Re: Electric fuel pumps

Tue Jan 07, 2014 9:53 am

Several years ago I had an Aerostar van that was my tow vehicle which I really liked. About 5k past warranty it started getting low on power and check engine light on. took it to dealer, and he called with good news and bad news. good news, the fuel pump which was a 500 dollar repair had to be changed but Ford would cover it. Bad news, I had to pay for tune up. I did not think any of it was bad news.

Re: Electric fuel pumps

Wed Jan 08, 2014 11:27 am

Your issue may very well be a failing fuel pump, but the cause of the failure needs to be found.

Low fuel pressure on the fuel rail will cause an engine to run lean. The O2 sensors will sense the lean condition and ask for more fuel causing the pump to work harder. The low fuel pressure may be due to a plugged fuel filter. Most cars today have a couple of them. One under the body probably near the footwell and one small one near the throttle body. Check your vehicle manual for the replacement schedule, but they should be replaced about every 35,000 to 75,000 miles. Some vehicles have an "in tank" filter.
This important service is often neglected because the "car runs fine".

Edit: Some vehicles have two fuel pumps. A high volume electric pump that moves the fuel to the engine compartment and a mechanical pump that is camshaft driven to pressurize the fuel rail.

Re: Electric fuel pumps

Thu Jan 09, 2014 6:48 pm

outdoors4evr wrote:
Your issue may very well be a failing fuel pump, but the cause of the failure needs to be found. Low fuel pressure on the fuel rail will cause an engine to run lean. The O2 sensors will sense the lean condition and ask for more fuel causing the pump to work harder. The low fuel pressure may be due to a plugged fuel filter…

Yes I agree one of the first things to look at is fuel pressure and fuel flow.

Other things that could cause a lean condition is check for high concentration of alcohol in the fuel, (alcohol will make an engine run lean) vacuum leaks ect….

If anyone is interested….This is a problem I had on a Truck I bought with a fuel pump problem that made me lose some of what little hair I have left.
Re: Cars Today Are Smarter Than Me
by JackF » September 7th, 2012, 7:10 am
http://www.farmallcub.com/phpBB2/viewtopic.php?f=4&t=73375

Re: Electric fuel pumps

Sun Jan 12, 2014 2:13 pm

Replaced the fuel pump relay and have driven the car on a few errands about 25 miles total with no problems. Did not run it up to the rev limiter. As far as I know, only the franchised dealer has equipment to check the fuel pressure on this car under all operating conditions. Minimum of about $150.00 for that. The previous run-on of the pump after the switch was off makes the relay suspect in my mind. Could the car start and run for a couple of seconds if the relay failed to pull in and run the pump? Could the relay stick in both contacts closed and contacts open positions?

Re: Electric fuel pumps

Mon Jan 13, 2014 5:33 am

Bus Driver:-Could the car start and run for a couple of seconds if the relay failed to pull in and run the pump?
I don’t know Nissans, but the engine will not run unless the relay activates the fuel pump.
Could the relay stick in both contacts closed and contacts open positions?
Mechanical relays I guess can fail many ways. Usually from the points arcing (opening and closing) will cause a deposit on the points tip in most cases to cause the points to stick close.

Try taking the cover off the old relay and look at the “pull in points’ tips.