Jump to content
SAU Community

Recommended Posts

It's not OBD1. It's Nissan Consult. Their own protocol. It's easily readable with any workshop grade diagnostic handset that has Nissan config files. I did it (for HICAS diagnosis) with a generic workshop handheld on my car back in about 2000, immediately before I rendered HICAS unable to f**k with me any more.

And 10 years after that I ripped out every single HICAS related thing in the car, except the CU (which is needed to keep the power steering happy).

HICAS is the devil. It is made to make 7/10ths drivers look like 9/10ths drivers. But if you drive the car harder than 7/10ths, it actively tries to kill you. It is too stupid to handle real driving.

HICAS is also very hard to diagnose, because from what I can tell, the CU rapidly forgets codes if the initiating failure does not stay present. So you can really only diagnose it while it is in the process of losing its mind.

'twere I you, I would put a HICAS delete kit on the car. With decent upgrades to suspension arms/bushes, tyres and a wheel alignment, the car will turn in 11ty times better than the apparent improvement given by HICAS back in the dim nostalgia days of the late 80s.

  • Like 1
8 minutes ago, GTSBoy said:

It's not OBD1. It's Nissan Consult. Their own protocol. It's easily readable with any workshop grade diagnostic handset that has Nissan config files. I did it (for HICAS diagnosis) with a generic workshop handheld on my car back in about 2000, immediately before I rendered HICAS unable to f**k with me any more.

And 10 years after that I ripped out every single HICAS related thing in the car, except the CU (which is needed to keep the power steering happy).

HICAS is the devil. It is made to make 7/10ths drivers look like 9/10ths drivers. But if you drive the car harder than 7/10ths, it actively tries to kill you. It is too stupid to handle real driving.

HICAS is also very hard to diagnose, because from what I can tell, the CU rapidly forgets codes if the initiating failure does not stay present. So you can really only diagnose it while it is in the process of losing its mind.

'twere I you, I would put a HICAS delete kit on the car. With decent upgrades to suspension arms/bushes, tyres and a wheel alignment, the car will turn in 11ty times better than the apparent improvement given by HICAS back in the dim nostalgia days of the late 80s.

im in agreeance with you there, Im actively looking at the different kits and what all is into locking it out and getting rid of the light aside from unplugging the bugger. I see tomei has a kit that you can basically falsify the A-OKAY  report back to the ECU, and uses shims. I imagine that is probably the way to go, but im checking out my options as we speak.

9 minutes ago, oSkylines said:

I see tomei has a kit that you can basically falsify the A-OKAY  report back to the ECU, and uses shims. I imagine that is probably the way to go, but im checking out my options as we speak.

Nah. Complete removal and destruction. The use of lockout collars and lockout bars, retaining the crappy old tie rods and tie rod ends is....the nasty 90s style way of doing things. These days you can get brackets that are used to mount to control arms that replicate the setup of non-HICAS rear ends. These are literally called HICAS delete kits, as opposed to the HICAS lockout kits of yestercentury. You can knock the ball joints out of the steering arm on the knuckles and replace with bushes or bearings that get rid of the slop.

What I did instead was replace the entire rear subframe with a non-HICAS one, pulled out the solenoid valves, plumbing and changed the PS pump (this is an R32 with an R34 motor in it, so was hydraulic HICAS, which is the worst of them all, and the R34 motor brought along its PS pump for a no effort contribution to the HICAS eradication programme). But I suspect that that will be a bit harder on a GTR. I could use an A31 Cefiro subframe which I found lying around.

And you don't need to worry about any happiness or otherwise of the HICAS CU and anything it might say to the ECU. For one thing, you have a Haltech and it simply won't care under any circumstances. But I don't think even the stock ECU would give 2 shits. It certainly doesn't in the R32. Remember, these are vintage cars. Not the heavily integrated shitboxen of the last 20 years.

  • Like 1
3 minutes ago, GTSBoy said:

Nah. Complete removal and destruction. The use of lockout collars and lockout bars, retaining the crappy old tie rods and tie rod ends is....the nasty 90s style way of doing things. These days you can get brackets that are used to mount to control arms that replicate the setup of non-HICAS rear ends. These are literally called HICAS delete kits, as opposed to the HICAS lockout kits of yestercentury. You can knock the ball joints out of the steering arm on the knuckles and replace with bushes or bearings that get rid of the slop.

What I did instead was replace the entire rear subframe with a non-HICAS one, pulled out the solenoid valves, plumbing and changed the PS pump (this is an R32 with an R34 motor in it, so was hydraulic HICAS, which is the worst of them all, and the R34 motor brought along its PS pump for a no effort contribution to the HICAS eradication programme). But I suspect that that will be a bit harder on a GTR. I could use an A31 Cefiro subframe which I found lying around.

And you don't need to worry about any happiness or otherwise of the HICAS CU and anything it might say to the ECU. For one thing, you have a Haltech and it simply won't care under any circumstances. But I don't think even the stock ECU would give 2 shits. It certainly doesn't in the R32. Remember, these are vintage cars. Not the heavily integrated shitboxen of the last 20 years.

well, i can say an entire subframe swap is not likely something ill get that far into, but I am watching a video right now about the delete kits that essentially just replace the control arms and stuff to lock it into place. So, if the haltech isnt gunna care about the HICAS system if i lock it out, I'll likely just do that then. I did read on one of the HICAS threads that you actually were on ( i think from like 2021) something about pumps potentially overheating or something , so ill have to re-find exactually what was being talked about there for context, but i think it was something along the lines of if you were just blocking things off, whereas if you just delete the whole rear hicas system , there shouldnt BE any pumps to overheat, so unless the concern would be with some other pump somewhere its probably a nonissue. That being said, cant hurt to re-read so i can make sure i dont bugger something up unintentionally out of ignorance. 

So the potential issue with the pump is that it has 2 stages, the first is for power steer and the second for hicas. If you just block off the second stage outlet it will kill the pump.  

You need to either:

-Open the pump and remove the rear pump vanes, then block the outlet, or

-Reroute the power steering lines so the second stage feeds the PS cooler (then back to the reservoir) and the first stage just does the steering rack.

-replace the factory pump with a single stage pump, keep in mind the number of ribs in the PS belt are different between R32 (4 rib) and R33 (3 rib)

-loop the HCAS feed back to the HICAS return near the diff, although this keeps a lot of unnecessary weight and leak opportunities

  • Like 1
10 minutes ago, oSkylines said:

something about pumps potentially overheating

3 minutes ago, Duncan said:

So the potential issue with the pump is that it has 2 stages,

This is all only true for R32, which had hydraulic actuation of the rear rack. The R33 onwards cars had electric rear racks, which obviate all the hydraulic concerns.

Edited by GTSBoy
Just now, GTSBoy said:

This is all only true for R32, which had hydraulic actuation of the rear rack. The R33 onwards cars had electric rear racks, which obviate all the hydraulic concerns.

if this is accurate with the R33 not having  this issue, that is quite good news.

49 minutes ago, oSkylines said:

if this is accurate with the R33 not having  this issue, that is quite good news.

If by "this" you mean only the hydraulic associated issues with deleting HICAS, and not the fact that electric HICAS is still equally capable of trying to kill you as hydraulic HICAS is, then yes. It is easier to get rid of R33 HICAS than it is on R32.

  • Like 1
10 minutes ago, GTSBoy said:

If by "this" you mean only the hydraulic associated issues with deleting HICAS, and not the fact that electric HICAS is still equally capable of trying to kill you as hydraulic HICAS is, then yes. It is easier to get rid of R33 HICAS than it is on R32.

i was just referring to not having to worry about the pumps on the 33 overheating, since its not the hydraulic system and doesnt have the extra fins and pumps and shit running to the back. 

 

As for the HICAS being a death trap at one point or another, You have me sold on that. Well you, mixed with the fact that my car tried to do the cupid shuffle on its own , nearly taking out a motorcycle driver ( if it had been moving to the left instead of the right on its random swerve)

18 minutes ago, oSkylines said:

i was just referring to not having to worry about the pumps on the 33 overheating, since its not the hydraulic system and doesnt have the extra fins and pumps and shit running to the back. 

 

As for the HICAS being a death trap at one point or another, You have me sold on that. Well you, mixed with the fact that my car tried to do the cupid shuffle on its own , nearly taking out a motorcycle driver ( if it had been moving to the left instead of the right on its random swerve)

Almost every I know with an R32 GTR has some story about the HICAS trying to steer them in an unintended direction. The R33s seem more reliable in that regard. I'm pretty sure my HICAS is not locked out and I can't even really tell if it's working or not.

8 minutes ago, joshuaho96 said:

Almost every I know with an R32 GTR has some story about the HICAS trying to steer them in an unintended direction. The R33s seem more reliable in that regard. I'm pretty sure my HICAS is not locked out and I can't even really tell if it's working or not.

well, if the R33 is more reliable in this regard, maybe i am just wildly unlucky. Either way , If im planning on making changes in the near future by way of increasing power , after this week, I want mine off and in a dumpster somewhere. The injectors are the last part im waiting for to upgrade my fuel system at the moment, and then I have to run a few logs for my tune, one of which being a WOT run. Last few times i did my WOTs i was somewhere up in the 130ish mph area... I dont even want to know what would would've happened if my HICAS decided to go rogue on me when I'm doing my WOTs for tuning. 

Edited by oSkylines
4 hours ago, oSkylines said:

well, if the R33 is more reliable in this regard, maybe i am just wildly unlucky. Either way , If im planning on making changes in the near future by way of increasing power , after this week, I want mine off and in a dumpster somewhere. The injectors are the last part im waiting for to upgrade my fuel system at the moment, and then I have to run a few logs for my tune, one of which being a WOT run. Last few times i did my WOTs i was somewhere up in the 130ish mph area... I dont even want to know what would would've happened if my HICAS decided to go rogue on me when I'm doing my WOTs for tuning. 

I have had two separate R32 owners tell me about 2-3 incidents where they were either in a turn and the HICAS was trying to make the car go straight or they were going straight and the rear end was crabbing out to try and make the car turn. Neither could get it to reproduce again afterwards. It absolutely destroys confidence in a car when the system can randomly misbehave like that. My R33 doesn't do that but I have heard of bad yaw sensors causing behavior like the rear end crabbing out under braking or excessive vibration/exhaust noise doing something similar as well. The R32 doesn't have any form of feedback control and as far as I can tell the HICAS is really far more aggressive compared to the R33.

HICAS in the R32 and R33 both belong in the bin.

First real handling mod I did was delete HICAS, followed by a proper mechanical LSD (albeit I have a GTS-t shit box).

R34 HICAS is barely ok, if I had a R34 I would delete it as well.

2 hours ago, joshuaho96 said:

I have heard of bad yaw sensors causing behavior like the rear end crabbing out

No yaw sensors in HICAS. It's usually the steering angle sensor, but also can originate in the HICAS CU. The Oz delivered R32 GTRs had a factory recall to repair the CUs which sometime had a loose screw running around inside shorting shit out, and electrolytic capacitors all eventually reach EOL, etc etc.

 

2 hours ago, joshuaho96 said:

The R32 doesn't have any form of feedback control

No HICAS has any form of closed loop. It just sends out the "wiggle the rear end signal" when it thinks you'd like it to turn in. If that happens to be when you are sawing away at the wheel trying to fight understeer midcorner on a wet track, then so be it!

37 minutes ago, niZmO_Man said:

My HICAS actively tries to kill me (random kicks in the steering, rear end is looser than a drunk 18 year old at Ivy).

That 1986 shit should go straight in the bin.

Please delete it.

  • Like 1
11 hours ago, GTSBoy said:

No yaw sensors in HICAS. It's usually the steering angle sensor, but also can originate in the HICAS CU. The Oz delivered R32 GTRs had a factory recall to repair the CUs which sometime had a loose screw running around inside shorting shit out, and electrolytic capacitors all eventually reach EOL, etc etc.

 

No HICAS has any form of closed loop. It just sends out the "wiggle the rear end signal" when it thinks you'd like it to turn in. If that happens to be when you are sawing away at the wheel trying to fight understeer midcorner on a wet track, then so be it!

image.thumb.jpeg.89539a505f7ffa85e5a8fb421945bbed.jpeg

As far as I know there's actually a yaw sensor in the back of the R33 and R34 GTR which is used for HICAS. It vaguely helps maybe. In practice the R33 and R34 group N cars AFAIK kept the yaw sensor but deleted the HICAS and fed the signal into the ATTESA/ABS controller instead to control the A-LSD.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Harness is for a s1 Rb25det, and it is engine and lower harness.  the old harness had broken off plugs and was in very rough condition/exposed wires and splices etc. it is not able to be put back on the car, I could visually inspect to see if they had rewired any pins on the ecu plug. The fuel pump definitly isn’t turning off it’s an external pump and very loud you can hear it. Will look at the other harness tonight, am also going to pull the fuel rail and watch the injectors spray, will update here with what I find. Pretty sure at this point it has to be something to do with injectors because car will fire up on starting fluid and cas is clicking the Injectors. Fuel pressure is steady 43psi 
    • Check the injectors flow evenly, and are actually flowing what you and the ECU think they should be flowing. If it's starting up on starter fluid, you have a fuel issue. Is it possible under cranking your fuel pump is turning off?   The harness you replaced, is that the whole engine harness? Do yourself a test, and drop the old harness on and plug it into the Z32 ECU. It's possible they've wired things different. From memory S1 to S2 is different in RB25 and you may have a wrong loom
    • I haven’t pulled the injectors to watch them spray yet but they are clicking from the cas and all of the spark plugs are wet with fuel. I’ve thought the cylinders were being flooded from the beginning and was hoping fuel pressure would fix it. Tonight I am going to pull the rail and watch the injectors spray. Don’t know how to test/diagnose if the plugs are firing in correct sequence but that should be a timing thing and as far as timing goes my car still has the half moon for the cas can only install it 1 way. And my mechanical timing is 100% correct I posted photos above. Confirmed with the balancer on and off. 
    • I checked spark on all cylinders and they all visually have spark with the plug pulled and grounded, but plug 1 is the only one that fouled. This was a running swap that blew up and was rebuilt by a machine shop, put a new wiring specialties harness and did all gaskets, studs, and bolts while it was out.  compression is 135-150 across all cylinders. Aside from that from my understanding with the z32 ecu and maf the car should start regardless. The wiring for TPS and the dual 02 sensor/ dual knock sensor stuff shouldn’t actually stop the car from starting or even running well, (just slightly rich)  they just give fault codes. Car supposedly is supposed to start as long as you have z32 afm and ecu with the nistune base map and that’s info coming from a well known and trusted tuner who does a lot with SR/RB (Rsenthalpy). After more trouble shooting today where I’m at right now is that the cas is sending signal to the injectors they click while spinning the rotor, Fuel pressure is now set at 43psi, all cylinders have good compression and all of the plugs looked great (just wet with fuel) except for cylinder 1 which was very black (cylinder 1 has 150psi compression). all of the coils generate spark if pulled out and grounded out on the head. On the fuel pump car just pops into the exhaust. On starting fluid car will fire off. Hard to tell if all cylinders are firing off but definitley a couple. sounds like all of them but it’s only for 3-5 seconds hard to tell. 
×
×
  • Create New...