View Full Version : KA24 fuel pressure is static. Regulator or vacuum problem?

Mew2Senshi: The Driver
07-17-2013, 10:34 PM
The KA engine in my S13 still bogs under load. Recently put a fuel pressure gauge to measure pressure. Reads 45 psi on idle, but doesn't change when engine accelerate. I found two vaccuum lines disconnected, one of them from the FPR. Connected them back, but symptoms remain. Could the FPR be ruined, or is there a vacuum problem?

07-18-2013, 07:53 AM
Did the fuel pressure drop when you connected the vacuum line? It should have.

The KA vacuum system is extremely simple... Buy up a few feet of silicone vacuum line & replace them... and cap off whatever you may not be using anymore.

Fixing bogging under load can be as simple as new [properly gapped] plugs, dist cap, rotor & wires along with clean air filter & only using 93 octane fuel.

Mew2Senshi: The Driver
07-19-2013, 09:48 AM
To answer the question: no. The pressure stayed at 45 psi when I connected the vacuum line, whether on idle or accelerated. Since I'm still running the car in stock, wouldn't replacing all vacuum lines be a pain due to the lack of working space between the engine and firewall? Last time I worked the lines they were OK.

This is a recent problem that arose, and I'm sure the use of 89 octane leads to reduced performance, but not like this. This is something that I know it's a quick fix. Since I have a spare FPR, could I check if it's one or another?

Mew2Senshi: The Driver
07-23-2013, 12:25 PM
Never mind. Seems that looking around the vacuum hoses revealed that there was a vacuum leak. Got it fixed and it works well. Thanks.