Hit a deer, now engine is running lean

[zach1990]

About a month ago I hit a deer at roughly 50mph with the front driver side. Pushed in the bumper, knocked the lights loose, and snapped the PCM housing loose. Fixed all that but it's constantly throwing a code for engine too lean (bank 2). I've been clearing the code out for a few weeks thinking it may be from the combo of my cold air intake and cold mornings but its back with this warmer weather. The only thing I've noticed since this code came up is that the engine runs very rough idling until it warms up. My question is what should I be looking for to remedy this? I've searched around under the hood but I don't see anything immediately obvious.

[zach1990]

Well decided to start at the fuel filter even though it's not very old and low and behold its all clogged up. Replaced it, changed the oil, and put in a new battery (unrelated issue) and now the old thing is purring fine. Hopefully it's fixed. Sure feels like it

 

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[Doug_Scott]

Well decided to start at the fuel filter even though it's not very old and low and behold its all clogged up. Replaced it, changed the oil, and put in a new battery (unrelated issue) and now the old thing is purring fine. Hopefully it's fixed. Sure feels like it Sent from my LG-D800 using Tapatalk

 

If you want to take a stretch at tying the rough running with the deer incident, maybe the jarring the truck took on impact, disturbed a layer of crap in the bottom the fuel tank, that got sucked up in the 15 to 20 seconds the truck ran after crap got stired up and fuel filter did its job.

[bossier62guy]

What would concern me is, "why is a relatively new fuel filter clogged?"....hopefully it was a fluke and not an indicator of problems to come.

BTW, I don't buy the logic from the above post....lol.

[zach1990]

Not that I noticed. Ill look it over some more tomorrow when I've got more time

[MikeNH]

Did the deer damage an O2 sensor?

[EX-F150 owner]

Did you see what was clogging the filter up? Could be clogged again. Maybe the filter on the pump is bad and debris from the tank is getting by.

 

Also have you checked the MAF sensor? I had this same issue with my Lesabre and cleaning it worked for a while. When the codes came back I just replaced it and no more issue.

[zach1990]

Sensor is clean and the filter I replaced was full of black sludge. Just nasty nasty sludge. I thought about that but it doesn't explain the complete loss of all power until I reconnected the battery after checking the terminals... Idk

 

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[zach1990]

Hmmm it did roll under the truck and I didn't think of that. Ill check that too

[Btuggle88]

Sounds like O2 sensor and it could just be bad timing on its demise. If it's throwing a code it probably is a sensor.

[Doug_Scott]

What would concern me is, "why is a relatively new fuel filter clogged?"....hopefully it was a fluke and not an indicator of problems to come.

BTW, I don't buy the logic from the above post....lol.

 

Really? Think about it, you drive your truck for x number of years, and x number of miles. Over that time if you get your fuel from mostly the same station and they have a dirty underground tank, you may get dirt in the fuel. It sinks to the bottom of the tank where it gets to sit for the vast majority of the day. You vehicle is parked more than driven, so the fuel has lots of static time for contaminents to sink to bottom of tank. After a while it ends up like one of those instant hot chocolate. A layer of sludge on the bottom. One day you are driving along, not a care in the world, then bambi decides she really misses her mother so she ends it all by stepping into traffic. A vehicle something as large as a deer will feel it (not as much as bambi, but it still jars the truck) and the sudden shock to the vehicle will cause a violent movement of fuel in the tank(unless it is full) and that mini tidal wave stirs up the fuel in the tank, and the crap in the bottom. Truck is still running, so fuel pump pulls in the now cloudy fuel, and off the fuel filter it goes.

 

Not sure why you don't understand the logic of it. Before you offer that the sock on the fuel pickup will catch the stuff, if it did, why would you need a fuel filter? And if the gas station does not pump dirty fuel, why do we have fuel filters? Obviously dirt gets into the fuel tank.

 

For some reason this reminds me of when I worked in a Firestone Auto Garage. We used Kralinator filters. A week did not go by without someone complaining that they just changed the air filter x number of miles ago, they must be crap filters if they plug up so soon.

[zach1990]

Well so much for that.... got a po171 yesterday and about an hour ago I got in it and cranked it and noticed it was idling funny. Gave it some gas and everything died even the electrical. I was sitting there a minute when I noticed that there was this strange clicking noise coming from under the dash. Could not locate the source. Played with the battery cables a bit and when I disconnected and reconnected the battery everything came back on. It then cranked but was idling bad still so I walked over to the engine bay and noticed it was sucking the hell out of air through the CAI. It was very loud till it stopped after about 30 seconds. Idle never smoothed out. If I can get it to work tomorrow I'll play with it some more and report back with further.

 

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[zach1990]

Ill definitely look into it in the morning

[Doug_Scott]

When you say the engine runs rough when cold, but runs smooth when warmed up, is this idle quality you are talking about? And once you pull away engine smooths out and runs fine? Next set of lights, rough idle is back, and by 5th set of lights, it is running good.

 

I can't see it being a fuel pump and only giving codes for lean bank. If pump is causing this, it should be spawning other codes. I think there is a code for injector duty-cycle. A bad pump should cause a long duty cycle for the injector. The two codes you posted are very generic basic codes. You will need to do a lot more testing and checking. Anyone ever check for ODBII for Dummies? I have found that series to be quite helpful for learning the basics first. Nothing worse than getting a manual that is written for experts.

[zach1990]

I don't understand it either but I've got 320k miles and know my truck pretty well. She's running like she's supposed to. Let it idle for half an hour and took a 12 mile drive and no codes. I'll report back if it changes. Thanks for all the help guys!

 

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[zach1990]

The rough idle is during cold starts. I've got straight pipes and you can notice it kinda going in and out sort of like its loping. Does it till it warms up to running temp than goes away.