Failing emissions... :(

[doc65]

Trying to get the SX4 to pass emissions without too much expense as the engine will get replaced with a 4.6 injected engine in the next couple months, just be nice to drive it around & deal with the other issues like T-case & axles in the interim.  I rejetted it, readjusted the timing tuned the mixture for best vac etc, and now the highspeed(2500 rpm) test easilly passes, but the idle numbers actually got worse, though in fairness the rpm is a better 650 vs the original test which was about 815 I think I have a vac leak, and am pretty sure it has to be at the intake manifold to head surface as all the vac lines are plugged/gone except the vac adv(it is DEFINITELY on a ported source) and PCV.  I swear I hear a vac leak, but with hearing loss(at some frequencies) in one ear it's tough to tell WHERE.  It is currently way high on both CO & HC at idle, but both are really good at the 2500rpm.

I'm thinking that the idle mixture is too rich in order to compensate for the vac leak, I can also hear an occasional mis at idle, lean mis-fire??

The config is MC 2150(1.08 with 45 jets, though those aren't really in play at idle), 82 SX/4 with later duraspark module, so no computer control of spark, Bosch platinum plugs, all gaps checked & re-checked, MSD Blaster II coil, 7.5mm premium NAPA wires, TFI Cap/Adapter/rotor setup, timing set at 12 BTDC which should be about right for
 4500 MSL altitude

Thoughts?   

[GRONK]

What are your failing #'s at idle?

Will the testers allow you to test tune while on the machine?

[BenM]

Do you have your cat hooked up still? If you do, connect a vacuum valve to the downstream valve. The extra oxygen will allow the cat to burn off the extra CO and HC at idle. If the numbers are close that could make all the difference. The ECM had the downstream open on warm idle.

[doc65]

Gronk,

Tuning while testing sadly not possible, the machine is paid for by the operators, but controlled by the county, it doesn't show numbers while the test is run, only once the veh either pass or fail, then you can get the numbers out of it.  I was the one in the car running the throttle while it was running, got to go up to 2500 & hold for 30 seconds, then back to idle and it tests for 30 more, then gives a pass/fail.  Numbers are:

high speed(good)
HC standard 220 me 70
CO standard 1.20% me .07%

Idle(BAD)
HC standard 220 me 319
CO standard 1.20% me 7.92%

Ben,

The exhaust is completely new 2.5"(little big, but I had a new unused CAT in that size on hand) so yes there is a CAT installed, but it sounds like what you are referring to is the Extra air fitting on the side of the CAT, that is not installed, never was.  This car initially had an airpump, but that is gone, and for what it's worth, my wagon originally had Pulse Air  injection setup, but it's gone as well, so it is very similar config except that the exhaust in it is OLD & original, it passed VERY easily.

[GRONK]

The failed CO could be from the larger exhaust.  When you open the exhaust it puts less pressure through the cat (less heat) that's why at open throttle you are good.

re you running the lowest octane fuel possible?

Find what your MAX idle speed is and increas your idle speed within 50rpm of the limit, that should help.

I might also suggest a hotter T-Stat for the HC.  You need to creat more heat w/ the open exhaust.

[eaglefreek]

I had a similar situation when I lived in CO. I needed to pass emissions with the Carter before my tag expired and wanted to install the 2150 but didn't have the funds at the time. I put about a 50/50 ratio of  E85/E10 and it passed with flying colors. Can't say that it will work for you though.

[doc65]

I had actually thought of the t-stat, as the temp guage does read low, I'm wondering if a PO put a 160 in it, guess I'll pull the housing & check.  I forgot to mention that it does have a gallon of "alternate fuel", ie denatured alch, mixed in with a full tank of regular 85 octane fuel that "...may contain up to 10% ethanol..." The EGR isn't connected to vac right now, so it's not opening, but while testing it with a vac pump I don't think it moves anyway, would fixing it help at idle?

[GRONK]

I would say NO on the EGR.  I never run them and never failed the E-Test when we had it. 

[doc65]

I don't really WANT to buy an egr if it's not going to be a magic bullet as it would be wasted money once teh stroker motor goes in... but I do want to get it going till them.

[thereverendbill]

does utah still have the 300 dollar exempt rule?

[Draekon]

Check to make sure the intake manifold bolts are tight.  If they are loose, it could cause a vacuum leak.

[ammachine390]

EGR is inactive at idle, it won't help you to replace it. The only thing it would affect is NOx emissions, not HC nor Co.

Loose Intake manifold would cause a vacuum leak, that would make the engine run leaner. Lean engine conditions cause higher NOx levels, and LOWER Co and HC.

High HC and Co are a result of incomplete combustion, usually caused by too rich of a air/fuel mixture. What I would do is make sure the intake manifold bolts are snug and you have no vacuum leaks, then try to lean the idle mixture. Adjust until you have the highest manifold vacuum. If this doesn't work, you could just lean the idle mixture for the test, then bring them back to where the highest vacuum reading is.

[doc65]

Bill,

Never heard of $300 rule?!?

AMC, my thinking exactly on the mani bolts, already done though.  I did notice on an extra intake that I have that the EGR was loose, and when looking at the gasket it looked like it might have a vac leak at that point on that manifold, so I went & looked at the one on the car, it was barely snug, and the gasket came off in pieces, so new gasket(already had it) Now I don't seem to hear as much of what sounded like a vac leak.  I also pulled out the trusty vac guage & had lower vac than when I last adjusted the idle mixture(like 2 in Hg) so I started readjusting and probably screwed in each mixture screw like 3/4 turn.  I have a new manifold gasket on hand if it gets to that, but I'd rather not, it's a bit of a pain...  I'm also a little worried that if I were to start down that road the EGR interconnect tube might be damaged and that's an order it item

I'll probably adjust it just a LITTLE on the lean side, though going far enough to cause lean mis-fireing would be counter productive as I'd then be pumping the whole fuel air charge for that missed firing out the exhaust...

[ammachine390]

I'll probably adjust it just a LITTLE on the lean side, though going far enough to cause lean mis-fireing would be counter productive as I'd then be pumping the whole fuel air charge for that missed firing out the exhaust...

Correct, ideally, you want to be at the stoichiometric ratio (perfect air/fuel of 14.7/1) where there would be VERY little CO, and VERY little HC, however, this is a carburetor, not fuel injection, so the perfect ration will be impossible to get too. When the engine is producing the most intake manifold vacuum, that should be near the stoichiometric rate. If thats not enough, then you may have to lean it out more to take car of the HC and CO. But as you said, too lean, and you get a misfire, then you just shoot your HC levels through the roof as you just pumped a whole gas charge right into the exhaust.

[carnuck]

Do they show the NOx readings? That's a good way of testing timing. High readings = too much advance and misfire at idle can happen.

[doc65]

no NOx, just CO & HC taht matter plus CO2 that is printed but no standard set...

[thereverendbill]

Bill,

Never heard of $300 rule?!?

back when I lived in salt lake if your car fails and you spend 300 dollars in repairs (with receipts) and it shows improvement you can take everything in to the DMV and they will give you an exempt for the year.

What i found that works for passing is the berryman's guarantee to pass emissions stuff, just dump a full bottle in at 1/4 of a tank and take it in to do the test   

[doc65]

Bill, I've not seen that, might look into it, but since I refuse to take something like an eagle to an "Emissions Shop" that would easilly charge me that much I doubt I'll get there.  If it doesn't pass with a few semi-external things I will just wait till I get the 4.6 built & installed with injection then it should be a no-brainer.  I'd guess that the Berrrymans is likely just a pint of ethyl alch that they are throwing in, I will look into it though. 

With all that said I THINK(hope)I may have found the culprit in the EGR, not in wheter it's working or not, but in it's leaking, both around the valve(stuck part way open with carbon), and with a gasket that I think was leaking.  I pulled it, cleaned the heck out of it, go it to seal closed, and re-installed it with a new gasket.  It is not functional as the vac operated diaphragm leaks, but at least now it's not providing a leak to manifold vacuum.  I should probably have installed a new one, but I don't want to put the $50-$80 into a part that will be obsolete in a couple months.  I know lots of people remove them, but I can't really in this case as it has to at least BE there for the visual portion(with the engine swap it'll pass because there is no visual place for it to go& they just flag it as N/A)
I though about a chunk of 1/8"-3/16" aluminum as a "gasket" that didn't have the holes in it and might do taht later.

Anyway once I cleaned & put it back on I couldn't hear the vac leak that I swore I heard before, and using a vac guage I was able to re-adjust the mixture screws in about 3/4 turn for max vac then without having it start dropping off & pulsing.  I also pulled the t-stat, it was a 192 which is correct, but when I boiled it(and watched the temp with a probe) it seems to open right, but is VERRRY slow to close so I stuck a new 195 that has been sitting here for a while in.  I'll see if any/all of this helps in like an hour and a half when I run it back over there...

[doc65]

Well, good news bad news, still failed, but both high & low rpm HC is now with in allowable, however CO is still out for idle, though not by too much, significantly reduced, strange part is that the high RPM CO was now significantly higher, and is now out of spec, so summing up, HC is now in on both rpm ranges, CO are both out,  only thing I can see on the high rev is that last time I was on the throttle, this time inspector was, and revs were slightly higher, and less stable than I was. I'm wondering about the less stable part causing an issue due to the accelerator pump???

[ammachine390]

The EGR valves on Eagles should NOT hold vacuum when the engine is off or idle. They use a positive back pressure EGR valve, and will not hold vacuum until sufficient back pressure closes the seal inside them.

[thereverendbill]

on a little side note if you have relitives or friends that live a little north that you could say move your registration to there is still no emissions in logan utah

[doc65]

Bill, I know that, Brigham & Tremonton areas same way, as well as most anywhere that ISN't Salt Lake Valley & Provo Orem are, sadly I'm a transplant that was dropped here by the USAF so no fam around here

[BenM]

Ben,

The exhaust is completely new 2.5"(little big, but I had a new unused CAT in that size on hand) so yes there is a CAT installed, but it sounds like what you are referring to is the Extra air fitting on the side of the CAT, that is not installed, never was.  This car initially had an airpump, but that is gone, and for what it's worth, my wagon originally had Pulse Air  injection setup, but it's gone as well, so it is very similar config except that the exhaust in it is OLD & original, it passed VERY easily.

Yeah, that was what I was talking about, the air fitting in the CAT.

I might try a new set of plugs and wires if they have a few miles on them, fresh plugs always fire a little stronger. Before that run a couple of bottles of the Chevron Techron cleaner through in a tank, there are a couple of others that help but most cleaners are snake oil. Maybe block the PCV hose and the vapor purge to prevent anything adding to the HC load.

[doc65]

Ben,

Last go around passed HC, but failed CO, the funny part was that it also failed co at higher rpm now(2500 ish) where it wasn't before, already got new wires as part of TFI install, plugs are pretty clean Bosch Platinums, not real sure of the age, but they look good & Clean & were re-gapped (none were really out of specs)...  I went & got a 2 week temp for the ability to run it some

[BenM]

Platinum plugs should be good for a long time, and the TFI should help. You're still getting incomplete combustion somewhere.

[carnuck]

The vacuum leak cleaned up the CO at high speed before. Your cat needs air getting in to function and convert the CO. Did you fix the thermostat yet? Made a HUGE difference in CO in every carbureted car I've owned.

[GRONK]

Suggestion on plugs, I have found that the cheap-o copper core plugs, (Champion/Autolite cheapies) are the best plugs for the I-6.  platnum/splitfire/etc seem not to perform as well.  I run the cheapies on all my I-6's and replace them yearly.

I still think you need to get more heat to that cat.

[doc65]

Carnuck,

Yeah, when I found that the 192 that was in it was very slow to respond to a decrease in temp I just put the new 195 in that I had on hand in and closed it up .  I really think that some of the high RPM issue may have been in the tester's not getting it stable in the middle of the allowable RPM range and just keeping it there, he was all over the range, it was in there, but not stable, and that means the accel pump was moving.  So I think that it I lean out the idle a "little" I should get it there.  Don't want to put too much into it as the 258 will come out & get a 4.6 with injection as soon as I get it built(probably a month), it would just be nice to be able to drive it around & work out the bugs in the new engine as well as tune the injection settings before I have to deal with inspection garbage  

[doc65]

Gronk,

I actually had a set of autolite 965 comes to mind, but they were the plug autozone showed as being correct, ran like &**^% so I pulled them out & one plug looked like it had been pushed on by a piston, the reason i pulled them back out was it was running (*&( and it sounded like there was an issue.  It looks like the piston was hitting the ground arm where it bends to go over the electrode.  When I compared the length to the Bosh that came out the were slightly longer, like 1/16".  On the CAT, not reall sure how to get it hotter short of cutting into a brand new exhaust & putting a restriction in-line after it like slipping in a 2 1/2" to 2" reducer(I've thought about it, but really don't want to cut the exhaust)  Guess I could get a couple rectangular flanges and put a flange after the CAT then when I need to have it sniffed pull the bolts & slip in  a restrictor for temp... Hmmm... DANG pains in the @$$ sniffer test!!!

[doc65]

Well I finally got the SX/4 past emissions testing today.  I had adjusted & re-adjusted the 2150 that was on it and it was a fresh rebuild, but it just WOULD NOT pass.  I finally decided to swap the carb from the Wagon which passed so easilly a couple months ago.  I just unbolted & swapped them, I did hook up a vac guage & go to set the idle mixture, but it was pretty much dead on already, the sniffer test came back with HC numbers of 13 & 8(high-speed/idle) with allowable of 220  and CO numbers that were so low that they showed up as 0.00 with 1.20 as allowable, so she now has plates!!!

Some other revealing things from this whole endeavor:

1. The carb IS what is causeing the severe flat spot just off idle where the car wants to die, as it moved fron the wagon to the SX/4
2. There seems to be a MAJOR difference in the emissions of the MC2150 with the VARIABLE high-speed bleed(this is the one with the metereing rods that hang down like mini baseball bats) system vs. the FIXED high-speed bleed system... 

[carnuck]

The electrode could be bent from carbon. The flat spot is probably the accelerator pump being clogged if that's the Carter BBD.

[doc65]

Nope, I'm referring to two different 2150's, I have like 6 Carters around here, but none in use(one is a new rebuild that came with the SX/4 if anyone needs one...)

[BenM]

Nope, I'm referring to two different 2150's, I have like 6 Carters around here, but none in use(one is a new rebuild that came with the SX/4 if anyone needs one...)

You wouldn't happen to have photos of the differences, would you?

[doc65]

I could take some, but this thread talks about the differences & displays it pretty well:

http://tekatlarge.net/Motorcraft-2150-2V-Internal-Carburetor-Systems.php