Gevo

Two topics... probably related.

I picked the 4Runner up from the muffler/mechanic shop. After he put the new cat and muffler on, he ran the car a while to heat up the cat and then ran a test to see if it will pass smog. Smog failed.

1st pg at 15 mph


2nd page @ 25mph


He said it's running way to rich (HC reading is 132 but max is 84), i told him I have installed different injectors that I was told the ECU would adjust eventually. He said, well, that is possible, give it a few more miles and come back we'll see. He said I can manually adjust the AFM to change the ratio.. So, I knew about that since I read it here on the forum, and i liked that he was aware of these things. I trust him a bit more now.

The next thing he said was that the engine is backfiring.. but I didn't quite understand this, except that I know the engine doesn't do that big blow back.. pretty much ever. It seems to run very smooth. He told me to advance the timing to about 12 degrees, that can help a bit. Then he said, also, your charcoal canister could be the issue, it may be saturated.. etc.. which makes sense since recently I tested it and it failed. I just forgot to purchase one.

So, lets say the charcoal canister, more driving and timing fix the smog issue.. how will that affect the intermittent power loss?

Please give me any other advice on the smog issue.

NOW, the intermittent power loss::::
As I explain what is happening, keep in mind i suspect an electrical short of some sort but am not sure it can even cause this symptom.

As I drove today for a few miles, it was excellent. MUCH stronger than before the new cat and muffler, I was very satisfied. After about 15 miles, it rather quickly lost power. It wouldn't rev, and when i kicked it down it didn't wanna go. So, I stopped, turned the car off, turned it on and it was good again. I drove for about a mile, and it started losing power again. So, I stopped, turned it off, on and again it was good for a few more miles until I got home.

Reason I suspect electrical short is because yesterday when I was driving it the 4wd light came on when clearly it wasn't in 4wd, and as i got this same power loss issue the 4wd light was flickering. Eventually things moved around or something, the light went off and the car was better. I haven't had time to check the short issue, but I am thinking it is NOT the cause of this power loss.

To me, the power loss felt like a 'bog' down, like when my dirt bike engine is cold and i pop the throttle it wants to die.. I'm thinking how can the 'rich' condition and the power loss issue be related?

As usual, long winded post. I appreciated your guys thoughts!

scope103

How many miles had you driven on your "different" injectors? If the learned A/F ratio is ever going to catch up, it should do it within 10 miles. And you are running REALLY rich (average passing HC in California is 27ppm, average CO is 0.02%). You're basically dumping unburned fuel out the back; I'm surprised you've got any power at all.

The unburned fuel hits the hot exhaust stack and gets mixed with atmospheric air; it burns there and causes "backfire." The engine is designed to pull the vapors out of the canister, so if it is so full it is actually dripping, that might over-richen the mixture beyond what the ECU can cope with.

Any reason you can't install the correct injectors? Sounds like that would go a long way to solving your problems.

Incidentally, even though you passed on NOx, you are VERY high. Average passing in CA is 37ppm (limit is 373). You may have a problem with your EGR system, but it will be hard to tell until you get the mixture somewhere close to the right neighborhood.

Gevo

I have about 40 miles on the new injectors now. Maybe 25 since I last reset the ECU (in case that resets the learned mixture)

Can I adjust the air flow meter to compensate?

Fuel Pressure regulator contribution to overly rich mixture?

Also, I forgot to add.. the fuel is in fact being dumped somewhere because I put about 40 miles on 1/2 a tank.

scope103

If the fuel pressure regulator is stuck closed (no fuel in the fuel return line), that is "a" cause of over-rich. You can easily check; get a 10mm line on the FPR into a gas can; see if fuel flows out with the pump on.

There is no Toyota recommended service to the VAF. I can't rule out that it might be possible to modify it (with a new potentiometer perhaps) to make the ECU think that less air is entering the engine, so that the ECU will shorten the injector time.

But once you make that modification, what else will you have to modify? I'm sure not smart enough to say.

Do you have non-stock injectors? If you think that is the problem, is there a reason why you can't fix the known problem? Or is there something else going on? I'm having trouble grasping why you're worried about the FPR or the Evap if you already know what the cause is.

Sturmcrow

Did you test your VAFM according to the FSM? I might be busted or it could well be that you need to turn it a few clicks leaner.

I have seen decent looking wide-band Air/Fuel gauges for $150 or so. I cannot seem to find a temporary one, but the permanent install kind could be useful for tuning in those injectors to maximize efficiency.

Gevo

Scope, I have yhe orange flamethrowers that are supposed to be at the same rate of flow as stock. I got talked into the whole fuel spray pattern aspect of it and would like to try to keep them. I will check the fpr again, and then test the afm per the fsm. I c
Tested it before but later found my multimeter was busted and havents tested yet. Assuming everything checks out to spec I will try to lean the afm out and see the results.

Scope you are helping a lot with me thinking everything througha nd putting things into some perspecrive. Thanks!
Also, I have to send my oem injectors to get them rebuilt, so I wont be able to put them I for a while. And id love not to do the job as I took a risk and wired the new injector connectors onto my engine harness. Old ones were broken.

Gevo

Sturmcrow, I wouldnt know what to dowith that gauge. Lol. Alsi as I mentioned above, il check the vafm specs again

scope103

If the injectors are "supposed" to have the same flow rate, you might want to start with that assumption. Meaning; don't mess with the VAF (the multimeter tests, which you should do, are not for calibration but just to check basic function)

A leaking injector will certainly make it run rich. A bad O2 sensor could. (another use for that multimeter http://www.harborfreight.com/7-funct...ter-98025.html) You could try removing one plug wire at a time; mis-fire is a common cause of high HC, so if one cylinder isn't firing it may show up that way.

Good luck!

Punchy

There is no real change between in HC low and high speed, Good chance EGR is getting stuck open and not regulating correctly at high speed.


Pull the vacuum hose from the top of the main EGR valve and give it another test run.
Green VSV can be plugged as well.

scope103

The EGR is supposed to be open with the throttle open. http://personal.utulsa.edu/~nathan-b...18egrsyste.pdf How would the EGR valve cause the engine to run that rich?

(I'm all for simple experimentation, but I'm guessing that each of these smog checks costs around $50)

Gevo

Scope, yes I understand that the fsm tests are to confirm the vafm is within spec and not for calibration.

And, as much as people say that the orange flamethrowers have the same flow rate it seems they need some time for the engine to adjust, which tells me something isn't adding up.

I sure hope I don't have a leaking injector. I had to do enough work for one of the injectors being bad! I already have pulled the plug wires to the cylinders to see operation. All but #1 was good, injector was bad so i changed that now... it runs well without any shuddering of the engine.. other than the way to rich aspect.

I guess best case scenerio at this point is a bad afm. lol... worst case we don't know how to fix it

Gevo

OK, I literally lost many hours of sleep last night thinking about this and over all feeling SH**TTY that I STILL haven't fixed up this car enough to drive it. This is what I'm going to do today.

Test VAFM: If bad, everything stops there until I get a new one.
If good --> Test FPR (I just remembered something stupid that I did which may have damaged the FPR, although I don't think so. When doing the leak test after installing the one new injector, i turned the fuel pump on, but i had blocked the fuel return hose out of the FPR, and some fuel was seeping out but it took me a couple of minutes to realize what I'm doing before I removed the block. After that I have not tested it's operation, however i didnt leave the fuel pump on for that long. I let it build pressure and disconnected the leads. )

If FPR is good --> test injectors..... this is where my problem starts. How the heck will I be doing this? I simply can't. So, thinking through it it seems the only way the injectors can be causing SUCH a high fuel ratio is if they are staying on, not just 'leaking', but staying on all together. Even then i figure most of the 6 injectors would need to be staying on for so much fuel to be dispensed, how likely is this? I CAN do a fuel pressure test, but if the injectors are staying on DURING engine operation how would it show on the pressure test, slightly less pressure? Obviously if too much pressure then new regulator and hopefully that would solve it... I don't have starting problems, so no fuel accumulates in cylinders that I could tell.. further telling me injectors are not 'leaking'...

Electrical problem? So, I will probe the injector wires (only two sets since each 3 fire at once) and see if there is a constant voltage.

My 02 sensor is new, but I have the old one which I can swap if there is a for for that... I doubt it though. As Scope said, easy enough to test.. will do that.

EGR - as I understand it, I can rule out any EGR issues by isolating it, and all it takes is isolating the one vac hose that goes to it at the top (between pressure modulator and vsv), correct?

Also, sorry I forgot to mention earlier, due to the high HC from the smog test he said check your charcoal can, and then unplugged the vac line to the canister and said "let your engine breath in some cleaner air", so I drove home with that unplugged, however I felt no difference in operation (as I figured) and the intermittent loss of power was still there)

PAIR reed valve, I tested this before and it works. And same with the VSV that controls it. HOWEVER, looking at the FSM diagram ( http://personal.utulsa.edu/~nathan-b...78pulsedse.pdf ) even if it is not working properly, how would it cause any of my issues? anything to do with backfiring? (I hear the gurgling noise on throttle release, according to fsm that's good).

PCV valve is new

Cold Start injector---> tested, works. However, I will unplug it after engine starts and run it unplugged to see if i notice any difference in engine operation/response/power, which may translate into CSI spraying fuel the whole time, will check voltage during engine operation as well... this CAN cause rich condition, but I doubt it can cause such a high fuel ratio still... thoughts?

I read somewhere else on yotatech an exhaust leak cause cause rich condition, and the idea was that air would leak in giving false, high O-2 level reading via O-2 sensor.. I don't think this can be my problem, exhaust is pressurized so if anything it should leak OUT, opposite effect.... thoughts?

I will advance timing to 12 degrees.

scope103

I doubt the truck would run with an injector stuck on; it would flood. In fact, if stuck open it would probably hydrolock and you couldn't even turn it over.

You're looking for something a little more subtle than that.

Use your voltmeter on Ox1. (and probably VF1 http://personal.utulsa.edu/~nathan-b...42oxygense.pdf) Unfortunately, your rich condition has probably "pinned" to O2 sensor so the voltage won't flip at all. But it's an easy test for exactly what you're looking for.

Gevo

Afm is within spec. Every measurement is good.
O2 sensor next.

Gevo

Pressure regulator is working properly. I took a video and will share it soon. Following my idea that the pressure in the tank is affecting things, I studied the fsm some more and as I pictured the whole system is connected through the charcoal can. I already ordered a replacement yesterday since I knew it was bad.

Here is the test I did and you guys can tell me what you think. I put. A hose on the return line right where it connects to the fuel pressure regulator, I blew into the hose and found there to be a bit of resistance. Ofcourse I u derstand my weasily diaphragm pressure of maybe 1psi is not much, but the it started to blow back, higher backpressure and I could barely hold it with my diaphragm pressure. I went to the tank, openned it and sure enough lots of pressure is released. I come back to blow again through return line and minimal resistance.

Dince the car had been stationary for many hours its safe to assume the vapor pressure in the evap system was lower than would be when driving. Then its safe to assume that the pressure working against the pressure regulator is significant and this is causing more pressure in the fuel rail amd out the injectors.

Im goin to let the evap line open to the air and drive it around and see if I feel a difference.

What do you guys think, am I on the right tra k? Is there hope?

im going to do the fuel pressure test now just incase.

O2 sensor was wothin spec, didnt wanna start car yet to test feedbavk voltages. Soon!

scope103

I'm not sure what you think is going on here.

The fuel pump can put out considerably more than 60psi. But at about 44psi (depending on the pressure in the intake manifold), the FPR "dumps" the excess fuel back into the tank. Keeping the pressure in the rail a fixed amount higher than the pressure inside the intake manifold. The static pressure inside the tank has nothing to do with this; the "dump" pressure is set by the pressure in intake. As long as the tank is less than 44psi (so the fuel can get back through the return line) the FPR can do its job. And the fuel tank would explode long before it got past 5-6 psi.

As the pump pulls the fuel out of the tank, the vacuum it could create in the tank would cause the tank to crush like a beer can. So the cap is vented to allow air in -- not out! The vented cap won't let air/vapors out as they are full of gasoline fumes. So when the temperature rises and the vapor pressure outruns the vacuum created by the fuel pump, the vapors get adsorbed into the canister. Later, when you start the truck, those fumes get sucked out of the canister into the intake (through the TVV when the engine is warm enough, and only when the throttle is open a little). While these fumes enrichen the mixture slightly, the O2 sensor just flattens that out. Unless you have so much liquid gas sitting in the canister that it exceeds what the O2 sensor can handle.

Excessive fuel rail pressure will cause you to run rich, if it is so high the ECU can't compensate. But you check that with a fuel pressure gauge, and don't worry about the evap side of the pressure equation.

If fuel is not actually dripping out of the canister, I doubt there is so much fuel in there as would cause a problem. You could try disconnecting it at the TVV (which would make it a vacuum leak, leaning out the mixture, but again not so much) just to check, but a sharp-eyed smog check will catch that (so it's not a long-term soln).

Good luck with your pressure test.

muddmadness

Where is the best place to find the charcoal canister? Do you have to order it from the dealership or did you find it some where else? mine has a rattle in it and I suspect it needs replacing before I go to the referee to get it smogged and inspected.

Gevo

Scope,

thanks for that thorough explanation, I understand the fuel tank evap system much better now. And, I realize my thoughts on that back pressure is all flawed. As soon as I saw the fuel rail pressure to be 48 psi, it hit me, that is going to overpower any back pressure without any effect to it... lol.. anyway. so past that.. below is the result of my fuel pressure test.

- at startup and idle fuel jumps right to a nice steady 44psi
- at ~ 1500 rpm it is steady at 42 psi
- when throttling up then releasing, it momentarily drops to 38-40psi then very quickly back to 44 for idle.
- when i shut the car off, it holds 45-48 psi for at least 5 minutes, and then I stopped testing.

i repeated all of these tests multiple times.

I checked the cold start injector for leak (I did this before the overall pressure test, I know it's superfluous at this point).. it was perfect.

As I mentioned earlier, the AFM was spot on.

ran out of time to check warmed up o2 sensor outputs... booo

I went to advance the timing, and ran into something I don't understand.
I tried to adjust it to 14 degrees advance... but the furthest counterclockwise i could go only took me to about 10-11. Also, before the smog check and the new catalytic converter, i had it dead set at 10degrees advance. I am 100% certain of this and had checked it a few times throughout all this work, however when i went to check it today, and before i had loosened the distributor it was down below 0, so it was retarded a couple of degrees.. what in the world could cause this??? I am pretty sure it's not a belt related issue, everything is new. So, I went to adjust the distributor over one tooth, and I did... i think this aftermarket distributor is the problem, i'm gonna put another one on when i get back to it. so, after that the lest advance it would go was 16 degrees at which point i got code 52, knock sensor. I just did research here and it seems far enough advance will do that.
now, her eis finally the part i don't understand (apart form retarded timing).. at idle the mark stays dead on 10 degrees (or whatever it's set to) then at the slightest (and i mean EVER so slight) touch of the throttle the timing JUMPS to a way advance, the mark is about an inch or more before even the 15 degree mark. I think this can cause my backfire issues...?

So, how is all of this coming together to give me the smog fail problems...

stupid SoCal sun was frying me out there

Gevo

Mudmaddness i got a used one from ebay. As long as the seller says its in good working order, get it, test it per fsm right away and if it's good, use it.. otherwise return to seller or get your money back and try another one.

RJR

Did you connect terminal TE1 to E1 on the diagnostic port before checking the timing? That connection tells the ECU not to advance timing as rpm changes. Otherwise you'll get exactly the results you saw, and your timing adjustments will be bogus.