joshuaho96

TPS sensor needs to be adjusted such that idle voltage is 0.45V, then relearn the TPS if applicable. From what I recall in the R32 GTST and similar ECUs they care far, far more about the actual TPS closed switch but later models seem to only keep track of voltage.

Oh yeah, always always always turn over an engine by hand first.

Adjusting the idle screw is usually (emphasis on usually) just covering up deeper issues. Stuff like the cold start valve not closing properly. Throttle shaft seals on the way out. Coolant temp sensors getting out of spec. Coolant temp sensors especially can be a bear to diagnose because they can fail subtly. My dad just spent weeks chasing down his high idle. He cleaned the coolant temp sensor and everything but the resistance curve just drifts over time and if it's been 20+ years they also get super slow to respond as well. Has a massive effect on fuel economy as if it's off the ECU is going to run richer and command high idle for far longer than it should otherwise.

It's more like on average the things I see a lot of things going wrong. Yes, usually the people who reach out are the ones who are having problems but on average it feels like mechanics and tuners here aren't really competent. I swing between thinking my standards are just way too high and wondering whether people really are just this dumb. I just had the strangest 10+ reply argument on a Facebook group over someone insisting that the factory R34 GTT boost control solenoid reduces boost pressure to 5 psi when it's on and raises boost pressure to 7 psi when it's off despite showing the exact plumbing in the factory service manual and the solenoid behavior detailed in the FSM.

I say it often, none of this stuff is really Skyline-specific per se. But in general there's not a lot of people who actually know what they're doing. A lot of people charging like they do. Agile software development probably isn't the greatest idea for an engine controller.

For me at least the reason why it bothers me is because it's indicative of a deeper problem. And that will nag at me forever. Especially because I have tailpipe emissions testing + evap leak testing every 2 years.

The RPM is just a target, the ECU will adjust things to try and hit that target but it's by no means guaranteed. If the IACV duty cycle is 0 or something like that and it's actually closing up fully then the idle is as low as it can physically go without reducing ignition timing. The problem can be something like the cold start valve in the IACV not closing fully, worn throttle shaft seals, torn rubber diaphragm in the brake booster allowing unmetered air, etc.

If it's been tuned idle rpm can be changed.

The bumper you're talking about looks like this: Rear wing is this different version which is more GTR-esque:

That is the option code, not the VIN. Regardless all of that production is considered series 2: https://gtr-registry.com/en-ecr33-vin-table.php

Type "M2" means it's a series 2. I would not be shocked to learn that the production changeover was somewhat lax and a late 12/95 production car actually got mostly series 2 parts with a bit of series 1 leftover. Post the VIN and it'll be easier to investigate.

As a general rule removing rubber fuel hose is so difficult I would replace it if it hasn't been done in the last 5 years. The risk you damage the liner or one of the inner layers is pretty high if it's not almost brand new. BMW's recommendations around coolant hoses is similar. My R33's fuel hoses at the fuel tank were so perished that they were ready to burst FYI.

Yeah, that's what he's referring to as far as I can tell. His profile picture shows what he's talking about. Two fuel hoses at the front of the manifold but it's terribly zoomed in.

I really doubt there's a restrictor. Most likely it's just marked so you orient the hose if there's something special about it like sheathing positioned in a specific area to avoid rubbing a hole into it. Or they don't want you to mix up which hose goes where. The one with the filter goes to the fuel rail, then the regulator. Then on the way back it goes through the damper. If there was a restrictor on the damper line it would artificially raise fuel pressure and reduce the ability of the FPR to actually regulate pressure.

I have seen a case where the starter motor shorting against the casing caused a massive voltage drop + so much EMI that it caused all the sensors to spew garbage data at the ECU. Test the battery to make sure it has acceptable CCA/capacity first, I have gotten "brand new" batteries before that couldn't even power a 10W light bulb without dying probably because it sat in a warehouse too long without being charged. Only easy way to diagnose this 100% is put an oscilloscope on the battery and also look at key sensors to see if there's any clues.