running great but

[MaTTSuN]

ok my car with the mega squirt is running great ive been trying to tune it for emissions but i cant seam to get the idle right

my "driving" test passes no prob very well acually but when the do the 30 sec idle test my hydrocarbons are like 3- 4 times past what is allowable

 

i have 1420 and your allowed 400....

i have my idle timing at 26 adv and my wideband is at about 15- 15.5 afr

 

i dont have a cat on my exaust and id rather not put one on if i can get around it by tuning the program

i was just wondering if anyone knows anything about this

like more or less timing or more or less afr is being on the lean side of things making my hydrocarbons shoot up and should i make it a little rich?

[Brad-ManQ45]

MaTTSun:

 

I'm sure you're speaking of HC's although you weren't specific...

 

Lean A/F ratios are great if you also don't have a problem with NOX levels (higher combustion temperatures = more NOX)

 

A couple of things that may be of importance to know (and people don't have to search to get the info to help you):

 

Nissan set initial timing at 24 on the 83's so I would imagine there isn't a good reason to change that. If you are too advanced you may be misfiring, thereby causing extra HC's...

 

What size injectors and are they PH or saturated?

 

What are your settings in Megatune for open/shut time and what do you have set up for low battery correction? (this CAN affect injector output)

 

Settings for simultaneous or alternating and number of injections per cycle.

 

On a side note, I always get my car tested with regular gas (only 1/4 tank) and I put a bottle or two of ethanol in it. This serves several purposes:

 

Regular gas burns faster and potentially more completely

Ethanol burns cooler than gas so reduces NOX

Ethanol burns cleaner

Ethanol has its' own oxygen so reduces HC counts by providing more oxygen during the burn process and out the pipe

 

After I pass, I go fill up with ethyl and git on it! Needlelss to say I keep it to low boost with jus thte regular in the tank...

[eec564]

First of all, if your hydrocarbons are that high (I'm assuming parts-per-million), then something is wrong with your engine. It could be a LOT of things, but the HC out the tailpipe is unburnt fuel, and that's coming from somewhere, and not getting burnt for some reason. There could be a miss-fire, incomplete combustion, a leaking injector, a whole bunch of things.

 

Without knowing exactly how your car is configured, anything I say is just a wild guess. Presuming you're running a stock turbo engine, then your timing and AFRs are higher then what's considered (generally, I'm in CA and we all have CATs here) safe to run in the era of goosing for lower emissions. I would recommend changing your timing back to 17-18 BTDC at idle and get your AFRs aroubd 14.7-14.5, maybe even a bit richer. That mixture and timing should help with complete combustion.

 

Also, doesn't your 78 have a place for a cat? You could have a muffler shop (or DIY, if you have the tools) weld in flanges for a bolt-in cat, and also keep a bolt-in straight pipe so you can change them easily. The cat isn't the fix-all end-all for emissions, but it can help for cars that are just over. Your wide band could also be lying to you, as a misfire can also introduce large amounts of oxygen into the exhaust, making the sensor read far leaner than you are. Remember, an O2 sensor measures O2 out, not fuel and air in.

 

As is, it sounds like you have bigger problems, but I don't want to guess at anything else without knowing more. For instance, asside from what you've already mentioned and what's in your profile, some other needed details here would be:

Dizzy setup (stock CAS, EDIS, N/A unit, etc)

Other emissions readings (NOx, CO2%, CO%, O2%, etc. A high O2% with high HCs nearly always means a miss-fire)

Engine compression readings (possible fault, have you adjusted your valves lately?)

Stock engine, or odd parts?

What injectors are you running?

Any other details that come to mind, specifically anything that wouldn't be assumed in your swap.

 

Edit: Brad posted while I was composing, but play with things. Try a timing light on all six plug wires to see if any of them ever 'skip', pull your plugs and check for signs of abnormalities, something just isn't right. There are HybridZ members in CA getting their non-cat cars to pass smog with results cleaner than catalyzed emission standards.

[MaTTSuN]

ok here it is

 

on my driving test

 

max allowable-------vehicle reading-------average passing

hydrocarbons ppm----223.0----------------14.00-----------------63.00

carbon monoxide %-----1.58------------------.34--------------------.48

oxides of nitrogen ppm--2255---------------363.00----------------1025

 

 

idle test

 

hydrocarbons ppm 408------------------1445---------------------94

carbon monoxide % 4.51-----------------.55--------------------1.14

 

this was with the timing at 26 and the afr at about 15.5

i just looked at my last one where i had it at 24 deg advanced and about 15 afr it did worse on CO 6.64 and a little better on HC 1238

 

the day of the latest one it was running allot hotter so that might play a factor

the last driving one was ok as the timing and fuel was not changed since just the idle

[MaTTSuN]

my injectors are stock

injector opening time 1.0 ms

batt correction .10 ms/v

simutanious and 2 injections per cycle

 

its a stock engine with a bov and 3 inch exaust all the emmisions stuff are taken off except the pcv valve

 

when i leaned it out it had a good effect on the CO on idle but the HC went up 200 ppm i added some more timing also from 24 to 26

NOX is not read during the idle test so should i maybe try to lean it out even more?

[mario_82_ZXT]

Guess what a cat does?

 

Once it heats up it helps burn off excess hydrocarbons. Just throw one on to pass emissions then take it off afterwards.

Mario

[MaTTSuN]

i might have to do that i guess but i just redid my exaust and i like the way it is ha

one other thing it might be is i have my electric rad fan hooked up to a toggle

when i turn it it drops a couple houndred rpms and runs a little ruffer

could that be taking some spark away from the ignition and make more HC i think it may be because the driving test very clean running

if i dont have the fan on it might over heat and i dont want to heat that baby up anymore than i have to

 

ill be looking for a cat i have one but i think its a little small

[eec564]

Drop some timing, you could have some pinging that's going on and blowing out the flame front causing unburned fuel to exit the engine. Also, what exactly are the requirements for passing an emissions test in BC? In california they check timing, all hose routing, emission control functionality, and tailpipe emissions. If you can, raise your idle speed to 100 or so above your alternator excite RPM, that should help eliminate the stumbling. My 82 N/A also has a valve that adds extra air when the A/C is on, if you have one of those you could use it to cut in extra air when the fan is on if it really draws enough power to slow the engine that much. Also, a catalytic converter helps reduce ALL three of those controlled emission substances, so with some tuning you can generally balance them to a point where all are low enough. Good luck.

[Brad-ManQ45]

I'd drop the initial timing back to 20 degrees like the '81 and '82 turbo cars had and see how much effect it has.

 

The problem with that much extra HC's is that they'll burn a cat up, but then how long do you idle?

 

What is your idle speed set at? Have it set as high as possible and still be within testing specs - obviously you are having a problem at idle but at higher rpms you're fine.

 

What VE settings do you have set up in the idle range:

 

You might want to take a look at what Dave (Cygnusx1) and Randy have done with theirs, along with ignition timing in this thread:

http://forums.hybridz.org/showthread.php?t=99689&page=2

[randy 77zt]

i would take the idle timing down to about 12-14 btdc,then lean it out some .if you are running old injectors get new injectors or have the old injectors cleaned & flow tested-the spray pattern is critical for emissions.fat drops of fuel from old injectors dont burn completly.cam timing or a non stock cam can raise hc.i have had well tuned cars pass california emmissions with hollow cats.the cat is a mop-up for a poorly tuned engine-fuel should be burnt by the engine.program some kind of ignition advance curve into the ms-take advantage of its capabilities.idle should be 12 -20 btdc.cruise should be 36 btdc or so.full throttle about 28 or 30 with no boost.my retards back to 24 btdc after 4 psi boost-it pings on crappy 91 cali gas.looked at readouts-you might have lean misfire-try retard timing and about 13.8 or 14 a/f

[woldson]

Like Mario said cat needs to be HOT. Good freeway drive come off and take the test asap. Pick a day when emmisions are not to busy. Out side of spending 15 bucks for 2 tries at emmisions they dont care how many times you try in spokane wa. Hummm. would a dyno tune help? Ive got a 83 cat that only has 76,000 miles on if you can have free exept shipping i think ive got to cheack.

[RTz]

Idle at 14.7:1 and back timing down... try about 10 degrees.

[MaTTSuN]

ok so what im getting is have the timing down to about 12-14

get the afr to 14.7

and get the idle as high as posable

i had my idle at like 1000 i think the limit is 1200

ill try and get 1150

it goes up and down about 100 or so while its idleing

 

is there any settings in the spark menue i can work with as well?

like dwell?

i could turn the fan off aswell when the guy gets into my car to do the test and that should help burn at low rpm

ill be tuning it this weekend keep it comming love the ideas

 

Matt

[eec564]

I'd stick with an idle timing closer to around 16-18, as that's a pretty high idle. Going a little richer than 14.7 at low RPMs generally helps the engine stay stable. Remember 14.7 is the theoretical ideal for perfect combustion/low emissions. That's again theoretical, different engines run better at different AFRs.

 

As for idling up and down, that's generally a vac leak. Check ALL hoses for cracks, especially around where they connect. The only time your engine idle should change is when something changes. Namely, higher/lower load or more/less air/fuel. The fan-on could do it, as that's pulling more energy out of the alt, but at that rpm it shouldn't make much of a difference.

 

It still sounds like something is wrong with your engine. Pull your sparkplugs and check them for fouling and fuel. Put a timing gun on ALL six wires (one at a time) to check for consistent spark, and that it isn't ever 'skipping'.

 

You can't just slap on a new tune and make everything happy, this may take some work. Go ahead and check your valve clearance too. Just start trying things. If there's an emissions test place where it's pass or don't pay, take it there, and play with the timing and VE table between runs. But do that AFTER you do lots of work trying to find something that's wrong. When you swapped the engine did you replace ALL rubber and the cap/rotor/wires/plugs/etc? If you're still having trouble, you could pull the injector rail and have one injector at a time fire into a cup to see if any have a horrid spray pattern.

 

We'll see if Ron pokes his head up again to agree with me, but I think there's something actually wrong with your engine. Most likely simple, such as vac line or valve adjustment, but there's gotta be something.

[RTz]

I'd stick with an idle timing closer to around 16-18, as that's a pretty high idle. Going a little richer than 14.7 at low RPMs generally helps the engine stay stable. Remember 14.7 is the theoretical ideal for perfect combustion/low emissions. That's again theoretical, different engines run better at different AFRs.

 

My original statement was centered around *only* passing emissions at idle. My suggestion would 'kill' a perfectly good running Z

 

 

As for idling up and down, that's generally a vac leak.

 

On a known good tune, that would be my first guess. On a standalone system, with only a 100 rpm hunt... statistically, its a tune problem.

[MaTTSuN]

im going to be going over all the lines and pull the plugs and check the valves

 

i really dont want to put a cat on since my muffler is tucked up when the cat should go

 

can u put a cat at the end of the exaust or is there not enuf heat to make it work, i really dont want a cat just wondering ha

 

ill be messing with my idle tune and try to make it as steady as possable what other settings can i change to make the spark hotter or more intense at idle?

 

this weekend ill be going full force on this badboy

 

thanks again

[eec564]

No, a cat won't work right that far away from the engine. They have to get quite hot to work, I've seen many of them right on the engine off the manifold, rather than tucked under the body.

 

Start out by checking over everything, and dropping a ton of timing, then see how it runs in the emissions test. If they have any of those pass-or-don't-pay places take it to them.