96 ranger XLT 4.0 v6 won’t pass smog
 

Hi all! I am new here. And basically have been in tears but hoping this group can help:..

this 96 ranger was passed from my grandpa (former GM at ford) and to my dad to me. Never had any issues passing smog or anything really that wasn’t just fixing up a few things as normal maintenance.

fly forward to last March 2019: out of nowhere my radiator blew which I replaced and the water pump too. My area has no trustworthy mechanics so they just put in Whatever without checking things so next I find I have a blown head gasket. After searching for a new car cause no one wanted me to put anything into this I just couldn’t do it and took it to a restoration shop. Full engine rebuild; paint and body work looks like new and runs great .. $10k later I saved up on my own.

now to re register in CA I have to pass smog which it has passed flying colors since being in CA for 18+ years (it’s a federal car). Now I’m going down a road of illegally drive a PNO, replaced O2 sensors and still check engine light on and feel I’ll be going down a road of let’s check this and pay this with no avail. I am so deep into this I just want someone To say This needs to be fixed and I’ll pay just to pass smog and get this on the road. BAR won’t help me as the repair was done at a muffler shop (that they advised me to go to). If there’s anyone out there in SoCal who knows a place that can help me or what I can do please help. I am not even sure if it’s really my exhaust system or maybe the rebuilt engine (only got this back after 50 miles driving). It’s just disheartening as I am trying to support my entire family financially but I also can’t sell a truck I put so much into. Thank you so much.

If the check engine light is on, there must be codes stored in the computer.

If you can get those codes and post them here, we might be able to help you.

Write the codes down, DO NOT tryand remember them, giving us the wrong code is worse than no code.

thank you!! The mechanics never show me the codes and sort of keep it hidden - I’m a bit shy (I’m a girl here) and so I feel weird to ask. Maybe I’ll ask him tomorrow as all I got was my upstream sensors were bad (3 places told me this so finally when I found this guy who seemed upfront and honest, he replaced those). I usually take my dad with as he had the truck before me but even he’s getting tired of this so I may be on my own. I’ll try and get the new codes tomorrow.

quick question- the CEL came back On after only 8 miles of the 100 they told me to drive. I did another 20 to be hopeful. Any chance it could get fixed by driving any more? My issue is my rebuilt motor says I cannot go above 60 mph or freeways to break it in so I wonder if that has any cause in the cycle. Also if anyone may know if a Blown head gasket Could have caused other issues other than O2 sensors? Thanks so so much for your Quick reply, I can’t tell you how much I appreciate it.

Stop by any Auto parts stores and they can read the Code(s), as said write them down, and DO NOT buy anything at that time, auto parts guys are good at what they do, selling parts, they are not mechanics

Or assuming you have a Smartphone, you can buy a Bluetooth OBD2 reader for $15-$25, these work on ANY vehicle sold in the US/Canada 1996 and up, so not a bad investment if you plan on driving any car/truck in the future
The ELM 327 seems to work OK with most APPs

APPs are free or $5, the free ones would do for now, and its easy to use


But you DO need to get the codes FIRST, you can't pass smog with CEL on and you don't know why CEL is on until you read the codes

Ford Code list here: https://www.therangerstation.com/tec...II_codes.shtml

You can see there are close to 1,000 codes, and this is not even all of them, but most, so guessing is out of the question, lol


Also do you have a manual or automatic trans, and is it 2WD or 4x4?
Probably won't matter but..................it might

I second the ELM327. Got one for my F250 diesel that they said would not work on, and it worked perfectly. Found my bad FICM with it. The only downside (for me) is that it's small, and I misplaced it somewhere. Gone forever.

You guys are awesome!!! Even in this awful time, I feel so good to know there’s support out there. It’s a automatic transmission 2WD. XLT extended cab. Posted a picture of my little guy :) I really hope I can get it fixed. In our neighborhood you aren’t allowed to work on your cars or else my dad would help with small repairs. My only fear is they say replace the cats and thousand dollars later and it still won’t pass. Sigh..

https://cimg9.ibsrv.net/gimg/www.ran...30377e39b.jpeg

Nice looking Ranger :biggthump

While its possible for a head gasket issue to cause Cats to fail, i.e. coolant vapor in the exhaust, it not a likely outcome

Keep a good thought, a code can be set for leaking vacuum hose or Blown up engine or transmission, so there is a pretty big range that CEL being on covers
Once you have the code(s) you will know more

Ok so before I go back to the mechanic I went up to autozone- the tests are free, not sure how reliable as it was a small little tester and the mechanic has something that looks like an iPad lol!

so this is interesting and something I had forgot to mention- the mechanic also told me he replaced My EGR Sensor pressure and the upstream O2s. Auto zones results show P0401 and recommend replacing the DPFE. Isn’t that the same thing this guy just replaced? My dad was thinking of replacing the actual valve as it’s old and seeing what happens.

P0401 Exhaust Gas Recirculation Flow Insufficient Detected

Yes, could be a couple of things

The DPFE sensor is connected by 2 hoses to the EGR exhaust tube, which is between exhaust manifold and EGR Valve on the intake manifold

The rubber sensor hoses are different sizes so there is an "order" in where they are connected on the exhaust and on the DPFE sensor
The DPFE sensor measures the pressure difference between the 2 hoses, when EGR valve is closed then no difference in pressure
As Computer opens EGR Valve the hose closer to the valve will have a pressure drop greater than the one farther away, DPFE sends that data to computer

P0401 means as computer opens EGR valve the pressure difference is not what it should be

So yes it could be DPFE sensor, common issue, but if it was just changed then maybe a hose came off or is cracked, worth a look

It could also be EGR valve and tube is dirty, so restricted flow, so DPFE sensor is correct
You can put a longer vacuum hose on the EGR valve, start engine, then "suck" on this hose to create vacuum and pull open EGR valve manually, engine should start to stumble and will stall if you hold EGR Valve open long enough, this means Flow is OK, not clogged

Could be EGR solenoid or its vacuum hoses
Computer uses EGR solenoid to open EGR valve using Vacuum, as above
Computer pulses 12volts to solenoid to let a little or alot of vacuum flow to EGR Valve to open it a little or alot
If vacuum hoses are leaking then EGR Valve is not open at all or too little, so P0401 low flow
Follow the EGR Valve's vacuum line back to the EGR solenoid, then follow its other vacuum line to a "T" usually, make sure all hoses are OK

Bad EGR solenoid should set a different code

Ron-thank you for the thorough answer and information! My dad and I will be double checking all this and have looked at some of this yesterday after reading this.

here’s the next interesting piece of the puzzle. I wanted to go back to the mechanic today as he had told me and plus free code scan to compare to see if all is the same. Interestingly enough the only code showing now is P1000- all my systems were set and ready (including EGR) except my catalyst monitor and my CEL is still on. So he’s having me do some drive cycles (as I’ve only driven 50 miles since he last cleared the codes) and going back Saturday and he’ll clear them again if nothing has changed. I felt somewhat relieved but then read about the P1000 code nightmare on Ford trucks And how people have driven thousands of miles to no avail. I’m just worried as my tags expired in Jan so I’m illegally driving this car to and from the repair shop and for the cycles. The DMV is closed due to Covid and I’ve called tons of times to try and get a temporary driving permit for 60 days. I’ll let you guys know the outcome! I really sure hope that this thing completes and clears the CEL.

For catalyst monitor

Do this after engine is warmed up

Drive in stop and go traffic conditions.
Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period.
This Executes and concludes the Catalyst Monitor test

Most tests will only occur with gas gauge between 1/4 and 3/4, and outside temp between 40 and 100deg, just FYI, usually its only the EVAP system test but.................these computers have parameters for testing systems, so best to do whats recommended for all tests

thank you!! :) fingers crossed! By the way- thanks a ton for being so responsive. I really appreciate it!

Update! Finally passed smog. Wanted to just share the rest of my experience. May not be 100% ranger related but still helpful. The drive cycles did nothing it turns out and the ERG code came back.

huge thanks to Ron as yep, it was a vacuum hose. Super easy fix - turns out when the put my engine back in they put it on wrong and it was slightly cracked. Cats are fine and I passed with flying colors. :)

my next project that is ranger related is trying to fix my seatbelt receiver without buying a replacement. I’ll be searching the forums but just wanted to say a huge thanks for all the help!!

Good work

Thanks for the update

thank you! I would’ve probably wasted tons of money going down a crazy route if you hadn’t suggested all those steps with the ERG. There’s so many vacuum lines it can be hard to miss especially when cracks can be so tiny! Glad I came here because this was the best advice I got (some wanted to replace the valve and whole system, the cats, and many other things!).

try a squirt of silicone lube in the latch. look in see if some debris is lodged inside. ive fixed 2 that way.

thanks for the tip!! This has been years of an issue (I just buckle into the passender side haha!) but nothing is in it (like a coin, etc), the Spring is just broken. I can’t find the part in a junk yard nor have The tools to do this but I was watching some videos about popping the latch open and fixing the spring/clip? Anyone heard of this ? My dad and I have been trying to pry it open with a screwdriver but hasn’t worked yet! Maybe what you suggested will at least help open it up! Thanks!!

I'll admit it has been a while since I've been under the hood! RonD is right on track, he sounds like he was under a hood just this morning!