I recently purchased a 58mm TB(portmatched it the plenum)and AZ.S&M runners(portmatched them to the plenum). This was my 1st disassemble/re-assemble by myself. I'm having trouble getting it to idle correctly (backfires,erratic idle, etc.). I double checked all if the sensors to ensure they were plugged in correctly. I made sure all of the vacuum? lines were attached. The new TB had the idle screw all the way out. I tried adjusting it after the TPS. Any suggestions on wich to set 1st? Do I need any special diag. tools for the TPS? Thanks, Daniel U

 

Does it idle high?
Did you check for vacuum leaks?
I don't know about AS&M runners, but on SLP runners it's possible to install them on the wrong side of the intake and have a huge vacuum leak. Don't ask me how I know that.

Did you reset the IAC contol motor?

I'm not sure if the MAF will compensate for all that extra air flow you now have. You might need a bin change.

 

When I had idle problems, I set the IAC and base idle first, then adjusted the TPS accordingly with a multimeter using the tech articles on here ....

 

Hi,

Kinda big TB for a 350 unless highly modded.

Buy or borrow a digital voltmeter, don't need an expensive
one. 20-30 dollars.

What I do is take off ducting, open blades and stick fairly
thick piece of paper in, set screw, to close blades all the
way. Adjust set screw to where you can just pull paper out,
lite pull.
Top two wires on TPS plug are where the meter probes
go into. Sensor plug needs to be plugged in. I use two needles taped onto probe ends and stick them into wires
for good contact and free up my hands to adjust tps.
Loosing up the two torqex screws slightly on tps so it will
hold position while adjusting.
Key on but don't start to check or adjust.
On yours believe idle setting are .540 volts and 4.00 or more at WOT.
Just my way of doing it
Might check to see if IAC is clean and working also.

HTH

Later

 

Yup, no vacuum leaks. The runnersare on the correct side. I blocked off the 9th cold start injector and burnt a prom to compensate. I may hook up the laptop tommoro if my buddy makes it over. Where is the IAC motor located? BTW I still have the stock base intake. I only bought the 58mm TB and runners for the future 383 motor. I took the previous polished plenum/runners/TB/etc. and put in on my '54. The cast runners/TB/and plenum will lend to the "stock" appearance I'm looking for. Thanks, Daniel U
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Thanks, I check it out....

 

The bigger TB/runners will help me out later. I hope that I'll be able to tune it for the stock L98. I have Craig Moates software for PROM burning, I just need to learn about it. My buddy Jason should be by tommoro with the voltmeter. Thanks for the settings. I'll try to get back on here tommoro if I get her to idle. BTW, the car fires, but revs high and then dies. Daniel U