State Emissions Failure where to start looking

[kimcrwbr1]

How old is the PCV valve and have you pulled the codes.

 

[Mark_88]

It passed after pulling the initial timing setting back from 11 deg to 8 deg and by...replacing the cat.

Pulling back the timing was suggested as a "trick" that is generally helpful, but didn't do too much, left it there. Put a new cat on it and it came down pretty radically. Went to local shop which still had something to measure tailpipe output to check things before going back to the state inspection. Unburned HC after driving was down around 10ppm. Over a period of time at low idle it would creep up to 40ppm.

I expect the engine still is putting out the unburned stuff and the cat is just converting it. Probably not the best of situations. I actually think at the retarded timing it runs a bit worse so will probably tweek that back to 10 deg.

Ironically when I went for the test today, unlike previous times where they had me turn it off the ignition immediately, and there was a 10 minute gap before they turned it on. They had me keep it running and only asked me to turn it off immediately before they had me get out and the guy got in to do the test. It was off for less than a minute. It probably would have passed last time had they done that.

I wonder if my bitching last time got into the ear of someone and they looked up how they were supposed to treat older cars. I dunno. Different people this time than before.

Good to hear...not that you had to go through so much...

Been there and done that...for 14 years...each test and subsequent repairs over the last 7 tests (every two years) has cost me at least $600...

My Suzuki Sidekick was refused at the test center because it had a pinhole in the down pipe...instead of trying to simply plug the pinhole with some liquid metal I went for a whole new exhaust...cost me $2,000 and two days work because the guy broke a few exhaust manifold studs in the process...

Anyway...the cat is designed to burn (or convert) those extra HCs and when it doesn't do that the only solution is to replace it. Not sure what the amounts should or would be otherwise but it is always good to be as efficient as possible...tweaking it might get your mpg a bit higher as a bonus and if it was my truck I'd want to do that too...but I always have to ask "at what cost"?

Biggest problem with that sort of troubleshooting is the added cost of getting the truck into a test center to make sure what you are doing or have done is working it in the right direction...so maybe reset the timing so it runs better and be done with it...not sure what the centers charge for follow up testing (in Canada it's $15 to $35) but it might be worth your while to have it tested again after the tweaks.

Personally, I'd reset the timing and be done with it...as long as it's running good...

 

[ab_slack]

How old is the PCV valve and have you pulled the codes.

I have no idea. I expect there is a fair chance it was the one from the factory. It had Ford logo on it. It is always possible the previous owner (I am second owner, 2 years) got parts from Ford or had it always worked on at a dealer. It was in horrible shape.

And yes I pulled codes for the first time. I was surprised that there was only 2 issues, both EGR related. See below.

Personally, I'd reset the timing and be done with it...as long as it's running good...

More or less what I intend.....although she is a resto project of sorts. Not a true everything perfect restoration, but I really am trying to get her in very good running condition and address the small body issues before they turn into big issues. No real mods planned from factor cause I love these BII as they came. I've thought about making a thread for her, done so much already.

The good thing about this whole exercise is it did force me to get the codes, check out all the sensors and such. Stuff I had no idea if they were working right or not. And I had my suspicions about the cat, but while I will change some parts while I have something apart for another reason if they are cheap enough, I don't like to just throw parts at easily accessible items. It also put me onto the messed up PCV system which I hadn't given due consideration till I seen RonD mention it here and a few other threads. So I don't begrudge the $600 or so I put into her during this exercise. I learned lots.

For the curious, this is what I did from after original emissions failure.

KOEO self-diagnostic test returned code 31 EGR Position Sensor Fault, replaced sensor, KOEO no longer returned any code other than system tested okay. No memory codes present other than the 31 which has also cleared.

KOER test which returned 33 indicating EGR valve not opening. Inspected EGR valve, was full of crap, monitor port completely blocked, couldn't be sure it was closing all the way so replaced. This did not resolve the KOER test code. Further troubleshooting showed that no vacuum is making it too the input side of EGR control valve so even when valve gets energized it can’t open the EGR. I did not follow this further at this time as I was confident the EGR valve is closed (new one) and since the emissions test is only at idle I am left this as a too be addressed item for now. No other KOER codes were reported by the ECU.

PCV valve and crankcase vent - The grommets on both were sort of chemically melting from age. PCV valve had been mostly pulled out and had sucked up its grommet so was clogged. Replaced PCV valve, replaced both grommets, verified vent hose and PCV vacuum hose was clear.

TPS – Checked sensor, seems to generate proper signal range and generates smooth signal change with throttle opening.

MAP Sensor – Performed diagnostic that indicated bad, replaced sensor, diagnostic with new sensor returned same result. Found out I used wrong diagnostic procedure, re-checked original sensor and it passes using correct procedure. I did not put old sensor back on, left engine using new sensor.

O2 Sensor – This was replaced about 6 months ago. Immediate increase in fuel economy was observed at the time, some other running symptoms also cured. Was concerned that something else is causing it to run rich and that in turn may have clogged up the sensor (and cat). On the other hand, I haven’t seen the same symptoms that were present before the O2 sensor replacement so assumed it is still okay.

ACT Sensor – Pulled sensor out of throttle body to inspect. Sensor was badly coated with oil and packed with stuff. Replaced with new sensor. This smoothed out idle somewhat.

Thermostat – Engine temperature was not regulating as well as it had been, was tending to sit lower than usual. Coolant level was good. Had been suspicious for some time. Replaced thermostat, temperature back to steadily running mid range.

ECT Sensor – Reports 41K when engine cold, that is correct value for 65F and reports 2.7K when warmed up which is the correct signal for 195 deg so it looked good, took no further action other than some contact cleaner (also sprayed on contacts of any connector I unplugged while testing. I noted plastic housing around connector plug is partly cracked away. Had I seen that when changing the thermostat would have changed ECT too but since it is a pain to get at and output is correct I left it.

IAC valve – Figure it is pretty dirty given the ACT sensor condition. On my list to clean but too no action yet.

Timing – Gave this a quick look. Should be 10 deg with SPOUT connector removed. Looks like it may be 11 deg. During the KOER timing check it gives the appropriate 20 deg advance and falls at about 32 deg which is within the 27 to 33 deg. Took no action with this prior to first-retest. After failed retest retarded initial timing to 8 deg at suggestion of a local mechanic.

Air Filter – Replaced, it was surprisingly dirty. It had been two years so I guess that is reasonable.

Oil and Oil Filter – It had just come due so changed these.

Cap, Rotor and Wires – These are also 20 months old and about 15K miles on them. Only gave a quick look at the wires, verified spark plug connections when checking the plugs. Didn't pop cap to see the inside..

Spark Plugs – Plugs are about 20 months old. Pulled them out, they all looked like still in good shape, gaps were in the 0.044 to 0.045 with one out at 0.046.

Fuel Injectors – Condition unknown. These are the original injectors as far as I know. Did a quick check for leaky injectors by monitoring fuel rail pressure when engine is turned off. Fuel rail holds pressure which I believe eliminates any serious leaking of the fuel injectors. Ran a tank of fuel with Seafoam in it to clean the injectors.

Intake, Valves, Cylinders - I had a new short block put in 15K miles ago so expected it to be pretty clean, but clearly the people who put that in took no care with the stuff they pulled over (valve covers with the nasty PCV valve, old fuel injectors, throttle body) I expected very dirty. Who knows what crap may have pushed in from the PCV system not working. So I ran some Seafoam thru the intake to clean out any deposits that may have occurred. I doubt this did much with the crap in the throttle body so that remains on my list to pull apart sometime.

Catalytic Converter – Had my suspicions but no hard data on this. After the second fail and check at local garage, just swapped in an new one.

And then success. As you can see there are a couple follow up items like the EGR, IAC, timing.

I should add that at least half those things I went thru are only things I became aware of thru TRS and the people here who offer their advice. I have learned a great deal. Thank you.

 

[Andy D]

One of the pluses of a '94 Ranger is that in MA, only OBD2 is subject to emissions testing. .