resident twEECer guru...

Hey all,

Just starting to get back into things after about 18 months away from stang'dom...

Is it true that there is/are now tweecer gurus on the site here?

Reason I ask is before I went away from the stang obsession, I fought a deceleration idle issue on my 90 for about a year and could never get it worked out.

(most mods in sig, basically a 306 24# CnL h/c/i car, A9L)

On decel if I was steady state throtle or light acceleration and went clutch in, it would drop to an idle just fine as I came to a stop. If I was actually throtle full closed on decel and went clutch in, the damn thing would die upon coming to a stop. If I jacked the IAC decay rate way up, it would hold, but of course then I would get the dreaded hanging idle problem...

Any ideas, or at least anyone willing to help me think through it, if I get off my butt and get the car driveable again?

If we have an "expert" ( uh-oh, he used the E word... ) to pester with questions, I might actually try to take up the battle again.

(I still have the car, but it's sat for over a year... yeah I know, I have to drop the tank, flush the lines, etc... don't remind me)

Thanks,

Dave

No I don't have another MAF.

( I did clean the maf wire... several times, in case it was coated with crud but no change )

I also-
cleaned the IAC valve, multiple times
reset the idle, multiple times
reloaded and retuned the MAF curve twice
replaced the IAC solenoid
removed and reinstalled the TB (70mm acufab) looking for vac leak
removed and reinstalled the upper intake, twice looking for vac leak
disconnected and reconnected the 10 pins (3-4 times)
had the injectors flushed (was running 19s with sky high fuel psi)
replaced the injectors with 24s (lowered fuel psi to reasonable levels... 38-40psi at idle if memory serves)
reloaded the base tune and retuned the entire program from scratch (fuel, timing, everything...)

I have run with adaptive enabled and adaptive disabled both, it still does it.

Again any help would be greatly appreciated.

I love my ride, I really do... but it just got to where I couldn't bear the thought, of another weekend spent fighting with it.... ya know.

Thanks fellas,
Dave

no codes

vac leak? see above... checked and rechecked multiple times.

x3z sigh, oh goodie... reprogram everything from scratch - again.

I mean damn guys... thats like 6 weeks worth of work to build a complete tune. ( tune, datalog, download & analyze logs, crunch numbers, make a change, repeat the sequence... about 50-60 times ) Frack.

I dont supoze anybody has a TF Track Heat top end on a 306 (TF stage 2 cam if poss...it's similar to my Lunati), and would be willing to share their numbers for comparrisons sake?

vristang said:

I don't think you have a tuning issue... After reading through this again, it sounds more like standard efi troubleshooting will help you more than messing with the tweecer... at this point anyway...

Are you getting any Diagnostic Trouble Codes?

Click to expand...

No trouble codes...

And I was a ASE cert tech in f.i. & eimssions cont. for several years before going in the military, so if it's basic troubleshooting... I'm stumped.
( my kingdom for a Sun engine analyzer )

Like I said, I fought this same problem for well over a year (before I finally gave up).

So what would you suggest I look at for a possible cause?


Remember now it ONLY does it on closed throtle deceleration to clutch in, when you come to a stop it dies.
Steady state throtle or accelerating, go clutch in to a stop and it will idle fine.