Failed Smog Check High Nox :(

[mopar-tech]

so the number 1 biggest problem is the 2.5, they were equipped from the factory with egr for a reason, they have issues passing nox. so if the egr is not hooked up or not working properly that's a problem.

Federal 2.5 Turbo I engines have no EGR system.

Agree on the timing. I'd suggest finding TDC and marking the converter with a sharpie so you can set the timing. Have to make sure your baseline is in place and base timing is an important one.

[shadow88]

Federal 2.5 Turbo I engines have no EGR system.

Agree on the timing. I'd suggest finding TDC and marking the converter with a sharpie so you can set the timing. Have to make sure your baseline is in place and base timing is an important one.

For sure!! First step for any smog check or any tuning

[crusty shadow]

Federal 2.5 Turbo I engines have no EGR system.

Agree on the timing. I'd suggest finding TDC and marking the converter with a sharpie so you can set the timing. Have to make sure your baseline is in place and base timing is an important one.

^+1000 on that. ignition timing is going to have the biggest overall effect on NOx

I would not retard the cam however- just set it straight up at "0"

you need a baseline so to speak so you want ignition and cam timing set "neutral" not advanced, not retarded. if it fails after that only adjust one thing at a time, record the results and see if numbers improve. if you start changing multiple things at once you'll get all turned around and create a giant heachache for yourself- Simon can tell you all about that.

[black86glhs]

^+1000 on that. ignition timing is going to have the biggest overall effect on NOx

I would not retard the cam however- just set it straight up at "0"

you need a baseline so to speak so you want ignition and cam timing set "neutral" not advanced, not retarded. if it fails after that only adjust one thing at a time, record the results and see if numbers improve. if you start changing multiple things at once you'll get all turned around and create a giant heachache for yourself- Simon can tell you all about that.

Just to clarify, I was saying to retard the cam timing a little because he said his adjustable cam gear had been slipping and the timing was off. Plus, he said he didn't have the timing marks. I should have said to set the cam timing in the middle of the adjuster as that should be close to "0".

[88C/S]

My SL has a 2.5, running a boostbutton cal and using E85. My first test, I had high NOx, I got a 3" cat from FWD, their cat is almost as long as the original cat the car came with, NOx came down, but not enough. I retarded the timing 2* and just passed. Was told you can retard as much as 3*.

[A.J.]

Federal 2.5 Turbo I engines have no EGR system.

Agree on the timing. I'd suggest finding TDC and marking the converter with a sharpie so you can set the timing. Have to make sure your baseline is in place and base timing is an important one.

If this is the torque converter I supplied with the transmission I built for him I believe he'll have to make his own mark on the converter because it's an aftermarket one and didn't come with a timing mark. It was listed for 2.2/2.5/2.0/2.4 and since the 2.0/2.4 didn't have distributors, why spend the money on putting timing marks on them.

My SL has a 2.5, running a boostbutton cal and using E85. My first test, I had high NOx, I got a 3" cat from FWD, their cat is almost as long as the original cat the car came with, NOx came down, but not enough. I retarded the timing 2* and just passed. Was told you can retard as much as 3*.

I've seen a lot of aftermarket cats have a block of cat material at each end but nothing in the middle so size really doesn't mean anything.

[OmniLuvr]

Federal 2.5 Turbo I engines have no EGR system.

but we live in cali-fornia, home of the smog natzi's! ive have to convert multiple federal vehicles to cali emissions.

so id put a stock cal in it, set the timing and test the egr...

I've seen a lot of aftermarket cats have a block of cat material at each end but nothing in the middle so size really doesn't mean anything.

this is true, but its because they are 2 stage cats, one part does nox conversion, the other does hc co...

[A.J.]

but we live in cali-fornia, home of the smog natzi's! ive have to convert multiple federal vehicles to cali emissions.

Alan could have a federal van even though he lives in Cali. I re-read his posts and he hasn't confirmed or not if his van has an EGR and if it does if it's even working.

[marc]

Camshafts with more overlap tend to lower NOx. I believe engines with variable valve timing increase overlap at certain times and eliminates the EGR vavle.

[OmniLuvr]

Camshafts with more overlap tend to lower NOx. I believe engines with variable valve timing increase overlap at certain times and eliminates the EGR vavle.

this is true, most of the new cars actually use variable exhaust timing for egr now...

[2.216VTurbo]

Sorry, I should have clarified the EGR question, no EGR, Woody is an OR Mini as in Ex Spiva


Yes AJ, same TC I really do like the stall/performance of it so no change there planned. I will get out the dial indicator and add a mark to it tho so I wont have to guess at ignition timing anymore.

I'm gonna set timing to 9' BTDC (max variance allowed in Cali) and run some teeny tires like
OmniLvr recommended. I think this will get the Nox to a passing grade. If this doesn't work ill spend another $300. on a fresh cat like Gary reccomended. This one is super low miles but is years old. Until this thread I didn't know that sitting on the shelf kills cats Always something to be learned here at TM.com

Prolly will try again on Tuesday.

[johnl]

Good stuff I always learn from you guys

[mopar-tech]

If this doesn't work ill spend another $300. on a fresh cat like Gary reccomended.

Actually I'd run an old turbo dodge cat if you have one in good condition, it is what I keep on the shelf.

The factory cats have far more platinum and palladium than aftermarket.

[OmniLuvr]

so is it going to be possible to throw a stock cal computer in it?

[Rrider]

I tried the smaller tire thing and it didn't help in my case.

You guys in other states also have a 613ppm max on nox??

[A.J.]

If this doesn't work ill spend another $300. on a fresh cat like Gary reccomended.

Eh-hemmmm......

These cars are very easy to get through emissions, even when modded. I second Gary on the cat. Vic had a turbo car that failed NOX and he insisted the cat was new/good because it was barely used but sat on his shelf for a few years. He brought me the car, I put it on the lift and put my heat gun on it and it wasn't heating up. He put another one on and it passed.

[going4speed]

Maybe try a new cat?

[crusty shadow]

before spending money on a new cat- check the one you have to see if its working.
get the car up to operating temp- drive it around for 15 minutes so the cat will have plenty of time to warm up to operating temp. at the end of the warmup drive, dont shut the engine off and get under the car and measure the inlet temp and outlet temp of the cat with an IR thermometer. inlet temp should be at around 400-450 degrees at the inlet and should be 50-75 degrees warmer at the outlet. if you dont have the temp increase between the inlet and outlet that cat is doa.

[2.216VTurbo]

^ Great idea, didn't know there was a 'test' for them.

I don't burn cals so no stock option unless I throw a stock SMEC at it, and injectors, and 2bar, and...

[A.J.]

^ Great idea, didn't know there was a 'test' for them.

Eh-hemmmm......

These cars are very easy to get through emissions, even when modded. I second Gary on the cat. Vic had a turbo car that failed NOX and he insisted the cat was new/good because it was barely used but sat on his shelf for a few years. He brought me the car, I put it on the lift and put my heat gun on it and it wasn't heating up. He put another one on and it passed.

Jesus tap-dancing Christ! Am I on ignore! ;-)