My engine is still running very rich. One thing I recently noted was that with the ignition switch "on" (engine off), the fuel pump comes on, but does NOT shut down after a second or two. In fact it just keeps on pumping as long as the key is "on". Could this be any reason I am running rich? Thanks.

Submitted by dougdwyer@adel… on Mon, 05/01/2006 - 02:10

First, William is correct---a fuel pressure test is very important.

Yes, you can eliminate the right side regulator.

Doug Dwyer
Longview Washington USA
1987 XJ6 Ser III
1988 XJS V12 Coupe

Submitted by bonnettoboot@e… on Sun, 04/30/2006 - 19:25

YOU HAVE TO FIND THE PROBLEM FIRST BEFORE CHANGING THESE PARTS! It could be any thing including a leaking injector? Get a fuel pressure test to establish a datum for your problem. Jaguar affectionado and etc.

Submitted by rleeds9@yahoo.com on Sun, 04/30/2006 - 08:05

Doug:
Basically, my CO levels are about four times the normal, and my gas mileage has dropped to about 10mpg. I'm planning on adding new o2 sensors, coolant temp sensor, air temp sensor, full tune-up including inspection of distributor and vacuum advance. Also, thinking of replacing the fuel pressure regulator(s). Am I missing anything?

Thanks!

Rodd Leeds

PS Can I delete the RH side fuel pressure regulator and run with just one regulator?

Submitted by dougdwyer@adel… on Fri, 04/28/2006 - 23:43

While what you describe is not proper operation of the fuel pump circuit it would not cause an over-rich condition.

The pump should run for about 2-3 seconds opon switch the key "on". After that it runs only when the starter is engaged and, of course, when the engine is actually running.

Common causes of rich running are the coolant temp sensor, a faulty pressure regulator, a broken enrichment switch at the throttle capstan, and disconnected/leaking vacuum hose the the ECU.....

Could you give us a memory refresher on the situation?

Doug Dwyer
Longview Washington USA
1987 XJ6 Ser III
1988 XJS V12 Coupe