Replaced Fuel Pump and Regulator...Survey Says, Still does the same damn thing

[1988WHTGT]

So i posted a while back about my car stuttering and acting weird. Finally ckecked the fuel pressure and it would drop when increasing revs. So I put in a Walbro 255 and a Kirban AFPR, set my prsssure at idle at about 43 psi with the vaccum hose off....rev it up and pressure still drops.....whats going on? Bad injector somewhere? Put a new sock on the pump and new filter when I did everything.

 

[txstang84]

kinked line anywhere?

 

[Polter83]

Where is the gauge inserted.. on the regulator or on the line near alternator?

 

[vristang]

kinked line anywhere?

I would think a visual check of all lines from the tank to the fuel rails would help. If that's the problem it should be obvious by looking at the line.

Can't think of any other potential causes right now.

 

[HISSIN50]

Does it dip for a second and return or dip and stay low?

 

[5.02GO]

Fuel pump is in backwards!



btt..........

 

[1988WHTGT]

The gauge was inserted on the line and it dips when I rev it but then goes back to around 43 at idle. Haven't checked the lines for any kinks yet

 

[ss93cobra]

Checked the filter?

 

[Look Its Aaron]

Check to make sure the filter is flowing correctly?

 

[vristang]

I just had an odd thought.

What is your engine vac like?
How is your vac to the regulator routed?
If it is spliced from the crankcase/pcv then blowby pressure could be affecting how fuel pressure changes?

just a thought.

 

[bsedwebt70-5.0]

just a thought - are you checking the fuel pressure with the vacuum line off and then tapping the gas for it to drop? or do you have the vacuum on and it drops when you tap the gas? It is supposed to go up a bit when you tap the gas with the vacuum line on and I believe it may drop a bit if you tap the gas with the vacuum line off because it is already at the max fuel pressure and you just caused the injectors to "steal" some of the pressure for a moment -- just a thought!

 

[1988WHTGT]

Put a new filter in....and it was doing it with the vac line on and off.....I just dunno....i did notice that the top of one of injectors is a little wet.....u think it could not be getting enough gas on that cylinder and making it break up a little?

 

[JB66]

Make sure your fuel return line is flowing. Has this always been happening since you had the car or did it start after you changed something?

 

[1988WHTGT]

It just started randomly....it was fine after the rebuild and then one day it just started doing it.