I'm not sure you're going to find something ready-made like that, but what you can do is join two 90 degree pipes together. I did something like that for my intake piping. These are two 45 degree pipes but you get the idea. Mocking things up with cardboard can help cut down the guesswork greatly.

 

It's a bit of an art I guess. I ordered a 180° silicon hose and another 90°. To be continued!

 

I'd be using a section of short bend radius spun donut, cut to size and welded in place rather than use silicon bends. That manifold and positioning of the turbo is pretty ordinary too, spacers almost guarantee exhaust leaks at some point in the future,

 

So here I am again this year. I have been busy studying exams for my job.

Hopefully this is the final stretch.

I started the car today with brand new plugs. There's an oil leak at the turbo oil feed NPT fitting. I didn't use any sealant. I think Teflon will easily melt. What is your idea, what do you use? I copied a picture of the oil feed line that I bought...

Thanks!

 

https://www.permatex.com/products/ga...-liquid-16-oz/

Works very well. I use it on the oil pressure sending unit in the rear iron.Never had a leak.

 

That product can withstand temperatures up to maximum 400°F. You sure it's enough?

 

Are you sure an NPT fitting is the right way to go for that connection? It looks like the factory oil feed (high pressure) lines use banjo bolts with crush washers, and the return (low pressure) lines use bolted flanges with gaskets.

 

If it's oil and water cooled, probably. If it's just oil cooled, well, hopefully you don't have 400 degree oil temps moving through that turbo or the leak is probably the least of the concerns. Oil coking occurs at less than 400 degrees.

 

Teflon tape melting isn't a concern, you'll be good there. That should be all you need. The Permatex that Mike linked will work too but if you have some Teflon tape in your hand just use it, no sense ordering something.

Oil temps are only like 200 deg. F, the pipe may get a bit warmer than that but you'll be fine.

Dale

 

Thank you guys. I followed DaleClark's advice and put some Teflon tape. No leak at this place.

Borgwarner S362 SX-E finally installed.

Engine ran for 75 minutes tonight.

Idles at 1,700 RPM but runs fine (VTA2 was at 1.45V when it should be at maximum 1.25V).

I tried to lower the value at 1.24V... I managed to keep it alive but it was running extremely rough. I'm not sure what to do from here. Fuel tank is almost empty and of course it has fairly old pre-mixed gas.

I still do not think that it is the issue. I removed so many things in that engine compartment. Do you think that I could have removed something that I should have left there? I included the entire vacuum diagram of the engine right now.

You Tube

 

That doesn't sound like a vacuum problem to me. If you have a wideband O2 sensor, what do you see at idle when it sounds rough? Is the engine ported or stock? What primary injectors are you running? Have you tried adjusting the fuel map by +10% and -10% to see if the idle smooths out?

I would inspect the spark plugs. And if you can run the engine at night, watch the spark plug wires and coils to see if there is any arcing. You can't usually see stray ignition arcing during the day, and you might not be able to hear it over the normal engine noises.

 

• Added some premixed fuel.
• Brand new wideband o2 sensor shows about 11.2-11.5 running rough at idle (600 RPM).
• Stock primary injectors.
• I didn't adjust the fuel map, not sure how to do it.
• Inspected the spark plugs, they are pitch black. They were brand new 3 days ago.

I'm going to inspect for arcings tonight, with my eyes and my hands!

 

That looks too rich at idle, and much too rich at part throttle. A stock 13BREW doesn't need to run that rich, although it might be hard to get a smooth idle at 15 AFR with stock injectors and a Power FC. I would aim for 13-15 AFR at idle, and 14.5-15.5 AFR at part throttle below 3500 RPM. I've never used a PowerFC so I don't know how easy or hard it is to adjust the fuel map using the tools you have. I've always used standalone ECUs with laptop software that shows the entire fuel map, never little screens like you've got on your console. Make small changes, decrease just 2%-3% from all of the low RPM / light load cells and give the engine at least 10 seconds to settle down and respond. In theory a 5% adjustment to the fuel map should result in about 0.5 AFR change on the wideband, but theory doesn't always match reality so make small changes and then repeat as needed.

I would also make a small adjustment to the idle air bypass screw on the throttle body, to get the idle speed up to at least 750 RPM when the engine is warm. I prefer my RX-7's idle around 900 RPM to avoid stalling, especially since I don't drive the car often enough to stay familiar with the clutch engagement point. Then after you have the idle and light-load mixture reasonably correct, I would swap in new spark plugs and see if that helps smooth things out. Your plugs are likely fouled from assembly lube and combustion deposits from such a rich mixture.

For reference, here are a couple of videos showing my car idling and driving, we happen to have the same wideband gauge.

 

Yeah you should be mid-high 13's AFR at idle.

Do you have O2 feedback turned off? It needs to be off if you don't have an air pump.

Do you have a map in the PFC or is it the base map? If it's base map you may want to do an All Data Init to make sure it's 100% clean.

Is your ISC in use and hooked up?

Dale

 

I forgot to mention that the engine is lightly ported. That's the 4th set of brand new spark plugs since I completed the rebuild... They're always fouling like this.

I do not feel super comfortable playing with the fuel map on the PFC. But I understand that the engine is running way too rich right now. If I play with the idle air bypass screw (front of the throttle body), the TPS values will surely be out of range, I'm already at the limit for VTA2 (which should be maximum 1.25V).

Neat installation of your wideband gauge though!

o2 feedback turned off.

Base map in the PFC, All Data Init has been done.

ISC in use and hooked up, I heard it buzzing last time the engine stalled.

I understand that the engine is way too rich. I would like to rewrite my fuel setup:

1. Fuel setup was all stock, then...
2. I deleted the fuel dampener 12 years ago and the engine was running fine without it.
3. During the rebuild, I replaced the fuel pump with a brand new Walbro 450 LPH.

Everything else is stock (including injectors and FPR). Is it possible that the fuel pressure is too high?

Thanks for your help... Always much appreciated.

 

Yeah it's worth checking fuel pressure. Do you still have the two stage fuel pump control like OEM?

Is the FPR just running to a straight vacuum port or do you have the stock FPR solenoid?

There's a particular nipple for the FPR that's best to use and in your vacuum diagram you have it shared. Always best to run mission-critical stuff like MAP and FPR with a dedicated line with no tee or anything. I've known at least 2 people that have blown engines due to a failed vacuum tee. That's also why I always recommend brass tees and not plastic.

Do you have the injector atomization hooked up? That helps idle and low load fuel spray patterns.

The throttle body should be totally shut, can't see light through it, and the ISC should be clean and happy. Back out the idle adjust screw a half turn and the PFC should idle on that just fine. With it so rich it's probably bogging down the idle.

I'd also double-check the basics like making sure your plug wires aren't mixed up.

Dale

 

Good idea to double-check the spark plug wires are all correct. I'm in the habit of adding air using the bypass screw that is only visible when the intake elbow is removed, since it doesn't change the throttle blade position or TPS sensor alignment. When searching for photos of the bypass screw it looks like people suggest some very specific methods for setting the throttle stop and bypass screw positions.
https://www.rx7club.com/3rd-generati...estion-490725/
https://www.rx7club.com/3rd-generati...ews-tb-712578/

 

I'm not sure what you mean by two stage fuel pump... Key on, it goes up to 54 psi, then stabilizes at 35 psi. Cranking shows about 46 psi. I do not know the fuel pressure when the engine is running though... But now I removed the fuel gauge. Would it be worth to install it back? I've seen some arguments on feed line vs. return line... What do you think?

You're right that my vacuum lines are very simple but still messy at the moment. Do I need a solenoid or something? Right now it could be too simple, I don't know. If I cheat with the ISC, it definitely idles better (and higher), but is definitely out of FSM specs.

Wires are fine (trailings are easy, and top on leading coil goes to the front rotor, bottom on the rear rotor).

I'll try to add air using the bypass valve located at the bottom of the throttle body. I'm not sure how that screw works though, I guess if I unscrew it, it will add more air?

To-do list:

1. Check for arcings (night time).
2. Adjust bypass valve.
3. Maybe reinstall the fuel gauge (on feed or return line?) and get the fuel pressure at idle. I'd bet it is way too high and I wonder if it could be the real problem.

 

Checking fuel pressure is a good idea. The fuel gauge goes on the fuel feed line, or the line between the injectors and the aftermarket fuel pressure regulator. After a wideband O2 sensor, fuel pressure sensor was the next aftermarket sensor I added to my car's engine bay. The fuel pressure regulator is vacuum referenced, it has a diaphragm inside that will adjust the bypass so the fuel pressure will always be a certain amount higher than its manifold vacuum/pressure reference port. For instance, stock fuel pressure is around 38psi with the engine off, and then it will go lower when the engine is idling (around 30 psi because of manifold vacuum) and then higher in boost (around 48psi because of manifold pressure). If your car has an aftermarket fuel pressure regulator, you may want to adjust it to match stock fuel pressure or whatever the fuel pressure was when the PFC map was tuned. In general lower fuel pressures are easier for the fuel pump but higher pressures might give a little more headroom if you have barely-adequate injectors but a strong fuel pump.

The factory fuel pump wiring has two relays, the main Fuel Pump Relay is a simple on/off relay to power the pump. Downstream of that is the Fuel Pump Speed relay which allow an inline resistor in the circuit (so the pump gets lower voltage and runs at lower speed) or it will activate and bypass the inline resistor for maximum fuel pump voltage / speed.

The factory rats nest includes an ECU-controlled relay that can connect or disconnect the fuel pressure regulator from manifold pressure/vacuum, if this relay is active the fuel pressure will be higher than normal at idle but lower than normal in boost. It's not active often, maybe at low RPM if the fuel is very hot.

 

I forgot to mention to DaleClark: yes, the injectors diffusers are installed.

So I reinstalled the fuel gauge, on the feed line.

I get 64 psi idling at 600 RPM. I tightened the ISC screw (I KNOW I SHOULDN'T) and I've got roughly the same, maybe 63 psi at 1,400 RPM. That gauge is almost new, about 2 years ago, only used on the FD. I'm confident that it is working fine.

So as I thought, fuel pressure seems to be too high. What do I need to do with that? Buy an aftermarket FPR?

Thanks, hopefully we've got something here...

 

Yeah that's insane fuel pressure at idle. Do you have the factory 2-speed relay setup that switches the fuel pump from 9v to 12v?

If you have a stock FPR that fuel pump is probably overwhelming it.

Any reason you need that much fuel pump? Would a Walbro 255 suit your needs? It's a pain and a lot of extra plumbing to put in an aftermarket FPR, you could be money and time ahead going to the Walbro 255. If you do need that much pump then an FPR is what you will need.

I guess also make sure that there isn't something else that's causing fuel pressure to be so high. I'd also check static fuel pressure with the engine off. May also want to see if other people with that pump have had pressure that high.

Dale

 

I really don't know about the factory 2-speed relay setup. I didn't change anything about that - however I know Derwin Tuning prepared some wiring at that pump before selling it to me, brand new, 2 years ago. It was pretty much plug and play after that. Damn, I'm not super happy about having to change that fuel pump again. Are you sure that there's no other easy way to reduce the pressure?

 

I can't speak for your tuner or your wiring guy, but the factory fuel pump wiring is barely adequate for the factory power demands on pump gas, so it's pretty common to make some minor modifications that retain the original fuel pump speed relay, also common to bypass all of the original wiring and run completely new wires. More info in this thread: https://www.rx7club.com/3rd-generati...ewire-1124167/ Post 9 shows the factory wiring diagram including the fuel pump speed relay.

Adding an aftermarket pressure regulator should work also, but is likely to snowball into a larger project if you add aftermarket fuel rails and injectors "while you're in there".

 

You may need to see what others have run into with that pump. I wouldn't have thought it would have crazy fuel pressure like that at idle but there you go.

Bypassing the stock 9v/12v two speed system is common with high horsepower setups.

It's also possible you have something else wrong that's jacking fuel pressure way up, like a crimped hose, bad FPR, backwards lines, etc. etc. etc.

Dale

 

I went and check that fuel pump setup. Local tuner Derwin Tuning sold it to me during the rebuild in 2019, and I remember they prepared the wiring so it would be the easiest installation possible. They had me bypass the stock relay with a simple 12V relay. I'm leaning toward installing an aftermarket FPR, if it is not too much of an hassle... I did not find many FPR reviews. Which brand or/and model would be trouble-free?

Thanks!