Hello guys...

Here is the issue, I installed a twin fuel pump setup last Saturday, did all the hoses and wiring... the secondary pump is set at HS3 to activate after I get 15 psi at about 4000rpm... did some test runs and everything seems to be working fine... Then after a couple of low speed test I noticed that while cruising around, when the car hit the 3500rpm it goes LEAN (like 20 AFR at my Innovate Wideband)... the car is in that lean condition from 3500 to 3800 rpm... and then is normal (before that and after that)... I haven't had the chance to Dyno tune it yet.. but the thing is that this lean condition appears just after the installation of the twin pump... why...?

Any help would be much appreciated..!!

Thanks,

Miguel

 

OK, here some things I did yesterday... I reduce a little bit of timing and added a little more fuel and that seems to corrected the issue a little bit, but now the lean condition moved at 3800rpm...!!!??? before this my maps were smooths, and flowing from low to hi in a steady way.. now has some bumps and spikes...??!!!!??


Later,

 

Check your base fuel pressure and your fuel pressure regulator.

 

Could be a bad fuel pump...?

 

I believe you need to have the second pump coming on sooner then 15 psi. I'd say around 8. If the pumps are brand new a bad pump is kinda unlikely but if not its a possibility. They don't last forever.

 

I'll try that... if the issue is solved, then I had a bad fuel pump..!!

Thanks,

 

OK... just did that and now the car is overly rich, so, I have a bad pump... time to change that sucker ..!!

 

I have the same problem is there a way to check the pump? Had the twin in there for about 2k miles

 

What twin pump setup do you have..? it easy to check each pump individually, each pump is connected separate from each other, so, just connect each one (one at a time) to a +12v source a see if it is working.
My problem was trying to set when the secondary pump activate. Remember with the AEM you can set it for a pre-set RMP, boost, throttle or Temp.... Once you know when you want the pump to start pumpiing, is just a matter of adjusting that parameter.

Later,

 

Thanks its a buschur set up. I have the second pump comming on with the hobb switch. The primary is not make and loud noise and I notice with the primary pump at 3k rpm rev in neutral the fuel pressure has a small "twitch" in pressure
Thanks

 

Sorry for digging up an old thread, but does anyone else have this problem? My car does this same exact thing at 3800 rpm or so, goes flat on the WBo2 and then recovers after 4k. If I am WOT I will have to ad about 35% fuel to make it not so lean.

I do also have a double pumper.

 

Sorry I dind't posted my solution before... In my case was a faulty MAP sensor. I changed the sensor and everything was nice and smooth again.

Good luck..