Not running VSS = engine dies?
03-08-2010, 03:31 PM
#1
Not running VSS = engine dies? I've got a transplanted 02 LQ9, DBW, originally came with an auto trans, in my 68 vette. I'm running a Richmond 6 speed manual trans without a VSS. I told my tuner that, he eliminate VSS so no code. I also mentioned that I had read cars would die at idle without VSS signal. He indicated that was mostly in cars with auto trans.
Now that I've run the car I've had the engine die a couple times when I'm going over 60 in high gear and depress the clutch for an extended time, ie braking to a stop, not when just downshifting.
Is there a computer "fix" to prevent this? Any suggestions or comments appreciated.
Now that I've run the car I've had the engine die a couple times when I'm going over 60 in high gear and depress the clutch for an extended time, ie braking to a stop, not when just downshifting.
Is there a computer "fix" to prevent this? Any suggestions or comments appreciated.
03-08-2010, 06:22 PM
#2
I'd heard this but never proven it. The way it was explained to me is the computer needs to simply know the car is or isn't moving, not the actual speed.
I think the option to display the check engine light may have been turned off, but the need for speed information is still embedded in the background code. I have been told there are a lot of things like this that can be disabled but are still active even though they don't throw a code.
Had you thought about getting one of those speedo adapters and wiring it in?
This is just info I have gathered, I am not a PCM programmer.
I think the option to display the check engine light may have been turned off, but the need for speed information is still embedded in the background code. I have been told there are a lot of things like this that can be disabled but are still active even though they don't throw a code.
Had you thought about getting one of those speedo adapters and wiring it in?
This is just info I have gathered, I am not a PCM programmer.
03-08-2010, 08:11 PM
#3
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without a vss signal, the computer wont know the car is moving and wont get out of its idle tables. you should look into getting a vss installed. dakota digital has them. is there a provision for a speedo cable, because thats all you need for the vss.
03-08-2010, 10:01 PM
#5
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I doubt it, the vss signal is a pulse, from what I understand. I don't think there is any way to create a sine wave pulse without using a speed sensor. I am sure the trans has somewhere for a cable type speedo, if it does, then Dakota Digital has a sensor that will work great for you.
03-09-2010, 02:17 AM
#6
TECH Resident
03-09-2010, 05:26 AM
#7
PS Tell your tuner that stick shifts have a lot more issues when not running a VSS, then automatics ever will
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03-09-2010, 07:47 AM
#8
I didn't realize it was that cheap and easy. I'll order one today.
Thanks all!!!!!
Thanks all!!!!!
You're defeting the purpose of what you're trying to do, since ifyou have a constant pulse it will never take over the idle functions, you would at least, have to make the pulse stop, when you step on the bake pedal. Just buy an aftermarket pulse generator for under $40 and put it in the speedo cable. Why do people alway take the hard way to try to defete, something, they could easily correct the right way?
PS Tell your tuner that stick shifts have a lot more issues when not running a VSS, then automatics ever will
PS Tell your tuner that stick shifts have a lot more issues when not running a VSS, then automatics ever will
03-09-2010, 11:04 AM
#10
Another thumbs up for dakota digital vss, SEN-01-4160 http://www.dakotadigital.com/index.c...rod/prd109.htm
My 70 vette has a 2 piece speedo cable, one from the trans to firewall and firewall to speedo, you could mount the vss there is it didn't fit on the trans.
My 70 vette has a 2 piece speedo cable, one from the trans to firewall and firewall to speedo, you could mount the vss there is it didn't fit on the trans.
03-09-2010, 12:22 PM
#12
Another LS vette on this board...excellent.
My 68 vette build thread.
https://ls1tech.com/forums/conversio...eed-build.html
My 68 vette build thread.
https://ls1tech.com/forums/conversio...eed-build.html
Another thumbs up for dakota digital vss, SEN-01-4160 http://www.dakotadigital.com/index.c...rod/prd109.htm
My 70 vette has a 2 piece speedo cable, one from the trans to firewall and firewall to speedo, you could mount the vss there is it didn't fit on the trans.
My 70 vette has a 2 piece speedo cable, one from the trans to firewall and firewall to speedo, you could mount the vss there is it didn't fit on the trans.
03-28-2010, 07:16 AM
#13
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I can always tell on my setup when the PCM is not getting a speed signal, just push the clutch in a speed and the engine sags. There is a ton of PCM progamming that relies on speed/rpm so I would recommend getting a somewhat real speed input into your PCM. I used the Dakota product and it worked great until I swapped in a GM automatic and don't need it any longer.
04-04-2010, 08:41 PM
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I sent my ecm to wait4me performance because I am running a th350 with a 5.3.He tuned my computer to have no transmission input and I have no stalling issues.
04-05-2010, 08:49 AM
#17
Wait4me did my computer too. He left the VSS functioning, he just disable the VSS error code from being sent. He did that because stalling without VSS is fairly frequent and he didn't want me to have to send the computer back.
Simply adding the DD 8k ppm VSS, eliminated thr stalling problem. The VSS will support a cable driven or aftermarket cruise control. It will not support the DBW cruise control. That uses the stock 100k ppm VSS. Ive heard from other that the computer can be retuned down in the 8k ppm, and some others say no.
DD does sell a converter, but I'm not sure if it will work with this setup. still looking into that.
Simply adding the DD 8k ppm VSS, eliminated thr stalling problem. The VSS will support a cable driven or aftermarket cruise control. It will not support the DBW cruise control. That uses the stock 100k ppm VSS. Ive heard from other that the computer can be retuned down in the 8k ppm, and some others say no.
DD does sell a converter, but I'm not sure if it will work with this setup. still looking into that.
