chevymad

Well I've been tuning and retuning this stupid thing over and over. Get it to where I think its going to work and then it all of a sudden changes on me. Back on the 305 it was starting to run lean and surge, so when I put my 327 in last month I rebuilt the carb again. Also did the performance tweeks to the secondarys(modified flap opening and changed rods) Now I've got good top end, but wont idle and cant get m/c to 30. Took carb apart again cleaned and blew everything out all over again. Drilled the holes behind the mixture screws out just slightly larger. Now I can set the dwell to 30 and it idles fine. but....

When the motors cold it misses and shakes and runs terrible. If you close the choke a little more it'll smooth out. With the motor warmed up it idles fine and is great wide open, but its too lean at part throttle. Surges and misses. Tried adjusting the rich and lean mixture screws...they dont seem to change this. Theres no check engine light either. Can't find any vacuum leaks and the egr is good, even tried disconnecting it which helped a little but still not right.

Tomorrow I'm going to put it on the scanner and check tps, ect, map, and o2 readings. If I dont find anything I think I'm going to rebuild an old quad I have from a 78 truck and change distributors.

Anybody have any other good ideas? I know this 327(bored to 335) likes it rich. When I bought an edelbrock carb for it when it was in my truck, the carb had to have different springs and 2 sizes richer metering rods to get rid of a small surge. Then it ran great.

Also if I switch to non ccc what do i need to control the tcc? I know I can wire a switch temporary but the wife drives the car and I rather it worked auto.

SSC

I dont know what to say aboout the qjet, it sounds like you tryed everthing I would have to keep it going. As far as TCC lock up is concerned there is a tech artical on locking it up as long as the computer is still intact at the main board. If you decide to dump the ecm and billions of wires Heres and artical that can help you http://smokemup.com/tech/transmission/700r4/700r4.cfm
or you could just break down and buy the kit to lock her up, B&M pt# 70244, it's around $160. Heres a generic one from Jegs $72 pt# 890-376600.
Good Luck!
SSC

'86tranzsheezam

iTrader: (2)

I've been lookin into using the cc carb on my 350...heard good and bad ...let me know if u get it straightened out....I do know that Painless Wiring has a kit to lock the tcc in 4rth {125 bucks Summit}if that helps any...good luck

five7kid

iTrader: (14)

I must be one of the lucky ones. The only things I've done to my carb are idle speed, choke pull-off opening, AV tension, and rods & hanger. Ever. Fires right up, idles smoothly, generally speaking runs like gangbusters.

I attribute part of my current success to the computer compatible cam.

Perhaps someone who's actually had a problem and figured out how to fix it can provide more input.

chevymad

Well after looking at the data on the scan tool tonight, I've come to the conclusion its not the carbs fault but somewhere in the electronics. Possibly the computer. The O2 data doesnt agree with the values actually measured at the sensor. The computer is seeing it much richer than it is. At idle the O2 reading is stuck at .86 rev it up a little and it starts jumping around normally but still to the rich side. Spray a little carb cleaner in the carb and the engine smooths right out. Also the m/c dwell on the scan tool does not agree with the measured dwell at the carb.

A few months ago, I replaced the computer because of both of these problems. Directly afterwards everything worked normally. Looks like now, whatever happened to the first ecm has happened to this one as well. Not sure what is burning them out but I'm not replacing it till I find out. I also dont want to burn a valve or something in the meantime. So.... it looks like I put my spare carb and accel distributor in for now.

Anybody know if the aftermarket type accel dist. will work with the stock external coil?

chevymad

By the way, the tranny is a t350. It was installed new by a dealer just before I bought the car in 91. The lockup convertor is plugged into the original harness though.

SSC

Ah one of the truck Th350's with TCC lockup its a good tranny. Your could extrenal coil will work you just need to use the dust cover from the CC one. I was having the same problems as you (computer related) Try the old ecm and swap O2 sensors it might help for a while.
SSC

chevymad

I've tried 3 O2 sensors in the last year. This ones a month or 2 old is all. Also the old computer went back as a core. Looks like saturday I put the non-ccc stuff on

Oh well, I'll just pile it up with the old 305. Just in case originality ever becomes worth something.

chevymad

Well I did it today. Installed a quad from a mid 70s sb 400, and an accel small cap hei. The rest of the computer is still hooked up, lights on but it seems to still lock up the convertor. Going to experiment tomorrow with disabling ecm and checking the difference. If it makes alot of difference i'll just pull the ses bulb. Running much better though! Also sounds better at idle. Had one little problem....found out that you cant install an accell distributor with the engine in the car. Had to bend the metal lip on the cowl to get enough clearance to go in.

Should have done this sooner I guess. Would have saved me money. I had both the carb and the distributor sitting on the shelf. All I had to do was rebush and kit the carb.

toosloz

i never had to do that to the lip......without the cap it slids in without a prob

chevymad

This was without the cap. This is an accell 51000 series dist. Even though it uses a small cap, I think the dist. is longer than normal. It was a surprise anyway. The stock gm small cap dist slid out with no problems.

five7kid

iTrader: (14)

Not that it matters much, but I question the origin of that carb. GM never put a 4-bbl on SBC 400's.

The TCC still locks? Are you sure about that?

Since you've taken out the carb and distributor the ECM controls, the only other thing it does is control the TCC. You don't have anything else to "disable", so what exactly are you thinking of doing to the ECM?

chevymad

Left it in and pulled the ses bulb. Trannys working same as always so I'll leave it be. According to the carb books at the napa where i work that carb number comes out as a 1978 400 sb in an elcamino. Or 75 or 76 350 or 400 chevy pickup. I think its the 78 because it has torx head screws. But could be wrong.