LS1 Wiring harness for 87 Mazd
 

Hey guys need a little help. I'm doing my first build with my RX7. I plan to buy an LS1 to put in it. Going to buy the conversion kit from granny speed. But I was wondering about the wiring harness for the dashboard? How it was going to hook up to an LS motor? Different plugs or what? Help me out. Thanks

Generally speaking very little needs to connect to the dashboard harness as the engine is taken care of by the LSx ecu and the body is taken care of by various other things.

Many LSx FC guys who go T56/TR6060 end up swapping to an intengra electric speedo and connecting the tach to the LSx ecu tach output. You can get a great deal more complicated than this either mechanically or electrically depending on what you keep as far as accessories go.

Regardless, I would recommend against the granny's kit if you're going LSx. There are better kits out there from more responsive vendors.

thank you!

Go to NoRotors.com. Every question you have has been addressed. The Integra speedometer swap is well documented there

Skip the Granny's kit and get the Ronin Speedworks LS1 install kit. It is simpler, lighter, much easier to route the exhaust around, and easier to install the engine.

You're quite welcome. As LOF mentioned, norotors has some good resources regarding the v8 swaps. The reality is that the swap can be as simple or complicated as you yourself make it and in general it gets more complicated as you try to retain or modify systems like A/C, P/S, etc. I would suggest looking at peoples build threads, both here and there to get ideas (even of things you don't like) to help you along.

Lastly, if you end up keeping the LSx ecu there is a known issue of stalling on clutch in which decelerating. You'll need to hook up the clutch switch to the ecu which is a part of the dash harness.

edit: You might want to check out mine, clokker, eage8, and other builds in particular. Different flavors or reporting on the build process and different avenues as well. Reading everything you can get your eyes on will help you a great deal in finishing your build.

Any clutch in engine dying issues under decel can be easily fixed in the tune. It means your idle settings are not quite right typically. I don't have anything clutch related wired to the LS1 PCM in my car. There can be different idle parameters engaged when the clutch is in vs out.

But yes, do as much research as possible. You'll find things you like and get ideas from many others that came before you.

FWIW, I was told that by one of the prominent and few trusted mail order tuners and that it was an artifact of the LSx ecu and how it looked up tables. He further mentioned it could be tuned for but there were no guarantees; especially with a lightweight flywheel. At the time of my looking into keeping the stock ecu this was corroborated on LSx forums and I think a post or two on norotors as well.

Most people I know don't have any clutch wiring to the ECU at all. I have a light flywheel and a cam with a tight LSA (110 degrees) and have no problems. I also have a forward facing intake that gets a lot of air.

The issue can be easily mitigated in the tune and with proper setup of your throttle body. If IAC counts are within spec, and other aspects of your idle control are correct, it is a non issue.

A mail order tuner will give no guarantees because he is a mail order tuner and the issue can be problematic to fix without a datalog. The catch is if you have the equipment to datalog, you can just do the research on HPTUNERS forums and fix it yourself.

Good for you?

It's a known problem in the LSx community and is related to dash wiring.

Yes, there are ways to mitigate it that require a great deal more money than wiring in the clutch switch and take you further from an OEM tune than simply wiring in said switch.

You are forgetting you need a tune on the factory PCM anyway just to start the car in a swapped state. It is a pretty easy fix, and hardly a reason to even worry about using the factory PCM. It is not really even a problem with PCM itself. It is the result of putting aftermarket parts (intakes generally) that are not sized appropriately or have the MAF in the improper place.

The reason the clutch switch is even involved is because there are different idle values for clutch in vs clutch out, all of which are adjustable.

Where did I forget what? You are forgetting that I am speaking on general things relevant to a question, not attempting to make myself look good/more knowledgeable to others.

ecu doing something 1 way, that is the root cause of an issue, is not a problem with itself? lol

Here we go again. Since we are swapping the engine and an ECU into a car it was not intended for, it will NEED an ECU tune to remove the VATS, (vehicle anti theft system) just to start the car. Also, typically modifications are added to the car as part of the swap - different intake and exhaust at a minimum. A proper tune for those modifications will eliminate any problems.

The part where this all goes wrong is when you mentioned "mail order tuner". I have nothing against them, but if you have a mail order tuner that says their tune will be perfect without datalogs and adjustments, you should not be doing business with them. That is not to say your car can't run well with a mail order tune, it is just not going to be perfect or make optimal power. Any mail order tune should be verified on a dyno to be safe. A good tuner will not leave your car dying when you push the clutch in, if the switch is wired up or not. That is not a dig on mail order tuners, they are just simply not there to tune your specific combination. They are giving you a tune based on what generally works.

I used a mail order tune on my car from Frost on my swap to get it going. The car fired up and idled the first time I hit the key, it was great. After I got the car running and driving it was running lean. I bought HP tuners and I ended up redoing 90% of the tune. I messed with some idle, settings, redid the VE map completely and redid most of the timing map. I am still very satisfied with my transaction and decision, it saved me a bunch of time getting the car up and running.

If you have a means of doing datalogs and a good mail order tuner, a few datalogs, and some emails back and forth can probably get you dialed in very close as long as you don't have some off the wall setup.

3 takeaways -
LS1Tech is full of more misinformation than it is with meaningful tech

NoRotors is about 95% meaningful tech. If you have a problem, someone there has most likely had the same problem before, solved it, and will give you some guidance.

A good, accurate tune makes all the difference in the world.

And yet even with proper tunes people still report those problems and the cause is known. You even said the cause. Go figure.

And yet a stock ecu with VATS eliminated is cheaper than a VATS+tune that would not be necessary (the tune part) if a single switch, that is already there, is properly wired into the system. And both of these options are again cheaper than buying hptuners, standalone, etc. I did not go down this route since Foxx didn't ask and it would have been apparent when he started reading/researching.

I have noticed you like to talk at/around people on the forums, especially those who have disagreed with you in the past. In doing so you, generally speaking, help others while subtly (or sometimes not) insulting the person you quote. I'd appreciate it if you stopped doing it with me. Adding information is great. Doing so in the manner you often do, where you also seem to contradict yourself at times and then start arguing semantics, is not.

You're right, here we go again. I hold no animosity towards you but I'll say it again I'd appreciated it if it didn't happen again.

As you have now agreed, the root cause is because the intake, MAF, throttle body, tune or any combination of those is not correct. So why would you not just fix the actual problem? A problem with any of those will effect the power and reliability of the car not just the idle. You are making my argument for me here. Just adding a wire and continue to let the car run like crap is not the correct solution.

From Frost there is not a cost difference for disabling VATS alone to flashing a tune for your modifications into the car. Other tuners pricing may vary. Frost is probably one of the best mail order LS tuners in the business.

My point is if you need a tune, get a tune. There are few people who put a stock engine in the car disable VATS and run it. Typically those who do don't have problems because its a stock tune on a stock engine. If you put a proper size intake pipe on the car, it works fine.

Your tip, while sometimes valid to solve a subset of stalling problems is a band aid. And band aids can stop the bleeding, but they don't heal the problem. There is not a need to run any more wiring than you have to to make the PCM function. Additionally If you are running an ECU from a car or truck that had an automatic trans, running a wire to the clutch switch does NOTHING because the ECU does not care about the clutch switch. Again, a tune fixes things here.

I am merely rounding out the tech one liner you provided. Saying "Just add this wire because LS1tech says there is a problem with engines dying" does not really help anyone.

You can't have things both ways. If you want to propagate partial or misinformation, people are going to call you on it. If you want to dismiss the personal findings of myself and others in past threads but now push upon us the findings and experiences of people on LS1tech with poorly tuned cars as universal truth, you will encounter resistance. I don't have any animosity towards you either FWIW, but dismissing the experience some of us have had as invalid or "lucky" does not fly.

That is not what I stated. Do not put words in my mouth.

Where I received my information from was Frost (as well as forum posts) and just like I'm sure he didn't promise you the world he was very specific about potential issues when I went over my setup, this was one that he brought up because IT IS A KNOWN ISSUE and has been experienced by people who disable the switch such that they can no-clutch start their car and previously did not have the issue. While a tune can bandaid it, the actual fix is to reinstall the switch such that the ecu can do what is was programmed to properly, switch tables. At the time I contacted him for tune/vats there was variable pricing for everything done.

A tune does NOT fix the underlying issue of the ecu NOT switching tables because a switch that needed to be connected was not.

If you want to dismiss other peoples/tuners experience and claim that if it goes against yours then it must be some other reason that does not fly as it does not fly that you dismiss an entire forum of people because ???

I was not giving partial information. I was making Foxx aware of an issue he could run into. Your complaint is like saying because I did not go into the exact detail of how the ecu is programmed, down to the 1's and 0's, hardware, etc. that my answer is incomplete. You even added into the mix auto trans to muddy the waters further despite talking about a clutch switch. Seriously?

Regardless, good luck Foxx.