakes up. Often times though it will just bog right out and you can roll it dead to a stop with the throttle pinned.

Things I changed since it ran last year
1. Oil Delete
2. BMP can

What I checked.

1. Belly pan off, checked my Oil Delete plug and intake hoses, everything is tight.
2. Intake has no cracks in it, and TB's are right to reed cage boots.
3. Airbox is making a good seal.
3. Disconnected TSS with no effect.
4. Put new exhaust springs on (had wrong springs so a little loose), no change.
5. Checked all wiring plugs, no change
6. All plugs look lean.

A little backstory is the first time I started it this year I could only get it running on one cylinder. I tapped the injector on one side and it started running on both.

I am thinking that the fuel pressure is not up to par causing it to run lean? I need to get a gauge on it to check that out. I am also going to pull my injectors and clean them in carb cleaner. Would reeds have any effect like this?

 

[WyoBoy1000]

What are all your mods???

drain all gas and put new in, don't soak the injectors in carb cleaner it can eat stuff, just spray them,
A oil delete can lean it out a tiny bit because the oil takes up the room of gas where as before it was added to the gas.

Need to know all mods

 

[mutti_wilson]

I drained the tank when I did the BDX oil delete, and refilled with fresh gas prior to my ride. My only engine mods are the oil delete and the BMP full velocity muffler. Other than that no motor/clutching mods.

 

[strong]

I had the bmp pipe on mine with the bmp fuel reg. (pos imo) same kinda thing was going on, then the ECU went out. then it ran fine.

 

[mutti_wilson]

Pipe or just can? ECU went out and then it ran fine? Or you replaced the ECU and then it ran fine?

 

[WyoBoy1000]

Check fuel pressure, your going to want to be 44-46psi,

 

[strong]

I had to replace it, then it ran fine. and it was the pipe.

 

[mutti_wilson]

So I got a gauge and installed it. Could only get the sled to start long enough to just get the lights to come on. I would pull it once with no fire, the second time just a short little run. I didn't believe the gauge because it only had 10psi registering. I remembered I had a friend's '07 ECU still (Diagnosing an flashing check engine light, that goes away with his ECU) and I hooked it up. Ring ding ding, running solid, 44psi on the gauge all is well. Toss mine back on, it starts up and goes into a high crappy sounding idle, totally leaned out. So my ECU is the culprit.

I have a friend who is a hillclimber looking into if a reflash may solve it. I will keep you updated.

 

[strong]

spendy lil pricks. Hope you get to ride soon

 

[WyoBoy1000]

But what caused it, ecu's dont just fail, they usually fail from a short or something, so if you replace it it may do it again.

 

[mutti_wilson]

But what caused it, ecu's dont just fail, they usually fail from a short or something, so if you replace it it may do it again.

So true. Apparently my buddy talked to a guy at Cat who said that the '07 CCU's had issues with voltage spikes that could take out ECU's. He said the '08 CCU fixed this. Sucks big time to replace both, but what else do you do? My wiring harness has been gone through completely and is short free so must be what it is.