digital fuel psi gauge

[85 ttypewh1]

does anyone use a digital guage with a remote mounted sending unit with a 2 wire conn, the reason i am asking is i hooked up my guage and my fuel psi was 39 at idle line off with the stock fpr. then i installed the adj. fpr by accufab that i got from poston and keyed up the car and got only 19psi. tried to start the car and it would die, turned the allen screw it jumped to 25 psi tried to start and died, turned again it jumped to 30 then 35 then 40 as i was turning it little by little. started the car and got it to 43 @ idle vac line off, hooked up line and it went down to 38. While just normal driving it stayed at 39 and when i boosted it went up 1 for 1, the ? i have is will the psi move from 0-20 hg vac or stay the same and did anyone elses start at 19 psi, and does the sending unit react slow and since this is a 2 wire does the unit body need to be grounded, right now the allen screw is about half way screwed in is this normal. Thanks.

 

[charlloots]

what size injectors do you have 43psi at idle with vac off sounds about right yes it will drop when you put the vac back on 19 psi is way to low thats why there called ajustable fuel regulators

 

[85 ttypewh1]

I know 19 psi is toooo low, i was asking if anyone elses started at that point because now i only have a couple of threads left to adjust which does not give me much room. The instructions said the psi would drop 10 psi with the line on and it only dropped 3-4 and i wanted to know if this was the norm.and i have stock injectors.

 

[2QUIK6]

I think the norm is closer to 5-6 lbs drop with the line connected. You should have about 15-20in of vac at idle in a good healthy motor, if you don't have that much vac then a cam lobe may be wiped, but a good 20in of vac will only pull it down about 6 lbs has been my experience with it. Now, it does sound like your fp reg may be wacked if you only have a few threads left and only have 43# with the line off. Mine is screwed in about half way to get 43#, I can easily raise the pressure up to about 52# with line off if for some reason I wanted to. You shouldn't need any more than 47-48# with stock injectors. If still running lean at that psi fp, then you need bigger injectors. Make sure you upgrade the fuel pump also. I say the fp reg and pump should be the first mod to any TR thats 17 years old if you want to ever push the pedal more than 75% down....and what fun is a TR with the pedal being pushed down 100% ?

 

[2 SLOW]

I also run a accufab regulator. I wouldn't think anything would be wrong with it . I would check the fuel filter to see if it is plugged (I just had that problem). When you get it off and get the gas out of it, try blowing through it. If there is any resistance it is plugged. And I would just get a new fuel pump. Why take the chance? Its an old car and you probably don't know when or if they have been changed.

Good Luck

 

[2QUIK6]

One other thing I forgot to mention, use a manual gauge hooked up to the schreader valve on the fuel rail. Electric fuel pressure gauges can be way off sometimes, and the next day they are right on...I've always had wacky results with electric fp gauges and connecting grounds directly to the sender never seemed to help. I've had VDO, Cyberdyne, and AutoMeter electric gauges, and the AutoMeter is the only one I've had work consistantly so far, but its off by a few lbs.

 

[85 ttypewh1]

I just installed the hot wire today, that harness was just long enough. I have a walbro 340 just have not put it in yet, I want to do it now but i still have 3/4 tank of gas and its getting dark out and everytime i try to do something at night it alwayus takes longer and something will go wrong. Thanks for the input guys i did notice when i got the hotwire done my fuel psi reacted quicker for some reason and not it changes in the vac range.