Too high fuel pressure

sreddock · 12-09-2007, 03:38 AM

My pressure gauge has arrived. My fuel line - measured at the tap point on the LH fuel rail - is 50PSI on a 1.8. This is with the engine off & the fuel pump hot wired to run all the time. When the pump stops the pressure drops to about 30. There are no obstructions in the return line or anything like that. The car does have a non-genuine pump fitted but the stock regulator is fitted.

This is pretty high from what I've read. The engine does not run well and will die without your foot on the pedal. Pulling the plugs showed them to be quite black, but given that I've barely warmed up the engine in years it is somewhat expected.

New regulator time?

Cheers, Steve

Jared at Pelican Parts · 12-09-2007, 11:02 AM

Quote:

Originally Posted by sreddock

My pressure gauge has arrived. My fuel line - measured at the tap point on the LH fuel rail - is 50PSI on a 1.8. This is with the engine off & the fuel pump hot wired to run all the time. When the pump stops the pressure drops to about 30. There are no obstructions in the return line or anything like that. The car does have a non-genuine pump fitted but the stock regulator is fitted.

This is pretty high from what I've read. The engine does not run well and will die without your foot on the pedal. Pulling the plugs showed them to be quite black, but given that I've barely warmed up the engine in years it is somewhat expected.

New regulator time?

Cheers, Steve

50psi is too high. The regulator is adjustable. I would play with that before replacing it. You should be running 29psi at all times. If you cant get it to where you need it, then replace the regulator

Jared at Pelican Parts · 12-09-2007, 11:03 AM

also, do you know the flow rates of the new pump? might be a factor as well..

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Jared, wrong EFI system. The 1.8 regulator is non-adjustable, and is referenced to manifold vacuum. It should show higher pressure when the engine is not running (or the vacuum hose to the regulator is disconnected) and lower pressure when the engine is running. Haynes has the pressure spec for when the vacc hose is disconnected; I think it was around 42 PSI?

--DD

sreddock · 12-10-2007, 01:58 AM

Interesting. Thanks all. My vacuum pump is in the mail from our favourite retailer so I'll do more testing once it is here.

This has also answered my next question and I won't be buying the 1.7 regulator which has popped up on Australian ebay as it would be one of the adjustable ones.

Cheers, Steve

Jared at Pelican Parts · 12-10-2007, 07:14 AM

sorry, man.

I totally spaced out on that one. I must have been thinking you had a 1.7

sreddock · 01-04-2008, 01:12 AM

I knew something was up when the running fuel pressure went up to 70 PSI. I had the tank out to rotate the feed/return lines a bit and I felt that there was a little sediment in the filter so I should rise out the tank. I noticed that something was wrong with the return connection - it looked like a thick washer was on the connection. Turns out this was my missing fuel strainer, which was on the return line. As there was no other filter in the system (stupid PO) this was collecting all the crap which didn't end up in the injectors or jamming the fuel pump and was keeping the pressure up. I now have a new strainer on the INTAKE and all is well.

I keep finding stupid things the previous owner did...

Steve

PS Yes I put a filter in line, it was the first thing I did.