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car dies when clutch depressed comming to stop?

16K views 61 replies 26 participants last post by  lllpulselll 
#1 ·
please help me work out my last bug. ive tried idles at 1300-700rpm's, biss screw, dashpot and. it still happens. i can double clutch or goose the gas but i hate that shit. my car looks to good for this crap, dieing at lights, my god its embarrassing! i have to coast down the rpms and let out clutch at 1500 rpms. it will die or it sometimes dips to 200 rpm then right back to 1000 and holds like a rock. something to do with clutch or vac? im stumped.
 
#2 ·
dashpot fixed it for me. Could you adjust the dash pot out more and then re- adjust the BISS to get the idle down.
 
#5 ·
Didn't you just finish a rebuild? It sounds like you forgot to hook up a vacuum line, and or one came loose.
 
#6 · (Edited)
How many "trips" do you have on it?

The ECU (and I'm assuming you still have the ECU) takes several starts/run/stop/restart to find a happy IDLE....its even worse in some cars if you run OPEN LOOP....

Bob. :)

EDIT: AFTER a ECU reset....
 
#8 ·
How many "trips" do you have on it?

The ECU (and I'm assuming you still have the ECU) takes several starts/run/stop/restart to find a happy IDLE....its even worse in some cars if you run OPEN LOOP....

Bob. :)
thx bob, she idles where ever i want her to(700-1300). she just dies when im under a load and push in the clutch comming to a light. less than 10 trips and 110 miles.
 
#7 ·
i have a vaccum block for all my accesories. a dedicated line for each item:boostgauge,fpr,knockbox,bov,wastegates. there is no other vaccum nipple or hose to connect. i like it simple. also pressure tested and have great holding power. i ordered a new iac/fiav overnight for the am but, i tried cleaning the one i bought for it recently(less than 4years ago <10k miles) with a brush and it didnt change anything. so ive got my fingers crossed.

could be these 2 step colder plugs and the under 50degrees air temps so far this year. might just need to warm up, who knows at this point? ill make sure and post a solution for the sake of others that find this thread.(like i always try to do)
 
#13 ·
Is your BOV vented or recirculated? If it's vented, I'd be willing to be that's your issue. Either that, or it's crankwalk.
 
#16 ·
got the new fiav(oring and bolts) installed, no help! idle did go up a bit but still dies when clutch depressed. tried diff idle rpms and dashpot is out real far but will still closes. i never touched the tps it still has white marking to indicate its still in proper pos..

what is the connection between the clutch and idle? she idles fine but dies when pushing in the clutch. downshifting 3 to 2 she dies unless i double clutch. she dies when shifting from 2 to 1 if rpms are over 1300 when clutch depressed. up shifts are not an issue its just the above and, it sucks.
 
#25 ·
my piggyback(arc2) doesnt allow me to do that but ive tried lean ildes at 17.af and rich and she still does it. ive read a cause could be the rps flywheel but then why do so few have this issue?

have been reading alot of forums and it seem the only real solution is to up the rpms till it doesnt do it. today ill try that and hopefully after a few hundred miles the damn ecu will figure shit out and i can start to slowly bring the idle back down to 800ish.

stroker yes, same tune(15lb max boost) as td05's for the break in. others are ready to do at the push of a button. im starting to like my eboost2 ebc.
 
#24 ·
Wow i thought I was alone in this. My car does it too. She idles fine, runs awesome, but when coming to a stop she dies on me.

If I'm slowly coming to the stop and downshift she's fine, It's more when it's a fast roll downshifting to 2nd, as soon as i press down the clutch she dies.:confused:

BTW: '91 Stealth ES
 
#26 ·
well with rays help we ruled out crankwalk so its back to this thread. ive tried tightning my bov and no luck, will try looser when it stops raining.

also have a tuner friend that says since i deleted my a/c and have a larger plenum could cause the drop in vaccum when clutch pressed. his solution is to ground the a/c relay pin at the ecu so it will bump up the rpms when cluch pressed. anyone else do this?
 
#31 ·
power/preformance adders:
3sx tdo5 kit with ss headers,3sx terminator big ballers(50 trim t3/t4 tripple ceramic ball bearing) turbos,ss dumppipes,ss downpipe,tial external wastegates(1.0bar spring,leaded gas),high flow fuel filter,bigger fuel lines,fuel rail adapter,fuel lab fuel pressure regulator with guage. denso fuel pump hotwired(rdr method at the pump),kenne belle boost-a-pump,arc2 with big mas,2 arm(narrowband a/f)units,one per bank,k&n filter,720 denso injectors,rps cynergy segmented flywheel,spec stage 4+ clutch,dynamic racing stage 2 heads(ported polished, headlift fix by ray),ported polished lower intake,custom plenum with internal velocity stacks,huge fmic,ceramic coated fmic pipes 2&3 inch,e boost 2 ebc,j&s safeguard timing control box(individual cylinder knock control),prosport digital egt and a/f ratio guages,hand held halo hybrid datalogger,oil catch can,radiator breather tank,hks super seq. bov(recirculated),solid motor mounts,tc bracket,rear cusco strut bar,billet oil pump gears,stillen drilled rotors&pads,ss brake lines,caliper stiffening bolts,samco hoses,single shot cat back,no cats,magnacore 10mm silcone plug wires,2 step colder plugs,19 row oil cooler,a/c delete,cruise delete,power radiator,flexalite fans,3sx cam gears. oh and a brian crower billet steel crank kit from 3sx with 3sx rods and forged pistons with wrist pin upgrade 3.4l.

stock shit replaced since 2009:
oil pump,timing belt,tb tensioner,tb pully,tb hydrolic tensioner,tb covers,water pump,power steering pump, ps tensioner pully,ps belt,alternator,alt. belt,harmonic balancer, a shitload of bolts!

NEW IAC, NO CHANGE!
 
#28 ·
Again, it sounds like your ISO motor has gone bad because if the motor is cool-everything is running fine. But as soon that engine start to heat up a little, the contacts in the ISO motor will lose it continuity, thus causing it to operate when you press that clutch pedal in to come to a stop. There is thread about this problem concerning the ISO motor.
 
#30 ·
Have you ohm-tested the IAC even after cleaning it? If so, what were your results?
 
#33 · (Edited)
yuppers! like i said i can drive her but i have to pay attention as i have to push in the clutch, remove from gear and, let clutch out, while i milk the gas and hope i can stop with the ebrake if not and i dont think the ebrake will be enough i have to brake with right foot. if rpms have come down enough(below 1600) its fine, if i have to brake sooner the rpms will keep dropping and car stalls. bummer dude!
 
#34 ·
 
#35 ·
needs to be moved to my crank walk thread. it took me a minute to get it. at first i was like whats that doing here then after i left the computer i was like ohh.... got it. great post!:p j
 
#36 ·
My daughter and I have had the same problem, except when you get on it when it's cold, it will die and not start back. I finally figured out that it was partly our driving technique. I told her not to down shift-Cause brakes are cheaper and easier to change then clutches. So the car croaks on her the other night and I come to try to figure out what the heck is going on. I finally reason in my mind that the car is flooded(Fuel and fire just won't run). I pulled the fuse on the fuel pump hot wire and the car starts up almost instantly. She was getting on it hard then just pushing the clutch in causing to much fuel to be left in the engine. Now we down shift letting the fuel get cleared out(Verified this by watching the wideband). Problem Solved!
 
#37 ·
Are you running an aftermarket FPR? Because that doesn't sound right. You should be downshifting when coming to a stop as it's safer. When in a higher gear, the car just wants to keep moving. When you downshift, the car naturally slows down. Sounds like you have too much fuel pressure when you depress the clutch.
 
#39 ·
It was mentioned before but the lightweight flywheel seems to make mine do similar things. Trying to tune out a mechanical issue seems useless to me so I just blip the throttle before coming to a stoplight and it never does it. I think it may have to do with the rpm's coming down faster than they're supposed to and the ecu reacts too slowly to correst it. Simply pressing the throttle slows this deceleration and allows a smooth idle transition. Good luck to ya.

Jeff
 
#40 · (Edited)
I dealt with the same thing until I set my base idle timing and adjusted the BISS accordingly afterward. I think the "effects" were stacked with my lightweight pulley. My car still sometimes shuts off if I go into neutral after a third gear pull WOT. It does not exhibit this behavior in second gear pulls or if I shift into fourth after to coast.
 
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