92 2.3L Ranger runs leans and lacks power

pad2383 · #1 04-07-2010, 08:41 PM

Hi,

I've got a '92 ranger going on 210,000 miles. For the most part it runs great, but it lacks power on accelaration and at high speeds. I also think it could be getting better fuel efficiency (I average around 21mpg). I change the oil regularly, and I recently replaced the air filter, fuel filter, spark plugs, and spark plug wires. Pulling the old plugs revealed the engine was running lean. At high speeds on long trips the check engine light will come on. The code reader gave me the codes 334 (EGR closed-valve voltage higher than expected) and 172 ( Lack of Oxygen Sensor [Hego][HO2S-10] Switches, indicates lean). Anyone know what condition might prompt these two codes? I'd love some tips to get my truck running optimally. How can I get more power back, increase my fuel efficiency and correct the lean combustion. All information is welcome and appreciated. Thanks.

W1D0MAK3R · #2 04-12-2010, 10:06 PM

same truck here and oddly enough I just had all that stuff changed on my truck as well at school with the addition of a serpentine belt and head gasket. but mines got an extra 10 thousand. I would've guessed it was your fuel pump but you changed that too, I had a problem with my truck running too rich and it was just wasting gas.

Going to college for an aircraft mechanic has its advantages though, in aircraft the fuel is also used to cool the engine while its running, run it too lean like yours and it will run hotter, possibly causing preignition just as the pistion reaches top dead center, best ignition is just after TDC. But run it too rich like mine was and your engine will run on the cold side and ignition will occur later then it should, hurting fuel efficiency. Then youve got to take in account the spark plug fire timing, too soon and your hurting power and too late and yet again your hurting power.

My best guess from what i know is to just adjust your engine settings a little bit at a time till you hit that sweet spot. Not everybody has fancy testing and diagnostic equipment to hook up an engine to for this purpose. But if you do figure out the best settings for your engine let me know so I can save some fuel too.

stephensimmons · #3 04-13-2010, 05:18 AM

Quote:

Originally Posted by pad2383

Hi,

I've got a '92 ranger going on 210,000 miles. For the most part it runs great, but it lacks power on accelaration and at high speeds. I also think it could be getting better fuel efficiency (I average around 21mpg). I change the oil regularly, and I recently replaced the air filter, fuel filter, spark plugs, and spark plug wires. Pulling the old plugs revealed the engine was running lean. At high speeds on long trips the check engine light will come on. The code reader gave me the codes 334 (EGR closed-valve voltage higher than expected) and 172 ( Lack of Oxygen Sensor [Hego][HO2S-10] Switches, indicates lean). Anyone know what condition might prompt these two codes? I'd love some tips to get my truck running optimally. How can I get more power back, increase my fuel efficiency and correct the lean combustion. All information is welcome and appreciated. Thanks.

IF you are running lean it coul be you o2 sensor,coolant temp sensor, or you mass air meter. Also check you intake air charge sensor because that could cause it too it it screwed in to your intake.

pvcooper · #4 04-13-2010, 05:19 AM

have you replaced timing belt , these belts stretch after a period of time cause the timming to advance a little to where it still runs but not as good, take a timing light to it see how far off the mark it is and when you are shooting it its not goin got be on the TDC mark, youll have to check and find out where its suppose to be, But 1 tooth jump on a timing belt can make alot of trouble

pad2383 · #5 04-14-2010, 01:28 PM

I removed and cleaned the Mass Air Flow sensor but I haven't noticed any dramatic improvement. I haven't changed the timing belt but it looks alright upon inspection. I'm trying to do the little easy fixes first before I jump to more expensive things. I'm thinking it's not the 02 sensor because the 02 sensor gave me a code for the engine running lean which is accurate based on the spark plug wear and performance. I'd like to change the PCV valve on it but I can't find where it is. Any more tips or advice are appreciated and thanks everyone for the feedback so far.

pad2383 · #6 04-17-2010, 03:05 PM

Update: So I finally got my hands on a fuel pressure gauge and hooked it up. The manual said the fuel line should be pressurized to 40 PSI with ignition on, engine off, then with the engine turned on the line should drop in pressure by 3-10 PSI. Well, my fuel line pressure reading with ignition on, engine off was only 20 PSI, and then with the engine turned on it jumped to 30 PSI. So, I'm now pretty sure my lean combustion problem is related to low fuel pressure. With these readings anyone know what the problem could be? I checked the fuel pump fuse and it is clean and fine. Advice at this point is definitely appreciated. Thanks.

pvcooper · #7 04-17-2010, 03:14 PM

the pcv is right under the intake , looks like its plugging into the back of oil pump but its on a pretty big rubber hose

pad2383 · #8 04-18-2010, 07:27 PM

I replaced the PCV valve and I ran some more fuel pressure tests today. As it turns out, everything is up to manufacturers specs. I don't have any gas coming out of my fuel pressure regulator, pressure increases when I remove the vacuum line to it, like it should, and I was able to get the 40 PSI by keying the ignition on/off a couple times to give the fuel pump a chance to build pressure without the engine on. Fuel pressure raises just like it should when the accelerator is pushed. Everything fuel pressure wise checks out so my initial reading on having low fuel pressure was wrong. My Pump, regulator, and fuel filter (I just replaced it) all check out. So I'm back to square one. What is causing the lean condition? I think my next move may be to replace the 02 sensor. Thanks for all the tips so far and keep them coming.