Speed sensor??
Thread Starter
Staging Lane
Joined: Mar 2004
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Speed sensor?? I`m just finishing off LS1 into Ford(mercury)Capri install and I`m using a Tremec TKO11 5spd gearbox with Mcleod bellhousing etc. I`ve used a harness and modified ECU from Injection Specialties(Texas) which I shippped over here to the UK. They tell me I don`t need to use a vehicle speed sensor at all because I`m not using the T56 6spd. Does anyone know if that is correct? Surely the sensor is required for the ECU to sort out the various calibrations? Thanks for any help......Robert
From Jags That Run:
Basically, the VSS tells the ECM how fast the vehicle is going. Most people think the VSS is only used for the lock-up torque converter. The VSS is also used to control the EGR valve, the charcoal canister purge valve, the electric cooling fans, idle speed, and air/fuel ratio. This is all explained in the Chevrolet shop manuals.
It must be emphasized that the VSS is used to control the idle speed when the vehicle is moving. Without the VSS, a vehicle may have stalling problems under certain conditions. Needless to say, this is dangerous. Raising the minimum idle speed with the adjusting screw can eliminate stalling, but the engine will still not run optimally without a VSS.
Basically, the VSS tells the ECM how fast the vehicle is going. Most people think the VSS is only used for the lock-up torque converter. The VSS is also used to control the EGR valve, the charcoal canister purge valve, the electric cooling fans, idle speed, and air/fuel ratio. This is all explained in the Chevrolet shop manuals.
It must be emphasized that the VSS is used to control the idle speed when the vehicle is moving. Without the VSS, a vehicle may have stalling problems under certain conditions. Needless to say, this is dangerous. Raising the minimum idle speed with the adjusting screw can eliminate stalling, but the engine will still not run optimally without a VSS.
Thread Starter
Staging Lane
Joined: Mar 2004
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Thanks for that. I`ll make sure my ECM is still set up for the sensor. So every swap I see listed on LS1 tech should be using a sensor right? Irrespective of transmission? Am I asking for trouble by not using it?
Last edited by Uk Robert; Aug 12, 2004 at 02:56 PM. Reason: grammar
Teching In
Joined: Oct 2002
Posts: 25
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From: Tennessee
Originally Posted by Uk Robert
Thanks for the replys. Better get one fitted then!!
--Davey
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9 Second Club
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From: Norn Iron
I would enquire with the people who supplied your ecu, as they would know how its programmed.
I see no reason why that section of the ecu's control couldnt be removed from the programming, in the same way other features can.
Demon Tweeks sell speedo cable-electronic pulse convertors, for use with the TerraTrip equipment in rally cars. They may be of some use ?? Their just over £20. Or they also do some for the Brantz equipment, again in-line design, slightly dearer.
Pages 141-143 of the Motorsport catalogue.
Hows your car coming along ??
I see no reason why that section of the ecu's control couldnt be removed from the programming, in the same way other features can.
Demon Tweeks sell speedo cable-electronic pulse convertors, for use with the TerraTrip equipment in rally cars. They may be of some use ?? Their just over £20. Or they also do some for the Brantz equipment, again in-line design, slightly dearer.
Pages 141-143 of the Motorsport catalogue.
Hows your car coming along ??
Thread Starter
Staging Lane
Joined: Mar 2004
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I`ll remember that idea about twisting the wires together...could be useful. Injection specialties (reprogrammed my ECU)have now confirmed that in most cases the engine will operate better if the speed sensor is connected. Jags That Run do a reluctor wheel that goes on the prop-axle flange which could be another option. Budman 78, yes the Tremec does have a speedo fitting and I am going to speek to Tremec tonight(time difference!) to see if they do an electronic output for a Mustang which uses the same 8.8 axle as my Capri. Stevie turbo, project back on its wheels now, just fuel pipe and exhaust downpipe to do but my 3yr old son likes lots of playing so I don`t get to spend endless hours on the car anymore!! On top of all that I`ve sold my house so will be moving soon. Had to get suspension back on to make car mobile but it`s a huge morale booster to see it on it`s wheels again with engine/transmission etc in.
9 Second Club
Joined: Nov 2003
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From: Norn Iron
Mines still in the air....taking shape well though.
Got my new heads, fuel rails. Ordered bigger injectors, and wiring loom is pretty much sorted for my ecu.
Still having trouble getting the std coils to work though. I may just re-use the old bosch coils I had on the rover engine to make things easy.
Was actually very surprised the box fitted into the tunnel without any mods !!
Had to cut the crossmember though to make room for the sump, and alter the sump to clear the steering rack.
Also need a new anti-roll bar, the crank pulley wants to rest on top of the current one !!
Waiting on pics of some Holden manifolds to see if they are suitable. Clearance on the drivers side is very very tight with the steering. The cast ones almost fit, but the 3 bolt flange hits the UJ.
Hopefully mid-late october should see it running
Got my new heads, fuel rails. Ordered bigger injectors, and wiring loom is pretty much sorted for my ecu.
Still having trouble getting the std coils to work though. I may just re-use the old bosch coils I had on the rover engine to make things easy.
Was actually very surprised the box fitted into the tunnel without any mods !!
Had to cut the crossmember though to make room for the sump, and alter the sump to clear the steering rack.
Also need a new anti-roll bar, the crank pulley wants to rest on top of the current one !!
Waiting on pics of some Holden manifolds to see if they are suitable. Clearance on the drivers side is very very tight with the steering. The cast ones almost fit, but the 3 bolt flange hits the UJ.
Hopefully mid-late october should see it running
Does the VSS signal have to be correct, or can it just show the PCM the vehicle is in motion? How much does the Park and Neutral safety switch come into play with the idle and driveability issues?
Last edited by Lesrace82; Oct 4, 2004 at 07:20 PM.
Originally Posted by Swamper104
I was able to take the leads that would connect to the VSS and simply send them to a ground. This cured all my stalling and stuttering issues. Driveability seems great to me.
If you drove it with a proper VSS and its current setup, you wouldn't say that.
Originally Posted by Lesrace82
Does the VSS signal have to be correct, or can it just show the PCM the vehicle is in motion? How much does the Park and Neutral safety switch come into play with the idle and driveability issues?
I switched to a Th400 this year and a H/C setup. We have been having some probs getting the car to idle when coming to a stop and things like this. Now im wondering if the VSS has had something to do with this.
I switched to a Th400 this year and a H/C setup. We have been having some probs getting the car to idle when coming to a stop and things like this. Now im wondering if the VSS has had something to do with this.
Historically, the VSS signal for drivability doesn't need to be 40 pulse / revolution. They went to that for ABS and traction assist reasons.
As far as the correctness, you don't want to be totally out of the ballpark. If the PCM sees 55mph and you're doing 70mph, it shouldn't be a detriment to drivability. I wouldn't want it heavily off though. In other words, I wouldn't want to run a 4004 pulse per mile signal in a vehicle with a 40 pulse / revoluation requirement; that's a HUGE difference.
Add the TH400 VSS parts.
Thread Starter
Staging Lane
Joined: Mar 2004
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Budman 78, what exactly were you referring to with regards the old TPI engines? I much prefer that speedo housing adaptor idea. We have American parts specialists over here in UK who could obtain the part you refer to if I had more info and part numbers etc. Other people must have used speed sensors in an LS1 swap before.......what did they all use! Anyone got a definitive answer? I`ve got a few suggestions reading the above replys and I know that various reluctor wheels are available but surely there is a speedo houing adaptor suitable for a Tremec? By the way, Tremec were unsure of exactly what my application involved and suggested calling GM!
Originally Posted by Uk Robert
Budman 78, what exactly were you referring to with regards the old TPI engines? I much prefer that speedo housing adaptor idea. We have American parts specialists over here in UK who could obtain the part you refer to if I had more info and part numbers etc. Other people must have used speed sensors in an LS1 swap before.......what did they all use! Anyone got a definitive answer? I`ve got a few suggestions reading the above replys and I know that various reluctor wheels are available but surely there is a speedo houing adaptor suitable for a Tremec? By the way, Tremec were unsure of exactly what my application involved and suggested calling GM!
All of which (with 2002 and 4004 pulse per mile signals) is irrelevant to a Gen III swap.
Originally Posted by LS1swap
I don't run a VSS, and I have noticed no drivabillity issues?????
If you drove it with a proper VSS and its current setup, you wouldn't say that.
TECH Apprentice
Joined: Jun 2002
Posts: 319
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From: NH
Originally Posted by LS1swap
I don't run a VSS, and I have noticed no drivabillity issues?????Why does the PCM care how fast the car is moving with a manual trans?
Originally Posted by jmd
None of the TPI equipped GM cars had a cable to signal converter at the speedo cable. The cable speedo cars (f-bodies anyway) had a 2 pulse VSS in the speedo itself. The mechanical gear driven VSS's were 4 pulse. What he's probably talking about is the unit avail. from JTR or frankly a GM dealer that was used in certain year squad car Caprices which had a takeoff for VSS somewhere inline in the speedo cable. I don't know the details right now.
All of which (with 2002 and 4004 pulse per mile signals) is irrelevant to a Gen III swap.
All of which (with 2002 and 4004 pulse per mile signals) is irrelevant to a Gen III swap.