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Losing fuel pressure when in wot


V8 Beast

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Before going to NTR a week and a half ago...

Before going to trails I was in my garage doing a safety check on my nitrous setup. I could not get enough power to the bottle heater to do anything more than get it warm. I ended up having to recharge a brand new yellow top after using my bottle heater for 3-5 minutes. Even with the car running I was only able to get a little bit of heat from the bottle warmer. I charged the batter then headed out to trails.

 

At trails...

I noticed after my car sat in line for a while idling my fuel pressure dropped into the 40's. After giving the car a little bit of gas the pressure went back up to 59/60. I also noticed my battery was not charging until I started moving as well. It wasnt struggling to stay running but I had to turn off the ac because it looked like it was draining the battery. After racing there was a faint smell of something burning near the back driver side but I couldnt pin point what it was. After about 10 minutes the smell went away and I drove the car home.

 

Move on to this last Saturday..

When in WOT the fuel pressure drops to 50. At one point while idling (after just turning it on) the a/f went 18 to 1, but the fuel pressure was at 60 when it happened. The car sputtered but did not stall. I turned the car off, then turned it back on and it went back to normal.

 

So what do you think?

Bad alternator, bad ground for the fuel pump, bad relays, bad car battery? bad alernator wiring, just a bad car period? :( Before I start spending money and time this late in the year I wanted to check with the experts.

 

Also the car is commanding rich and wont respond when the tune is changed. Linked to the crazy fuel pump, or just another ghost issue for my wierd car?

 

Running #42 injectors and a racetronix kit. I'm not even at full timing so the pump should be able to handle it. Any help would be appreciated.

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You sir need a volt meter. Check voltage at pump, and battery. Check for fubared grounds, especially at the battery. Finally have battery and alternator load checked, you will need to take it somewhere for that, advanced usually does that for free.

 

Most importantly here is to verify that you are getting good voltage and ground through out the car. It really sounds like it is more than your fuel pump since other stuff is screwing up. I would be looking really hard for bad connections somewhere, battery/chassis grounds, leads from battery and alternator, something like this should be ruled out before condemning any parts.

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All the grounds for the racetronix are inside the frame rail on the driver side rear (infront of the spring). The relay wouldnt be the problem, it will either work or it won't.

 

Have the alternator checked out, have you replaced the battery? I know it used to die on you all the time.

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Thanks guys. Rob I replaced the battery earlier this year. Remember we had this exact same problem but it went away on its own after you put the tranny back in... wierd huh?

 

On the bright side I know why my mph was low on that 10 sec pass. Looks like I lost power somewhere in the run. Hopefully I can find some time to fix it before this weekend.

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Thanks guys. Rob I replaced the battery earlier this year. Remember we had this exact same problem but it went away on its own after you put the tranny back in... wierd huh?

 

On the bright side I know why my mph was low on that 10 sec pass. Looks like I lost power somewhere in the run. Hopefully I can find some time to fix it before this weekend.

 

 

I thought it was randomly not starting then? Was it just losing fuel pressure? Maybe it's been a dying alternator all along.

 

Otherwise check grounds, but they should all be 100%, Maybe the pump is taking a dump, I can check that...

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throw a voltmeter across the battery with the car idling and see what the alternator is putting out....should be ~14.4 volts. I'm assuming you tapped your racetronix kit into the back of the alternator right? That could explain your fuel pressure loss. You could check all the wiring like someone above said but I personally would start by checking that alternator.
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You sir need a volt meter. Check voltage at pump, and battery. Check for fubared grounds, especially at the battery. Finally have battery and alternator load checked, you will need to take it somewhere for that, advanced usually does that for free.

 

Most importantly here is to verify that you are getting good voltage and ground through out the car. It really sounds like it is more than your fuel pump since other stuff is screwing up. I would be looking really hard for bad connections somewhere, battery/chassis grounds, leads from battery and alternator, something like this should be ruled out before condemning any parts.

 

It sounds alot like the alternator, but do the free stuff first. You may only be tighting up stuff that will keep working loose over time. Isn't that worth the extra effort?

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So by me being gay and rob knowing this. he is there fore by default gay as well. and since you are the one passing along the news of me being gay, i then am to assume that you are in fact gay too.

 

Figure out that logic.

 

 

 

Oh and back on topic so my posts don't get deleted, ummmm check your fuel pressure regulator

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