Ozz1967

iTrader: (4)

Ok, so I have been trying to get my carb tuned in this weekend and I'm having one hell of a time.

Idle mixture screws, 4 turns out each. Reseated each to make sure.

Lean stop, Three turns down from top.

Rich stop, four turns up from seated.

1.8" travel on solenoid.

IAB is 5 turns up from seated.

When car is cooler, dwell sits on the low end, 20* or below on the six cylinder scale. When it warms up, it rolls up to 50* when the fan kicks on. After fan turns off it will drop low on the scale again before going back up until it gets hot enough to kick the fan on and it starts over again. So either I'm way out and need to restart this mess or something is wrong. Maybe my 160* thermostat is too "cold" and I should bump it to a 180*? The link below is my dwell meter. Sound quality is terrible and I'm sorry for that.

MCS Dwell Video as it is now

Sparkytfl

Check the resistance of your coolant temp sensor, the one in the thermostat housing. Should be between 450ohms at 160degrees and 185ohms at 210degrees. The book says anything under 1000 on a warmed engine should be fine.

If you're using the normal oxygen sensor with headers that might be a problem. Barely gets hot enough to give a good reading when the car is just idling. I usually end up having to do some driving, then get out and check it immediately.

Ozz1967

iTrader: (4)

T-stat is newish 160*. My swap that out tomorrow for a 180. Only sensor I have for coolant temp is the one in the head on the drivers side. Fan sensor on the passnger side. Car never gets as high in temp driving unless i get stuck at a light as it does idling.

five7kid

iTrader: (14)

You must have a CTS in the thermostat housing. Without it, the ECM can't go into closed loop.

Ozz1967

iTrader: (4)

Electric sensor with two wires coming off it in the housing? Yes, I have that. I got rid of the vacuum sensor thingy that was in the T-stat housing when I switched to a serpentine belt set up from an 88. There was no hook ups for it with the newer AIR pump stuff.

naf

iTrader: (7)

You can rule out the CTS kicking you out of Closed Loop by shorting the pigtails of the lead. This will confuse the ECM into thinking the motor is 'full hot'. Don't think it's an issue here.

I suspect your O2 is getting a little cold at times. Pretty common, especially with headers.

I'd maybe swap in a higher t-stat. Not to do anything with the dwell, just because I think 160 is too low overall, especially if you drive any in cold weather.

You can swap in a heated O2, but you really look to be fine as you are. The motor won't spend that much time at idle under normal driving. Dwell looks pretty good otherwise. If you do a lot of stop and go and cold weather driving the heated O2 may pay for itself in slightly better mileage-it will allow the motor to go into Closed Loop slightly earlier when warming up. It runs around $50.

If you're not experiencing any throttle transition issues I'd leave it alone other than to tweak the IAB to get it closest to 30 degrees on the V6 scale when hot. Otherwise, it looks fine.

Ozz1967

iTrader: (4)

I haven't been experiencing any throttle response issues. I also haven't driven it since I fiddled with the mixtures so I will find out today. Also no codes for running lean or rich.

How does a heated sensor work? Would I have to run a separate power wire to it?

naf

iTrader: (7)

You'd have to tap into an "ignition on" source. There's a couple you can hook into at the driver's side firewall. It pulls very little little amps so it's not a big deal.

Ozz1967

iTrader: (4)

I supose I could use the wire I ran to the fuse box when I ran my electric fuel pump relay. that's "hot-on" when the ignition is turned on. Going to try a 180* thermostat first though. In the video, the fan is on at 195 and off at 185. Current thermostat is 160 so that may be to cold...especially with headers and the winter combination.

naf

iTrader: (7)

Have you swapped the t-stat? Your fuel/air mixture 'may' burn differently at different engine temps, especially in colder weather when fuel atomization can be a problem.

Don't think you'd see it much sitting with it idling in the driveway though. I assume it was shirt sleeve weather?

Random current project pic:

Ozz1967

iTrader: (4)

I have not yet swapped it out. Thats my project this eeknd. I was waiting for a new set of plug wires so I could do both at the same time as its my new daily driver. I can't have it down for an extended time. The question is, do I go with the 180 sitting on the shelf in the garage or go with a 195? I'll probably just use the one I have. Saves a little money anyway.

naf

iTrader: (7)

If you have to pick up a new gasket go ahead with the 190 and get the rubber/steel gasket that's re-usable instead of the paper one.

Ozz1967

iTrader: (4)

The thermostat housing I use has a rubber gasket on it. I got rid of the original when I went with the new smog equipment from the 88. I didn't need the additional vacuum set up (or couldn't use it as there was no place to hook it up anymore). So I only have the one electrical sensor in there now. Anyway, replaced the gasket on it while it was out is what I was trying to get to.

I replaced the thermostat with the 180* stat and that seems to have fixed my dwell issues. Warmed up it will swing between 45 and 25 on the meter (colder to warmer), wavering back and forth just a bit as it's s upposed to.

Would have had this done last week except my fuel pump died while I was burping the radiator.

On my car at least, if something's not broke or doesn't work, then it ain't right. LOL!

naf

iTrader: (7)

Good deal. Glad you got it.

Ozz1967

iTrader: (4)

Thanks! I think you were right when you said that these cars like to run hot. It definitely seems to tune better now than it did. Can't believe 20* makes that much difference