4L60 VSS Code 72 cause surging?

[Vette40th]

I know its I have a code 72, and a fresh rebuild on transmission.. Transmission runs great and pulls through 4th gear behind my 396LT1. States gear selector switch circuit. Neutral safety sswitch part of circuit?
But at part throttle/cruise I get a slight surge. Engine is new, sensors are all new within engine, tuned by good reputable company, never any problems. But now I have this code, can it cause a surge with a 4L60?

[Vette40th]

One other symptom is imtermittent start. If i jump it fires right up. Battery is new and always on tender.

[SQUIRMIN VERMIN 84]

Originally Posted by Vette40th

I know its I have a code 72, and a fresh rebuild on transmission.. Transmission runs great and pulls through 4th gear behind my 396LT1. States gear selector switch circuit. Neutral safety sswitch part of circuit?
But at part throttle/cruise I get a slight surge. Engine is new, sensors are all new within engine, tuned by good reputable company, never any problems. But now I have this code, can it cause a surge with a 4L60?

My first guess is, are you feeling a downshift or actual surge? Tranny
problem or engine problem?
My 'expertise stops at 1984. I'd go back to the shop that tuned it and see
if they can check it over.
As for the intermittent start, does it turn over or just sit there? Do you hear the starter solenoid engage?

[Vette40th]

Originally Posted by SQUIRMIN VERMIN 84

My first guess is, are you feeling a downshift or actual surge? Tranny
problem or engine problem?
My 'expertise stops at 1984. I'd go back to the shop that tuned it and see
if they can check it over.
As for the intermittent start, does it turn over or just sit there? Do you hear the starter solenoid engage?

Its a surge for sure. I will datalog and check tune via tts and cats tuner.
The car has no clicking sounds at all when it intermiittently doesnt start. Same if you dont put clutch in on stick or are in gear when you try to start.

[SQUIRMIN VERMIN 84]

Originally Posted by Vette40th

Its a surge for sure. I will datalog and check tune via tts and cats tuner.
The car has no clicking sounds at all when it intermiittently doesnt start. Same if you dont put clutch in on stick or are in gear when you try to start.

With key ON, you should have a standing 12v on the feed side of your clutch
start switch and no voltage on the out going term UNTIL the clutch pedal is
fully depressed. Clutch pedal down and you should see 12v on both terms
of clutch switch. From there, it's off to your starter solenoid.

Hopefully you have a FSM for the car. The electrical schematics are VERY
useful!!!!

[Vette40th]

I do have the FSM, and TTS datamaster to log, and CATS to burn my chips. I will datalog tomorrow. And I will troubleshoot via FSM..
Hopefully I can find a smoking gun. It could be something simple..

[Vette40th]

Went out and data logged the car. When I am at converter lock up speed, 45-40 mph, it is where I am having surging, in my mind issues. It is the converter locking and my cam causing it to chug along and surge. Its a 230/236 544 555 114 LSA cam. Not huge, but kinda big and idles a little rough.
I am thinking I need to raise the speed for lock up and be done with it. I have a B&M stack cooler along with BeCool radiator internal cooler.
Thoughts?

[SQUIRMIN VERMIN 84]

No thoughts as I'm not familiar with your cam or setup. Have you tried
"the other place" such as C4 Tech/Performance or C4 Scan/Tune?

Other members, feel free to chime in. I know this thread is viewed...
(over 48 views)

[Vette40th]

Originally Posted by SQUIRMIN VERMIN 84

No thoughts as I'm not familiar with your cam or setup. Have you tried
"the other place" such as C4 Tech/Performance or C4 Scan/Tune?

Yel. Recommended 56 lock 50 off.. cam surge due to lope causes converter to buck driveline

[SQUIRMIN VERMIN 84]

Looks like you may have your answer in #7...

All Greek to me. I'm glad we were able to help you out..

[WW7]

When I installed my 383 with a bigger cam in my 89 Vette, I had the same problem..You could feel the cam surging at certain lower rpms in high gear with the convertor locked up , mine was always at 1100- 1150 rpms...I reburned my chip to set my high speed convertor lockup at 53 mph and unlock at 49 mph and the symptom went away... I'm also running a stock torque convertor, if my convertor had a higher stall speed like 2200-2400 I may not of had the problem in the first place.....WW.