Fuel pump recommendations
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 915
Likes: 55
From: Muskoka Ontario
Fuel pump recommendations
I have been tracing my non idle issue on my 93. I replaced the fuel filter and no change. I checked fuel pressure and it's at forty but it will not hold at all. Fuel pump next, but what brand ??
Thanks Fred
Thanks Fred
Racer
Joined: Sep 2011
Posts: 462
Likes: 30
From: Riverside California
Team Owner
Joined: Jul 2004
Posts: 28,343
Likes: 3,252
From: Hartford WI
Have someone turn the key to run and not crank, At that moment, crimp off the return line. See if the pressure holds. If it does, look at the regulator next. If it doesn't, repeat test and crimp off the feed line. If it doesn't hold then, go with injectors.
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 915
Likes: 55
From: Muskoka Ontario
Thanks for the info guys. I did my top end build in 2005 when everything was replaced and put about 4000 miles since. So will track down soon I hope, as it will only be on the road for another month.
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 915
Likes: 55
From: Muskoka Ontario
I finally got time to check the old girl again. No fuel in the vacuum line to fuel filter regulator. Checked oil and sure smells of gas. Can I assume that I have a leaking injector ?? It also does backfire sometimes as well, must be too much fuel in a cylinder.
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Melting Slicks
Joined: Jan 2014
Posts: 2,178
Likes: 378
From: Lunenburg MA
A lot of people here use https://fuelinjectorconnection.com/
Burning Brakes
Joined: Apr 2009
Posts: 1,185
Likes: 33
From: Charlotte Michigan
As long as there is some, fuel pressure doesn't have anything to do with idle quality. Marginally-performing fuel pumps usually show up as drivability issues, not idle quality. Please expand on the problem you're having. The way you word "non-idle", to me suggests it won't idle if you take your foot off the throttle. If = yes, things to check would be vacuum leaks, Idle Air Control motor, EGR valve is closed; things of that nature. If you have access to a scanner, info like IAC position, EGR position, BLM and INT fueling, even O2 sensor activity may help focus attention on the culprit.
As far as "fuel pressure drops quickly" when pump shuts off: My experience has been that engines do NOT care one iota what the fuel pressure is when iit is not running. As long as the pressure comes up to spec quickly enough to allow starting, especially with cold oil and temperatures, who cares what it is at rest, or how long it takes to go to zero? Check that the vacuum line on the regulator doesn't contain fuel (it will idle black smoke rich if it does), and that the oil isn't fuel diluted from a very leaky injector (highly unlikely), and forget about the pump if it is easy to start first time of the day.
As far as "fuel pressure drops quickly" when pump shuts off: My experience has been that engines do NOT care one iota what the fuel pressure is when iit is not running. As long as the pressure comes up to spec quickly enough to allow starting, especially with cold oil and temperatures, who cares what it is at rest, or how long it takes to go to zero? Check that the vacuum line on the regulator doesn't contain fuel (it will idle black smoke rich if it does), and that the oil isn't fuel diluted from a very leaky injector (highly unlikely), and forget about the pump if it is easy to start first time of the day.
Replaced the tank and had to clean out the line that was plugged with all those little bits of charcoal witha piece of stif wire and a vacuum from the sensor all the way to the canister.
Team Owner
Joined: Jul 2004
Posts: 28,343
Likes: 3,252
From: Hartford WI
Sure sounds that way. Are the injectors original? You can test further by watching the fuel pressure, but if the oil is diluted I wouldn't run it until I had new/rebuilt injectors in there and changed the oil. It's possible for a leaking injector to hydrolock the engine bending and breaking things. Also, diluted oil doesn't lubricate very well.
A lot of people here use https://fuelinjectorconnection.com/
A lot of people here use https://fuelinjectorconnection.com/
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 915
Likes: 55
From: Muskoka Ontario
They are not original they were replaced back when I did the top end. I thought the same thing about running it. The problem I have now is I don't remember what size injectors I put in back in 06. She puts 350 to the wheels after the tune I had. Thanks for the help.
Melting Slicks
Joined: Jan 2014
Posts: 2,178
Likes: 378
From: Lunenburg MA
FIC can clean and test what you have as well.
Thread Starter
Burning Brakes
Joined: May 2005
Posts: 915
Likes: 55
From: Muskoka Ontario
Problem is I live in Canada and it would be a load of paperwork to send them to the States. Any fellow Canadians know of anyone in Ontario that offers this service ?? I will post this in the Canadian section as well.