Failed emissions... Damn!

about 500 milse ago I did a small tune up; cleaned MAF, replaced the plugs, O2 and swapped out the coil for the MSD 8239, new wires. Not sure where I was at before this but when I had emissions done 2 years ago when I first got the car my CO was @ 6.5 GPM after all the tune up stuff it came in @ over 25 GPM. HC was high too. I don't notice any mis-fire and there are no codes anything. Gas mileage also went from ~ 26 to ~22. Thinking it could be the MSD. Anyone else have this problem?

 

I've done a couple of searches on this and other forums about what would cause these to run rich and most points to what I've already done. I also tried resetting the ECU and that just causes her to have a truly erratic RPM at start up that will even out within 30 seconds. I've attached the detailed diag info any help would be awesome!

 

95 Legacy EJ22 230,000.

 

-Jason

EmissionsDiag.pdf

I've read that some people report lower gas mileage with the msd and the explanation being a cleaner burn confusing the ecu causing it to read a false lean, thus it dumps fuel in to correct causing bad mpg and a rich exhaust or some such.

 

Now.....at the same time, I have read some other's responses to those people calling them everything but right. So as with anything found online....taken with a grain of salt on both sides. But if there is something to the "false lean" claims, then that would explain your current predicament. Didn't happen to keep your stocker by chance, that you could do the ole swap test with?

 

-LT

Now that you mention it I do remember reading that about the MSD... I was just under the assumption I was just using the gas peddle a bit more since it was running better. I took the connector off a donor coil at the junk yard when I got the one of the Mopar car.

 

I'll be putting the original coil/wires back on after work tonight and see if the changes things.

mine had similar results when i first took it through emissions, i also have the msd coil. mine turned out to be a broken hose nipple on the charcoal canister and a small vacuum leak by the manifold. and a bad gas cap. replaced and fixed that all, it passed without anything else. my wagon wit the msd still will get 29-30 mpg on hwy, and usually gets me 26-27 in the city.

Hello;

Could be the coolant temp switch is faulty causing the car to run rich all of the time. Vacuum leaks are a killer as twisty has noted, Steven.

Twisty

 

I had a good look for vacuum leaks and couldn't find any, I'll have to check the evap canister...

 

I wonder if an EFIE will help or if I've horribly whacked something out on this, would hate to think so had such great plans.

 

snederhiser - would I have any other symptoms on the coolant temp switch haven't had any over heating issues...

Hello;

You have two temp sensors, single blade for the temp gauge, twin blade for the computer. When the car is started out of the cold it is running rich, as the coolant heats up the engine will run leaner. You gotta remember there is no choke or enrichment valve on later EFI's, Steven.

Coolant sensor looks to be good though when looking over the emissions readout. Reading 90C or there about.

i know its probably a dumb question, but did you go through the tune up parts before taking it through emissions? the first time i took my wagon through (when i first bought it) i didnt even pull the plugs to see what they looked like. it passed, but i could tell it needed a tune up. turned out the coil and wires were way out of spec and the plugs were little burnt mushrooms. the MSD was actually cheaper than the OEM coil, and i found a good set of NGKs locally for teh cheap as well. new NGK platinums and it ran like a champ. the vacuum lines/ canister leak were the last part of the whole ordeal when i took it through the second time a year later. also, instead of paying the 65 bucks for a new can, i pulled one off of an impreza at the junk yard for 12 bucks.

if you want to just get it done.

run your car for about awhile so it is HOT

have about a gallon, half gal in your tank when you goto emissions test

pour 1 bottle, (1qt?) of isopropyl alcohol. (rubbing alcohol) in your gas tank soon before the emissions test

this will make those HCs burn off before they reach the exhaust for emissions testing

 

seriously.

this always works

ya thats an easy way to get it through. make sure to put the alcohol in right before the test, if you wait it will evaporate out and be a waste of time and alcohol.

if you want to just get it done.

run your car for about awhile so it is HOT

have about a gallon, half gal in your tank when you goto emissions test

pour 1 bottle, (1qt?) of isopropyl alcohol. (rubbing alcohol) in your gas tank soon before the emissions test

 

That's Awesome! may have to try that if the stock coil being put back on doesn't work. have plenty of alcohol in the garage but don't think the car would enjoy it as much as I would...

 

twisty - I did the same thing with mine when I first got it, didn't check a thing and took it in and had no problems. This time since I've been driving it for years doing nothing but changing the oil thought I'd go through and do things. The old coil and wires showed some age but no issues. And the plugs were just a bit pitted.

 

I've had the stock coil on there with old wires and maybe it's just me wanting it to resolve the issue but the gas gauge seems to be going down slower...

before switching the coil and stuff, test them to make sure they are good.

 

http://imageshack.us/a/img811/1831/0r6k.png

So after putting the old stock coil and wires back on I've passed emissions @ 10GPM CO so there's something to be said there I guess, after I check the new coil wires I'll look into something to modify the signal from the O2 to give the computer what it wants to see... I really like how smooth running the MDS coil is.

 

thanks all for the help.

 

Twisty - what other mods do you have? are you running 2.2?

after putting the old stock coil and wires back on I've passed emissions .......

 

after I check the new coil wires .........

 

I really like how smooth running the MDS coil is.

 

just a thought,

can you try the coil with the old wires, or vice versa?

it may be one but not both, or maybe the combination, causing the issue.

won't be able to do that because the posts on the coil are different... all components old and new checked out resistance wise

So after putting the old stock coil and wires back on I've passed emissions @ 10GPM CO so there's something to be said there I guess, after I check the new coil wires I'll look into something to modify the signal from the O2 to give the computer what it wants to see... I really like how smooth running the MDS coil is.

 

thanks all for the help.

 

Twisty - what other mods do you have? are you running 2.2?

 

i have a 95 wagon with 2.2 and a 96gt with 2.5. the gt is pretty much stock so far, the wagon has the msd coil and 8mm wires, and both the big 3 and grounding kit. thats as far as ive gotten with mods so far, kids are my more important money sink lately. when i do get extra cash im gonna get uel headers and new exhaust for both, hybrid intakes and upgrade the coil/ wiring in the gt as well. the wagon will get new suspension and rsb before that happens tho

twisty, if the 2.2 HAPPENS to be an automatic, I did a mod on my 2.2 1998 brighton wagon yesterday that was amazing, "sport mode" transmission mod", 1 wire, ten minutes, LOTS of results and it was free

yup, its on my list of things to do.