92 2.3 Killing the plug mod......Or not......?

[RidnRed]

So this- http://therangerstation.com/tech_library/4cylinders.shtml -is the place i found an answer about my cyl location on coil packs about 6 months ago, I only had the question because one is aftermarket, and one is motorcraft -it may have come from a different vehicle but nevertheless- on the mc pack its labled 1234 starting from the bottom left and going clockwise (if the connector is facing you) so #2 and #3 are just swapped. According to the plug mod thread, this should not affect anything because they fire at the same time.

I've had the truck since march last year, registered shortly thereafter, emissions passing with flying colors so I expected the same this year, not the case. I had over 8% CO and nearly double Utahs 220 max ppm HC. I couldn't figure out wtf was going on, until I remembered my plug wires. I hooked them up the way is says on the MC coil pack, dumped some 1/2 can of seafoam in the tank and passed beautifully.

So whats the bottom line? Is seafoam is some really awesome, miricale working liquid gold, or we should leave our plug wires alone?

Also, the coolant temp sensor spliced into the hose above the alt. What the hell is it? i thought the ECT was on the lower intake manifold? I've unplugged it with no change in my gauge. Thanks for any help, and your opinions....

 

[Mark_88]

The original wire configuration is meant to help burn off gas that is not burned in the initial combustion...so it would make sense that the emission test showed more than should be there...I don't think it was the seafoam at all...other than cleaning out carbon deposits and allowing for more actual compression of the gas it would do little.

On my last test the allowable HC was 200...mine was at 2300 or so and I went home and turned down the A/F mixture on the carb...after that the CO passed, and all levels dropped considerably...except the 2500 RPM test which more than tripled to over 6,000 PPM HC...

Which totally baffled me...

Anyway...maybe some pics of what you are looking at for those of us who may need a visual aide...but someone familiar with that particular engine setup might know what you are talking about...

The good news is...your truck passed...not sure what the local authorities would say if you swapped the wires after the test...but who cares...just plead insanity...works for me!

 

[scotts90ranger]

there are two coil outputs on the coils (one for 1 and 4, the other for 2 and 3), swapping 1 for 4 or 2 for 3 will make no difference (think about it, two coils, 3 wires going to the coil, it can't control 4 cylinders independently) and they use that same coil on several V8 engines.

If I had to guess why it wasn't working would be on how you drove to the testing and how long you had to wait in line. If you started the truck up, drove gingerly over to the testing station then waited in line idling 90% of the time the catalytic converter will not be working as it never got a chance to warm up, on the other hand if you drove it over to the testing station like you stole it then didn't have to wait in line and went right in, it would be working and you would probably pass if you didn't the first time.

 

[RidnRed]

I know the way our coils work, thats why this has got me stumped and I posted here. There was nothing ginger about the drive, and I was 1st in line.
Your point is that the engine and cat were not hot enough to achieve a proper burn and I get it. I can assure you that it was much hotter on the first test. I had my fan off and half the rad blocked on the first test and all winter. I put them on the morning of my 2nd test (2 days after the first) because the weather has been warming up here. I'm not trying to disspute the way these ignition systems work, i'm just posting what happened this instance.

Now i have passed the smog and I know under what conditions, i'll again swap the 2 and 3 and have a friend re-test it to see if i can duplicate the results.

 

[Mark_88]

I'd like to have them test mine again and allow me to adjust the carb while they test it...but I don't think they would do that just for laughs...

Mine got a conditional pass and I think it might have passed if I put on the air pump and a new cat...but that will have to wait for another two years...hopefully the program will be scrapped by then and I won't have to bother with it...

 

[scotts90ranger]

Your point is that the engine and cat were not hot enough to achieve a proper burn and I get it.

ok, that doesn't make a whole lot of sense then.

Although the coolant temp doesn't have a whole lot to do with anything after a certain point, the engine is looking for the coolant temp to be above a certain point before it goes into closed loop fuel control, that's just to give the oxygen sensor a chance to warm up and the block enough time to warm up so the puddling of fuel in the port is warm enough to vaporize.

The cat is what is important to be working properly, having high CO and HC the engine is either running rich or the cat isn't up to temp. But being a '92, it isn't perfect so odd things can happen... Although if the NOx was in range the engine could have been running rich and the cat was working, in which case I'd look at the MAF and see if it's dirty or something, otherwise it was a fluke or something, if the idle is a little low that wouldn't help anything.

I'm not trying to be a jerk or argue like some people, just trying to share things I have learned (and learn things as I go)... I do emissions testing for a living (well, sometimes, other times are just general engine tuning...) just for marine and industrial engines not on road stuff... If you do find something out with your friend, let us know as I'm curious...

 

[Mikel89us]

As stated in the other threads that cover this, this mod is useless and does NOTHING!!!!!

 

[RidnRed]

So how would you know if it was rich or lean? If you do smog testing you know that high CO could be a rich mixture, and high HC is an indication of either a lean fuel mixture, or improper ignition timing. I'll post a pic of my plugs, they're just as ghost white as everyone elses on these forums. Nothing rich about them.

 

[scotts90ranger]

Actually high HC is rich or timing/ignition, high NOx is lean, if all 3 are high then the cat isn't working from being cold or melted or something.

 

[RidnRed]

having high CO and HC the engine is either running rich ...

I'm sure being a smog tester you know this, but yes high co indicates a rich condition, but high hc indicates a lean condition and or improper ignition timing... so how can you tell if its rich or lean? My 8 pasty white plugs will tell you just like they did me. Its really not a big deal, I just wanted to share what i've found. I'll get with my friend to do a re-test.

 

[Mark_88]

Plugs do tell the tale in most cases...we just have to listen to them...

Let us know what the retest values are if possible...and thanks for updating your thread...always nice to hear happy endings...

 

[scotts90ranger]

not sure how unburnt fuel (HC) is running lean, but ok...

 

[Mikel89us]

High hydrocarons can be an indication of a lean system, and a single cyl rich. Usually if you have high HC and NOx Its caused by a missfiring cylinder. The unburnt fuel will tell the O2 sensor the system is rich, and it leans out the whole engine, causing high NOx. But high HC is NOT an indication of lean, it IS an indication of a rich condition. It can be a side affect of a missfire caused lean.

 

[RidnRed]

Sorry, my bad. I guess I should stop believing everything I read... http://www.smogtips.com/failed-high-hydrocarbons-HC.cfm

 

[scotts90ranger]

Their description on that area is a little odd, on a mass air flow system yes it will run lean if there was an unmetered air leak (air leak after the MAF) but it would have to be pretty bad to cause a lean misfire (most vacuum lines are very small), and the oxygen sensor should be able to compensate for minor leaks. The only way running lean will cause high HC is when there is a misfire, if it's lean before the point of misfire it'll have high NOx, lean to the point of misfire would be both being high (but that's probably in the 17:1 AFR where it should be bouncing from 14.2-15.2 or thereabouts). The unmetered air thing gets a little complicated in my situation with the turbo, if there's a leak after the turbo it'll run lean before it's boosting then once the pressure after the turbo goes positive it'll run rich...