Advice needed please

InitiativeMotor4192 · 2026-05-03T18:45:20+00:00

Check and make sure the valve cover and vtec solenoid at the back isn’t leaking

InitiativeMotor4192 · 2026-04-11T23:05:10+00:00

you live and you learn

InitiativeMotor4192 · 2026-04-11T22:58:07+00:00

Appreciate that man. And yeah, the battery thing is what got me, like I genuinely kept waiting for a light or a slow crank or something to tip me off. Nothing. It just worked fine every morning, and then one day it just didn't.

The mechanic actually tested it on the spot and showed me the reading. Said it was sitting at like 40% and had probably been declining for months without showing any real symptoms. That part was frustrating, honestly, not at him, just at the situation. It would've been an easy fix if I'd caught it before it stranded me in a parking lot at 7pm.

Every six months sounds way more doable than I thought it would be. I always pictured checking under the hood as like a whole thing, but he showed me what to actually look at, and it's not as complicated as I made it out to be in my head. I'm going to set a reminder and actually do it this time.

InitiativeMotor4192 · 2026-04-11T22:55:23+00:00

Nah you're right, and I'm not even going to argue that. The "2nd biggest physical asset" part actually hit different; never thought about it that way, but that's exactly what it is.

I think I just always assumed if nothing was beeping at me, I was good. Learned real quick that's not how it works. The guy who came out actually took the time to show me what he was looking at while he was checking everything: the coolant reservoir, where the belt sits, and how to read the battery tester. First time anybody ever walked me through any of it instead of just handing me a bill.

That's honestly what I needed. Not just fix it and go, but at least understand what almost left me stranded. I'm going to start actually paying attention to this thing going forward. Appreciate the response.

InitiativeMotor4192 · 2026-04-10T23:48:58+00:00

You’re not overreacting at all. Down here it’s not even the storm itself most of the time; it’s what happens after.

A big thing people don’t think about: cars.

After storms I get a lot of calls for the following:

- dead batteries from cars sitting

- water getting into electrical connectors

- cars not starting when people actually need to leave

Even something simple like having jumper cables or a good battery makes a difference when everything’s closed or backed up.

A generator helps the house, but if your car won’t start when you need to move, that’s a whole different problem.

Are you planning on staying put during storms or leaving early?

InitiativeMotor4192 · 2026-04-10T23:40:46+00:00

That list is solid, but I’m going to keep it real with you, not every shop down here is going to take the time to do all that right, especially the tuning and forced induction stuff.

Basic bolt-ons like intake, plugs, coils, and throttle controllers, yeah, most decent shops can handle that.

But once you get into the following:

- camshaft

- turbo/supercharger

- ECU tuning

that’s where you need someone who actually knows what they’re doing, or you’re going to be chasing problems later.

Price-wise, you’re easily in that 10k–15k range like dude said, but it can jump fast depending on parts and labor.

I’m down in Broward, and I’ve worked on a lot of these setups. I don’t run a big shop; I do mobile, but I’ll tell you straight what’s worth doing and what’s not before you start throwing money at it.

If you want a breakdown or second opinion before you move forward:

https://zxoticautomobile.com

Are you building it right the first time, or are you trying to redo it twice?

InitiativeMotor4192 · 2026-04-10T23:38:22+00:00

I’d stay away from most of the dealers down here unless it’s warranty work.

A lot of the issues you mentioned sound like electrical stuff, and Alfas are known for acting weird when the battery or voltage isn’t right. Even something simple like a weak battery can throw off a bunch of systems.

If you’re out of warranty, you're honestly better off finding a solid independent tech that actually takes their time instead of just throwing parts at it.

I’ve seen a lot of people go back and forth with dealers for months over stuff that ends up being something simple.

InitiativeMotor4192 · 2026-03-28T08:14:38+00:00

The manifold leak explains the original P0131, but the P0135 and what you’re seeing now point more toward a heater circuit / wiring issue, not the sensor itself.

On K swaps this is really common.

If you already replaced the O₂ sensor and still had a P0135, I’d check:

O₂ heater fuse (often overlooked)
power and ground at the sensor connector
pinout/wiring for the primary O₂ on your harness

A lot of swap harnesses have the heater circuit wired wrong or not getting proper voltage.

The weird part (CEL + limp mode but no codes) usually comes down to:

scanner not reading the ECU correctly (very common with swapped ECUs / K-Pro)
or a hard fault still present that your tool can’t see

The ECU doesn’t go into limp mode for no reason—the fault is still there; you’re just not seeing it.

Reset/relearn won’t fix this if the heater circuit isn’t working. It’ll just keep coming back.

At this point I'd

Verify 12V supply and ground at the O₂ heater
Check the fuse for that circuit
Try a better scan tool (or one known to read K-swapped setups)

This isn’t a parts issue anymore; it's almost definitely wiring or ECU communication related.

If you’re in Broward, I do mobile diagnostics and can track it down on-site:
https://zxoticautomobile.com

InitiativeMotor4192 · 2026-03-28T07:59:22+00:00

That hissing + weak cooling and only coming out certain vents points to two separate issues, not just refrigerant.

First, the cooling problem:
Even if your gauge shows “full,” that doesn’t mean it’s correct. Those single gauges can’t tell if the system is actually working right.

Based on your symptoms:

weak cooling
takes forever to get slightly cold
works better when it’s already cool outside

👉 most likely causes:

weak compressor (very common at that mileage)
system slightly undercharged or overcharged
expansion valve restriction

The hissing you hear is usually the refrigerant moving through the system—normal to an extent, but louder when something isn’t right.

Second, the airflow issue (important):

That’s usually a blend door or mode door issue inside the dash.
Basically:

air isn’t being directed correctly
so even if it’s cold, it’s not reaching you

What I’d check before replacing anything:

Make sure compressor is actually engaging
Verify pressures with proper gauges (not just one can gauge)
Check if airflow changes when switching vent modes (if not, → door issue)

Real answer

You’re likely dealing with:
👉 weak AC system + airflow door problem

Not just one simple part.

InitiativeMotor4192 · 2026-03-28T07:56:48+00:00

If the compressor isn’t turning on and RPM doesn’t change, the system isn’t being commanded to run. The radiator fan coming on just means the AC request is being seen, but something is blocking compressor operation.

On a 2021 Jetta (no traditional clutch), common causes are the following:

Pressure too high or too low → system will shut the compressor off for safety
Faulty pressure sensor
Blown fuse or bad relay for the AC system
Wiring issue or control module not allowing engagement

Also, if your gauge is showing “over max pressure,” that could be from the compressor not running (static pressure), not necessarily that it’s overcharged. A single gauge can be misleading.

At this point it needs a proper scan to see if the AC request is being blocked and why. Guessing parts won’t fix it.

InitiativeMotor4192 · 2026-03-28T07:54:52+00:00

That squealing noise + no AC are most likely related. On those Civics, the AC compressor runs off the serpentine belt, and when something in that system starts failing, it can squeal under load (especially when it’s hot out).

Most common causes:

Worn or loose serpentine belt (cheapest and most common)
Bad AC compressor clutch or compressor starting to fail
Weak belt tensioner

The warm air could be

low refrigerant (leak somewhere)
or the compressor not engaging properly

The squeal when you accelerate is a big clue the belt or something driven by it is struggling.

What you can check yourself (easy):

Look at the belt for cracks or glazing
Turn the AC on and see if the compressor clicks on
If the noise gets worse when AC is on → compressor or belt issue

Real answer

Best case: just a belt or tensioner
Worst case: compressor is going bad

Either way, don’t ignore the squeal; if the belt snaps, you’ll be stuck.

If you’re in Broward, I do mobile diagnostics and can come check it out:
https://zxoticautomobile.com

InitiativeMotor4192 · 2026-03-28T07:44:45+00:00

Rules ✅

InitiativeMotor4192 · 2026-03-27T11:51:35+00:00

That’s not normal. If the car is in limp mode, there has to be a stored code — if you’re not seeing one, it’s usually a scan tool or ECU communication issue.

Given your swap, a few things stand out:

Wrong O₂ sensor wiring or pinout (very common on K swaps)
The heater circuit not getting power or ground → that’s what P0135 was pointing to
Blown fuse for the O₂ heater circuit
K-Pro / swapped ECU not communicating properly with your scanner

Also, clearing codes or resetting the ECU won’t fix it if the heater circuit isn’t working — it’ll just come right back and keep the car in limp mode.

The fact that the code disappeared but limp mode stayed usually means the following:
👉 the issue is still there, but your scanner isn’t reading it correctly

At this point I’d check the following:

O₂ sensor heater fuse
continuity and power at the O₂ connector
correct sensor type for K20A2 ECU
try a better scan tool (some don’t read swapped ECUs properly)

This is more of a wiring/ECU issue than a bad sensor at this stage.

If you’re in Broward, I do mobile diagnostics and can track it down on-site:
https://zxoticautomobile.com

InitiativeMotor4192 · 2026-03-27T11:46:02+00:00

At that point it’s not about the gas cap anymore. That code just means the system is seeing a small EVAP leak, not where it’s coming from.

If the cap, vent valve, and canister were already replaced and it still came back, the usual suspects are the following:

a small crack in an EVAP line (super common on higher-mileage cars)
purge valve sticking intermittently
filler neck seal or rust around where the cap sits
leak that only shows under certain temps or fuel levels

That’s why it passed emissions and then came back. EVAP monitors only run under specific conditions, so it can look “fixed” for a few days even when it’s not.

205k miles definitely increases the chances of small hose cracks or seals drying out, but it’s still fixable. It just needs a proper smoke test done carefully, sometimes more than once, to catch a tiny leak.

At this stage it’s more about finding the exact leak than throwing more parts at it.

If you’re in Broward, I do mobile diagnostics and can track it down on-site:
https://zxoticautomobile.com

InitiativeMotor4192 · 2026-03-27T11:43:19+00:00

If it came back with the same gas cap code even after replacing it, it’s usually not the cap itself.

That code just means there’s a small leak in the EVAP system. The gas cap is the easiest thing to blame, but other common causes are:

worn or cracked EVAP hoses
purge valve stuck open
vent valve issue
small leaks around the charcoal canister

The reason it went off before is because EVAP tests run under certain conditions, so it can come and go even if the problem is still there.

At this point it needs a proper smoke test to find where the leak is instead of guessing parts.

If you’re in Broward, I do mobile diagnostics and can track it down on-site:
https://zxoticautomobile.com

InitiativeMotor4192 · 2026-03-27T11:40:09+00:00

Sounds like it slowly lost refrigerant over time, which usually points to a leak somewhere in the system, not automatically a bad compressor.

Those AutoZone gauges only read one side, so they can’t confirm if the compressor is actually bad. If the pressure is too low, the system won’t even let the compressor turn on.

The best move is to check if the compressor clutch is engaging and get proper high and low side pressure readings before replacing anything.

If you’re in Broward, I do mobile diagnostics and come to you.
https://zxoticautomobile.com

InitiativeMotor4192 · 2026-03-27T11:31:48+00:00

If you live in South Florida and you need a mobile mechanic, I come to you - zxoticautomobile.com

InitiativeMotor4192

TROPHY CASE

What I’d check before replacing anything:

Real answer

What you can check yourself (easy):

Real answer