14 replies to this topic

[skingry]

So, I've failed smog twice... and I'm getting frustrated.

Some background:

Car: 83 GL, EA81 w/ ~343k miles, California model, Hitachi feedback carb (can't replace it with a Weber, because I live in California ), all new vacuum hoses, new plugs, new wires, new cap, new rotor, new CARB spec catalytic converter, new Denso O2 sensor. De-carboned the engine with plenty of distilled water trickled into the intake...

So here are the results (top line is 15mph, bottom line is 25mph):

First test:

HC:
MAX - 152, MEAS - 15
MAX - 123, MEAS - 9
CO:
MAX - 1.05, MEAS - 0.12
MAX - 0.85, MEAS - 0.12
NO:
MAX - 1191, MEAS - 1690
MAX - 1021, MEAS - 2181


Second test:

HC:
MAX - 152, MEAS - 0
MAX - 123, MEAS - 0
CO:
MAX - 1.05, MEAS - 0.11
MAX - 0.85, MEAS - 0.10
NO:
MAX - 1191, MEAS - 2624
MAX - 1021, MEAS - 2401


All sources point to the EGR (or at least to me... if something else stand outs, let me know). So, I pulled the valve and cleaned it out with a dental pick and some B-12. The diaphragm is good and holds vacuum. Now, when I manually apply vacuum to valve, the engine does nothing. No stumble, no stall, no nothing. This leaves the EGR pipe, but that SOB is a PITA and doesn't want to budge (not to mention my busted knuckles).

Any pointers removing it... or maybe cleaning it in place (pipe cleaner)?

[skingry]

I think I may have solved my own problem.

What do you guys think: a piece of steel cable with some short pieces of copper filament soldered on the end to make a bit of a brush. Put the non-brush end of the cable in a drill and then feed the brush end down into the EGR pipe. Leave the valve off, blip the engine a couple of times to blow the carbon bits out.

With that said... does anyone have a spare EGR pipe on hand they would sell me if I decide to go medieval with a hack saw, a 17mm socket, and a torch?

Edited by skingry, 14 May 2012 - 09:48 PM.

[TomRhere]

I have used a length of coathanger wire in a drill to clean out the EGR passages.
You have to work slowly, and let it work it's way thru the carbon. Not to much pressure on it, it will bend all to heck.....
Carb cleaner spray will help soften the crud some.

Won't be able to run engine with EGR valve off, major vaccum leak..

[skishop69]

You also need to look at your timing. If there is an issue there causing too much advance at cruise you will get high Nox as well. If you open the EGR at idle, it should just about die. If not, something is plugged.

[skingry]

Yeah, double and triple checked my timing. Set at 8 degrees BTDC (was at 25 degrees BTDC when I got it, how it even ran, I have no idea). The timing is verified during smog here in CA (the tech pulled out a timing light, had a little bit of trouble finding the timing marks, but I showed him how they are on the flywheel on older Subarus).

The car doesn't even have a drop in RPM when I manually apply vacuum to the EGR valve at idle (even after I cleaned it and verified it's operation), so I definitely know something is up with the system.

Edited by skingry, 15 May 2012 - 10:58 AM.

[GeneralDisorder]

Vise grips and a hammer to get the EGR pipe off.

Clean or replace the pipe and the passages in the manifold and head.

Definitely your problem.

GD

[man on the moon]

I have a bottle of solvent something I use to get rid of carbon and oil build-up. It is a purple bottle. I forget the exact name, but you can buy it at auto-zone and o'reilly's.

It resembles this, except in a squirt bottle and not aerosol: http://www.oreillyau...N0442&ppt=C0090

Almost anything along those lines will obtain magical properties if it is accompanied by the proper persuasive tool.

[skingry]

GD, you're a life saver. Vice grips and a hammer and the pipe came right off.

I've managed to get the EGR pipe cleaned out (it was really clogged up), and I'm pretty sure the passage is clean in the head (sprayed some aerosol Seafoam into the hole and it drained down quickly).

However I am not sure the passages are clean in the intake manifold (the car still doesn't stumble or stall when I manually apply vacuum to the EGR valve). The best I could do was squirt some of the Seafoam into the passages and hope it was cleaned out. Is there some sort of cleaner that does a better job than others at liquifying carbon? Oven cleaner?

Also, when vacuum is applied to the EGR valve, is it normal that the only thing that moves is the center post (and there by the actual passage that exhaust flows through is small)?

[skishop69]

Manifold passages can be cleaned with a coat hanger cut at an angle. Yes, the center post is the moving component and unless you have it off and test it, it is all you will see move. The valve attached to it is much larger.

[letank]

Did you fix it?
Reviving the post... same issue, same issue with an 84GL with the 1800cc and hitachi, we have high nox on the 15 mph at 1400 but the 25mph is 650.

No vacuum going to the EGR when you revup the engine at 3000-3500 after 8min.... This is what the manual specs, there is a timer for a 8 min delay.

I applied vacuum to the EGR and no drop in idle...and the plunger moves.... so I did as described, pulled the EGR which was full of crud and oily deposits.... reinstalled and no change.... applying vacuum to the EGR did not changed the idle. This is an 1800cc, there is no side pipe.

I was trying to find an alternate source for ported vacuum to activate the EGR... but this is such a mess of hoses.... most of them are so hard. I suspect that the Thermo valve is not up to specs... but not too sure where is sits... the manual is totally useless...

So if someome has a pict or a detail on that thermovalve... is it the yellow one....

Thanx for my neighbor..... I am helping him....

[skingry]

Yeah, got it fixed.

The side pipe was full of carbon and were the manifold passages. Fashioned a brush from a piece of steel cable and a long slender spring (sort of like a pipe snake). Cleaned out the passages and the pipe, engine full out stalled when I manually applied vacuum. A can of the spray Seafoam helps too (the one with the long squirt tube).

You need to double check that the engine doesn't have a side pipe... and probably clean out the manifold passages.

On a side note, I also replaced all of the hoses with new silicone ones when I bought the car. Parts were less than $30. Do one at a time, and follow the vacuum diagram on the underside of the hood, use logic, go slow, you'll be fine.

[letank]

Yeah, got it fixed.

The side pipe was full of carbon and were the manifold passages. Fashioned a brush from a piece of steel cable and a long slender spring (sort of like a pipe snake). Cleaned out the passages and the pipe, engine full out stalled when I manually applied vacuum. A can of the spray Seafoam helps too (the one with the long squirt tube).

You need to double check that the engine doesn't have a side pipe... and probably clean out the manifold passages.

On a side note, I also replaced all of the hoses with new silicone ones when I bought the car. Parts were less than $30. Do one at a time, and follow the vacuum diagram on the underside of the hood, use logic, go slow, you'll be fine.

Thanx, very helful, managed to pull the side pipe which was full of oily carbon deposits, tried to snake and spray the manifold. The owner said that it was never done.... Engine has 191kmiles.
Bought the seafoam, sprayed the manifold.... But still no stall if I move the EGR.... I cover the opening holding the EGR, and the engine cranked up.... So the manifold is really plugged up.
The owner in his seventies said to forget about it, will buy the $50 extension sees if it passes smog...and get a newer vehicle in a few months.... After cashing the $1000 to junk the car, a lot of rust around the windshield and rear window.
Too many hoses to replace.... vacuum and coolant, we patched a few exhaust leaks....the engine is pretty steady, many oil leaks.
Thanx again.... Will update the smog results...

[scoobiedubie]

The vacuum pumps may go out at about 350K miles or get cracked at the nozzles. Then you lose lots of suction that helps advance the timing at high rpm. Mine were on the passenger side over the wheel well.

[letank]

The vacuum pumps may go out at about 350K miles or get cracked at the nozzles. Then you lose lots of suction that helps advance the timing at high rpm. Mine were on the passenger side over the wheel well.

vacuum pump..... hum.

The distributor has vacuum, I tested it, no vac at idle and vacuum starts at some higher rpm.... I was going to add a little vacuum to the EGR valve from this port.... but alas the intake carburetor port to the EGR is blocked.

[letank]

We sprayed some seafoam, then put some more in the gas. He drove the car for the last month, and decided to go for a smogcheck.
The NOx has dropped from 2600 to 1200 but still over the 834 threshold. All the other values were dead on for a lambda of 1.005
So I tested the egr and this time, applying vacuum made the engine rpm drop and more vacuum made it stall.... This is so good.... but no vacuum signal from the thermoValve, which is impossible to access, I got a little vaccum when reving past 4000 rpm, but nothing in the 1500rpm of the smog test.
I decided to install a secondary vacuum hose from the thermovalve feed, which is reading vacuum, and added a small restrictor, the EGR gets vacuum as soon as 1500 rpm...

from this port




Replaced some very cooked vacuum hoses, and the PCV valve hose was barely holding due to major cracks... decided to replace it, plugged with carbon deposits, so was the manifold for the PCV hose by the oil filter cap.... no wonder the engine is leaking oil.... I cleaned the other PCV hose as well....
Will post results when the owner comes back.

The old data with only the pipe clean up



NOx dropped from 1196 to 645 at 15 mph and 1800rpm (limit 834)
then 595 to 306 at 25mph and 2900 rpm (limit 706)

CO increased from 0.38 to 0.56 at 15mph, no changes for 25mph. (limit 0.65) so that is a big change to be addressed later.


Here is the printout passing with the EGR hose vacuum upgrade



and the initial Gross Polluter data as this has been viewed quite a lot since the initial post

Edited by letank, 21 November 2012 - 08:45 PM.
added smog reports