powerpigz-51

Hi guys....I am having an issue. My car flunked emissions yesterday, it has one more year to go and no more tests. It passed cruise with flying colors, but flunked with a 450 on hydrocarbons at idle. (limit 220) I then took it home and fixed my wildly fluctuating fuel pressure reg.(BBK) I had left out the slug spacer washer on install as the adjustment bolt was way too long. I replaced the spacer and shortened the bolt, now it is holding steady at 43 pounds idle. I have 19 pound ford injectors. I also cleaned the ISC and ports. This may or may not have helped.....what else can I do? Increase the idle speed? Currently at 590. How about adding alcohol to gas? Timing was set at 5 degrees as I am having detonation issues. Much less now that the reg is fixed. Advance or retard for idle hc's? Oh....I have no EGR (new one on the way) and deleted air pump. Thanks in advance

theadmiral94

Don't worry about the EGR, it does not operate at idle.

Nor about the AIR pump -- its purpose is to inject extra air at start-up to warm-up the o2 sensors -- usually only runs for a couple of minutes.

jeffp1167

it's cause your air injection system is missing and without air going into the cat converter it cant function correctly and this air also helps cool the converter as well. The egr should reduce the detonation issues but if it were me throw a new cat on. I have done that on my nearly gross polluting trans am in california and it then passed with ease. a new converter will cut your emmisions in 1/2 with ease, just make sure to keep it hot before a test and run it a day before your test.

JrRifleCoach

Sounds kinda weird but here's a step I always preform before hitting the check station.

Let the fuel load run down to a few gallons then add a pint or so of denatured alcohol.

It thins down the fuel and does not create hydrocarbons. So if your on the edge of failing it helps to keep you in the green.

jeffp1167

yeah but he is beyond the edge of failing he is 2 times the limit.

powerpigz-51

I realize the EGR does not function at idle, I am only replacing it due to my pinging issues. I have now heard it both ways on the air pump and I am sure a new cat would help but I don't want the expense just to pass this one test. The alkie sounds like a go. Now do I want to retard or advance the ignition for lower HC's at idle? Will raising the idle speed help? Anything else? Thanks for the ideas.

jeffp1167

you if like in california are only allowed + or - 3 degrees on your timing from what the factory set them at. Are you testing on a dyno smog machine? A long time ago a mechanic friend disconnected a vacumn line on my 1982 corvette to get it to pass (probably caused it to lean out a bit) check o2 sensor, I've heard changing plug gaps can lower emissions, theres a few more tricks like inducing a small exhaust leak.

ChrisWhewell

retarded timing could be contributing to unburnt fuel content of exh gases.

detonation could be from carbon build-up, which can glow red hot causing pre-ignition. When my engines would display knock, I warm them up and then get under the hood, open the throttle up to run about 1500-2000 rpm and spray water into the air intake / tbi / TB, etc. carbon is a reducing agent w/respect to water under combustion conditions and will turn to gas. Its why when one blows a head gasket and coolant pisses into the cylinder and you later pull the head, that one cylinder is clean as a whistle. just don't go too much too fast with the H2O. My usual dose is a quart and my hands always hurt like he77 afterwards from squeezing the spray bottle a thousand times to get that quart in there. Next time, I'm going to use a garden hose, with the valve on the house cracked open just a C-hair, and the spray gun on the very most misting possible. If the carbon has really built up in there, your chamber volume will increase back to its stock size if you get it all out. Then timing could be set to spec and HC emissions may become acceptable, if carbon build up was the cause in the first place.

powerpigz-51

Thanks Chris, but I don't think carbon is my issue, as my motor only has about 3k on it. I am running over 10-1 compression with iron heads and my EGR has been blocked off, and I am only running 1 degree retarded, which I think will be fixed when I replace the EGR. I can run as much advance as I want to get through emissions, if that is the way I need to go to pass the test. I just want to know if advance or retard will help my cause at idle? I was under the impression that retard is the way to go, but maybe that was for excessive NOx. I had 57 HC with a limit of 150 on cruise, so I have some room there.

JrRifleCoach

Darn, then its gonna mean 2 pints of alcohol; one for the car the other for the tester!

FICINJECTORS

I think your problem is the 19 lb injectors. The 85 uses a 24 running at 36psi I bet your Blk Lrns are pegged at 160 making the computer add a lot of fuel at idle, Did it ever pass with those injectors?

powerpigz-51

Jon, your going to get an order out of me yet! Sounds like I need to get a cable for my laptop (finally) and do (learn) a scan. Everything else would just be whizzin' in the wind. 24 pound injectors will be in the budget soon I believe. So, for educational purposes, are we in open or closed loop at idle? If I understand correctly....open loop? I was figuring closed for some reason........

powerpigz-51

And no....it has never passed with the 19 pounders, hasn't been through a test since '97, and I have since rebuilt, replaced and messed with everything since.

Vett-eight-nine

Starts in open until the o2 sensor is warm enough to go to closed loop. At that point, info from the sensor is used in making fuel calculations.

mtwoolford

This will sound counterintuitive, but its true: a too lean condition can also cause elevated HCs (too much air, too little fuel, some fuel remains unburned)

First step, determine if the engine too rich or too lean.

The test consists of hooking the car up to an exhaust analyzer aka smog machine; while the engine is running an unlit propane torch valve is opened feeding propane gas into the intake manifold; if the HCs go up, the engine is too rich; if the HCs go down, the engine was too lean.

I had an engine fail the HC test once; I had replaced the purge hose between the charcoal canister and the intake manifold. Failed HC test; above test showed engine too lean. Further research revealed that the factory hose contained an (hidden) orfice which significantly reduced the volume of air passing into the intake manifold. Jury rigged what I judged to be a similiar size orfice into the purge hose and passed with flying colors.

Any vacumn leak could cause a similiar problem; in my case it wasn't big enough to cause an elevated idle issue.

good luck.

bowtie350_428

Hold on a sec. I don’t want to put anyone on the spot, I just want to have a better understanding of things...

I thought the Air Pump was supposed to heat the cats up to operating temp, not cool them off. I also understand that if you delete the AIR, it would only mean that your cats will take a bit longer to get up to operating temp but should function properly once they have heated. Besides the AIR only functions at startup then turns off and stays off until the next engine startup. So how is the deleted AIR going to effect his test results at idle once the engine is heated?

Randy93

Did you get your car tuned for the FI's or get a adjustable fuel pressure regulator to set the right pressure for your FI's?

If not, that is your problem and you should get a tune or a AFPR or set back to stock w/new FI's from Jon.

SunCr

Depends on year and no, the air pump doesn't cool anything off! Anyway, non heated O2's use the afterburning created by the air to get to 600 degrees and closed loop for any startup - air to headers; then switch directly to the CAT for this Year. It's a continuous feed except when you let off the gas (which keeps it from backfiring) or backup (code set). Like any car that fails, hooking up a scanner will tell you what's going on. None will pass unless it's closed loop and a 14.7 to 1 mix and the scan will show you what it is and what you need to do to fix it.

bowtie350_428

So then the Air pump serves various purpose depending on the year. Interesting... Thanks for clearing that up. Trying to get a handle on your emissions is enough to make your head spin.

Question though, for this year where does the continuous feed go to? Cat or header?

powerpigz-51

I agree that I am in need of some kind of analysis to see if I can tune it better, I am going to get a cable for my laptop and see what it says. I did find that my fuel canister was not hooked up to the throttle body and that port was leaking vacuum, which could have been my whole problem. Thanks for all the help folks! I will let you know how it goes.