I just replaced my O2 sensors upstream. I went to Auto Zone and had him check the codes. P1131 Lack of HO2s bank 1 switch and P1151 Lack of HO2s Bank 2 switch.I know I got a valve cover leak on bank 2 side could that cause lean codes, maybe I got one on bank 1 side too not as bad.

 

No, valve cover's air is pulled in thru the PCV Valve so is an accounted for air stream

You either have a vacuum leak or low fuel pressure

If you lose power at higher RPM/load then could also be clogged exhaust

 

I am going nuts with the check engine light on. I checked the codes and I got P0174 lean bank 2 and P0171 lean bank 1 still. I took off the IAC valve which I bought STANDARD IAC valve a year ago give or take. It was filled with carbon, I cleaned it out with carb cleaner. Let it dry for 20 min. I use to have to crank it, stop and ceank it again before it would start. I barely turned the key and it started right up. I hope that fixes the lean codes. The STFT B1 24.2% LTFT B1 23.4% STFT B2 9.4% LTFT B2 22.7%.

 

I tried buying a smoke machine. sjxnag@163.com It got delivered somewhere in my town, but UPS said my name and address are not on the shipping label. I called Paypal they said they give the seller 10 days to respond, its been 5 nothing yet. Does anybody know were I can get one for like 100.00.

 

Yes,

Buy a Cigar and a bottle of Bourbon, some say the bourbon is optional...............I think not
Cheaper cigars have more smoke, but expensive cigars work just fine

Set the intake up for smoke test, seal off throttle body opening
Use the power brake booster hose to send smoke into the intake

Lite up, you don't inhale just puff to get good smoke, and blow it into the intake, then have a sip
Repeat until you find the leaking smoke, or you run out of Bourbon, get more Bourbon
Works great
The smoke travels on the path of air that can exit the intake, so blowing the smoke into the hose sends it to the leak point, its only way out

Doesn't work for a shop anymore, most customers wouldn't pay for a test like that if they saw it, lol, so "smoke machines" were invented
But this method was used since early 1900's, smoke is smoke, my grandfather taught me this method, and he learned it from his father

 

The Bourbon is on back order LOL!!!

 

I went out earlier to diagnose P0171 and P0174 lean codes. I found out that this was not happening at idle. It said closed loop at 1535 rpms, STFTB1 24.2% STFTB2 9.4%, LTFTB1 23.4% LTFTB2 22.7%. Does this mean its a fuel pump, or should I do other test before getting one. Now I went out to check in live data. The code was set at about 1500 rpms. I reved the engine up to about 3000 rpms and the fuel trims went down to -3 to 4 and back and forth very confused now HELP!!!

 

Certainly possible with those numbers, but.............................
I would try to test fuel pressure with a gauge, at idle and then hold engine at say 2,000 rpms and see if pressure slowly drops
1995 Ranger should be 30-35psi

Slow drop at higher RPMs could be dirty fuel filter or the pump
If its low at idle then could be Fuel Pressure Regulator, on the engine, or fuel filter, maybe pump but less likely

And on the other side is a dirty MAF sensor, or failing MAF sensor


What Lean codes on BOTH banks mean is that the computer is calculating the air/fuel mix based on faulty info, so its having to open the fuel injectors 20% longer than calculated to get a good burn based on O2 sensor feed back, engine is never actually running Lean

Computer relies on MAF sensor data for the Weight of the incoming air
Computer "assumes" 30psi fuel pressure, it has no fuel pressure sensor
It uses these and Engine RPMs to calculate how much fuel to add, and its off by 20%

 

I did a fuel pressure test and found the fuel pressure regulator bad. But I didnt accelerate the engine up to 2000 rpms. Ill do that next Thank You!!!

 

And hold it high for a minute or two, steady drop means pump is failing, or filter is dirty

 

I did a fuel pressure test today koeo it was 32 lbs. Than I held it at 3000 rpms and it stayed at 33lbs. Than I got a cigar!!! I put it in a transfer pump. Smoke started coming out of the barrell of the IAC valve, than it started coming out of the vacuum hoses of the dpfe sensor. Is that normal it just had to escape somewere? Still no BOURBON DAMMIT!!!

 

No, the DPFE sensor does not have vacuum lines, those are exhaust lines, from the EGR tube

EGR valve should be close with engine off

And exhaust valve and intake valve can't be open at the same time so not sure how smoke in the intake would get into the EGR tube and DPFE

 

But can it be seeping out of the barrell of the IAC valve!

 

No, it shouldn't do that either

 

Ok I was going to test the egr valve with a vacuum pump. Do you think the IAC valve is bad if smoke is leaking out of the barell in the test?

 

IAC Valve shouldn't leak air to the outside of the intake

Not sure what you mean by "barrel"
IAC sits on a passage that by-passes the throttle plate, so can pass air around it to set idle levels, smoke can travel thru this passage

IAC Valve has an equalizer vent(black plastic cap) that is behind the Valve itself, this allows the valve to move in and out without trapping air behind it, this vent can make a whistling noise when valve's seal is leaking, no smoke should come out there
Cap just pops off

 

Smoke came out of mine when I did a smoke test, so that means it's defective ?

 

Yes, the seal on the valve is leaking air to the vent behind it, and alot, if you saw the smoke coming out the vent(plastic cap)

 

That's on a new part too, aftermarket though, it's Standard Motor Products.
Photo shows purple arrow where the smoke is leaking out, metal cap on this one, not plastic.

 

Shouldn't leak there, thats just an air pressure equalizer

Only use Motorcraft(Ford) or Hitachi IAC Valves.............................period

 

Ok now that I had the battery disconnected, putting a new starter in it cleared my codes, P0171 and P0174 lean on both banks. It took a day for the check engine lite to come back on. Checked the codes again P1131 Lack of upstream heated Oxygen sensor indicated lean bank 1. P1151 Lack of upstream heated oxygen sensor indicated lean bank 2. When I stopped at a light the truck would shake real bad the longer I was stopped the worse it would get. I put it in Neutral it would stop. I was thinking the IAC valve. I saved the original it looks like a motorcraft., I cleaned it with throttle body cleaner with the barrell up and q-tips.. I put it on , didnt go for a ride yet but it is humming real loud. It use to do that when it was real cold than truck warmed up it stopped. Thats one of the reasons why I changed it.Is there a way to stop the humming or should I get a new valve Motorcraft 105.00 Hitachi IAC valve $54.00. Still have to see if putting that valve on stops the shaking!!!

 

The whistling(humming?) means old IAC valve is leaking so yes replace it with Hitachi unit

You are having misfires at low RPM, you feel it "in gear" because there is a Load on the engine, but misfires are still there in Neutral

 

Thank You. I do feel it in Neutral just not as bad to shake the truck!!!

 

I found out that the IAC valve I bought 2 years ago was guaranteed for life. SNP IAC Valve. I put it in and today driving to work the truck wouls shack back and forth. So I feel it is missing. I took every wire one by one off the coil pack and they all have good spark. Is it the IAC valve buy the Hitachi valve and that will solve the problem or should I do other tests?

 

IAC Valve shouldn't cause misfires, it can cause high or low RPMs or wandering RPMs
I wouldn't replace it with "SNP"??

But if it worked OK for 2 years then maybe they are OK on Ford system as well