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Adjustable fuel pressure reg


quest4me2
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So, I think I'm having some fuel pressure supply issues. I have the trilogy Delphi injectors and I'm having the typical " sputter on boost" trouble that is typically a secondary injector issue. I have cleaned the inj clips ....I cleaned the conical filter from fuel pump, and checked tank filter. Everything looks good, tank had no rust

 

now, I'm concerned about fuel pressure . I have never check this. The car idles a little rough . I placed the primary inj clip on the secondary inj and it idles great. From what I understand , the delphi's idle a little lean due to spray pattern and possibly could use a few more pounds of fuel pressure .

 

I'm considering getting a rising rate pressure reg with built in guage to allow me to boost pressure a bit to help inj flow at idle and during boost . I don't have a wideband AFM guage. I don't want to tap the injector hat to npt for fear of cracking housing . I figured I might kill 2 birds with one stone ( guage and some control of fuel pressure)

 

any thoughts?

 

Eric

Edited by quest4me2
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if the engine idle'd fine with the sec inj you deff do have some fuel pressure or supply problems,, it should have gone real rich and idle'd like crap,,

 

that small cone filter ,, remove it and place a 3/8 in/out clear plastic carb filter in the supply line ahead of the pump check I-X net and the SOS for how to

 

http://starquest.i-x.net/viewtopic.php?t=1031

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Shelby ,

 

it idles fantastic, rock solid on sec inj ...I'm assuming the green sticker on the injector is the secondary... I'm assuming Trilogy uses same color scheme as stock... I only had one injector clip connected to be sure I had only the sec inj on

 

I do plan on the larger fuel filter before pump mod

 

thanks Shelby,

Eric

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Indiana ,

 

yes I have 146 to 150 psi in all 4....Burns no oil. Runs great otherwise.. Cold a/c!.. I pulled engine when I purchased and went thru it .. Rings bearings , headcheck, new radiator, clutch fan conversion, oil pump, waterpump,timing chain ,fuel filter in engine compartment etc...

 

I really need to check fuel pressure now and really don't want to damage TB top hat trying to install guage , but may have to take a chance.

 

Eric

Edited by quest4me2
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so today, i decided to put the primary inj on the passenger side and the secondary inj on the driver side....but i still had the primary (650 cc delphi) as the primary injector( firing away on the passenger side tho..) .....my idle immediately improved and my sputter on boost is gone....i tested for about 30 minutes and it ran fantastic.....

 

on the delphi's, the 650cc has a 24 degree spray pattern, and the 950cc i think has a 17.5 degree spray....if you look at the business end of the injectors, the 650 has a larger diameter circle of the 6 pin-holes for the fuel to escape.....this must be in play....

 

will test for a few days to see if this continues to hold true....

 

i have Trilogy injectors...

 

eric

Edited by quest4me2
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I really need to check fuel pressure now and really don't want to damage TB top hat trying to install guage , but may have to take a chance.

 

Eric

 

If you do it correctly, there is little chance of cracking the Injector Holder Housing.

 

Remove the Injector holder from the Throttle body.

Place it in a vise.

Use a 6mm, 3/8 inch drive allen head socket to remove the rear plug.

If it does not come out, apply a little heat to it.

After removal, Tap it with a 1/4 inch NPT tap to appox. 3 or 4 threads.

Blow the entire Injector holder out with compressed air and wash it in fuel.

Install a 1/4 inch 90 degree fitting (Male to female)

Install a 1/4 inch male to 1/8 inch female straight fitting.

Install a 1/8 inch Fuel Pressure Gauge.

 

Your done ;)

 

To check fuel Pressure on boost, just remove the FPG and install a 1/8 inch male fitting with a hose bib and buy a piece of hose long enough to reach the Windshield. On that end install a 1/8 inch female fitting with a hose bib. Attach your Fuel Pressure Gauge to it and tape it to the Windshield. The reading is a 1 to 1 ratio. So if you are running 36 psi fuel pressure at idle, and your boost psi is 10. Your Fuel Pressure on full boost should read 46 psi.

 

Good Luck,

Bill

Edited by Caliber308
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Thanks 308....

 

I will do it exactly as you say, with confidence!

Thanks

 

Eric (1911-45acp)!

 

Glad I could help.If you have any other questions about it, just post back.

 

Bill

Edited by Caliber308
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be sure to use a fuel rated hose with propper hose connections, fuel pressure can get quite high, and you don't want it to spray fuel on the hot exhaust manifold.
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be sure to use a fuel rated hose with propper hose connections, fuel pressure can get quite high, and you don't want it to spray fuel on the hot exhaust manifold.

 

That kind of goes without saying :rolleyes:

 

Bill

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so today, i decided to put the primary inj on the passenger side and the secondary inj on the driver side....but i still had the primary (650 cc delphi) as the primary injector( firing away on the passenger side tho..) .....my idle immediately improved and my sputter on boost is gone....i tested for about 30 minutes and it ran fantastic.....

 

on the delphi's, the 650cc has a 24 degree spray pattern, and the 950cc i think has a 17.5 degree spray....if you look at the business end of the injectors, the 650 has a larger diameter circle of the 6 pin-holes for the fuel to escape.....this must be in play....

 

will test for a few days to see if this continues to hold true....

 

i have Trilogy injectors...

 

eric

 

 

I know someone on here that says spray patterns don't mean Jack but only ignorant people think like that.

 

You aim an injector at idle and low rpms at a crack on either side of a nearly closed throttle plate and hell yes the spray angle matters.

Edited by Indiana
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I know someone on here that says spray patterns don't mean Jack but only ignorant people think like that.

 

 

 

So, we must have a lot of ignorant members who have installed Delphis in place of the Stock injectors and their cars have ran just fine.Mine does ;)

 

Bill

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Still collecting some parts to test fuel pressure....but I tried a few things today...

 

I put my VOM meter on my o2 sensor at idle with a warm engine on the primary inj and was reading .188 to .250 or so.... Revving the engine., I could not get it to read over .3 or so.... From what I understand, this indicates lean

 

next , I moved my inj clip over to the secondary inj, and I read .7 to .9 at idle ...this indicates rich, .45 I think is the midpoint...when I rev the engine it goes above 1.0

 

I think the o2 is fine. I think the primary inj is lean for some reason, either regulator , pump, or injector.

 

So I move inj clip back to primary. , read .188 on o2, then pinch off return line on regulator to cause fuel pressure to rise...my o2 sensor reading doesn't change...so either my pressure is not rising or the injector is clogged....

 

Any thoughts ?

 

Eric

Edited by quest4me2
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so, today i put my Voltmeter across the o2 sensor so that the o2 is still connected to ECU ( parallel with circuit ) and at idle with engine warm ( and nose switch disconnected so that it operates open loop, reading the o2) i see around .023 volts (lean) that will increase to .9 or so when i rev it, then it settles back to .02 or so (again lean).....but if i turn on the A/C, i see the output voltage swinging between .02 and .9 back and forth without revving the engine ( i believe this is the ECU correcting mixture)....

 

why doesnt it swing back and forth with A/C off?....it just wants to stay lean... should the ECU be doing the same with A/C on or off?

 

thanks

eric

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