Скачать или смотреть No Smoking Gun… Lean Mixture & Low Vacuum | 944 Turbo Troubleshooting

This video continues my mini parts-restoration series on a 1987 Porsche 944 Turbo (951), and this time the focus shifts from reassembly to diagnostics.

In the previous episode, I successfully completed the reassembly and fired the car for the first time. Unfortunately, once the engine starts to warm up, the car begins running very lean, and I’m also chasing a low vacuum at idle condition, which adds another layer to the problem.

In this episode, I walk through a structured diagnostic process to try and track down the cause of both the lean condition and the low idle vacuum. The goal isn’t just to fix the problem — it’s to rule things out logically and avoid guessing, especially on a turbocharged, 40-year-old Porsche.

Here’s what I test in this video:

Smoke test of the intake system to check for vacuum or boost leaks

Verification of engine timing using the flywheel and camshaft sprocket timing marks

Resistance testing of the AFM Idle Air Temperature (IAT) sensor

External vacuum check to confirm my boost gauge accuracy

Exhaust header runner temperature checks to look for cylinder-to-cylinder variation

Unfortunately, none of these tests reveal a clear smoking gun.

And that’s actually the lesson here.

For any DIY’er working on a classic turbo car, this is a perfect example of real-world troubleshooting. Projects don’t always go as planned, and sometimes progress means eliminating possibilities, not finding instant answers. Creating a test plan, gathering data, and narrowing the problem space is just as important as turning wrenches.

If you have experience with Porsche 944 Turbos, low idle vacuum, lean conditions, or classic turbo diagnostics — I’d really appreciate your input.
👉 Leave a comment if you have ideas on what I should test next.

If you’re following along with this restoration, make sure you’re subscribed and have notifications turned on so you don’t miss the next steps as I continue chasing this issue.

Helpful Links:
Smoke Test Machine:
https://www.amazon.com/dp/B0CFL5RB1L

The Friendly Porsche Forum!
https://Carpokes.com

Keywords:
porsche 944 turbo, porsche 951, 944 turbo running lean, 944 turbo diagnostics, porsche 944 smoke test, 944 turbo timing check, porsche 944 afm, 944 turbo intake leak, classic porsche diy, turbo car troubleshooting, 944 turbo restoration