TPI users.....
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
You need a VSS of some sort to make the system work properly. Look in the GM-ECM section at www.diy-efi.org for more info.
Le Mans Master
Joined: Jul 2001
Posts: 9,622
Likes: 16
From: absecon nj
yes use the vss,the vss controls alot of functions,i just recently swapped from the stock one to a painless wiring one.
Heres an excerp from chevy thunder
You must be able to use the VSS (vehicle speed sensor) with your tpi setup, even if you don't use a overdrive transmission. The VSS is needed because many tpi functions are directly related to it, such as idle speed and A/F ratio, etc. There are aftermarket suppliers such as B&M that has a speed sensor kit so you can use the VSS.
Don't count on top performance from your TPI without it.
Heres an excerp from chevy thunder
You must be able to use the VSS (vehicle speed sensor) with your tpi setup, even if you don't use a overdrive transmission. The VSS is needed because many tpi functions are directly related to it, such as idle speed and A/F ratio, etc. There are aftermarket suppliers such as B&M that has a speed sensor kit so you can use the VSS.
Don't count on top performance from your TPI without it.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Yes, you need VSS. You may have stalling problems coming to a stop without it. You can get them from Howell, Street and Performance, Painless (Jegs/Summit), Jags That Run, Fuel Injection Specialties, Etc.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Originally Posted by toyvet1
I have a Howell harness in the car now without it. I'll have to get ahold of them and find out how to update the harness for one....
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
I'm not sure what happened to the page - I'll see what I can find out. Personally, I wouldn't eliminate the VSS - it's there for a reason - if the job could be done better without it, it wouldn't be there.
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Burning Brakes
Joined: Sep 2002
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From: SF East Bay CA
Last edited by timbo79; Jan 24, 2005 at 12:22 AM.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Originally Posted by patsnitrovette
Just remember theres 2 different vss's for tpi,youll need to know your year.
Speed-Density is 4000 pulses per mile as is LT1 and Throttle-body
Instructor
Joined: Jan 2005
Posts: 235
Likes: 1
From: West Seneca New York
I have a couple of questions about TPI in a C3 myself.
My vette is an '81. I'm gathering all the parts and pieces for a TPI system for my car. The question is, am I better off getting a tank and sending unit out of an '82 crossfire injected vette?
Or would it be safe to use an inline pump and put a return line in the existing sending unit and use the original tank? I'm just worried about fuel starvation problems.
Thanks in advance. Darryl
My vette is an '81. I'm gathering all the parts and pieces for a TPI system for my car. The question is, am I better off getting a tank and sending unit out of an '82 crossfire injected vette?
Or would it be safe to use an inline pump and put a return line in the existing sending unit and use the original tank? I'm just worried about fuel starvation problems.
Thanks in advance. Darryl
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Originally Posted by patsnitrovette
youshould be able to put a 82 sending unit in yours with the right pump and use your existing lines if there in good shape.You should use 3/8 feed and 5/16 return.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
If anyone is interested, the diy-efi page seems to be alive and kicking again. The GM-ECM section has a lot of info on modifications/retrofits of factory GM fuel injection.
Instructor
Joined: Jan 2005
Posts: 235
Likes: 1
From: West Seneca New York
Thanks guy's. I will check in the diy-efi section.
If I can get away with just the sending unit/pump assy. that would be great. I see that '82 tanks are hard to get due to the sump inside and nobody repro's them. And they are also pricey.
Darryl
If I can get away with just the sending unit/pump assy. that would be great. I see that '82 tanks are hard to get due to the sump inside and nobody repro's them. And they are also pricey.
Darryl
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
I have a tank and sending unit but it will be expensive to ship.....too bad.
As for the VSS issue, why not install a GM one, all 82 & 81 vettes have a VSS screwed into the back of the speedo (it's an optical emitter & sensor combo that shines into the back of the speedo, then a rotating mirror - conencted to the drivecable - spins and the optical sensor pics up the signal), all TH350C (lockup) cars have one also. It's a blue or yellow box with a small flat cable on it w/ green, black & a brown wire.
Here's the wires:
back of cluster, VSS clearly visible:
optical emitter/sensor
screws into this: if yours down's have a threaded hole use a self tapping screw
Here you can see the mirror "rotor" part
As for the VSS issue, why not install a GM one, all 82 & 81 vettes have a VSS screwed into the back of the speedo (it's an optical emitter & sensor combo that shines into the back of the speedo, then a rotating mirror - conencted to the drivecable - spins and the optical sensor pics up the signal), all TH350C (lockup) cars have one also. It's a blue or yellow box with a small flat cable on it w/ green, black & a brown wire.
Here's the wires:
back of cluster, VSS clearly visible:
optical emitter/sensor
screws into this: if yours down's have a threaded hole use a self tapping screw
Here you can see the mirror "rotor" part
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
What's hard about installing that? You lower the column a but, don't need to lower it to the seat, just undo the 2 bolts a bit then remove the cluster, it's a couple of screws a speedo cable and a harness connector. Can be done in say 15 minutes.
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Mine was a pain in the ARS to reinstall with mech speedo and tach not to mention all the little dash bulbs that seem to wiggle free plus I must have pinched the headlight switch hoses because it worked when I tested it before putting the dash on and then the lights did not come up after it got it together. 