Topic: Code 52

[chrisfranklin]

A couple of weeks back on the Rubicon I noticed the engine was having some problems at startup.  We just replaced the starter with a Mean Green starter before we left because the old one was seeing better days (needed a rock hit).  And the new starter worked great.

But when I stalled out -- and that was quite a bit early on -- trying to idle over rocks, I'd have problems when trying to start it back up. 

The engine wouldn't fire after repeated attempts.  Finally when I gave it some gas it fired up. 
That was the situation the whole way through the trail really.   

Driving on the highway back from the trail, I saw a check engine light come on. 

I got back and cleaned out the air filter, changed the oil/filter.  Then I ran the codes and got a Code 52 -- O2 sensor detects a rich running condition.  (pretty vague code; basically happy hunting for the problem  )

Well I figure the air filter is clean and the intake isn't obstructed in any way, hoses are all in good shape and on tight, electrical connections all good, fuel filter is only a year and a half old. 

So I am guessing its probably some bad or dirty sensor -- maybe 02, maybe TPS, may Idle Air Bypass valve, maybe CTS.  What do you guys think or what did I forget?
 

[stan98tj]

this may or may not help. when i first bought my jeep i was having rough starts for a while. basically would have to pump the gas to get it to start and i was basically running rich. did some compression tests and realized i had a cracked head, which made it harder for the combustion to occur-causing me to have to send more fuel (pumping gas while starting) for the engine to start. if you're sure your head is good-it's prob a sensor issue-clean em off and go from there-if that doesnt solve it-take a compression test to make sure everything is where it's supposed to be at.

[chrisfranklin]

Didn't think of that one.  Probably high time I do a compression test anyway. 

[stan98tj]

do a wet compression test. there's plenty explanation online on how to do it if you're unsure-i had to look it up. if u do find a crack or the head being shot otherwise i went with a head from clearwater cylinder heads in florida. those dudes stand by their warranty and craftsmanship..they did real well by me. case in point: my cracked head was the start of all my troubles-i ran hotter plugs not realizing that i was dumping fuel to get combustion-the resulting detonation blew a hole through the piston and dumped coolant all in my oil pump. long story short, i bought the head but the engine was toast-60 miles later oil pump crapped out, engine blew. they took the head back with all the scarring on it etc and refunded me completely even though they knew the ending failure wasnt caused by a fault in their head.

[chrisfranklin]

I've been searching around on Code "52" and I've seen a few say changing the O2 sensor fixed the problem. 

I figured if it was the O2 Sensor it'd flash Code "21," though.  But I'll give things another look

[chrisfranklin]

Don't tell me I'm only the second here to get code 52? 

I pulled the O2 sensor and it was soot covered; I replaced it today. Didn't disconnect the battery to reset the computer because I didn't have the chance.  Drives better but idle is rough still. Haven't seen a check engine light but I wouldn't be surprised if it comes on again.     

[aw12345]

Well Chris the first question is does your Jeep run on all 4 cylinders?
If not that is the first thing you need to adress, before you detroy the catalytic converter

[chrisfranklin]

Well Chris the first question is does your Jeep run on all 4 cylinders?
If not that is the first thing you need to adress, before you detroy the catalytic converter

It runs on all 4 cylinders, Art  ... 

[sharpxmen]

Don't tell me I'm only the second here to get code 52? 

[...]  Drives better but idle is rough still. [...]

what's your rpm at idle?

[jdarg]

The fuel pressure regulator has come unplugged or went bad. That will raise fuel pressure by about 10 psi during conditions where it doesn't need the extra fuel and it will run rich. Test w/ a pressure gauge on the schraeder valve on the rail.

If its not that my money is on the MAP bad or leaky vac...idle can be really poor when that happens but it will run.

[chrisfranklin]

Idle RPM is normal but it will start to stumble after about 15 seconds.

Here's the list of possibilities I've assembled thus far based on searches and responses here:

-O2 Sensor (Replaced this already)
-Bad Connection or Wiring  (Checked wiring/connections all around)
-High Fuel Rail Pressure; Fuel Pressure Regulator problem
-Oxygen deprived intake setup (Cleaned air filter, no obstructions)
-Electricity for good spark is weak; alternator problems (Not hearing whine, everything powers normally)
-TBS or IAC problems
-Vacuum hoses, especially to map sensor or general vacuum leak  (Checked hoses, all look good/attached)
-Map sensor problem
-Plugs, wires, cap and rotor replacement; plugs may be fouled  (Plugs don't have more than 10,000 miles, everything else is PD gear that's just a 
 couple years old and maybe has 10,000 miles)
-Leaking injectors (Not smelling fuel, don't see evidence of leak)
-Coolant Temperature Sensor problem
-Thermostat, coolant issue; thermostat may be stuck open running engine in rich condition

I don't know but personally if any of the sensors were having problems -- TPS, IAT, CTS, IAC, MAP, CPS, O2 -- I would suspect I'd see a code directly indicating a problem with said sensor(s) (above/below accepted voltage etc).  Right now it's just 52 -- Rich condition. 

Looks like this is going to turn in to a long process of elimination.  Going to check the plugs, spark

[sharpxmen]

you seem to have a pretty good picture of what's going on. imo i don't think the following would result in that code: IAC, air filter, thermostat, crank/cam sensors (unless you have hiccups at higher rpm) or vac leak (unless it's on the map vac line, otherwise you would just have an increased idle rpm), but the other ones you listed i think could result in code 52.
like jdarg mentioned the fuel pressure would be the first thing to check, and what you suggested already the ignition components to make sure you have that covered (inspect the plugs and see if they are wet and/or black), and from what i remember TPS could also give you a rough idle (when mine went bad i remember it was not happy at low rpm, but i did have the code for it).
also for the rough idle if it's still there once you identify and fix the problem i would look at the valve cover breather hoses and fittings to make sure they are not plugged and free flowing - the motor get part of its air at idle thru the valve cover, if there is an obstruction that would cause the rpm to go low and idle rough(er)

you can check the output of the sensors with a multimeter, it won't be perfect but you could see in case of something that is extreme (if for example it jumps up or down when you open the throttle partially could mean you got a bad tps or map - the pcm should identify that as well though but you never know)

[Torch_Ind]

One thing to check because I had this problem "being a rock crawler".  I hit my tank shield crawling over rocks before causing the shield to hold the tank up against the return line inside the tank. aka causing my fuel pressure to be at like 80psi because the return line was plugged. had to pull the tank down and trim the return line so it wasn't so long in the tank and been fine ever since.

hope it helps.

[chrisfranklin]

One thing to check because I had this problem "being a rock crawler".  I hit my tank shield crawling over rocks before causing the shield to hold the tank up against the return line inside the tank. aka causing my fuel pressure to be at like 80psi because the return line was plugged. had to pull the tank down and trim the return line so it wasn't so long in the tank and been fine ever since.

hope it helps.

That sounds like a strong possibility in this case. 

I didn't notice I was having any start-up problems until I was actually already well in to the Rubicon.  The new starter was working but the engine wouldn't fire until I started pumping the gas. 


Check engine light only started showing on the 400+ mile highway drive back

In the days prior and while driving up 400+ miles, no startup problems -- if there were, I wouldn't have even gotten on the trail in the first place, at least not until the problem was fixed. 

[chrisfranklin]

Changed the plugs.   Old ones were soot covered.  Reset battery and then check codes.  No Error Code 52!  That lasted about 5 minutes on the highway.  Then the check engine came back on.