Vehicle Speed Sensor Issue

Wagonman · Post by **Wagonman** » Mon Oct 24, 2011 11:14 pm

Hey Guys,

Long story short.

I have recently converted my carby L series to EJ22. After that I had a few issues where the engine was in limp home mode, ecu controlled fan stayed on all the time. (with ign on) and it was bumping up the idle..

After some chatting and hard work with RSR 555 (Paul) with figured that it needed the vehicle speed sensor hooked up so the ecu knows how fast the car is going so it doesnt freak out. Being a carby L it had no VSS so we painstakingly put a EFI cluster with the VSS in it into my L. (look out for a 'how to' post later on possibly)

At the time as well as the vss code (33) getting a purge valve code (35) and coolant sensor code (21).. After replacing the purge valve just to get rid of the code, i erased the codes and all was sweet..

Then after driving for a about 10mins the Eng light (code 33, VSS) came back on, engine fan stays on and idle bumps up to 1k.

I put it into test mode briefly (green plugs together) then start her up n go for a drive and then about the same time later light comes back on etc etc..

My thought is a faulty VSS from the EFI cluster (not that im complaining about it, it looks great with the factory tacho and fuel light made into engine light

Was thinking of hooking an LED to the VSS wire and monitor its bahaviour and see when it flips out??

Any ideas anyone?? Don't hold back, even blame me i dont care i just need to sort it out

Post by **TOONGA** » Tue Oct 25, 2011 10:09 am

section 2.7 of the 92 liberty / legacy FSM ?

https://www.rapidshare.com/files/147158 ... Turbo_.pdf

I know it says fuel injection system but it has all the trouble shooting diagnostics for the sensors

TOONGA

RSR 555 · Post by **RSR 555** » Tue Oct 25, 2011 2:45 pm

John.. you'll need to plug both the green and black plugs in if you're trying to clear the codes.

But try and get the codes out of memory first (using the black plugs) and let me know all the codes.

Wagonman · Post by **Wagonman** » Tue Oct 25, 2011 9:01 pm

Well, i connected the black plugs and im still getting just code 33 for VSS.

Connecting just green plugs putting it into test mode (?) gets rid of the light until i start up and go again. I've been checking it and each time it comes back on after roughly 9mins.

The manual says that the sensor gives off 4 pulses (0-5v) per revolution of the reed switch. The code comes up if the received voltage is not right. Meaning its either a faulty speed sensor or the resistance in the wire we put in or somewhere in the circuit could be too high causing a voltage drop???

Post by **TOONGA** » Tue Oct 25, 2011 9:39 pm

have you tried clearing the code like this?

TOONGA

Wagonman · Post by **Wagonman** » Tue Oct 25, 2011 11:43 pm

Not yet..

When i cleared the codes originally i did it the 'battery dance" way.. Good point though.

Ill give that a go tomorrow seeing as it is the subaru specified way and see what happens.

Wagonman · Post by **Wagonman** » Wed Oct 26, 2011 10:29 pm

This time I checked the codes properly.. still getting code 33 for the VSS and then i cleared them properly and went for a drive. After about the same time as every other time the engine light came back on. POOP!

Next i guess ill try test the speed sensor and its circuit according to the manual.

Post by **TOONGA** » Thu Oct 27, 2011 8:07 am

Remember that the resistances out lined are for the harness from the liberty/legacy so your results may differ.

TOONGA

RSR 555 · Post by **RSR 555** » Thu Oct 27, 2011 4:37 pm

TOONGA wrote:Remember that the resistances out lined are for the harness from the liberty/legacy so your results may differ.

TOONGA

Can't see it being a resistance issue as we used the old ECU wiring you left at the shop. My guess is you got a dodgy secondhand dash cluster.

guyph_01 · Post by **guyph_01** » Thu Oct 27, 2011 4:49 pm

I've got one that comes from a carby touring wagon and with tacho. Not sure if its got that integrated speed thing tho.

Wagonman · Post by **Wagonman** » Fri Oct 28, 2011 1:28 am

Well i gotta check it anyway just to confirm if its a dodgy cluster or a resistance issue how ever unlikely it is. In the event of a cluster being dodgy id either have to find another cluster or get a sensor put inline..

Guy, ill get in contact soon and have a look.. umm Dibs lol.

Post by **TOONGA** » Fri Oct 28, 2011 8:46 am

RSR 555 wrote:Can't see it being a resistance issue as we used the old ECU wiring you left at the shop. My guess is you got a dodgy secondhand dash cluster.

sorry I left out the cluster components could have different resistances to the liberty/legacy specifications (another reason I want an AU delivered FSM pdf)

If the cluster is dodgy I can get you a credit for it

TOONGA

RSR 555 · Post by **RSR 555** » Sat Oct 29, 2011 4:18 pm

IMO, they should be the same as they both use the same system inside the cluster. The resistance is only in the wiring and/or connections, which is what the manual is trying to diagnose. The other thing that comes to mind is original wiring loom was in Guyph's car (but again I don't think the VSS wire was hooked up) but maybe there's an issue with the ECU? Have you tried another one John?

Wagonman · Post by **Wagonman** » Sat Oct 29, 2011 5:49 pm

This is first for me in terms of checking resistances but shouldnt their be very minimal resistance through the wiring.. So basically if there is 'some' resistance it'll be a problem?

I have not tried another ECU.. I have the ECU that came out the liberty that the engine came out of. It had a 3 plug loom but Guys is a 2 plug loom.. Is the ECU be the same between the two?

guyph_01 · Post by **guyph_01** » Sat Oct 29, 2011 7:48 pm

yeah i think the ECU are the same even with auto or manual.

When the loom was in my car it would make the fans stay constantly on until i hook it up with the speed sensor wire. I remember there were two types of looms with different colour wires for the speed sensor. Mine was a 4 plug instead of a 3 plug EA ECU. Maybe you hook it up to the wrong one?? how many plugs did the car you got the cluster from had?? Have a look at my link below

showthread.php?t=18159

Hope it helps:)

Post by **TOONGA** » Sat Oct 29, 2011 9:27 pm

The other way to set up a VSS is like this

showpost.php?p=170742&postcount=270

yes it was for cruise control but it would still do the same thing

TOONGA

Wagonman · Post by **Wagonman** » Sun Oct 30, 2011 1:00 am

So you could just get a magnet and a generic pulse generator to send that signal to the ECU?

Ill keep that in mind.

Im gonna see if i can get time to throw in the other ECU i have and see what happens..

RSR 555 · Post by **RSR 555** » Sun Oct 30, 2011 11:59 am

Wagonman wrote:So you could just get a magnet and a generic pulse generator to send that signal to the ECU?

Ill keep that in mind.

Im gonna see if i can get time to throw in the other ECU i have and see what happens..

I'd make sure it's not generating a pulse/current as the ECU only requires a earth trigger.. adding any sort of current to your ECU will cause concern.

Post by **TOONGA** » Sat Nov 05, 2011 1:50 pm

found this in Bennies thread as well

showpost.php?p=125815&postcount=94

seems the VSS wire is a very similar colour to the vortex wire

TOONGA

YouTube · Post by **El_Freddo** » Sat Nov 05, 2011 10:45 pm

I thought all L series instrument clusters had the reed switch built into it, the problem was working out where to tap the wire in from the EJ ECU to make it work.

I drove my EJ for a while without the VSS connected and didn't have any of the problems you describe there - which makes me think that there's something else at play here.

I'd also look into the Air Idle Control Valve to make sure it's operating correctly, then check the Throttle Position Sensor is setup correctly and getting the correct voltage. Also check for any vacuum leaks as these will do funny things to the idle speed, it could be a loose, cracked or disconnected hose somewhere...

Also are you sure that the other side of the reed switch is connected to something that will complete the circuit? I only remember having one wire for the VSS on my conversion.

Cheers

Bennie