Failed Smog test

[boomdriver]

I knew this but tried anyway, needing some idea of just how tough the Texas smog test really is...

Failed HC big time at hi & low speed.
Stand 157 tested at 562 hi 676 low

CO Stand 0.97 tested 220 hi 3.01 low speed

NOX Stand 1082 tested 355 hi 359 low (easily pass)
dilution >6 15.8 hi spd 16.0 low


So....
I'll remove the offroad prom and install the stock prom. Then ck the TPS, ck ign timing, get the op temp up to 220+ and burn regular gasoline with a healthy dose of alcohol. approx 1 qt to a 1/4 tank fuel.

The main cat is new ( less than 10k).
No pre-cats. not now anyway.

I'll also clean and ck idle air passages and maybe egr ports.

Darn thing passed easily last time in Az and it has not had that many miles since then. Texas may be tougher. I'll have to find the last Az test and compare numbers.

Anyone think of anything else? I get 1 free retest.hnoes All I have to do is get legal for 2 more yrs then I get an exemption for "Classic Car" registration.

 

[T.M.808]

sorry to hear. I'm no help at all, i've lived in hawaii for 20 years now, and we have no emissions testing of any kind. I have no cats, true duals etc.. i will be following your thread though. EGR...? o2 sensor..?

 

[toptechx6]

High HC indicates you have a misfire, check your plugs,ignition wires, distributor cap etc. On an L98 I would ohm check the injectors as well. The CO may fall into line once you sort out the HC issue, good luck.

 

[boomdriver]

well, the injectors were all R&R less than 10,000 miles ago and all o-rings and other fuel rail maint done. The rotor & cap last week.

It had a custom prom that was low temp, so This test today was done at 190 degrees at the most...and with the modified timing and fuel curve from the prom. That was doomed to fail. The whole tuning program is "off-road".

I swapped ECM's with a spare and have the stock prom & ECM installed now.
Also the TPS was way off....thats perfectly set now idle 0.54 to WOT 4.0v

Now it will eventually heat up to 230 degrees and the fans kick on....and the exhaust smells much better than it did this morning. Not nearly as rich.
I picked up another IAC and will install that tomorrow. I know for sure that the IAC is worn out. It does not get any bump when the a/c is engaged. It is supposed to go up 50 rpm idle with a/c.

It currently will idle in gear at 400 but its a little rough.. It will NOT idle in gear with the a/c on. I'll also pull a couple plugs and take a look to see if there is a generally rich condition from the off-road prom, or if there is an isolated problem. I think 90% of the reason it failed is the prom and settings. Thats now back to stock. I knew that it was rich...I just did'nt know it was THAT rich. Hopefully the new IAC will complete the "repairs".
It seems to smooth out anywhere above idle. Motor oil is new Mobile-1, everything else seems ok, no SES lite or stored codes, no blow-by from PCV valve. Oh yeah, I need to turn the fuel pressure down a bit as well.

I'll mix a "higher % batch of alcohol/gas and get that well into the system then retest.

 

[navy2kcoupe]

I'll mix a "higher % batch of alcohol/gas and get that well into the system then retest.

Hey boomdriver..........what type of alcohol do you use, and why do you use it? What does it do for you in regards to the smog test? Just curious 'cause I'm in the dark with this one. Thanks.............
Andy

 

[boomdriver]

This depends on which smog test and what kind of shape the motor is in. All this does is mimic the existing blended fuel that we have at gas stations now. Thats 10% ethanol. The alcohol is there to produce less emissions since it burns lots cleaner,. It is poor at producing a hi thermal energy unit, like gasoline, but alcohol burns clean.
So I will add some form of alcohol to a minimal amount of gas and that helps get a cleaner burn out the exhaust. Usually its some form of solvent or painters alcohol. Thats a more pure form than drug store alcohol thats diluted.
Once added, it has to be burned asap so that it does not do damage to any rubber parts,hoses or o-rings mostly. Although most O-rings now are resistant I do not want to risk it.

 

[navy2kcoupe]

Thanks for the info! I appreciate it! That's one of the things that make this such a great site..........people sharing info and experiences with others.
Andy

 

[WhalePirot]

I knew this but tried anyway

I can't believe you did this.. LOL.. (I'll stay off the amateur analyst's chair)

.. especially given all that you have done to boost the car's performance AND your expertise.

I will add, based upon a CA smog event and an overdrive 'repair', to ensure that your plug wires are good. I have posted a few times that I fixed a cycling +3 with a wire change.. ONLY. the stock wires were good for a long time, but around 70-80k they needed changing.

I passed a SMOG retest with an ECU reset; stock, while the engine had minor enhancements, so it had block-learned bad things. The new cam had lowered the manifold pressure, so it ran rich; the ECU 'thinking' the engine was under load. Obviously, yours is reset with the replacement. Failing a retest is not a good thing in CA (time wasted/referee/etc.);

probably not in Tx, either.

 

[Rex S]

If the PROM is that rich it's to much for the car the way it's set up right now anyway. Watch the alky mix! To much and it will attack some fuel system parts.

 

[boomdriver]

lol....
Pilot, I know.
I had skated by in Az 2 yrs ago and I'm pretty sure it was with the same prom installed. I had no idea of how tough Tex was would be, but they are just as strict as Ca was. I've dealt with referees and waivers and all that good stuff.

Anyway, I am glad that it came about. I needed to know how my engine was behaving after last yrs head gasket.
This morning I pulled the TB off and almost fell over.....looked like the cat took a crap in there. Gummed up, idle air passage full of goo, IAC motor fully extended with pintle rusted to seat. Water in IAC motor mount.
I'm on "break" right now after rebuilding the TB and installing the new IAC. Cleaned up and lubricated and ready to mount. There was a bunch of wet-carbon inside the TB bore as well as the plenum. Thats a little confusing. I only ran it for 30 seconds this morning to roll it into place for the work today....That got douched out and allowed to air-dry.

I expect a very different running motor when this is all back together. As nasty as the TB was, I can see poor test results.

I also pulled a couple plugs from rt bank and can see that the bosch plat-+4 plugs are a waste of money. They DO indicate a rich condition with a good thick carbon build-up, but they are also carboned up on the 4 electrodes and THAT is what is causing some rough running. It won;t be today, but this week there will be some Delco plugs back in there. Gawd I hate doing the left bank......

Rex,
thats why I will only run about 2-3 gallons of fuel like that,. The hoses and o-rings these days are resistant, but I don;t push my luck. Once added, the hi-alcohol blend gets run out that day and the tank refilled. I had an engine fire from degraded fuel hose in another car. Nissan had a recall on 300zx of specific yrs to replace fuel lines and injectors that had seals made of rubber that was not compatable with blended fuels. I was one of the lucky people that got a new fuel system on my Z-car when it was far out of warranty...
There are several products on the shelf that do the same thing (make gas burn cleaner for test) for the same reasons....and they are all either alcohol, xylene, or toulene with some type of upper cyl lube.

back to work before something nest in the plenum...

 

[T.M.808]

sounds like a lot of things have been touched on you're car. Before setting the TPS, you must set the timing and idle. Heres the procedure, follow it exactly, or you'll have to start over. This is pretty much a must on all c4 as their old cars now. Set screws wear down and linkage gets sloppy.

This must be done before setting the TPS.

First step is to set the minimum idle speed. If nobody has messed with this on your car before, the set screw will be covered by a pressed-in plug. It's located on the driver's side of the TB. Remove this plug if it's there.


With the IAC connected and the ignition "OFF," stick the paper clip into the diagnostic connector from "A" to "B." This grounds the diagnostic lead.
Turn the ignition to the "ON" position without starting the engine. Wait 30 seconds.
Now, with the ignition still in the "ON" position, disconnect the IAC connector at the IAC.


Remove the paper clip from the diagnostic connector.


Start the engine and allow it to reach normal operating temperature. The idle speed will probably be really low, and you may have to coax the engine a bit with the gas pedal to keep it running for a while.


If your car is an automatic, set the parking brake and put the transmission in "DRIVE." If your car is a manual, leave it in neutral.


Adjust the idle speed screw to obtain 400 rpm in drive or 450 in neutral.


Shut off the engine and re-connect the IAC.


That's it for idle speed.

 

[boomdriver]

Thanks for the proceedure. Mines a little bit different with the bigger Edlebrock TB. Not a big deal but it has to be driven for a few seconds at 40+ mph steady and the ECM will reset the IAC.
I will go back and ck the TPS tomorrow. Too tired to care right now.

After remounting the TB w/new IAC and freshly scrubbed idle ports I unscrewed the stop screw until it made no contact with the linkage. The engine wanted to idle at 900 then. Did the drive to set it, and it now idles in gear (auto) at 5-600 rpm with a/c on @ 210 degrees. Turning the a/c on now has a stable idle speed where yesterday that would lower the idle rpm by 100 at least. It gets the required bump up when the a/c is turned on. Currently the idle is a bit higher than it was, and a little rough like it was. Response is a little softer & slower with the stock prom/ecm and the reduced fuel pressure. I took my plenum off and turned that down to 35. It was 40+.

Tomorrow I'm going to retest ALL the 2 yr old injectors. I'm gonna be fairly P.O. if there are any that are bad. Oh well.... I am really tempted to buy a set of the Bosch III injectors that everyone is so pleased with.

Also going to change plugs. These Bosch Platinum plus-4 are in poor shape. Half fouled from the rich mix, I never liked them much anyway. Now I can justify seeing how far I can throw 8 of 'em.
Back to Delco. I should have known better. These plat plus-4 type plugs are for kid-car racers with ultra hot ignitions and higher revving little engines. These plus 4 plugs almost act like they are too cold for this motor...There is no visable exhaust smoke, but these plugs are black and pretty cruddy in the insulator and ON the neg electrode.

As if there were not enough things to do, the darn thermostat stuck open. The engine tried to stay at 165 (190 stat) for wayyyy too long. I finally got it to heat up to 210 by idling in gear for 30 minutes.

 

[WhalePirot]

I can see that the bosch plat-+4 plugs are a waste of money.

Reflects what I have heard for respectable sources. I heard the Autolite platinums are ok (big electrode).

 

[boomdriver]

I'll know more by end of today, but those plugs MIGHT be the majority of the problem....too cold, small spark, unable to ignite complete burns. They ARE carboned up on the electrode.

 

[Schrade]

Your burn temperature is too low. Not enough air, AND:

... too much fuel is the cause. Leaking injectors is definitely something to check. In the meantime, a bottle of Everclear 190 proof in no more than 3/4 tank of gas will make a temp fix, till the tank is empty (even 3/4 tank with a fifth bottle of Everclear might not be enough - you need to get close to the max equivalent of E85 alcohol/gasoline mix, to get your emissions in spec).

Alcohol will increase burn temps (lowering NOx, but you have room to spare, which is ALWAYS the case when HC is too high) by adding oxygen to the burn. Increased oxygen will also reduce HC count.

Short of adding ethanol, you'll have to reduce fuel in the burn with a tune/diags...

 

[boomdriver]

Schrade,

you're exactly right. Its been getting too much fuel AND the low operating temps have been promoting fouling. After spending yesterday and today digging into things I see several reasons why its doing what it is. I doubt the injectors are involved as they are only 2 yrs old, were all spec'd exactly alike in oHms, and my fuel system will pressurize and hold 90% of that pressure for at least 30-45 minutes. I always have to run it dry before any service because it holds pressure so well. Although tempted to buy the set that FIC offers, I can;t justify that just yet...

1st, the IAC was shot. Rusted closed.
TB was gummed up bigtime. Disassembled and cleaned passeges. Same for plenum.
Turned down Fuel pressure to <40.
Reset TPS. That was way too high.

Plugs fouled. Replaced with new AC Delco plat-Pros. (also jacked up a wire and now have a nice misfire thru the whole rpm range) (perfect, just what I wanted).

Most interesting and inobvious.....The tube for the AIR system to deliver fresh air to the CAT was broken off under the check valve.....repaired that and sealed the system with new ck valve and hose/fitting. AIR pump is new, last month. Probably the source of the intermittent pulsing noise that I could not pinpoint. Rythmic like something in the rotating assy but non-metalic almost like a rubbing. I was thinking flywheel or torque converter....Hopefully it was just this exhaust leak.

I just got my wires @ 6pm so that'll be tomorrow. Engine won;t be cool enough this evening to work on. Not sure which wire or why, but there was no 'misfire' until they were all pulled for plug replacement. I tried to pull one at a time while it was running to see which was the problem and got a mild jolt thru rubber handle pliers...so they get replaced.

I had forgotten about Everclear. Thats another good source of near straight alcohol.. I was planning on a qt of solvent grade alcohol to <5 gal of gas. Just enough to circulate thru the fuel system and get thru the test.

2 more yrs and its over....I'll be a "classic" and exempt.

Yesterday I cleaned 2 plugs and replaced them. After 20 miles of running with the higher temps, and stock prom/ecm and other repairs those plugs looked like they were trying to burn much cleaner. I am pretty sure that I can get past the smog test in the next few days. I'm actually more worried about the parking brake and why it would not hold the car....The C-4 parking brake is witch-craft to me.

 

[Schrade]

Not sure which wire or why, but there was no 'misfire' until they were all pulled for plug replacement.

Misrouted wires can cause BIG problems - GM HE ignition is just LOOKING for a way out, and if misrouted, as in, NOT in the original SP wire looms, and near something else metal, the wires CAN emit EMI - electro-magnetic interference - same as a nuke, and this can cause false codes from solid-state sensors, ESPECIALLY ABS module, and some codes which DON'T light SES. Ask me how I know that read it in FSM by chance after chasing a false code for almost 10 weeks in '08 yup UH huh YIKES.

The subsequent misfire COULD account for high HC count, lower exhaust, higher NOx count. That's a stretch tho'...

 

[boomdriver]

UPDATE

Today was progress.
Found the strange thunmping noise....that came from the AIR tube for the CAT. It was getting some exhaust backflow back out that broken tube. Thats fixed now.
New Delco plugs installed, although there was a dead cyl after putting the plugs in. Took a while to figure out, but it was just a broken plug with a cracked insulator. Easy fix. Installed new wires. Of course 3 are 6 to10" longer than they would ever need to be, so thats a hassal trying to route those and all that extra wire. I ended up tossing a couple new wires so I could use old ones that fit better.
TPS is set perfectly. IAC is set as well. New PCV valve with hose becasue old set up was a breather cap that have the PCV on its underside. With that system, it allowed the cap to fill of mist and then drain it all over the vavle covers and make a mess. Now...pcv is sealed and air-tight,. no leaks.

I will do a little road time tomorrow just to 'feel' it out. I already know that it runs like a stock c-4 but it has many virtues.

Smog check Sat unless something else comes up.

Thanks for everyones help and ideas ! when I needed then.

 

[navy2kcoupe]

Good luck with the smog test. You've put a bunch of time and money into this, and I hope you solved all of the issues.
Andy

 

[boomdriver]

Andy,
After having "stored" the car for many years while I worked my life away, I'm now retired and able to play with it. Being an 87 it needs lots of little things and I am in the process of doing a pretty good rolling restoration with the goal being a total strip & repaint.
The last 3 months I've been pouring Cash into parts, and replacing anything that was scratched or scuffed. Mechanical is non-negotiable as far as I'm concerned. Its going to be "right".
This smog thing was as much a report card for my use besides being required by the state.. I needed to know what was going on internally so I could evaluate and include engine work in the resoration process, if needed.I did find several problems that I needed to correct before they got out of hand.

I think its ready for the retest so i can get back to the all important work of interior and paint prep.