Prevalence of Knock Sensor Failures with SC?

[Bdnewyork]

I'll soon be diving in to do a full timing belt replacement job, valve cover gaskets and installation of a new TRD SC with a 2.2. An EVO 9 fuel pump and either AEM FIC/6 with blue Supra 23250-46050 injectors, or URD 7th to follow later. I'm weighing whether while in there now, if it makes sense to spend the addl time and money to delve deeper and proactively install new OEM Denso knock sensors and harness.

I'm @160k now - '99 SR5 Cali auto. Never thrown a P0325/P0330 code; but with the new SC going on, I've read some folks have experienced KS failures soon after SC installation. I'm seeking to determine if this is a rare or common occurrence.

There are also some on other forums who have opted to successfully substitute GM SU1075 sensors as they have similar frequency specifications ; but are more robust.

customtacos knock-sensors

What would you do? Thanks!

 

[gamefreakgc]

Wow, you've done some reading! I did mention somewhere the EVO 9 pumps are not plug and play right? Need the connector to go with it or some creativity to shave down the spade prongs.

It's hard to say how many do have knock sensor issues when installing a supercharger. It's the same for reading reviews on a restaurant, there's probably 100's of happy customers that love the food but when you look at reviews you only see the 5 negative reviews because they spent the time to write about their complaints. The supercharger does increase noise and frequencies but also can cause enough vibration that can ruin whatever is left of that old crispy wiring harness. I am very careful when ever I do work on the fuel system or in the intake valley not to ever, ever touch the knock sensor harness. I think that's where you run the greatest risk of developing the codes.

I know which threads you are mentioning about the GM sensor swap. That should be reserved for extreme cases for when the knock sensor is detecting the supercharger rotor frequencies as knock and pulling all the timing when its in boost. If you relocate the sensors to a location that the engine was not designed for with parts from a different engine family that play such an extremely critical role, you also run the risk of not detecting as much knock as you should and seriously damaging the engine. Personally, I would not ever do the GM sensor swap/relocation for that reason. That's saying something because I'm a pretty high-risk guy when it comes to these stout 5VZ-FE engines. Heck, I'm even considering adding a 50 shot of nitrous in the next year or so.

 

[Bdnewyork]

Hey Jerod, yes, I caught your post on the connector mismatch with the Evo 9 pump, thanks for the heads up. I've ordered a matching EVO pigtail from STM Tuned. Cost w/shipping is more than it's worth though not to the extent of a Boomslang... I'm an EE with an appreciation for connectors and I'd rather run the 3570 Denso over a Walbro 190.

I think your restaurant analogy is likely spot on. Those OEM Densos are expensive and I'd rather allocate those funds toward a pigggyback. So if it ain't broke, don't fix it then?

I agree regarding knock sensor relocation. Apparently some do that to facilitate replacement down the road, though it's not something I would ever consider. The SU1075s have a matching thread, though tapered, and supposedly do fit in the stock location. Still, a little too far out of the sandbox I think.

Not surprised you're considering N2O - I'd subscribed to your build thread some time ago, which has been pushing me toward the dark side: FIC/6. In fact, I'm likely going to just go ahead and install the larger injectors out of the gate. My SC also came with a 2.1 pulley in the box, so I'm planning on adding an Aquamist HSF-3 water/Meth system in the future to support that. I'll leave it to you to pave the N2O path though...

 

[gamefreakgc]

Hey Jerod, yes, I caught your post on the connector mismatch with the Evo 9 pump, thanks for the heads up. I've ordered a matching EVO pigtail from STM Tuned. Cost w/shipping is more than it's worth though not to the extent of a Boomslang... I'm an EE with an appreciation for connectors and I'd rather run the 3570 Denso over a Walbro 190.

I think your restaurant analogy is likely spot on. Those OEM Densos are expensive and I'd rather allocate those funds toward a pigggyback. So if it ain't broke, don't fix it then?

I agree regarding knock sensor relocation. Apparently some do that to facilitate replacement down the road, though it's not something I would ever consider. The SU1075s have a matching thread, though tapered, and supposedly do fit in the stock location. Still, a little too far out of the sandbox I think.

Not surprised you're considering N2O - I'd subscribed to your build thread some time ago, which has been pushing me toward the dark side: FIC/6. In fact, I'm likely going to just go ahead and install the larger injectors out of the gate. My SC also came with a 2.1 pulley in the box, so I'm planning on adding an Aquamist HSF-3 water/Meth system in the future to support that. I'll leave it to you to pave the N2O path though...

Depending on your elevation, there are some that did put the injectors in right off the bat and installed a wideband and oddly enough those injectors with a smaller pulley, gave pretty close to the right about of fuel needed for that 11.8 AFR target ratio. That's with no tune too. Of course it was sloppy and would start out rich in the low 11's and then at red line lean out into the 12's but it was actually a pretty good starting point. But you'll see that when you are installing the supercharger, the fuel rail and injectors are literally just a few bolts more and they are out. Might as well put them in all at once!

The AEM F/IC 6 has been discontinued. They may be hard to find so URD's products may be a better option now with more support.

 

[Black798]

Not related to the knock sensors but i can vouch for the blue top supra injectors working really well. I think the piggyback larger injector method is a far more effective, safer, and more powerful solution than the urd 7th system. When I looked into the tuning of my setup I was set on the AEM fic but once I found out it was discontinued I picked up a MAP ecu3. I chose this because it provides significantly more features than any of the urd tuners at a similar price point and the biggest advantage is it allows you to tune on the fly where as the URD units require a complete restart of the truck to update the tune. If you do end up going that route let me know as I can send you the tune Im running as a starting baseline if you want. Ive spent a lot of time with mine optimizing the afrs and egts for the best economy and power and have gotten it pretty damn well nailed.

 

[19963.4lsr5]

When you guys do the supercharger thing do you split the fuel rail into parallel instead of series?


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[Bdnewyork]

Wow, you've done some reading! I did mention somewhere the EVO 9 pumps are not plug and play right? Need the connector to go with it or some creativity to shave down the spade prongs.

It's hard to say how many do have knock sensor issues when installing a supercharger. It's the same for reading reviews on a restaurant, there's probably 100's of happy customers that love the food but when you look at reviews you only see the 5 negative reviews because they spent the time to write about their complaints. The supercharger does increase noise and frequencies but also can cause enough vibration that can ruin whatever is left of that old crispy wiring harness. I am very careful when ever I do work on the fuel system or in the intake valley not to ever, ever touch the knock sensor harness. I think that's where you run the greatest risk of developing the codes.

Looking back, I hope I didn't jinx you Jerod - I've read of your subsequent knock sensor woes and offer my condolences. I did choose to prophylactically replace the knock sensors and harness with OEM when the SC was installed. The EVO 9 pump went in fine with the MIT-MR497597 harness I found at STM Tuned. Thanks again for the FP info.

I also went with the blue 23250-46050 injectors; but stuck with the stock pulley. As expected, the injectors are normalized to 14.7 AFR by the stock ECU. So I've been running only 93 and going easy on the pedal. Time for that to change.

Which brings me to the next point:

Not related to the knock sensors but i can vouch for the blue top supra injectors working really well. I think the piggyback larger injector method is a far more effective, safer, and more powerful solution than the urd 7th system. When I looked into the tuning of my setup I was set on the AEM fic but once I found out it was discontinued I picked up a MAP ecu3. I chose this because it provides significantly more features than any of the urd tuners at a similar price point and the biggest advantage is it allows you to tune on the fly where as the URD units require a complete restart of the truck to update the tune. If you do end up going that route let me know as I can send you the tune Im running as a starting baseline if you want. Ive spent a lot of time with mine optimizing the afrs and egts for the best economy and power and have gotten it pretty damn well nailed.

Hey Phoenix, Finally received the MAPecu3 and am ready to install and migrate to the 2.2 pulley. I'd like to take you up on your offer for sharing your tune with me as a baseline - that would be very much appreciated. As my base elevation is just 500' here, I'm on 32's with 4:10, only extra weight so far is a 4XI rear bumper, I suspect I'll need to tweak what you've perfected a bit.

You mention egts, That really is definitive tuning data, isn't it. Did you monitor exhaust temps with test equipment or did you install permanent temp sensor(s)/monitoring? I checked your build thread; but didn't see mention of egt measurement components. I did see that you're now going the turbo route and hope that you still have your SC tuning maps available...

Thanks to you both. Your contributions are and have been invaluable to me and many others.

 

[Formidable]

Replace the sensors and sensor wire. Especially if you are running a smaller pulley.

Smaller pulleys generate a ton of heat and the sensors are directly beneath the supercharger.

 

[Bdnewyork]

Replace the sensors and sensor wire. Especially if you are running a smaller pulley.

Smaller pulleys generate a ton of heat and the sensors are directly beneath the supercharger.

Yup, did that. New OEM knock sensors & wiring harness went in with SC install.