3.6 liter conversion stalling at low speeds

[rcollins2867]

recently completed 1985 Chassis with a 1997 3.6 liter conversion, the car stalls at low speeds, anyone having the same issue, if so have any ideas as to how to solve the problem....Help would be greatly appreciated.....rcollins2867@yahoo.com

[VincentVega]

Did you install a chip to work with the lightweight flywheel?

[rcollins2867]

I guess I didn't will stop the stalling problem......

[POVI]

Hi I had good luck with the Centrix chip ..bought from instant G .. no problems with it !

Joe

[Moses]

Originally posted by rcollins2867
I guess I didn't will stop the stalling problem......

Absolutely. The stock program cuts fuel at idle. The heavy stock flywheel keeps the motor turning. You need a new chip in your DME. I'm using a Cyntex chip from Timmins and it works perfectly.

[MuffinMan]

I don't believe you need a special chip in the 993 engines to prevent the stalling. I also seem to remember Bill Verburg say that he used the stock 964 chip with a lighter flywheel & never had any issues.

[3.6 911]

while it possible to use the stock chip, the engine will more times than not stall when the revs are coming down. the stock chips assumes there is more mass (in the flywheel) to keep the engine turning. a custom chip like the cyntex chip offered by instant g will solve this problem as it takes the lightened flywheel into account.

[einreb]

Originally posted by MuffinMan
I don't believe you need a special chip in the 993 engines to prevent the stalling. I also seem to remember Bill Verburg say that he used the stock 964 chip with a lighter flywheel & never had any issues.

Its my understanding that the engine management system on the varioram engines can handle the lighter flywheels without being chipped.

I would first make sure that you have the normal culprits ruled out. O2 sensor working? CHT to spec? Vacuum lines ok?

Is it just at startup? when cold? all the time?

my 964 3.6 and lightweight rs flywheel stalled like a sonofabiatch. it turned out that i had BOTH a vacuum leak and a fault wire to my O2 sensor.

-bernie

[k9handler]

I have the original chip and every once in awhile it will die under hard decel. After some time you learn to tap the throttle at the right moment and it's no longer an issue...or I guess buy the chip.

QUESTIONS: How much are the chips from Timmons? Are they for both 993 engines with/without Varioram?

[911teo]

Hey
careful with the chips from Cyntex. I am sure that Steve Timmins will tell you but they used to have a problem when running hot. They would cut in at 6,200 rpms. Very annoying, especially at the track.
As far as I know the problem would occured randomly and would not affect all the chips.
My chip was affected so Steve Timmins swapped my Cyntex with another one (the one that was in his race car) and the problem was cured.

Smitty the chips were $575.

[k9handler]

thanks, that is a good price from what Ihave seen...although I would rather have a "No Bad Dayz" chip produced. hint hint (Mikez)

[scca_ita]

I would check for vacuum leaks and make sure the idle stablizer is working properly. Maybe clean it out to make sure it is not fowled.

[Bill Verburg]

I have or have had 3 different 964/993 engines w/ l/w flywheel. None have stalled(well the 3.8 is prone to stalling all the time when cold). I would look for either a vacuum or electrical switch issue.

also be sure that the ISV is clean and functiong

[Jim Williams]

I don't know how much of my experience with a 964 ('92) transplant into a 911 SC would be applicable to the 993 transplant. I retained my A/C in the SC, and when it was operating, I had problems with stalling when the RPMs dropped quickly off at a stoplight. I had a lightened flywheel and a Cyntex chip.

I researched this problem *a lot*. I determined that the 964 DME had inputs from the heater-A/C control box that told the DME box that the A/C was on. The DME then did *something* to amiliate the problem (I never found out exactly what as people who know these units don't want to share information). My guess was timing adjustments as well as possibly adjustment of the ISV.

I did figure out, however, the DME pin numbers affected, and what the heater - A/C inputs should be to help the stalling problem. I can say that the problem went away after I made the changes. I initially wired the changes in with switches so I could easliy disconnect the changes if I had problems, but I left the switches closed.

If anyone is interested in what I did, I'll be glad to explain what I found and post the wiring mods here.

[einreb]

Originally posted by Jim Williams
If anyone is interested in what I did, I'll be glad to explain what I found and post the wiring mods here.

Thats a very useful thing to post if you can. I'm not having the problem anymore, but it would be good for the 'knowledge base'. Maybe start a new thread.

-bernie

[Joeaksa]

Am using the No Bad Dayz chip in my 964 and it works very well. Also it allows you to switch from the modded chip to the stock chip with the flip of a switch.

JoeA

[k9handler]

rub it in Joe. lol

[Joeaksa]

HD, considering that I am 8100 miles away from my car, bet you are having more fun with yours than I am!

Have a real weitzenbier for those of us who cannot!

Joe A

[k9handler]

ok Joe...will hit the walk platz tonight and drink a few. BTW my car is broken at the moment...need to stop driving it like I stole it I guess. =o)

[Bill Verburg]

I really think that the stalling issue is more related to ISV sticking or malfunction or vacuum leaks or electrical faults than any thing else.

I have made both of the ISVs adjustable

on the 3.8 i can adjust it to idle well cold buut then it idles fast when hot or idle well hot then stall when cold

on the relatively stock '95 no stalling issues but it idles @ ~800 w/ a fresh battery charge droping to 600 or so after the battery gets used a bit. RS pulleys in both cases.