vss dash problems for ej swap

[Zippy310]

Ok so some back story, I have searched the webs and many forums for this problem, I have a 1988 subaru gl with a ej22 phase 2 engine in it from a 99 impreza. I then turbo'd it and it runs fantastic at 8 pounds of boost, UNTIL, limp mode happens. Now I have gotten a dash cluster which I think is compatible but it's from an 87 DL auto, which i thought had the reed switch thing I needed for the impreza's ecu to be happy, apparently not. So my question is what am I doing wrong, is the cluster not compatible or is it simply im not wiring it right, because a lot of people say to use the cruise control, but i have no longer  have the cruise control and/or wiring thinking I wasn't going to use an oem style speedo. Please help, even though it's probably been answered many times 

[Numbchux]

I've not seen an EA82 cluster that couldn't supply a VSS signal (I did one into a carbed '86 wagon years ago that I'm almost positive had the factory cluster in it). Certainly anything fuel injected would use it.

Sounds more like boost cut.

[Zippy310]

Ok so the cluster isn't the problem, but which wires do I use for the vss signal then because I hooked it to a multi meter with many different wire combos, and everybody has said to use the yellow/red and black, but the multimeter didnt change in resistance nor did it change in voltage, and it isn't boost cut because it did it before when i drove it n/a

 

Edited August 12, 2019 by Zippy310

[Numbchux]

It's been an awful long time since I paid any attention to an EA82 wiring diagram, so I don't remember. It was well-labeled on the diagrams, though.

Being a reed switch, it'll be pretty hard to read it with a multimeter (might read AC voltage while spinning the cable). 

[Zippy310]

Well if you have any info about it, I would greatly appreciate it, but I haven't seen any of the wiring diagrams that look like this dash, I always find the older ones like 83,84 and such

[FerGloyale]

Why did you get rid of the 88 dash?  DL dash has no tach?

It does have VSS though.

From the info in the 87 FSM you've got the right pin with the yellow/red wire.

that wire should OUTPUT a VSS signal (4 pulses per evolution)  

That wire should be connected to the VSS wire for the ECU.

it only makes a pulse as the cable rotates the speedometer.  So make sure your cable is correct int he trans and working.

Also, I am seeing a missing screw to the lower right corner of the speedo in your pic.  That may be the connection for that trace to the VSS unit.

Also, What ECU are you running to manage 8lbs of boost on a high compression EJ22?  Your issue may not have anything to do with speedo.

[Steptoe]

On 8/13/2019 at 6:06 AM, Numbchux said:

I've not seen an EA82 cluster that couldn't supply a VSS signal (I did one into a carbed '86 wagon years ago that I'm almost positive had the factory cluster in it). Certainly anything fuel injected would use it.

Sounds more like boost cut.

Every EA82 Speedo I have had including several carb had the VSS terminal on the rear panel. I never tested the output

[Zippy310]

Im still using the stock ecu, it also did the same naturally aspirated so I dont think it's turbo related, and I did connect the red/yellow to the speed signal wire to the ecu and nothing changed, it will run fine for about 5 minutes and then it has incredibly low idle (around 400 rpm) and revs out to only 4k

[Numbchux]

Codes?

[Zippy310]

There is something wrong with the harness and the codes won't read, so that's another big problem, but it ran fine in the impreza, and it ran fine n/a in the GL, except for the limp mode 

Edited August 14, 2019 by Zippy310

[FerGloyale]

seriously, that screw missing near the bottom right corner of the VSS unit looks like it is the contact to the trace sheet that corresponds to that pin with the Yellow/red wire.

[Zippy310]

I'll see if i can find a screw to fit and retry it, UPDATE, that screw was connected to the red yellow, but it still doesnt generate any measurable current with a multi meter, will it work regardless??

 

 

Edited August 14, 2019 by Zippy310

[Zippy310]

3 hours ago, FerGloyale said:

seriously, that screw missing near the bottom right corner of the VSS unit looks like it is the contact to the trace sheet that corresponds to that pin with the Yellow/red wire.

I'm pretty sure this was the fix, if I take the screw out and measure resistance while spinning the speedo there is no change... But with the screw in there is a change in resistance, still no voltage but something is different, does this mean it is working?? 

[el_freddo]

Voltage will only appear if you’re applying some sort of voltage to the system as you test it. 

I’m unsure, but I would imagine that measuring the resistance would allow you to determine whether the VSS circuit is working properly. 

Cheers 

Bennie

[l75eya]

No speed signal will cut you at 4k is that what's happening? 

[Zippy310]

15 minutes ago, l75eya said:

No speed signal will cut you at 4k is that what's happening? 

Yeah, I read on multiple forums that the ej phase ii goes into limp mode under two conditions, the knock sensor and the speed signal, Im pretty sure older ej's dont have this problem

 

[STi 22B]

Sorry for jumping in but there is another thing that might be causing this... check that your ecu doesn't (or in this case think it is) think you're still in neutral. If the ecu thinks the car is not moving, then the ecu will limit the rpm

Should mention that the neutral switch is a different input to the vss

Edited August 15, 2019 by STi 22B

[alexbuoy]

On 8/14/2019 at 12:34 AM, Zippy310 said:

Im still using the stock ecu, it also did the same naturally aspirated so I dont think it's turbo related, and I did connect the red/yellow to the speed signal wire to the ecu and nothing changed, it will run fine for about 5 minutes and then it has incredibly low idle (around 400 rpm) and revs out to only 4k

Is it still idling low? My brat did the same thing after startup it would run great then couple minutes later it would miss and barely rev. Turned out to be a fuel problem. 

Looks like your VSS is hooked correctly i did the same thing in my 91 loyale iirc. Good ground? 

Whats your fuel line situation looking like? Is evap line to vent or to original line.

Im thinking it’s more of a fuel related problem. I also wouldn’t trust an ej na-t with a stock EA FI fuel pump.

Edited August 15, 2019 by alexbuoy

[Zippy310]

10 hours ago, alexbuoy said:

Is it still idling low? My brat did the same thing after startup it would run great then couple minutes later it would miss and barely rev. Turned out to be a fuel problem. 

Looks like your VSS is hooked correctly i did the same thing in my 91 loyale iirc. Good ground? 

Whats your fuel line situation looking like? Is evap line to vent or to original line.

Im thinking it’s more of a fuel related problem. I also wouldn’t trust an ej na-t with a stock EA FI fuel pump.

It's a walboro 255, and its ran at 60psi, like i said it runs perfect before limp mode, I would assume a nuetral safety switch would have terrible idling problems straight as you start the car... Literally the car starts, idles fine, car warms up, idle goes down, drives at full power for about 5minutes and then idle is reduced to like 200-500rpm and max rpm is limited to 4k tops, it doesnt hit a ceiling but it sounds like a rev limit... Havent had time to try the gauge to see if it worked but im pretty certain it is the problem so it's not fuel related, and the ecu is from a manual impreza, even if you rev it when you first start it up it will rev all the way to 5500rpm, but after the "limp mode" described, it revs hard up to 3k and then kinda breaks up as if its not running on all cylinders

Edited August 16, 2019 by Zippy310

[Numbchux]

On 8/14/2019 at 1:20 PM, Zippy310 said:

There is something wrong with the harness and the codes won't read, so that's another big problem, but it ran fine in the impreza, and it ran fine n/a in the GL, except for the limp mode 

Fix this. Any other diagnosis/repair is a waste of time and money.

[FerGloyale]

12 hours ago, Zippy310 said:

 I would assume a nuetral safety switch would have terrible idling problems straight as you start the car...

 

It's not a "safety switch"

It is simply a signal to the ECU, and has ZERO effect on cranking or starting.

Cold start-up the ECU doesn't care whether in "N' or driving, it's all open loop, fixed maps for warm up.

After warm up, it goes closed loop, and that's when it matters for idle. (in combo with VSS)

It never has any effect on cranking.  The "lockout" to keep it from being started while a gear is engaged is from the clutch switch and a relay.

Neutral switch is not part of that system, so it's not a "Safety Switch"

just clarifying. (It's like when people say "Pollution Control Valve" for PCV....ugh.)

Your problem sounds more like VSS with the Rev limit and all.

[czny]

13 minutes ago, FerGloyale said:

Your problem sounds more like VSS with the Rev limit and all.

Notice the other hole in back of speedo with one angled & one straight barrier around it?

Maybe Zippy needs to look for a threaded hole connection in there - then bridge that to the nearest screw on pc board with some 16-22 ga wire.

Then ohmmeter test for VSS by slowly spinning the speedo again .

[Zippy310]

27 minutes ago, czny said:

Notice the other hole in back of speedo with one angled & one straight barrier around it?

Maybe Zippy needs to look for a threaded hole connection in there - then bridge that to the nearest screw on pc board with some 16-22 ga wire.

Then ohmmeter test for VSS by slowly spinning the speedo again .

I thought the same thing but there's nothing behind it, I thought it was that too but it is literally an empty hole, no threads or anything, it looks like if there was a different model gauge that whole would be used, but not used on this model, and concerning the diagnostics, I probably messed up the wiring when putting it in the GL 

[czny]

https://www.ultimatesubaru.org/forum/topic/95237-how-do-i-mimic-a-vss/

Post a pic of back of your 88 GL cluster so we helpers can compare them.

 

Edited August 16, 2019 by czny

[Steptoe]

On 8/15/2019 at 4:57 PM, Zippy310 said:

Yeah, I read on multiple forums that the ej phase ii goes into limp mode under two conditions, the knock sensor and the speed signal, Im pretty sure older ej's dont have this problem

 

It should not go into limp mode from knock sensor, unless the author meant a split second limp mode. All my knock circuit does on EA82 is pull the ignition timing back about maximum 10 degrees very quickly then progressively add timing back to normal until next knock sensed.

I would expect same of EJ ECU