Jump to content
Sign in to follow this  
ralt962

High Fuel Pressure

Recommended Posts

I've done a complete engine rebuild with a mild cam.  I wanted to see if others had an issue with fuel pressure.  Finally getting to start the thing, running at break in around 2000 rpm.  I started getting fuel coming out the vents.  Tried all the float levels and cleaned the needle and seat.  (brand new Holley 600).  New Carter fuel pump.  Today I installed a pressure gauge to see if that is the issue.  Again at break in speed, I was getting up to 15psi.  Pump is rated at 6.5 max.  It started at about 8 or 9 and climbed to 15.  

I have a Holley regulator I'm going to install tomorrow.  See if that helps. 

I cant run it more than a couple of minutes before the fuel starts coming out the vents.  

 

thanks

Share this post


Link to post
Share on other sites

I am running a Holley 780 cfm with a Carter m6905 and a fuel pressure gauge.  Never have any problems and the gauge reads 6 ish psi.  The regulator may help ?  I have never had much success in the past using them.  I think a phone call or email to Carter stating your problems might be something to investigate ?  I have emailed Carter before and found them to be very responsive and helpful.  Brian

69 Carb. Fuel Line 2.JPG

Share this post


Link to post
Share on other sites

I would double check the specs on the fuel pump.  Some pumps are adjustable and there may be a way of changing it's output.  Otherwise if it is that far off spec switch it out.  I run a Holley fuel regulator with a Holley 7-11 pump.  The regulator keeps at 8.  Smaller Holley carbs supposedly can handle 9 over that it will over flow one way or another. 

Also the regulator will fix your problem I think but if your pump is pushing higher pressure, deadheading it may create a failure waiting to happen with the pump.  Just my 2 cents.

Share this post


Link to post
Share on other sites

I'm running a Carter M6588.  spec'ed for 5.5-6.5.  But running 15.  I just installed the Holley regulator.  That did the trick.  Its running around 6.5 and the issues have cleared up.  

But MN69Grande, you have a good point.  If its running such high pressure, is it a failure waiting to happen.  

Brian,  thanks also good suggestion, I will get a hold of Carter.  Certainly seems like this could be a different problem down the road.

I do have to give credit to the Holley regulator.  Working as it advertised.  

Thanks for all the quick feedback.  Great suggestions.

Share this post


Link to post
Share on other sites

The Carter M6588 is merely a stock replacement fuel pump.  Something is definitely wrong with it.  When you get some time its worth replacing.  The regulator worked but is merely covering up the problem.  Like MN69grande mentioned, there may be a failure waiting to happen.

Between the pump and the regulator I'd guess you are reaching pressures of 15 psi.  Just be a little cautious if there are rubber hose and clamp connections in that section of fuel line. 

Share this post


Link to post
Share on other sites

Thanks,  totally agree something must be wrong with the pump.   I'm not on the road yet so I have some time and will contact Carter and go for a replacement.  

The guys building the Roush crate motors recommended the Holley pump.  Not sure which one, but I'm going to look into that.  

Have never seen so many new parts give such trouble.  Seems there is no more bolt it on and go.  Need to verify everything.  

Share this post


Link to post
Share on other sites

Hello all,

Just want to say I think the best solution is change the fuel pump.

I am not a big fan of the regulators - -especially the cheap models

Something is wrong with the pump = =change it or I fear you will have other issues in the future

 

Just thoughts from the old guy- -Print dad -Sam

 

Share this post


Link to post
Share on other sites
5 hours ago, ralt962 said:

Thanks,  totally agree something must be wrong with the pump.   I'm not on the road yet so I have some time and will contact Carter and go for a replacement.  

The guys building the Roush crate motors recommended the Holley pump.  Not sure which one, but I'm going to look into that.  

Have never seen so many new parts give such trouble.  Seems there is no more bolt it on and go.  Need to verify everything.  

Contacting Carter might lead you down a circular maze.  First thing to try is exchange it from where it was purchased.

The Holley mechanical fuel pumps I've seen that have lower fuel pressures designed to be used without a regulator are fairly poor quality.  Purchased one once, opened the box, looked at it., then returned it.  Their high end stuff will need a pressure regulator.  The Carter pump you have is a good stock replacement part.  Unfortunately, you just happened to get a bad one.

Share this post


Link to post
Share on other sites

I ended up buying an Edelbrock pump from Roush.  They have tested many units and exclusively use these on their crate motors.   I also got some information on why the Carters have issues.  So I'm sticking with what has been tested.  Roush says they have had no issues since shifting to the Edelbrock pumps.  I bought the street version since my engine is farily mild.  

I'm going to install the pump this weekend.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...