We're back!

Hey all - thanks to MechanicMatt's recommendation for a machinist and his help answering my questions, I got my little buddy going again. I have to change the nickname though - I saw a mini-pickup with "Napoleon" stenciled on it (my Geo was "Napoleon" because it may be small but it just kept on soldiering along).

In fact, with the machined block and some TLC, I'm now getting 46-47 mpg. :) It was 42 when it was running normally before disaster struck (I can't find the thread now, or I'd link it, but I had to deal with a cracked piston, burnt exhaust valves, and finally a thrown rod, the last probably being my fault for getting my end caps mixed up :( ). At any rate, at 3 bucks a gal for regular here in SoCal, the difference in mpg will pay back the work put into it pretty fast.

There's just one little glitch right now....I failed my emissions test. runaround
The numbers were ok, but my timing was 5 degrees AFTER TDC. :uhoh:
I can put the timing back to normal, but the tester is afraid that I'll fail the hydrocarbon test once it's back. Given the numbers, and the Wikipedia entry on catalytic converters, I think I'm running rich because of the timing.

HC at 15 - 90 (max 153)
HC at 25 - 86 (max 128)
CO at 15 - 0.2 (max 0.9)
CO at 25 - 0.31 (max 0.8)
NO at 15 - 232 (max 906)
NO at 25 - 127 (max 845)

Looking at the numbers, my HC are clearly high, my CO are high but shouldn't be a problem, and my NO are actually well below the average test values. High HC, high CO, low NO = running rich, probably.

Yes, the cat's old and with all the problems from before, it could easily have been poisoned or slagged a bit.

But what else could I do short of replacing the cat to pass emissions. Would those additives that guarantee you passing help? Remember, the car's got brand new rings and newly machined cylinders, new valves, and I just changed the oil/filter about 120 miles ago. The car had been driven about a hundred highway miles right before I took it in for the test.

I'm tempted to drill a hole in the exhaust pipe just behind the cat right now, even though that would probably wind up causing more problems down the road. :smokin:

Any ideas on how to get my HC down, even for just a day? Restrict the fuel line? Stuff some fiberglass in the exhaust pipe? Fill the fuel tank with acetone or ethanol? Maybe an idea that wouldn't lead to the destruction of my newly rebuilt engine? :naughty::evillol:

Thanks for the ideas in advance! I'll post some of the modifications and rebuilding steps when I have some time, maybe next weekend.

ADDENDUM: OK, I just checked my manual and stuff, and from what I can tell, 5 degrees ATDC would be very retarded timing, wouldn't it (literally, too ;) )? If that's right, the engine's running rich b/c the timing's so far retarded (and my mpg could potentially be a lot higher than 46). So wouldn't advancing the timing lean out the fuel mixture and actually reduce the hydrocarbons? I don't know how much this guy actually knew about engines, so he may just be totally backwards.

Zed;

While my metro hasn't failed emission, I have an older Camry that did - here's a link to what I tried and how it worked http://www.automotiveforums.com/vbulletin/showthread.php?t=650247&highlight=emission
In my case I finally had to resort to changing the ctalytic converter.

Best of Luck, let us know how you fare!

Zed;

While my metro hasn't failed emission, I have an older Camry that did - here's a link to what I tried and how it worked http://www.automotiveforums.com/vbulletin/showthread.php?t=650247&highlight=emission
In my case I finally had to resort to changing the ctalytic converter.

Best of Luck, let us know how you fare!

Hmmm...so where exactly do you get methylhydrate? Is that the stuff they sell at Autozone as the "guaranteed to pass" additive?

That and the cat are about all that's left to check, although I could pull the air filter temporarily too. The rest of the options in the thread I'd already either checked or did. But if my timing is very retarded like it sounds, wouldn't advancing it actually reduce my HC instead of increasing them?


EDIT: OK, so after hunting a bit more, I discovered methylhydrate to be another name for good-ol' methanol. So like they say, the HEET is on....ok, bad bad bad pun, I admit it. :)

Zed glad to have ya back online. Congradulations.

You are running rich because of the timing. It is absolutely imperative that you SET your timing properly ASAP! You are risking your exhaust valves, and placing a massive load on your catalytic converter.

5° BTDC. Forget the crap in a can additives.

I do not understand "I can put the timing back to normal, but the tester is afraid that I'll fail the hydrocarbon test once it's back." Advancing your timing is going to REDUCE your HC levels. Hydrocarbons = fuel, what you are doing with your retarded ignition timing is dumping unburnt fuel right out the exhaust valve. Your low NOx is due to the low combustion temperatures. Nitrogen and oxygen combine much more readily when temperatures and pressures are HIGH, which - your temperatures and pressure are now LOW because of the retarded timing.




There's just one little glitch right now....I failed my emissions test. runaround
The numbers were ok, but my timing was 5 degrees AFTER TDC. :uhoh:
I can put the timing back to normal, but the tester is afraid that I'll fail the hydrocarbon test once it's back. Given the numbers, and the Wikipedia entry on catalytic converters, I think I'm running rich because of the timing.

Looking at the numbers, my HC are clearly high, my CO are high but shouldn't be a problem, and my NO are actually well below the average test values. High HC, high CO, low NO = running rich, probably.


ADDENDUM: OK, I just checked my manual and stuff, and from what I can tell, 5 degrees ATDC would be very retarded timing, wouldn't it (literally, too ;) )? If that's right, the engine's running rich b/c the timing's so far retarded (and my mpg could potentially be a lot higher than 46). So wouldn't advancing the timing lean out the fuel mixture and actually reduce the hydrocarbons? I don't know how much this guy actually knew about engines, so he may just be totally backwards.

Perfect. Your guy's an idiot, fire him. I can't believe he was opposed to you advancing your timing, when your timing was retarded!. NO car should have RETARDED ignition timing - no exceptions. Your car will no doubt feel much more hearty as well. I keep mine at around 10°BTDC, much less 5°ATDC. Unbelieveable. Adjust that timing and prosper Andrew!

-MechanicMatt

You should also consider WHY your timing is so far off. If the distributor is anywhere near the middle of the slot, you've got the timing belt on wrong.

+1 ^

-MechanicMatt

+1 ^

-MechanicMatt

Nice to know there are other people who want to find out the "why"s also. :)

As to why the timing's off, the timing belt could definitely have been put on a notch off. I can go over it this weekend and put it back on I think, and do it right this time.

So I did go in for a retest today, and this time failed for having the timing too far advanced. :grinno: According to the tester, it was 18 degrees BTDC. The amazing thing is I'm running 89 octane and getting no pinging with all that advance. In fact, it sounds too amazing to be true to me. Can my engine *really* be that advanced and still be detonation free without using 99 octane superfuel? I do actually have a marginally higher oxy content coming from the tailpipe - 0.1%/0.2% instead of 0%/0.1%. And I swear I'm pushing the 50 mpg "magic number" right now too.

That asked, my HC levels went up - to 151 (15mph) and 126 (25). Both of which are just barely passing (by about 2ppm each). As expected, my NO levels went up a little too, but are still quite low - about 300/177.

The other thing going on - I'm idling fast, about 990 rpm instead of 800. I'm assuming the emissions and idling issues are connected. I can adjust the idle with the idle screw despite the admonitions against it by the label in the hood, but short of using trickery and deceipt to beat the test one more time, can the timing still be adjusted to fix the HC problem, or does it sound like there might be some other reason (the cat, for example) for the high HC?

So one last question - can someone give me a good detailed instruction or link to said instruction on how to use my timing light? It's an old Craftsman Inductive/Advance timing light. I get the basics, in fact I thought I knew how to use it, even though it's been a while since I could find the instruction booklet. But apparently the first time I used it I was way off, and this time I'm back to being way off. Check me on what I'm doing wrong:

1. Get the engine warmed up
2. Pull the distro vacuum tubes from the distro and plug them
3. Connect Timing light to battery, clamp the induction cable to #1 wire, get neato-cool 70's strobe effect with which to blind or disorient passing bicyclists at night. :evillol:
4. Set the advance dial on the back of the timing light to zero.
5. Point at crank pulley and spot the nick - it should be marking the actual engine timing by sitting under the mark on the timing belt cover.
6. The label says 5 or 6 behind TDC. I should expect to see the pulley timing mark sitting under or close to the #5 of the belt cover.
7. Loosen the bolts on the distro and twist the body against the crank rotation to advance timing, with the crank rotation to retard timing. If the pulley mark is, for example, under the 10 degree cover mark, I'm too advanced and need to retard the timing by twisting the distro body until the mark gets back to the 5. etc. etc.
8. Tighten the bolts.
9. Point timing light at self, pull trigger.:screwy:
10. :dupe: Ignore #9, skip to #11
11. Unhook the timing light, close hood, etc.
12. Go inside and :popcorn: until you have to work.


Did I miss anything? It's this simple, right? Like, Geico Caveman simple? The advance dial is mostly used just to test the vacuum advance in the distributor, as far as I remember.

So are my hydrocarbons going to be too high to pass if the timing is right, or will the continue to hover in the "high, but passable" range? Have I gone over the hump on a bell curve of HC emissions (that is, one extreme to another which keeps the HC emissions down in both extreme cases)?

Thanks guys!:grinyes:
I have a little time to try and figure out what would do this, and fix it.

That asked, my HC levels went up - to 151 (15mph) and 126 (25). Both of which are just barely passing (by about 2ppm each). As expected, my NO levels went up a little too, but are still quite low - about 300/177.

The other thing going on - I'm idling fast, about 990 rpm instead of 800. I'm assuming the emissions and idling issues are connected. I can adjust the idle with the idle screw despite the admonitions against it by the label in the hood, but short of using trickery and deceipt to beat the test one more time, can the timing still be adjusted to fix the HC problem, or does it sound like there might be some other reason (the cat, for example) for the high HC?

Check me on what I'm doing wrong:

1. Get the engine warmed up
2. Pull the distro vacuum tubes from the distro and plug them
3. Connect Timing light to battery, clamp the induction cable to #1 wire, get neato-cool 70's strobe effect with which to blind or disorient passing bicyclists at night. :evillol:
4. Set the advance dial on the back of the timing light to zero.
5. Point at crank pulley and spot the nick - it should be marking the actual engine timing by sitting under the mark on the timing belt cover.
6. The label says 5 or 6 behind TDC. I should expect to see the pulley timing mark sitting under or close to the #5 of the belt cover.
7. Loosen the bolts on the distro and twist the body against the crank rotation to advance timing, with the crank rotation to retard timing. If the pulley mark is, for example, under the 10 degree cover mark, I'm too advanced and need to retard the timing by twisting the distro body until the mark gets back to the 5. etc. etc.
8. Tighten the bolts.


So are my hydrocarbons going to be too high to pass if the timing is right, or will the continue to hover in the "high, but passable" range? Have I gone over the hump on a bell curve of HC emissions (that is, one extreme to another which keeps the HC emissions down in both extreme cases)?


Andrew, you have a two-way catalytic converter whose controlled pollutants are hydrocarbons (HC) and carbon monoxide (CO). Your CO levels are nice and low, despite your relatively high HCs which pulls me away from a problem with the catalyst. With the relatively high HCs and relatively low NOx, I'm wondering if you have an incomplete combustion issue going on here - are your ignition components (spark plugs, wires, cap, rotor) in good repair? Does the car miss under acceleration? Does the car feel sluggish?

It seems to me you have a good grasp on how to use your timing light. There is however, a pretty thick line bewteen 5°ATDC and 18°BTDC - which is a gross over-correction and will feasibly raise HCs. I can't say much else about your ignition timing. I have zero experience with vacuum-advance systems.

Your high idle could certainly be attributed to your overly advanced ignition timing. What I would do first is get that timing set properly - this may clear up your high idle and incomplete combustion if that is the case. It does appear to me that you have leaped over the bell-curve of low HC levels.

-MechanicMatt

Andrew, you have a two-way catalytic converter whose controlled pollutants are hydrocarbons (HC) and carbon monoxide (CO). Your CO levels are nice and low, despite your relatively high HCs which pulls me away from a problem with the catalyst. With the relatively high HCs and relatively low NOx, I'm wondering if you have an incomplete combustion issue going on here - are your ignition components (spark plugs, wires, cap, rotor) in good repair? Does the car miss under acceleration? Does the car feel sluggish?

That's kind of why I was thinking the cat should be ok, too. Nice to know my personal logic functions are working better than my PC's Windows version right now. :icon16:

I thought everything was in good repair - the car's definitely not sluggish and doesn't miss on acceleration. During the rebuild I polished the points and rotor cap metal with an old toothbrush, and they all looked pretty nice (still solid and cylindrical, not worn) and didn't have an excessive gap. What I did find - by using my timing light and clamping the coil wire and all the plug wires - was that the coil is sending a smooth pulse to the distro, and the #2 and #3 run fine when tested at the plug wires, but #1 has an occasional miss when idling. It's harder to see when the car was idling so fast, but I set the timing (correctly this time :smokin:) to about 6 or 7 BTDC. I still had to lower the idle speed at the screw a little bit, but not nearly as much as if it was at 18 BTDC. Once I got the timing back to normal, I noticed an occasional jump in the nick (about a 2 degree advance jump), so I held the light to the hood and noticed the infrequent skip that would be a miss. Doesn't happen consistently, but if it's visible by clamping the #1 wire, it's got to be something related to the distributor, right? I'm going to see if I can find a spare distro cap, and I know I have a spare wire I can use to check the wire itself. I'll pull the plug too just in case, when I check all three this weekend.

It seems to me you have a good grasp on how to use your timing light. There is however, a pretty thick line bewteen 5°ATDC and 18°BTDC - which is a gross over-correction and will feasibly raise HCs. I can't say much else about your ignition timing. I have zero experience with vacuum-advance systems.

Your high idle could certainly be attributed to your overly advanced ignition timing. What I would do first is get that timing set properly - this may clear up your high idle and incomplete combustion if that is the case. It does appear to me that you have leaped over the bell-curve of low HC levels.

-MechanicMatt

Thick line for my thick head - when I did it last time, I'd forgotten to check the advance dial (it was midnight and I was half-:sleeping: ). Yesterday when I reset it, I found the the dial was sitting around 20 degrees advanced. :owned: So I got it fixed right this time.:rolleyes:

So the only other thing I can think of if it's not incomplete combustion, is a very small oil leak through a valve seal. I'm not getting any smoking at the tailpipe, though, and I don't seem to be consuming oil, so it would have to be pretty small. Any idea if putting a UV dye leak detector in the oil would let me see dye in the exhaust from a small leak? The seals seemed fine when I inspected them, but maybe I missed something tiny.

So is there any way short of getting another test done to check my hydrocarbon levels, even in a less-than-perfect way? I mean, is there some way to guestimate things by holding a white piece of paper at the tailpipe and checking for sooty deposits, or smelling the exhaust, or something along those lines? I'd hate to think the tester is right and the car will fail the HC now that the timing's right, since he still insists 5 ATDC timing is too advanced :nono:.

Well, either way, thanks for the help Matt - I'd be :nutkick: without you and the other metroeans. :)

Once I got the timing back to normal, I noticed an occasional jump in the nick (about a 2 degree advance jump), so I held the light to the hood and noticed the infrequent skip that would be a miss. Doesn't happen consistently, but if it's visible by clamping the #1 wire, it's got to be something related to the distributor, right? I'm going to see if I can find a spare distro cap, and I know I have a spare wire I can use to check the wire itself. I'll pull the plug too just in case, when I check all three this weekend.

Out of the twenty-some metros I have adjusted the timing on, this has occured with the majority of them and ALL of the OBDI cars (pre-96). In fact my own personal metro has an audible miss at the tailpipe at idle which I attributed to the way I have purposefully misadjusted the TPS for some added spunk under throttle. In any case, I have disregarded this timing anomoly and haven't found it indicative of any problems.


So the only other thing I can think of if it's not incomplete combustion, is a very small oil leak through a valve seal. I'm not getting any smoking at the tailpipe, though, and I don't seem to be consuming oil, so it would have to be pretty small. Any idea if putting a UV dye leak detector in the oil would let me see dye in the exhaust from a small leak? The seals seemed fine when I inspected them, but maybe I missed something tiny.

I think the high HCs and low NOx, which indicate incomplete combustion, were a result of the over-advanced timing. Optimum efficiency is generally had with the highest cylinder pressure occuring somewhere around 20° ATDC. Combustion cylinder design and namely 'quench' will determine how many degrees the ignition must be avanced for a given driving condition in order to achieve this 20° sweet spot. Any deviation from this sweet spot will lessen efficiency. The correlation here is that HCs levels are an easy way of determining engine efficiency. The better an engine is running, the more of its available hydrocarbons it will burn.


So is there any way short of getting another test done to check my hydrocarbon levels, even in a less-than-perfect way? ... I'd hate to think the tester is right and the car will fail the HC now that the timing's right, since he still insists 5 ATDC timing is too advanced :nono:.


Short answer: no. What I can tell you though, is to ignore what this guy is telling you - I don't know how he got a smog license. Make sure the car is timed properly, and take it for a nice drive to get the converter warmed up before getting it smogged again.

-MechanicMatt