J-Rat

iTrader: (2)

Nope, the car is running like a TOP!!! As previously stated, the car starts right up, idles perfect, runs to the redline like a scalded dog, and generally behaves rather well. Whats a good method to check fuelpressure? Inline pressure gauge? I actually have one of those lying around. The only other thing I saw online was that the EGR could cause this. Any truth to the rumor? Plus this IS a new motor so I havent done the initial idle mix adjustments. I dont know if this comes into play since the idle mix is only active at idle. However idle readings are my worst ones. I will put a pressure gauge to the rail tomorrow. Does it matter which one? Or is there a spot that you prefer to use? i assume its after the pressure regulator, which I havent identified yet...

Rat

P.S. I want to personally thank you and Hailers for taking the time to help me....

HAILERS

Put the pressure gauge on the line that comes out of the fuel filter. Tee it in. With the engine idling you should have about 28-30psi and while its idling take that vac line off the fuel pressure regulator and it should jump to about 37-38 psi. That should represent the fuel rail pressure. To check the output of the pump just eliminate the tee and check the pressure right out of the pump(64-85psi). Maybe you'll get lucky and find that someone has put a turbo pump in the car.

J-Rat

iTrader: (2)

The fuel filter is AFTER the pressure regulator? That seems odd... Well, actually nothing on this car suprises me anymore....

HAILERS

No, the regulator is indeed after the filter, but its one of those regulators that bleeds off any pressure over what it is regulating at. You'll have 65-70 psi from the pump to the filter, but the regulator will bleed off anything over 28-30psi at idle and return the excess to the return line to the gas tank, so you'll see fuel rail pressure at the line coming out of the filter. And it goes without saying that if the gauge is stuck in the end of the output line of the filter with no tee and no where for the pressure to bleed off, that you'll have pump pressure of 60-70.
Long way of saying their is no fuel pressure sw that cuts off the pump when the required 28-30 psi is reached.
Just an aside, I found out recently that if one were to put pressure on that vac line that goes to the pressue regulator, the pressure will build up to 50psi in the rail. I used a MITTYVAC as a pressure source and built up 10psi on the vac line and saw the fuel pressure rise up to 50psi. Sorta what happens on your car when you stomp the pedal. The vac disappears and the pressure rises to atmospheric pressure causing the regulator to go from 28 to 37 psi. You'll never see anything higher on your car, but a turbo boosting 10psi should see 50psi if he had a fuel pressure gauge on his car. I've seen 43psi on my turbii when I was just boosting 8.

J-Rat

iTrader: (2)

For some reason I was under the impression that the regulator was like an air, or gas regulator that had high pressure on one side, and the regulated pressure on the other. From what you are saying, the fuel pump gives constant pressure (as most do I am sure). But the ENTIRE fuel line is pressure regulated from the pump outflow to the injectors by the pressure regulator. In essence, the pressure you see at the fuel pump outflow should be the same as the pressure at the rails assuming that you use a tee fitting. Removing the tee fitting and checking pressure BEFORE the regulator gives you the absolute pressure your fuel pump is putting out. Which should be 50-80 PSI. I get it...

Thanks!

Rat

HAILERS

Yep. You put it in clear terms. I ramble a bit and have to admit I'm not too coherent at times. Its going to be interesting to see what kind of pressures you have. No reply needed. Oh, there is a check of the egr that you can do. Find the vac line that goes from the egr solenoid, orange in color, and put a vacuum on that line with your mouth or mittyvac. Lots of times you'll find that the diaphram is broken. If it holds a vacuum, then the idle should get rough when a vacuum is put on the line. Those egr's cost bucks. I've passed submissions with the vac line blocked off. And the egr is under the dynamic chamber, just about inline with the position of the orange egr solenoid. Good to hear that you've got a nearly new engine.

Six Rotors

iTrader: (17)

Hey all good stuff you guys!I would not worry about the EGR valve unless you have a poor idle.You should have passed the NOX test easily.Also the mixture adjusting variable resistance(I am assuming you have an 86-88)only affects idle mixture--it may need adjusting.If you have a later car there is no adjustment.

J-Rat

iTrader: (2)

Yeah, I need to do that adjustment...I know its for idle only. But the motor is new, and the mix still hasnt been adjusted.. Hailers, I may post the pressures anyways just for kicks. Seems like this question gets asked quite a bit on this forum. Six Rotors, would you believe that Arizona gives NO NOX test?? Its only CO and HCs. And my numbers were signifigant, but greatly reduced with a new ACV and some GTP.

HAILERS

Yo. Would appreciate the pressure figures. A little over a month ago I bought a brand spanking new fuel pressure gauge and tee'd it into the fuel line and tied it on my windshield wipers. I was a little disappointed in that at idle I got 33psi and if the vac line was removed from the pressure regulator I got 41-42. Did it on both cars. Not worried but I did the same test 6mo ago with a compression gauge jury rigged to the fuel line, and the figures I got then were closer to the factory manual. 50bucks for a brand new gauge that quite possibly reads high. CheeeeZ. Someday I'll try a third gauge and average out the results. Like I say, not off that much, but still irritates me. What's the sense of measuring something if there's no accuracy. A lot like our oil pressure gauges. Just Feel Good gauges. Not for accuracy.

J-Rat

iTrader: (2)

yeah, the only thing my oil pressure has ever done for me as let me know when there wasnt any pressure at all...

J-Rat

iTrader: (2)

I got the pressures from the pump, inline. The pressure with the gauge inline, engine not running, pump jumpered, was 40PSI. At idle it was 35 PSI. And revving to approx 5-7000 grand, PSI was 38-40. So it looks like those numbers are pretty good. I am gonna hold off on probing any electrical equipment till I can get all the gas cleaned up... Any more ideas??

HAILERS

Well Irv had a good hunch. He mentioned that the previous owner might have put 550 injectors in the car instead of the 460's that belong there. You could look at the secondaries pretty easy and read the numbers off them. The last numbers should be -1350. There is a bit of a problem reading the primaries though, and those are the ones that matter since the secondaries are not operating during emissions testing. Thats all I can think of right now.

J-Rat

iTrader: (2)

YEah, I was trying to avoid that, i have never taken off the top half of that type motor before, and thats the only way that I can think of to get to the primaries...Is it too hard? Guess it doesnt matter, I gotta do it anyways. Another question....Where is a good place to get injectors?

J-Rat

iTrader: (2)

Also, from what you say, the pressure may still be a little high...Shoudnt I have seen 28-39 at idle?

J-Rat

iTrader: (2)

28-30?? OOps..

Six Rotors

iTrader: (17)

Right,well here's the trick(if you still have the pressure gauge hooked on)since you don't know how well the gauge is calibrated,you measure the pressure at idle and then pull the vac hose off the regulator-the fuel pressure should increase by about 5-8 psig.If it does your fuel pressure regulator is OK.

amemiya

hey man why don't you spread the riches, I am always running lean. lol
ok ok I know that J/K was

J-Rat

iTrader: (2)

Well, with the car not idling, but the pump running, I was seeing 40 PSI... And when the car was running, I was showing 35. But I will re-rig my little setup tomorrow and try it again while running, vac hooked up, and vac disconnected (I ended up getting the wrong size hose, so I was pissin a little fuel during the test). I am probably gonna have to yank the injectors out...I dont know how to do this, but I get the impression I am about to learn. This one has me stumped good... I wish I could run lean just for emissions!! But I would rather the car ran right... Six Rotors, if you come up with anymore ideas, let me know...! I am gonna take some O2 readings tomorrow.

Rat

J-Rat

iTrader: (2)

I am gonna try the EGR now...I go the idea from here..http://home.rmci.net/panther/egr_valve.htm