VSS with TH350 question (Urgent!)
Thread Starter
TECH Apprentice
Joined: Oct 2013
Posts: 350
Likes: 25
From: North Shore MA
VSS with TH350 question (Urgent!) Heres a question that's been asked a thousand times, but I still seem to get different answers. I need a straight answer, the car isn't much fun driving right now and I want to put some miles on it!
Heres the run down on the car:
69 Camaro
02 LQ4
TH350W/2800 stall
3:08 rear gear
27" tall rear tire
Heres the issue:
During deceleration the car acts like its searching for an idle. It never dies, but searches hard for a second before it'll catch itself. I don't have a VSS. I've read multiple threads where people don't use them and are fine.
Now....
I've contacted a sponsor on here about getting my car dyno tuned. I've called twice with no answer, so I sent an email with my phone number and my info. I got a 2 sentence response saying that I need a VSS. Nothing more in depth, no phone call, nothing. Keep in mind these are people I'm trying to spend my money on. I contacted another local dyno shop and they said they can tune it but they cant get to it until late August.
Now the million dollar question: Can you dyno tune this symptom out or is it truly the result of not having a VSS?
Would a mail order tune from one of our sponsors get it done?
Thanks guys
Heres the run down on the car:
69 Camaro
02 LQ4
TH350W/2800 stall
3:08 rear gear
27" tall rear tire
Heres the issue:
During deceleration the car acts like its searching for an idle. It never dies, but searches hard for a second before it'll catch itself. I don't have a VSS. I've read multiple threads where people don't use them and are fine.
Now....
I've contacted a sponsor on here about getting my car dyno tuned. I've called twice with no answer, so I sent an email with my phone number and my info. I got a 2 sentence response saying that I need a VSS. Nothing more in depth, no phone call, nothing. Keep in mind these are people I'm trying to spend my money on. I contacted another local dyno shop and they said they can tune it but they cant get to it until late August.
Now the million dollar question: Can you dyno tune this symptom out or is it truly the result of not having a VSS?
Would a mail order tune from one of our sponsors get it done?
Thanks guys
Thread Starter
TECH Apprentice
Joined: Oct 2013
Posts: 350
Likes: 25
From: North Shore MA
Thread Starter
TECH Apprentice
Joined: Oct 2013
Posts: 350
Likes: 25
From: North Shore MA
I didn't build this standalone harness and I don't think they left the pin for the VSS at all. I could pin it back in I guess.
Thread Starter
TECH Apprentice
Joined: Oct 2013
Posts: 350
Likes: 25
From: North Shore MA
Oddly enough the car runs amazingly well, it just acts up during deceleration. Gas mileage is great.
I'll check tomorrow and see if they removed the pin for VSS. IIRC its pin 50 on Red.
If I was to re-pin the VSS back in, could I use the Dakota Digital VSS they offer that installs between the speedo cable and trans? Its an 8k pulse generator.
I'll check tomorrow and see if they removed the pin for VSS. IIRC its pin 50 on Red.
If I was to re-pin the VSS back in, could I use the Dakota Digital VSS they offer that installs between the speedo cable and trans? Its an 8k pulse generator.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
I ran the Dakota Digital VSS generator on my 87 swap and it worked fine. You have to tune the pcm with the correct signal and put in the correct pulses per mile so the pcm see's the actual speed the vehicle is traveling.
First, everyone has different versions of "fine." I wouldn't take someone's word that their car "works fine" without a VSS, they may simply have a higher tolerance for things like that. I have very little.
The root of the problem is the PCM needs to know the vehicle is or isn't moving. If the vehicle is moving, execute this, if it's coming to a stop or stopped, do that. The "this" and "that" have to do with idle speed and how the PCM adjusts for and predicts what the engine needs to keep it from stalling coming back to idle. Depending on your setup (cam, heads, etc.) this may be more or less exaggerated than a totally stock engine.
Since you now understand why this happens, the solution is to install a VSS sensor to vehicle detect movement. It does NOT have to be speed accurate since you aren't using it for shift points, it only needs to work for the idle routines. The simplest is probably a Dakota Digital SEN-01-4160 (or similar) pass through speed sensor. This will allow you to keep your mechanical speedometer in your 1969 Camaro and send a signal to the PCM that you're moving or not. Best part, the sensor is less than $45 from Summit.
The root of the problem is the PCM needs to know the vehicle is or isn't moving. If the vehicle is moving, execute this, if it's coming to a stop or stopped, do that. The "this" and "that" have to do with idle speed and how the PCM adjusts for and predicts what the engine needs to keep it from stalling coming back to idle. Depending on your setup (cam, heads, etc.) this may be more or less exaggerated than a totally stock engine.
Since you now understand why this happens, the solution is to install a VSS sensor to vehicle detect movement. It does NOT have to be speed accurate since you aren't using it for shift points, it only needs to work for the idle routines. The simplest is probably a Dakota Digital SEN-01-4160 (or similar) pass through speed sensor. This will allow you to keep your mechanical speedometer in your 1969 Camaro and send a signal to the PCM that you're moving or not. Best part, the sensor is less than $45 from Summit.
Thread Starter
TECH Apprentice
Joined: Oct 2013
Posts: 350
Likes: 25
From: North Shore MA
I know what the VSS does, but most seem to not have any issues with the idle hunting around without one. I have no issue pinning it back in, was just confirming that the issue is in fact not having a VSS.
I still don't know why Slohawk never called me. I guess they have some serious cash flow coming in, they don't need mine.
I still don't know why Slohawk never called me. I guess they have some serious cash flow coming in, they don't need mine.
The result of no VSS is hit or miss. I've been told by others that theirs ran perfect without a VSS with manual trans. But on both my 02 and 05 I could reproduce the stalling issue almost every time when depressing the clutch and coasting to a stop.