Emmisions testing question

Hey guys, I know that advancing or retarding the timing will lower emmisions, but can't remember which way to go. Anybody else know?

Will lowering the fuel pressure help?

Thanks,
Cliff

Thanks guys!

Hey Mike, unfortunately here in Maryland they look for the cats. If you don't have, you're F---ed! I think my FP is already to low so I did not mess with that.

I run the timing at 16 deg normally. I don't know how far down I put it, did not check, but it was a bunch. I cranked the idle up to 1200 RPM, then turned timing down until the idle dropped to 800 RPM. It lost big time power and would barely run so I advanced it just a hair and I think it's alright.

The exhaust at least smells much better, but that could be the alcohol I mixed with the gas. This does not work well with EFI cars (I am finding out). That used to be my biggest help in getting old carbed engines through emmisions testing. Always worked great. Alcohol burns very clean. I would not recommend anybody trying it in an EFI car. Luckily I only had a couple gallons of gas, as I was pouring the alcohol in and it started mixing with the gas, the engine started running slower. I ended up having to fill the rest of the tank with gas to get it back to normal idle.


Oh well, I think I at least have a chance now.

Cliff

jaketuff said:

Post results man.... I am going to try and pass a 351W/Holley Carbed! (w/ some kinda cover over the carb to make it look stock mani, and EEC powered up w/02 sensors in, full cat system).

OUT

Click to expand...

I don't believe that the alcohol was affecting the EFI. I'm 99% sure the cats are clogged on the factory H-pipe I was trying to use. On my first attempt, the nitrogen was way high and failed, everything else was real low. The little paper they gave me had a bunch of possible reasons for this reading. First on the list was engine running lean (also included clogged EGR and malfunctioning cats). My engine has every bolt-on except heads. I have an AutoMeter FP gage that is way off, and I have been thinking my FP was too low, so I thought the lean condition may be the place to start. I cranked the FP up to 60 (from 56 on my bad AM gage) and went through with no other adjustments. This time, to my suprise, the nitrogen reading went up. Everything else was still good. So I went back out into the parking lot and popped the hood again. This time I went the opposite way, took the FP down to 40 on my gage and had to turn the idle up to just under 1,000 RPM to keep it running smooth. It was barely running and if you gave it more than 20% of the throttle it would stumble bad. BUT, on this third try it did pass with ease.

To make a short story long, this is where the problems started. I figured I would drive it home since it was not much worse than the way I drove it there, and It was hot as hell and tuning on the engine in the sun......
So I passed the parking lot and pulled out on the main road and was not 100 yards away when i realised I was not getting home like that. It wasn't really a problem yet, this road has a very wide shoulder and I pulled off in the shade. I was actually thinking this was better. Then as I was getting ready to crank the FP way back up, I dropped the allen wrench on the back of the engine. I almost was able to reach it at one point, until I hit it and it fell down to somewhere I could not even see it. So the only thing I could do at that point was turn the timing way up, just guessing I would say I had it back up around 15-16 degrees. The car would run, barely. I tried to shake it a couple times, and tried to buck it with the gas, clutch, and brakes a couple times but I could not get the allen wrench to fall. So I tried to limp home and did not get very far before it died. The first guy who failed me pulled up and had this bigass magnet stuck inside his trunk. I tried to stick it back there to pickup the allen wrench, after almost getting it stuck against the firewall on the driverside, I went to the passenger side, started guiding it down behind the engine and it hit the air tube on the back of the heads and spun around underneath and up against the block. Needless to say, it was not coming off of there. So back to trying to get the car running, I had to turn the timing way up, around 20-22 degrees for it to even start and it would not roll at all like that. So I'm sitting there talking to dude, neither of us had our sell phones, when the state police shows up. Luckily, this was my friend Ron who has a 67 Camaro SS clone. He had a screw driver kit with the different magnetic bits, including the 1/8 allen bit I needed. So I cranked the FP back up to 60 on my gage, I'm guessing around 42-43 actual and it ran much better, not good but it was running. I made it home fine.

Yesturday I went out and put my MAC Pro-Chamber back on and she was running good, just like that. I set the timing at 16 degrees and fuel pressure was left at 61 PSI and I dropped the idle down to 850 RPM. When I pulled in Friday afternoon the idle was at 1100. When I took off the stock H-pipe and put on the Pro-Chamber, no other adjustments, the idle was 1600 when I fired it up. I would say the cats were plugged up, causing all of my problems. Now she's tuned up and running good. Last night I even got my allen wrench back. Heard it fall out around a slow turn, stopped and picked it up.


Well, that's all I know!

Cliff