1st Gen Haltech ECU Discussion

Any recommendations for a fuel pump? My whole sending unit rusted and I'll need to replace the whole thing so I was thinking of getting a cheap sending unit ad replacing the pump. Any benefit to buying an oem sending unit over the cheap ones?

 

Aem 340, e85 version. You need to bypass the pins on the connector under the driver seat. Aka wire around the connector.

 

If you're NA, then just run a Denso from RockAuto. If you're lightly boosted (SC or under 8psi turbocharged) then DW200. Both don't require any additional wiring

 

Thanks, yeah, just stock pulley or a 2.2 SC nothing exciting. I was getting a "can't be sold to your location" on Amazon for both, so I'll try Rock. Recommendations on Harmonic Balancer / valve cover gaskets / h20 pump / timing belt kit? I've got some of the pulleys, mainly need the belt, pump, pump gasket and should I do the seals while I'm at it? Crank and cam seals are way cheaper from SKP / National / Timken than Aisin / oem. Assume OEM rear main is the only way to go rather than take a chance at it leaking.

 

The harmonic balancer is a tough one to find. The aftermarket ones seem kind of crappy. The only one I would particularly trust appears to have bad luck in shipping right now. So I would go OEM if you got the scratch. Crank, cam, etc OEM seals are all made by NOK. So if you can find those you've got the OEM minus the markup. If you need any shipping forwarded to California because they won't send you something just let me know I got your back

 

I always get the Aisin timing kit from Amazon, no problems. If you already have some stuff, maybe you can piece it together on there.

 

So idk if anyone has seen my thread on a DIY ADD switch, but it led me down a rabbit hole of inductor-led transient voltage suppression, and got me worried about the reverse-bias damage possibility for those of us running silicon-based (MOSFET/SSR) transmission solenoid control.
https://www.allaboutcircuits.com/te...ient-voltage-suppressors-tvs-an-introduction/

I've gone ahead and ordered several TVS diodes for my ADD project and to add to my trans solenoid drivers. Clearly they are not as bad (only 1A solenoids vs 10A+ DC motor), but ill try to scope the voltage spike when the order comes in to see how big a concern this is. The ADD motor had enough to blow several MOSFETs with a reverse bias limit of 55V with only a couple triggers. Solid state relays can be built in several ways, but my understanding is they are typically just back to back MOSFETs, so they're vulnerable by the same method, but probably more robust as they would have to have at least the reverse bias limit as the AC voltage rating of the relay. You can use triacs to build them but I don't think they're very common because they require additional considerations to get around clamping current.
https://www.digikey.com/en/products...A/688018?so=91574084&content=productdetail_US

 

I think you're the only one here that went with JFETs for trans control. The solenoids in these transmissions are so slow I'm not sure if there's any benefit other than silence. What you're saying makes sense though from a protection standpoint.

 

You and digi went with mechanical relays? Thought you had said solid state

 

No I said mini

 

Ah, we all tempt fate in different ways

 

I just sent him on his way with a bag of three spare omron relays. At least with this transmission if it has no power you still have 3 gears just using the shifter

 

Idk about that. If solenoid 2 fails you get 1st 4th. If HT not programmed, overrev

 

Yeah that sounds more like a you not programming your safeties problem. Remember the solenoids can fail even if your relays or JFETs don't, so don't count on that scenario not to happen just because you used solid state circuitry. That said it's much more likely for the relay not to engage when commanded than to fail when it's already engaged. You can make your own ultra safety using gear detection and a generic pretty easily

 

To Toyota's credit, they put much more thought into the vss and trans sols than we are. Haltech has no robust failsafe design for such losses from what I can find unless you set the gear ratio downshift prevention. Don't assume you'll stick in a lower gear.

 

I'm hopeful that they implement a failsafe tab or something similar because actually if they used the input shaft speed sensor and the output shaft sensor if could easily calculate slip for TC clutch savings which would make it easier to PWM and partial engage... and we could have quick detection of solenoid failure by ruling out TC slip immediately to decouple the other solenoid and make sure it enters 4th gear instead. There is no way to totally decouple the trans without mechanical intervention (the shift lever) but the valve body does have some safeties of its own for going down or up a gear at the wrong time at least. Like I said if you want to be super safe you need to use gear detection to detect an upcoming overrev and use a gen output to interrupt the power to solenoid 1 & 2 forcing it into 4th. You really have less to fear from Solenoid 2 losing power than you do from solenoid 1 randomly maintaining it when it shouldn't though...

Plus with all of the new transmissions they plan to support and dedicated support to all these older 4 speed models it only makes sense that they'll flesh out the protection controls at some point.

 

Id like to thank all of y'all for contributing to this thread. I have been slowly soaking a lot of this in.

I recently picked up an Elite 750, IC-7, WB-1 and SNP stand alone harness for the 3RZ I'm cramming into my new rear steer buggy build.
Goal is to run some boost with a GLFab turbo manifold, 3076 Pulsar Turbo, 750cc injectors.

Just getting the 3RZ and A340 mocked up now. I may have some tuning and newb questions in the coming months.

Pics of the project:

 

Looks fun! We have that exact same setup (minus the SNP harness and snazzy intake) so if you need anything let me or @2RZNoShi1 know and we can certainly help you get it all setup and dialed. We've seen some other folks with SNP full harnesses be miswired unfortunately and in some cases poorly crimped as well. If you have the pinout and wiring allocation sheet you should verify continuity now so there are no surprises later.

 

I picked up the 750, WB1, and IC7 harness second hand just ever so slightly used and working according to the seller. The fuel injector plugs look to be an EV6 connection. The 750cc injectors I want to order from SNP are the ND/Toyota type (standard pink top or the brown OEM version). It looks like the outer covers on the SNP harness can be unclipped and swapped to the correct ND slot type. Guess I need to call SNP and ask or maybe some of y'all may have an answer.



OEM Harness injector plug




Fits this Pink top




Injector connector on SNP harness

 

Ah yeah there's plenty of conversion harnesses to go from EV6 to ND if you wanted to do that I think you can get 4 adapters for like $5 on eBay. But you could also just splice in new ND connectors with flying leads if you don't have the crimp tool for their pins. I would skip ordering those injectors from SNP, you can get appropriate ones from FiveO motorsports and they'll come with all the data needed to configure them as well in the Haltech.