SMOG fail! ridiculously high HC levels

[thaibuddie]

My 90 Camry wagon V6 only has 116k and the HC levels came back almost triple what is acceptable. All other inspections and numbers were fine.

Any thoughts on what could be causing? I've recently replaced the distributor cap, plugs and wires.

I read something about a "fuel brain" at the bottom of the page HERE

I don't even know what a fuel brain is, does my car have one and are they prone to failure (article says they fail ~100k)

Any help is appreciated - THANKS!

[Doctor J]

I would like to know the CO level and O2 level as well.
"General" answer:
High HC very LOW CO and High O2 = vacuum leak
High HC and normal CO [0.15...0.25%] timing off, or leaking EXHAUST valve seals

[thaibuddie]

Here are the numbers:
...and do you know if this car has the said "fuel brain"?

[Doctor J]

The fuel brain is not technical term
The engine electronic control unit is managing the fuel mixture; most of the emissions mulfunctions are related to the external components, not the control unit, UNLESS someone "chipped" it.
Your car shows slightly elevated CO, and low NO.
CO2 is 15 % indicating full combustion.
I would recommend following tests:
PCV system-- make sure that hoses and valves are not restricted [the smog visual inspection is not checking for that]
Old engine oil
Charcoal canister--oversaturated
No vacuum at fuel pressure regulator -- the FPU system is not working right
Liquid fuel in the vacuum hose to the fuel pressure regulator--- broken diafragm of the regulator.
You need also to pull any trouble codes stored in the ECU memory
and measure fuel trim value [volts] between Vf and E1 terminals in the diagnostic connector with engine idling.
If no problems are found the exhaust valve seals can be leaking ; that allows fresh unburned oil to get into the catalytic converter.
Sorry for being to technical

[thaibuddie]

The PCV was replaced within the last 10k, I double checked and everything looks to be OK.

I will be sure to change the oil before going for retest (not that it's overdue).

How can I check the charcoal canister for over-saturation? I located it, but that's about it.

I wasn't sure where the fuel pressure regulator is, but I believe its this:
(if so, there is vacuum at both vacuum lines and no liquid fuel is present in them)



Trouble codes from the check engine light:
4,2,7,1
also notice my OD on/off light blinked: 4,2

Once the engine was warm, I measured just under 4V between Vf1 and E1 during engine idle. (If I did this correctly - those meters are a little confusing to me...)

THANKS!

[Doctor J]

Touble codes are 42-is for the speed sensor in the speedometer [if speedometer is not working it will show up]same code is from tranny
This may in some cases cause engine to run in the IDLE mode under load and upset the " actual" timing [while on the treadmill]
code 71 is for EGR gas flow; it usually accompanies HIGH NO reading, which is not [it is really LOW] on your car, so check the sensor pigtail for bad connection.
The fuel pressure regulator is located on the "front"fuel rail at the drivers side end.
when car is not driven for long time and canister is not purged the charcoal inside forms a"solid mass and the fuel vapors from the gas tank is sucked directly to the intake manifold when the engine is warm or hot [after the BVSV blue valve opens] this causes mixture enrichment.
To my shame I am not able to tell what is the part name on the picture you posted

[thaibuddie]

The speedometer has never been an issue - it works perfectly.

The connection at EGR seems fine.

I located the fuel pressure regulator on the driver's side of the front fuel rail - it has one vacuum hose connected to it with strong vacuum present and no liquid fuel.

The car has been a daily driver for us for the last 35k, it has passed smog 2x for us in the past - it doesn't seem that the clogged charcoal canister scenario applies.

While looking in the manual for info on the fuel pressure regulator - I noticed something about a cold start injector. Is it possible for this to be stuck "always on"? When the car was first warming up I disconnected the pigtail connection and there was no change. I have also disconnected it when the engine is fully warm with no change. Is it possible this is causing my rich condition - how do I troubleshoot or am I was off here?

Also, my friend seems to think the oxygen sensor(s) are suspect?

Please...any additional help is appreciated. THANK YOU!

[thaibuddie]

I looked further into the cold start injector (CSI) I had mentioned in my previous post and here's what I found:

Resistance at the CSI prongs is ~5ohms which seems normal.

There is absolutely no voltage at the pigtail connector. I measured it continuously from "cold start" until the engine was fully warm (fans turned on). My buddy says that it may just not be cold enough (it is ~80*F today) but I can't help thinking it's stuck on.

Talked to my friend again - he really believes I need to check the oxygen sensors - it there anything in the smog report #s that would indicate I do not need to check these?

THANK YOU ! ! !

Photo of CSI here (just to be sure I'm checking the correct thing)

[Doctor J]

Cold start injector is open ONLY when starter is running for 3 to 5 seconds. it is not energized [closed all other times]the fuel trim 4 v seems within limits, bad O2 sensor will cause it to be 0 volts [rich].try to fix the speed sensor issue;[however on 4 cylinder 87 model it has no effect on the emission testing].
make sure that EGR system is working right [there is alot of EGR flow 9 ppm, it usually 200 on new catalyst and good EGR, and about 700 with bad catalyst and good EGR]
If you get opportunity, try to measure HC at idle and 2500 rpm [2 speed test]
i may also suggest to plug the charcoal canister PURGE hos and do the pre-test. if HC reading improves the saturated canister is the cause

[thaibuddie]

OK regarding the EGR, can you please elaborate? It sounds like you are saying the EGR is flowing too much because of the extremely low NO levels. Can you explain how this would elevate my HC levels?

THANKS!!!

[Doctor J]

Too musch EGR flow will reduce combustion temperature and dilute charge. had New aftermarket EGR iinstalled on my friend's Oldsmobile. this valve had set of flow control washers with it [to fit several madels], but none of the washers wre installed.
After "repair" the car lost the power at acceleration and its HC levels were increased 3 times compared to the first inspection [failed NO -high].
The shop tried to sell new distributor to the owner but we fixed the car by installing correct washer.

[thaibuddie]

OK so do I just buy a new EGR or test it? I followed the troubleshooting sequence from the manual and it didn't really tell me that much:

STEP 1. The bottom of the filter seemed clogged. Since the filtration appears to be occuring at the bottom part (based on where the vacuum lines are) I simply flipped the filter over so the nice foam would be used).
STEP 3: Engine does not idle entirely smoothly, but that could be anything.
STEP 4: With the engine cold I DID get a vacuum reading here (low vacuum) and I was not supposed to (so my BVSV is bad? since this is only when engine is cold it should not affect my SMOG test, correct?)
STEP 5: What exactly is a LOW vacuum reading?
STEP 6: Yes, the vacuum reading was higher, but what is HIGH? Note that this did NOT seem to change how the engine was running (book cautioned of misfire).
STEP 8: The engine faultered and died.
THANK YOU ! ! !

[Doctor J]

I am using slightly different test for EGR valve
1) On EGR vacuum modulator, apply low pressure or vacuum to the lonely pipe on the bottom side. If there is leak, then the modulator diaphragm is damaged and modulator must be replaced. If it hold pressure or vacuum, go to step 2
2) Disconnect vacuum hose from EGR valve and attach vacuum gage to the hose [you may need to use extra hose to extend it], then using duct tape attach the gage to the windshield. Start the engine and warm it up. Drive at 15 mph; the gage should show about 15 in. of vacuum. Do the same at 25 mph. If vacuum is present the EGR system works properly.
3) Erase codes by disconnecting battery drive the car and re-check
4) If code 71 is present again, remove and clean carbon from EGR valve, transfer pipe and backpressure hose [one that connects the valve to the lonely port of the EGR vacuum modulator]. Presence of tar-like deposit indicates bad exhaust valve oil seals [and the possible reason for smog failure].

[thaibuddie]

Firstly, thank you very much Dr. J for working with me on this.

On step 1, I am essentially doing a leakdown test on the thing. Do I need to disconnect and plug the other lines? Also, what is considered "low" vacuum? and do you have any recommended techniques for applying vacuum/pressure (I do not have access to compressed air in case you were to suggest that).

THANK YOU ! ! !

[Doctor J]

For home mechanic the 2 oz bulb syringe and 4 inch long 1/4 inch diameter hose is what needed to test vacuum modulator.
Remove the backpressure signal hose from this lonely port on the buttom of the modulator and attach the 4 inch long test hose. Then squeze the bulb and insert its end into the open end of the test hose. Relase the bulb. If it stays 'collapsed' for 15 to 30 seconds the diaphragm is good.
If it "inflates" in few seconds there is a leak in the diaphragm.
Again on your car I would try to make sure that the charcoal canister is working right and the motor oil is in the good condition.