Cel P0170&P0172 coming on & off

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R

Rohan

Joined
Nov 5, 2009
Messages
776
Location
orlando,FL
2002 Honda Odyssey
421k miles

Last year I had a lot of cel on and I fix it, after that I had these codes on and going on back & forth. I'm going to listed cel codes that I had on last year.

Last year;

EGR Vavle code ( sorry can't remember that number)
P0300
P0301 up to P0306 (spark plugs been changed by me)
Cyclinder #1 rusted spark plug thread was strip by me been in there too long and put the new plug in but no misfire code
Bank 1 sensor 2 ( 02 sensor on the catalytic converter)
Bank 1 sensor 1 (original sensor never been replaced)
Coil pack ( original coil pack never been replaced)

All of these parts has been fix and after this I got other cel on for P0170 & P0172. At this point I look everywhere to see if I forgot to connect somethings back and I found pcv hose was not completely connected so I push it all the way in and after this time I crank the car up no more cel on. Yes, other cel came on catalytic converter (OEM 421k) and I believe those two codes destroy my catalytic converter so I installed non-fouled on the catalytic converter 02 sensor and now no more cel on. After 800 miles those two codes came back on p0170 and p0172. At this point I left it alone for 1 year no more driving.Everything else is still OEM parts never been replaced. Now I'm ready to fix it again.
 
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What is your MAP sensor voltage at a hot idle? Also, what is the fuel trim information at idle and at 2500 rpm?

The rich codes and the random misfire, combined with the van's mileage, makes me suspect that you need to do a valve clearance adjustment. Adjust the valves and clean the EGR to start, and see if your issues go away.
 
421k miles? I wonder if you can get a trophy from Honda.

By the way non-fouler trick and P0170/P0172 have absolutely nothing to do with each other. At these miles, recheck the vacuum hoses. They might be brittle and crumbling.

You need to post freeze frame data. You need to observe fuel trims at various RPM and engine load. You need to monitor MAP voltage. You need to locate and fix vacuum leaks. Check the fuel pressure and fuel pressure regulator. If the diaphragm inside FPR is punctured you will get P0172. See if FPR holds vacuum first.

Randomly throwing different parts will eventually fix it but that is not the most optimal method.
 
I'm going to get it check out everything you listed for me whenever I get the day off again. My question is can a bad battery cause this problems I find out that my battery is bad.
 
I forgot to mention that I did take out the throttle cable one time and barely put it back in the right place. I hope this doesn't has anything to do with this.
 
Do a valve adjustment first, then run a bottle of good FI cleaner and check your plugs. Hondas need to have regular valve adjustments.

Also, the non-fouler trick has no place on a modern OBD-II car with air/fuel sensors - and Honda was also first to market with those. Thankfully, your Odyssey uses an electric EGR valve and the only vacuum lines you'll see are for the EVAP and variable-length intake manifold.
 
I don't know where to start first. Should I check for vacuum leaks first or do the valve adjustments? P0170&P0172 came on after I did the spark plugs, EGR valve , and took off the intake manifold to clean everything. That's when the light came on for this codes.

I'm really lost I and need to know what should I check for first. If someone can tell me what those codes really mean in Honda FSM then it will be greatful to me. So I can check one by one myself.
 
Check fuel pressure and fuel pressure regulator and MAP sensor. Those are the things which can trip P0172.

The code is saying the system is too rich. This means either too much fuel is being injected or too little air is being fed to the engine.

If the FPR is leaking, you will get this code. There is youtube video o how to replace that on this particular engine but check before replacing it blindly. You need handheld vacuum pump.
 
Originally Posted By: Vikas
Check fuel pressure and fuel pressure regulator and MAP sensor. Those are the things which can trip P0172.

The code is saying the system is too rich. This means either too much fuel is being injected or too little air is being fed to the engine.

If the FPR is leaking, you will get this code. There is youtube video o how to replace that on this particular engine but check before replacing it blindly. You need handheld vacuum pump.


Thank you @Vikas for getting back with me on the thread.

What is handheld vacuum pump used for? Isn't that only used for when bleeding the brake system.
 
Yes, that is the one. It has vacuum pump and a gauge to measure vacuum.

FPR usually has vacuum line attached to it and that is how the fuel pressure is controlled. To see if FPR is intact, you hook up vacuum pump to the line going to FPR and see if it holds a vacuum. If the diaphragm inside FPR has a crack, it will not hold the vacuum. This will cause FPR not to regulate the pressure correctly. If the fuel pressure on the rail is higher than specified, more fuel gets injected leading the rich condition and P0172 code.

Usually, it is rare for modern computerized fuel injected cars to throw rich code versus lean code.
 
You could indeed need valve adjusted but that is not a job for anybody. The chances are that first timer would make it worse if attempted to do the valve adjustment on that Odyssey engine.

You can forget about battery, throttle cable etc for now and concentrate on doing proper diagnosis for P0172.

What type of tools do you have access to?
 
Whatever my ob2 can gather information I can provide you that information. If you click on the ob2 link it will tell you what can my ob2 can read and if you tell me what you need from there I can give you that information. Is intake temperature sensor mean MAP sensor reading? Does Short fuel trim mean fuel trim? I also have short and long trim fuel listed on my ob2.
 
I'm going to do the fuel pressure test instead of using handheld pump pressure on the line unless I can find some videos of how to used handheld vacuum pump on fuel pressure test.
 
I copied this from the link you gave

1.Read diagnostic trouble codes, both generic and manufacturer-specific, and display their meaning (over 3000 generic code definitions in the database).
2.Clear trouble codes and turn off the MIL (“Check Engine” light)
3.Display current sensor data, including:
4.Engine RPM
5.Calculated Load Value
6.Coolant Temperature
7.Fuel System Status
8.Vehicle Speed
9.Short Term Fuel Trim
10.Long Term Fuel Trim
11.Intake Manifold Pressure
12.Timing Advance
13. Intake Air Temperature
14.Air Flow Rate
15.Absolute Throttle Position
16.Oxygen sensor voltages/associated short term fuel trims
17. Fuel System status
18.Fuel Pressure

MAP is #11. I do not believe the Odyssey will give you #18. You will need real fuel pressure gauge to get that value. I am not 100% sure if it has Schroeder valve for hooking up the fuel pressure gauge. And intake air temperature is NOT MAP.

Have you purchased this "Elm 327 obdii wifi scanner user manual PDF"?
 
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Thank for making corrections and yes it has Schroeder valve which make me think is hard to do the fuel pressure test on this kind. Can't I just pull out the vacuum hose from the FPR and see if fuel is coming out from there? I did not get the manual with my ob2.
 
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So I went ahead got me set of handheld vacuum pump and hook that up to my FPR vacuum hose. It started leaking. Time to buy new FPR. Thank for help
@Vikas and other users. I will report back after I install new FPR.
 
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