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Your problem is easier to solve than you would think. Just add a fuel pressure regulator inline, with the return pipe connected to the return line and the outlet pipe connected to the returnless fuel rail. That way you're basically putting the fuel return where the original one is instead of next to the fuel tank. That's basically what the returnless system is: It has a constant pressure FPR next to the tank and a short return line.
Do I use the 90-93 FPR for this? isfo where do I mount it?
To do so will require an adapter where you mount it. In fact there should be a "tee" sort of fitting with an inline "damper" that resembles an FPR in an NB. You may be able to use/modify that.
But to be fair, just getting an aftermarket one will work fine. Standard pressure should be near 3.0 BAR if you will use pressure reference, otherwise 3.5 BAR is good. This works, from experience with other cars with returnless systems, not the MX5 in particular.
To do so will require an adapter where you mount it. In fact there should be a "tee" sort of fitting with an inline "damper" that resembles an FPR in an NB. You may be able to use/modify that.
But to be fair, just getting an aftermarket one will work fine. Standard pressure should be near 3.0 BAR if you will use pressure reference, otherwise 3.5 BAR is good. This works, from experience with other cars with returnless systems, not the MX5 in particular.
I think I will be trying to find a rail and use the 90-93 regulator. Finaly found one pretty close to me.
Posted just now lucky me Thank you for the amazing help though.
I'm currently in the swap process for a vvt engine, both engines are out (91 1.6, 03 1.8 vvt). I am going through the thread and following what needs to be done on the wiring side. I will be rewiring the alternator so the ecu(pnppro) can regulate the voltage (I'm using the 03 alternator). On this I need to do some more research on how to do that. For the rest of electrical stuff: What do I need to swap? the pigtails of the sensors or the engine harness in general that has the injectors and coolent temp sensors in it ?
the engine loom from the vvt motor
Man, if only someone had put all that information in a thread somewhere.
(I'll be a little helpful and tell you just to ditch the 03 alternator and go with a NA8 instead. Why bother?)
Ofcourse I've read the entire thread. It said that you can keep the OEM pigtails of the guage sender and and CLT sensor, but the plug where these 2 meet, the 6 pin plug on the intake obviousely differs from the 8 pin connector on the NB harnass.
So which plug do I use then ?
Thank you for the advice on the alternator though.
Ofcourse I've read the entire thread. It said that you can keep the OEM pigtails of the guage sender and and CLT sensor, but the plug where these 2 meet, the 6 pin plug on the intake obviousely differs from the 8 pin connector on the NB harnass.
So which plug do I use then ?
Thank you for the advice on the alternator though.
I think you're describing the injector harness? IIRC, it has the CLT sensors in it. The 1.6 was batch injection, whereas the 1.8 is sequential. 2 extra wires...
I think you're describing the injector harness? IIRC, it has the CLT sensors in it. The 1.6 was batch injection, whereas the 1.8 is sequential. 2 extra wires...
Read this thread a couple more times.
Thank you for clearafying this. It might be a good idea to read it a couple more times.
I've read in the 1.8 swap guide from flying miata that if you go standalone you do not need to swap the fuelrails. and thus you have to convert to a non return style fuel system. What will be the best solution since I have the pnp pro for the 90-93 chassis and that the fuel rail is extremely hard to find where I live.
You cannot use your 1.6L or early 1.8L fuel rail on the later 1.8L engine. I doubt the FM guide actually says this, because FM is a good shop and would not give such bad advice. If they did actually tell you to use your 90-97 fuel rail on a 99-05 motor, they are wrong and you should not do that.
Originally Posted by ThunderFox
Your problem is easier to solve than you would think. Just add a fuel pressure regulator inline, with the return pipe connected to the return line and the outlet pipe connected to the returnless fuel rail. That way you're basically putting the fuel return where the original one is instead of next to the fuel tank. That's basically what the returnless system is: It has a constant pressure FPR next to the tank and a short return line.
Suggesting that the OP convert his return-style car to returnless is a terrible idea. He would have to purchase an expensive aftermarket regulator as well as all of the fittings to connect this regulator. He would also end up with an inferior setup because he wouldn't have 2/3rds of the OEM NB fuel pulse dampers which make that system work. Please don't suggest this anymore. The OP should do what I recommend, which is buy a 99-00 fuel rail and use his existing regulator turned upside-down. In fact, the OP is probably in Europe based on his diction, so if he buys a used 99-00 rail from a breaker, it might even come with the proper NB1 return-style FPR, which is an even better idea which is also covered in the original post.
Originally Posted by c.v.r
Do I use the 90-93 FPR for this? isfo where do I mount it?
Yes, use your 90-93 FPR, mount it upside down, just like the first post in this thread says to. Please ignore ThunderFox.
Originally Posted by ThunderFox
To do so will require an adapter where you mount it. In fact there should be a "tee" sort of fitting with an inline "damper" that resembles an FPR in an NB. You may be able to use/modify that.
But to be fair, just getting an aftermarket one will work fine. Standard pressure should be near 3.0 BAR if you will use pressure reference, otherwise 3.5 BAR is good. This works, from experience with other cars with returnless systems, not the MX5 in particular.
No, no, no, please stop.
Originally Posted by c.v.r
I think I will be trying to find a rail and use the 90-93 regulator. Finaly found one pretty close to me.
Posted just now lucky me Thank you for the amazing help though.
Good.
Originally Posted by MX5RACER
On my car, I tapped the fuel rail where the regulator bolts to it, then used an A/N line to an aftermarket adjustable regulator.
You can tap, but I would be a little sketched out by the thickness of the rail. There are very inexpensive FPR adapters available which will bolt into place and give you a 1/8" NPT port to work with.
Originally Posted by c.v.r
I will be rewiring the alternator so the ecu(pnppro) can regulate the voltage (I'm using the 03 alternator).
Don't do this. You are just making your life needlessly harder.
For the rest of electrical stuff: What do I need to swap? the pigtails of the sensors or the engine harness in general that has the injectors and coolent temp sensors in it ?
Read the thread again. You don't need to swap anything. You use your original injector wiring. If you want sequential fuel, you will modify your original wiring. The NB wiring you posted a photo of belongs in the trash can.
Originally Posted by c.v.r
Ofcourse I've read the entire thread. It said that you can keep the OEM pigtails of the guage sender and and CLT sensor, but the plug where these 2 meet, the 6 pin plug on the intake obviousely differs from the 8 pin connector on the NB harnass.
So which plug do I use then ?.
Neither. You throw that away and use your original wiring. If you want sequential fuel, you will modify your original wiring. Trying to splice in the NB injector harness will go very badly for you.
You cannot use your 1.6L or early 1.8L fuel rail on the later 1.8L engine. I doubt the FM guide actually says this, because FM is a good shop and would not give such bad advice. If they did actually tell you to use your 90-97 fuel rail on a 99-05 motor, they are wrong and you should not do that.
Suggesting that the OP convert his return-style car to returnless is a terrible idea. He would have to purchase an expensive aftermarket regulator as well as all of the fittings to connect this regulator. He would also end up with an inferior setup because he wouldn't have 2/3rds of the OEM NB fuel pulse dampers which make that system work. Please don't suggest this anymore. The OP should do what I recommend, which is buy a 99-00 fuel rail and use his existing regulator turned upside-down. In fact, the OP is probably in Europe based on his diction, so if he buys a used 99-00 rail from a breaker, it might even come with the proper NB1 return-style FPR, which is an even better idea which is also covered in the original post.
Yes, use your 90-93 FPR, mount it upside down, just like the first post in this thread says to. Please ignore ThunderFox.
No, no, no, please stop.
Good.
You can tap, but I would be a little sketched out by the thickness of the rail. There are very inexpensive FPR adapters available which will bolt into place and give you a 1/8" NPT port to work with.
Don't do this. You are just making your life needlessly harder.
Read the thread again. You don't need to swap anything. You use your original injector wiring. If you want sequential fuel, you will modify your original wiring. The NB wiring you posted a photo of belongs in the trash can.
Neither. You throw that away and use your original wiring. If you want sequential fuel, you will modify your original wiring. Trying to splice in the NB injector harness will go very badly for you.
Holy **** you're amazing. I got all the solutions now on with the build
I completely understand why everyone suggests you when it comes to miatas, especialy this topic.
GOD!!!
So many bad posts in my good thread.
You can tap, but I would be a little sketched out by the thickness of the rail. There are very inexpensive FPR adapters available which will bolt into place and give you a 1/8" NPT port to work with.
I forgot to mention in my post, it depends on which rail you get. I have seen three different factory rails on NB engines, the NB1, the NB2 and a JDM NB2. I believe it was the NB1 rail that had the most material and I felt very comfortable tapping it. I had previously used an adaptor plate and had the o-rings fail several times at Sebring in the middle of a track day in July heat! Knock on wood, it has been two years running the tapped fuel rail and no issues so far.
Interesting, which adapter plate? The OEM FPR connects the same way (flange with an o-ring) so if it's correctly dimensioned it should be just as reliable as the OEM FPR.
The plate that I used had a cut out for the O-Ring to sit into, the factory FPR had an extension that the O-ring was inserted into the fuel rail on.
The first failure I had was the O-ring, the second was caused when one of the bolts backed out a bit. At the time the this was the only plate I could find locally.
I will be rewiring the alternator so the ecu(pnppro) can regulate the voltage (I'm using the 03 alternator).
Originally Posted by Savington
Don't do this. You are just making your life needlessly harder.
Disagree. I love the ability to regulate voltage for many reasons including (1) potential for hotter spark when dwell limited (2) ability to increase or decrease voltage with load, as appropriate for application (3) ability to use over run conditions to charge battery
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Disagree. I love the ability to regulate voltage for many reasons including (1) potential for hotter spark when dwell limited (2) ability to increase or decrease voltage with load, as appropriate for application (3) ability to use over run conditions to charge battery
Originally Posted by Savington
Ben, can you clearly outline the wiring changes necessary for the thread? I'll add it to the OP if you can.
Yes please. That would be very helpful. I could not find much info on this when I was doing my swap last year. I overcharged my battery which burnt my MS PNP Pro last year when I did my swap. I was using the 03 alternator on the NA chassis and I assumed it didn't require wiring changes, but I was wrong. Anyways ECU got repaired and I ended up using a NA8 alternator instead, however I'd like to be able to use the voltage regulation feature on the MSPNP pro.
04-04-2017, 08:24 AM
0
Thank you for the amazing help though.
on with the build 
