joshuaho96

For the RB26 ITB + turbo causes a lot of weird issues I think. Most of them are just ITB problems. At idle or low load IMAP is a very noisy signal because there's not that much vacuum volume. You can sidestep this with aggressive filtering or sampling based on crank angle but that makes it a slow signal. Then once you start using the throttle while I can clearly see vacuum during some part throttle cruise cases it easily saturates to atmospheric and spends a lot of time sitting around there for a solid half or more of the throttle travel until it spools the turbo. During cold start you also have to account for the fairly scattershot behavior of the cold start valve. The ECU doesn't even know of it's existence and it operates off of a very eyebrow-raising method of heating a bimetallic strip as soon as the fuel pump gets power to slowly close the shutter. It can get stuck open or start closing at a different rate with age so its relationship with actual engine warmup is loose to say the least. Then of course wastegate duty and all of that fun stuff affecting EPR also needs to be compensated for. My car has 4 cats on it from CA's emissions compliance requirements which has made a very, very noticeable effect on how much cylinder filling occurs despite running wastegate boost in both cases on an otherwise similar car. It used to hit the R&R corner of the map, now it actually doesn't exceed the factory intended load scale. I don't want to bother with tuning an engine twice in response to something as simple as a different exhaust. I've never tried EPR-based load to see what happens there but maybe in the future I might be able to muster the effort to evaluate it against the MAF load data to see if it helps tame the non-linearity problems. For now I plan on just using the factory MAFs and building a MAF load tune, then going from there. It's coming along well but the final 15% to make it drive like a factory car is taking 85% of the effort.

You can try tapping the MAF or tugging on the plug while the car is stopped and see if it reproduces. Not unusual for MAFs to have failed solder joints when old.

Looks like you want to check for power and ground on the CAS, then try seeing if there's continuity on the cam/home and crank signal wires from the CAS to the ECU harness. You can try also backprobing the ECU connector to see what kind of voltage those wires are delivering in the specified conditions in that table. Easiest way of course is an oscilloscope to read signal from those pins but not sure you can easily find one of those. You can also just use NDS while cranking to see if it reports RPM. If it does the ECU is getting some kind of signal. Oscilloscope will tell you how noisy it is.

What is the actual code? These aren't OBD2 cars, they don't use OBD2 generic codes. If the starter is dead it won't crank. Most likely the code is that your ECU is losing the signal from the CAS altogether for whatever reason. The ECUs in these cars are pretty basic and don't do anything like cam correlation codes or any other plausibility checks.

You need to do the following diagnostic flows to narrow down the issue: If you need a wiring diagram you can find it here under A-LSD/ABS: http://yariksteel.ru/manual/R33/Skyline_R33_elektroprovodka.pdf

I think he ran into similar issues, once it actually kicks over he experiences lean running for a little bit before it corrects. I suggested just papering over that problem with after start enrichment at high coolant temps but the whole thing is getting redone with a crank sensor because he's sick of fighting the distributor which was constantly misfiring at idle but weirdly not at cruise or full throttle. I'd see something like a full point of AFR lean-out in response to a misfire so I disabled all closed loop corrections even after I was done messing with VE tables. He's also using one of those old style AEM controllers that blasts the heater the second it gets power from the ignition switch so the sensors aren't going to last very long regardless and there's no real failure detection in those controllers either to my knowledge. Once he gets the new setup running I'm sure I'll have new and exciting issues to learn about.

Supposedly yes, but I have a theory that both are suspect. Haven't been able to get a pressure gauge on it to monitor what it's doing after shutdown as I got busy with other things since then but I suspect it would be interesting. This is a series 3 Jaguar E-type convertible. Prior to this it had Stromberg constant depression carbs which were absolutely horrific between that and the bizarre early 70s emissions vacuum retard distributor. I definitely agree that the conversion nature makes it hard to actually disambiguate what's going on but at the time of the hot soak we had come back from a fresh fill so the tank was full. The whole fuel system was just redone for the EFI conversion so I would be kind of surprised if it's leaking inside the tank but anything is possible. At the time of the tuning session it still ran the factory distributor, actually the ECU didn't have any engine position so there's no concept of anything like fuel injection timing or ignition sync. Verified the spark plugs were in fact firing too.

Curious to know if anyone else has run into this issue before. I helped a friend tune an EFI conversion a little recently and an issue we ran into is that after getting coolant temp into the 90C range, after shutting the engine down and letting the whole engine bake for 5 minutes it wouldn't crank over anymore. Adjusting the cranking fuel pulse width did nothing. Surprisingly what solved it is setting a long fuel pump prime. He's running an MS2 or something like that so it wouldn't allow him to prime for longer than 3 seconds but keying on and off three times to get about 9 seconds of priming has reliably allowed it to restart now in this hot soak scenario. Anyone know a good explanation for exactly what's happening here? My working theory is that the fuel in the rail has boiled from heat soak and the pump needs to cool off the rail to have functional fuel injection again but I'm curious to know what others think.

I can't really speak to modern cars, the calibration strategies are pretty opaque, probably because even the people cracking these things open don't seem to understand how any of it works. It seems viable, I just can't be bothered to take the risk at the moment trying to implement all of that on my end. The objection I have to alpha-N and blended strategies on things like Haltech and Link is that while it's nominally a simple thing to map it's a very brittle load sensing strategy that relies on too many assumptions to stay constant that I don't think will stay constant and requires a huge amount of additional compensations to function in an ITB turbo configuration like the RB26. It's not actually modeling mass flow through the throttle body or anything like that. Something as simple as AC/power steering/alternator generating more load at idle just isn't really accounted for without extra tables and has to be compensated for with all kinds of weirdness. The use of manifold pressure as the primary load scale for timing also just seems weird to me because it's non-linear with respect to actual cylinder air mass so at part throttle you basically have no resolution in your timing tables in many areas. My conception of a TMF model is that it should be able to overcome all of these concerns once set up correctly while not being hilariously slow and generally unreliable in transients like MAFs stuck to the very front of an incredibly long intake tract. I have no objection to speed density when applied appropriately either, I helped a friend tune a speed density setup on a Jaguar V12 recently and it works great when it isn't subjected to the weird idiosyncrasies of ITB turbos.

Regarding closed loop fueling going all wonky with a misfire - I think that's an argument for better modeling and misfire detection in a standalone ECU no? Not sure anyone is going to ever bother with it but if we want standalones to potentially be viable replacements for things going into the CAN/GDI age the software complexity has to ramp up pretty dramatically to make it all work. I would consider most standalones to only be good enough for something like an RB26 that is stone age as far as a lot of the controls go. Sounds like you're describing throttle mass flow when it comes to MAF/speed density replacements. I'd be curious to know how many cars actually use it and how well it actually works, from what I've seen if the pressure ratio across the throttle body is too close to unity modeling the flow rate becomes a challenge. Whatever the E9x M3s use sounds rather brittle as well, supposedly something as simple as an alternator bearing causing excess drag at idle will cause all kinds of running issues. I would be curious to know if someone has actually solved the problem of ITB mass flow measurement without a MAF. I have seen what alpha-N or blended alpha-N/speed density strategies are like and I'm not really a fan.

Not sure there's any great pictures online, if you stick an inspection camera down the muffler you'll probably see it.

The issue with retrofitting wideband on these cars is mostly related to control/where it's installed, way too many aftermarket controllers go full blast on the heater the moment the ignition +12V goes live, all kinds of weird calibration bugs, general firmware nightmares, etc. Haltech's recent woes with the NTK wideband comes to mind. Also questionable tuning/maintenance/build practices can all contribute to widebands that die seemingly every year or sooner. For these cars I would probably recommend running both just for the redundancy. At least you can probably trust that your wideband is working ok if the narrowband is cycling around stoich.

Quite literally the first post said a modern ECU with engine protections. What engine protections do you think you can run without wideband, oil pressure, and fuel pressure?

There is a spring-loaded flap that only runs it at high enough flow rates. Nissan did this to reduce noise at low load/RPM while reducing backpressure at higher flow rates.

Yes, ECU pin 18 controls the fuel pump relay using the ground switch method. The two other pins that come from the ECU to the FPCM are signals to the FPCM to switch the resistor on the fuel pump to ground. No signal on the two means full power, one is idle and the other is cruise.

The LHD is aftermarket, there are no factory LHD R33s.

Yep, a rubber dead blow in an appropriate size is my go-to but those transmission fill plugs often have RTV and way too much torque applied to them.

Blue threadlocker + tightening by feel is probably the way to go then. You can feel fastener stretch. At first it will be relatively easy but usually you will hit a sudden increase in resistance. Once you get there don't go crazy with the force. A bit more is good enough.

https://www.nicoclub.com/service-manual?fsm=Sentra%2F2005%2Fem.pdf As far as I can tell there is no listed torque spec as it was not intended to be disassembled. It is probably either something like 7 ft-lbs or 12 ft-lbs. Assess what materials you're tightening into. If it's soft aluminum 5-7 ft-lbs is probably what you want.

When I check nicoclub for the 2005 Sentra factory service manual it mentions this step, so I would follow it.

This is another good video that focuses much more specifically on the locking pin.

The Haynes manual is basically telling you to retract the locking pin in the VVT cam phaser and then advance the sprocket all the way to the limit of travel and use a pin to hold it there. Why it tells you that I'm not sure. Go by the factory service manual instead for your car/engine. It's possible you have to do the same procedure but I have literally never heard of anything like this when timing a VVT engine. You can verify that the pin is not ruined by checking that it is straight, no visible gouging on the surface finish, and no cracks or anything like that. The pin is designed to basically work such that when oil pressure is removed from the cam phaser it will naturally retard and hit the lock position at which point the spring pushes the pin into the hardened lock pin seat. Cam phasing is adjusted from there by using a solenoid that controls how much oil pressure goes to each side of the cam phaser. You can see a breakdown of how it works on a Toyota version of the same idea here:

It will reduce noise substantially. When I got my car CA emissions compliant they added a bunch of cats and despite the Apexi catback and HKS front pipe it's quieter than a 100% stock exhaust. It also causes a hilarious amount of exhaust restriction because of how many they added but at least for now that means my turbos on wastegate boost no longer hit the R&R corner of the map.

Probably the average age of everyone here has moved up a decade too and people have re-learned the lessons of the 50s and 60s. Only takes a small group of people decatting their cars to have a significant impact on local air quality.

Nah full decats are obnoxious AF to everyone behind you in traffic. If it's not a track car you trailer to and from the track you should run a cat.