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I had a bent o-ring somewhere around my fuel pump, that was likely a cause of a lot of my troubles.
I contacted Mine's a while back regarding a ecu I had like that with their name on it. They were willing to receive back the unit and advise what "tune" was programmed on it.
The Sensor Check screen in the PFC Commander is a great place to look for any faults. Shows all the voltages of major inputs. If something is unplugged it will be reverse highlighted.
First step is to make sure the fuel pump is running and you are getting fuel pressure. Jumper the F/P and GND terminals in the diagnostic box under the hood and turn the key to On, that will run the fuel pump full time.
Dale
Sensor check screen shows all good, as far as I can tell. However, my exhaust temperature light is illuminated, but the PFC manual doesn't go into anymore detail about what to do other than "check things".
Originally Posted by Redbul
It is the right PFC model for your car, right?
I had a bent o-ring somewhere around my fuel pump, that was likely a cause of a lot of my troubles.
I contacted Mine's a while back regarding a ecu I had like that with their name on it. They were willing to receive back the unit and advise what "tune" was programmed on it.
I never followed up.
Yes, it is the 8 bit ECU.
Thanks for the lead on the O-ring. I was actually doing some searching and this issue came up. See Below
I pulled the return line off the rats nest and did the fuel pump override. I can hear the pump running, but nothing is coming out the return from the FPR. When i pull the feed line i do get flow.
So then i thought i was getting flow, but not pressure enough to overcome the FPR and return fuel.
I did pull my fuel pump and in the process i think the little "hat" broke. Additionally i couldn't tell if the O-ring was seating in the bell. Upon reassembly i couldn't get the O-ring back in, so i opted to just cut the bell off, and use 5/16" fuel hose to connect the fuel pump to feed hardline. I was feeling really confident that this is why i was getting no return fuel flow off the FPR; the fuel pump was like a straw with a hole in it, meaning it could push some volume to rail but not any pressure.
Attempts to restart the car show the same issue. It's chugging and stumbling, trying to start. I think this is from lack of fuel pressure.
I guess next step is to get an in-line fuel pressure gauge on the feed line and see what's happening. Perhaps the fuel pump is bad? It was a brand new Denso Supra pump, but it had sat for years on a shelf.
Perhaps there is something clogged before the FPR?
Love the build and attention to detail. You have given me quite a few ideas. Thank you!
Question on your LED taillights - do you remember what lamps you got and where from? Are you still happy with them? Plug and play? This is now in the near future plan for me - not sure why I didn't think about it before! I've seen a few different recommendations around here so I'm curious how yours turned out and if there were any issues.
Love the build and attention to detail. You have given me quite a few ideas. Thank you!
Question on your LED taillights - do you remember what lamps you got and where from? Are you still happy with them? Plug and play? This is now in the near future plan for me - not sure why I didn't think about it before! I've seen a few different recommendations around here so I'm curious how yours turned out and if there were any issues.
I don't have any actual run time on them yet, so I worry about giving a recommendation that's not been tested out. Honestly i just browsed amazon for bulbs that looked reputable with good, REAL reviews and weren't crazy expensive. Hopefully they all work out.
Originally Posted by Redbul
The FPR needs vacuum to remain open, right?
If solenoid is not "sending" vacuum or the vacuum hose is disconnected or split the FPR will stay closed.(i.e. blocking flow).
I not sure that fuel pressure alone can move the FPR valve.
My guess is the vacuum acts as a kind of servo and helps the valve react to the fuel pressure against it.
The FPR is fairly robust but I had one that froze closed (blocking).
The way I understand the function of an FPR is a diaphragm that holds a gate closed until the pressure to overcome it allows flow past. I don't believe it requires a vacuum source to open. I think it works like a heavy door that only can open when enough force is applied to push it.
An adjustable FPR allows you to crank down on a screw that preloads more pressure, thus increasing static fuel pressure.
A rising rate FPR (which nearly all turbo cars have) reference manifold boost, and accomodate for the pressure. So if base pressure is 42PSI, and manifold reference is 10psi, then the actual fuel pressure becomes 52psi. This is to overcome the injector having to spray fuel into an "atmosphere" of 10PSI higher than normal.
It's interesting you noted that you've had one freeze close. I did some searching and it seems like most feedback is that they're pretty reliable and rarely, if ever fail.
To test this with parts i had laying around, I hooked up a Schrader valve to a fuel line, and attached that to the feed side of the fuel rail via the rats nest. I left the return line unplugged to see what would come out, if anything. I then applied air pressure, and somewhere above 40psi, i was nearly doused with fuel. To make sure it wasn't some kind of clog i blew out, i cleared the line for a while until all fuel stopped coming out. I then hooked the fuel feed line from the pump back up, leaving the return line open, jumpered the fuel pump relay, and let the system prime. No fuel is coming out of the return.
Not worth fussing around with especially if the pump sat for a long time. Drop in a new one and remove the variable from the equation. If you find that doesn't fix your problem, at least when you do eventually fix it you'll know you've got a nice new fuel pump with lots of life left.
Not worth fussing around with especially if the pump sat for a long time. Drop in a new one and remove the variable from the equation. If you find that doesn't fix your problem, at least when you do eventually fix it you'll know you've got a nice new fuel pump with lots of life left.
Thank you. I needed to hear that. I get stuck in my 'gotta solve this problem' mindset and the easier thing to do is just what you said. Ordered a walbro 255 and will move onto other tasks waiting for it to arrive.
I am just going by what I interpret from the FSM and the vacuum system diagrams and the table setting out what components are doing at various stages..
The stock FPR has a vacuum line attached to it regulated by a solenoid.
What goes on inside the FPR is a bit of a mystery to me.
I may be interpreting things wrong, and it seems counter intuitive that the vacuum needs to be on for the valve to remain open, rather than the vacuum causing the valve to close..
I read this as cutting the vaccum to the FPR allows it to close and, it seems, increase fuel pressure to about 40 psi. Maybe above 40 psi the diaphram lets fuel squeeze by?
To test my "stuck" FPR I used a hand vacuum gun to apply vacuum and tried blowing through the FPR. I could be that I did not apply enough vacuum? or blow hard enough?
I just lent out my spare FPR so I can not repeat the experiment atm.
While waiting for the fuel pump to arrive, i decided to knock some other tasks out. The front marker lights had some weird hazing or staining on them, so i polished these. I also did the taillights, although they are in slightly worse shape so I didn't get too aggressive with them. Just a little to shine them up. No pictures of them.
I also made a big mistake by rushing things. I decided to bleed the clutch and brakes since i had the master cylinder out for painting. I had my wife jump in and be pedal command and I'd be down in the trenches on the clutch slave. We tried for about 3 mins, and nothing was coming out of the bleeder. Then i started seeing fluid pouring from the inspection cover. I thought maybe my slave had sprung a leak, but I looked into the inspection cover and realized i didn't set the throw out bearing into the wedge collar. I realized what I had done but had no idea what the damage was.
Just a quick plug, this is why I love this forum. The years, decades, of knowledge buried in here if you know how to dig a little.
I was starting to get heartburn that I'd have to pull the trans out. So back to the car, and sure enough after removing my starter I found the slave rod was not pressing into the clutch fork. I was able to pull it apart and thank god all the parts came tumbling out.
This was important to fix, because I couldn't start the car with slave cylinder guts in the bellhousing, so it was perfect timing when the new fuel pump arrived.
I opened the tank again, and took a look inside. Now, I don't know if this was a contributing factor to the first pump dying or not, since the fuel pump does have a pickup sock, but i couldn't feel good about the sediment.
I siphoned it all out as best i could, and was pretty shocked at what came out. The tank overall is hardly rusty, but I'm wondering if this is just years of being careless at the fuel pump with dirt and other buildup.
The horror.
Alright, new Walbro 255 arrived from Banzai racing, SUPER FAST. Love those guys, big plug for them.
Lines hooked up. Return line from rail disconnected.
Key on, priming, fuel is coming out the return. Now we are getting somewhere.
I hooked the return up, turned the key, and here we go.
Woooooooooooooooooo! It runs. I could hardly believe it, it's running under it's own power since i picked it up 2 years ago! I've got a lot more little tasks to do, but this was a heavy one that had me really worried. The next hurdle is the shape of the cooling system... I'm saving that for the next update.
This morning I wanted to finish up flushing the coolant after a couple of heat cycles from yesterday. I remembered that the idle was high, and that the throttle cable wasn't adjusted to zero tension. I made that correction and fired the car up, it idled really low, as expected, for about 30 seconds and died. I could not get it to restart. I deflooded it, checked everything for leaks, even adjusted the cranking fueling, no dice. Then this:
I guess i should have known that I wasn't going to win the engine lottery with this purchase with as long as it sat. I also didn't get the full history straight from the previous owner. He had claimed it was a "new engine" but we know that isn't likely.
So I'm feeling fully deflated. I think I'm going to pause on this car for a while and focus on the FC i just picked up. The plan is to purchase an OEM engine from Ray Crowe, and while i wait for it to arrive, I'm going to rebuild the 13B from my S4. My hope is this will give me the confidence to tear into my FD engine and determine if a rebuild is worth doing, or if I just wait it out for the OEM engine to arrive. It's disappointing, but I have lots of other things I can focus on. It just means i won't be driving the FD come Summers turn.
I won't let this turn into a completely different build thread, but I will mark how this is related to building this car back up.
I've been on the hunt for a Turbo2 for probably 3 years, and my timing just couldn't be worse. Since Covid era, these cars have gone from budget tuner to collectible seemingly overnight. I missed out on purchasing several FCs over the last few years and every single missed chance has bummed me out more and more. I know it's a silly goal, but i really want to have all three generations, and as crazy as it seems, finding a CLEAN FC has been the most challenging. I finally found an NA FC local to me, and had to just pull the trigger. Yes, it's not a genuine Turbo2 (although it does have some of the exterior trim to fool you), but at this rate I'm happy i just have a mostly complete FC with no rust, and no accident history. The rest I can fix. The engine has mid 70s compression and I bought it knowing I would need to rebuild. Luckily over the last 3 years I've manage to snag some parts whenever I see them, including another 6port engine, and an S4 T2 complete engine.
So i guess to pivot onto something useful, I'm going to rebuild the spare FC engine I have as a precursor (and distraction from the disappointment of the FD condition) to dealing with the FDs current engine predicament. This will hopefully give me the experience and confidence to do it myself, should it come to it.
It was pretty gunky, and even after a pressure wash it's mighty filthy still Tear down Blown apart
I'll be cleaning and inspecting over the next few days and determining how usable everything is. It might be a nice change from working on the FD and give me some motivation to power through and finish it up.
What do you see that may have contributed to the low compression?
I pulled this engine from a running, although very rough condition 86, and externally it looks like it was treated really poorly. Some no-name header, the 5th port was removed but not wired one way or another, the 6th port left on but not attached. There was missing vacuum lines and just everything was a mess. Compression when i pulled it :
82 80 79
83 85 79
I think the car had 150k miles, but i didn't record that i guess. After cracking it open I discovered its never been rebuilt, as it has the factory 3 piece apex seals and the old school corner seal springs. I noticed that some of the side seals were stuck down. I think this contributed to it not building the best compression, but overall things don't look ultra worn out.
So far the rotors seem to be in really good shape, everything cleaned up nicely. I'm going to tackle the housings and irons tomorrow and inspect what is still usable there. I'm referencing the FSM, and the Rotary Engine Overhaul Criteria guide.
Why not spend the effort on the FD engine instead of the fc engine?
I don't want to say I have an anger problem, but i was worried I would stop being so careful after the let down of pushing so hard to the finish line, the high of the engine starting, then the low having to yank it all out again. I had a pretty lofty goal to make a car show in a few weeks and I'm realizing that can't happen now.I think I just need a short mental break from working on that car. I'm sure anyone who's toiled on a project can relate when **** doesn't pan out.
Also my take on rebuilding the FC engine is it gives me some practice that wont feel as detrimental if/when I mess something up. I'd be doubly upset if I pulled the FD engine down to rebuild it and I do something stupid that is easily avoidable (see above with the throw out bearing, etc), setting me back even further.
I think I just need a short mental break from working on that car. I'm sure anyone who's toiled on a project can relate when **** doesn't pan out.
Damn man that is rough. I know the joy of finally getting something to run only to be disappointed a short time later with bad news. Taking breaks helps clear my head because it can become insanely frustrating working on these cars, especially when you don't trust other people to work on your car like myself. Get back at it soon though brother, that car is too sexy to be sitting in a garage for too long.
If the engine has sat for a long time you likely have some stuck side seals, and everything just isn't happy. Crank up the idle speed a bit, fire it up, and drive it around for 15-20 minutes and get some heat in the engine and let those seals move around. May also be worth doing an MMO or water treatment.
MMO = Marvel Mystery Oil. That stuff, or ATF (auto trans fluid) can sometimes help un-stick stuck side/apex seals
Can confirm. Had a stuck side seal in my R1. A few sessions of ATF freed it up. Just make sure your neighbors are aware so they dont call the fire department on you.
04-25-23, 04:11 PM
