chinaman

Anyone know how to test an electronic egr for proper operation? I've failed emissions in GA couple times already and have tried swapping out two used egr valves, but the results are the same. Fails for high Nox 1269(712 allowed) on the 25 test but it passes the 15 test Nox 166(786 allowed). Hc and Co are fine for both tests. Just put new pre-cat o2 sensors and cats are 2 yrs old. Jus wanna test egr before breaking bank for new one. its a '94 LS no cel.

egr valve is not vacuum operated, here's what it looks like:
http://contentinfo.autozone.com/znet...R4177/image/6/

chinaman

any ideas why nox is so much higher on the 25 test?

Amskeptic

Three-way catalysts are more expensive to manufacture than two-way. Are your two year-old catalysts the correct ones or what you could afford at the time?
Colin

LiCelsior

iTrader: (32)

wish i could help but i have no idea.

u cant slip someone some money to pass you?? thats how i do it in NY lol. friend makes me the sticker and i just pay him the std fee.

chinaman

egr is not vacuum operated like most toyotas, its electronic. click on link on first post and u see what it looks like. so no vacuum modulator either. and cats were the cheapest i could find at the time. but i'm sure its not cats cuz hc and co readings are low and nox is very low on the 15 test.

nthach

Pull the EGR valve, spray a top engine cleaner or combustion chamber cleaner in the passages and use a tool of some sorts to clear the blockages. You've got clogged EGR passages more or less.

I'm thinking there's a test for the EGR valve too. After that, I'd run the same top engine cleaner through the intake and it let it soak for a few hours. Change the plugs, wires, oil and coolant and take the car on a HARD run with GOOD gas and bottle of Techron, SI-1, or Regaine in tank.

chinaman

i had ran seafoam through the engine a couple times already. changed the thermostat and temp sensor and took it to test today and failed with similar numbers as previous tests. maintenance is up to date.

nthach

You want to use something else besides Seafoam to clean the EGR passageways. I'd take the valve off and use a aerosol top engine cleaner and a gun cleaning brush to handle this task.

skperformance

iTrader: (6)

seafoam is nice to run through the tank to clean an egr but when used through a vac line it will not get in the egr as it only opens after the engine is good and hot and at that point seafoam evaporates so it can't clean it unless removed.

chinaman

sent old cats back for warranty and got new ones made by Walker. now it fails for high nox on both tests 1800 on 25mph and 1500 on 15 mph. checked with Walker and they said the cats are 3-way. i think i need some oem cats?

RA40

iTrader: (6)

+1.
That was what had to be done on a couple of my older cars in past times. Get that cleaned out, there shouldn't be any problems.

clipster

I'd like to clean the EGR valve and passageways, but can't find it anywhere. The factory shop manuals make no mention of it, but its listed in online parts catalogs and I've seen pictures of it similar to the one that the original poster included.

Does anyone know where its located on a 98 LS?

garrett113

hey if you havent already done a check on your egr there should be a red wire going in put a paer clip in at the connector in the red wire and jump 12v from the battery if its workin it should stumble motor or stall it. im speaking from testing egrs in the past never seen your particular one

willhickey

iTrader: (1)

buy the one from autozone swap it out and if it doesnt fix it return it and get your money back.... 9 times out of 10 they will let you do that and then you arent out any money . thats always what i do trial and error man . worth a shot right?

pishta

The EGR is on the driver side of the intake plenum, its directly opposite the TB. It comes off with 2 nuts and 2 bolts. remove the 2 coolant hoses and 2 electrical clips (one top and one bottom) Once off you can see where its clogged. I though mine was clogged at one hole, I then found that the entire backside was carbon caked so whet looked like a hole was actually was a trough when cleaned. I have high NOx on the load test (2500 RPM with a pretty good load on the rollers). Im hoping that is when the EGR kicks on and is supposed to cool the chambers with its inert gas introduction via this valve. Question to forum: will my EGR pipe on the rear of the motor look as bad as this, or is this the place where it builds up? Getting that rigid hose off the back looks complicated to clean. These are before and after pics. The EGR is in 3 parts. This AL piece is the one to clean, the cast iron "dogleg" can be cleaned at the pintle seat, and the top servo piece can be removed to clean the pintle itself with the 3 small bolts. You dont need to unscrew the small screws.