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Old 09-18-2017, 10:20 PM   #1
lummert
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Default LH2.2 AMM, Fuel Injectors, and Fuel Pressure

LH2.2 AMM, fuel injectors, and fuel pressure. As long as there is still adjustment range remaining on the LH2.2 AMM POT screw (checking AMM with LED test tool) can I increase fuel pressure and injector flow rate. Such as going to 4-hole injectors (which have flow rate comparable to OE Turbo injectors) plus increase from 3 bar to 3.8 bar FPR.

Already running the 30 lbs/hr, 330 cc/min 4-hole injectors on 88 765 w/B230FT. Already have 3.8 bar fpr in my parts stash.
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Old 09-19-2017, 03:23 PM   #2
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Located fuel pressure specs for 1995 Buick Riviera Supercharged:
Ignition on, engine off: 40-47 psi
System pressure while idling: 30.5-44.0 psi
Fuel pump pressure with the return line briefly restricted: 47.0 psi

Same injectors I have installed on my 88 765 Turbo wagon.
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Old 09-19-2017, 04:05 PM   #3
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That screw won't do everything you need it to do. The fuel tables aren't linear. I got brown tops to work with an adjustable FPR and made 209hp/233tq to the wheels on a b21 but it was running out of fuel and still idling a little rich. You should just bite the bullet and MS if you want to have better control of what's going on.
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Old 09-19-2017, 08:31 PM   #4
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This afternoon I experimented with the Dodge/Bosch 3.8 bar FPR. The engine didn't like it. The idle was rough, even after setting the base idle mixture using the LED test tool. The AMM adjustment was nearly out of range at 46 ohms. Seemed to be less crisp on WOT acceleration from a stop. Put the 3 Bar FPR back on and adjusted the AMM using the LED test tool. AMM ended up being set to 136 ohms. With stock injectors the AMM was set to 385 ohms.
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Old 09-21-2017, 12:34 PM   #5
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Info on the injectors I'm running:
0 280 150 934 Also available as Ford Racing Red-top 0 280 150 945
28.05 lb/hr 28.55 lb/hr
294.8 cc/min 300.1 cc/min
212.1 grams/min 215.8 grams/min
36.25 rated psi 36.25 rated psi
2.5 bar 2.5 bar

when rated @ 43.5 psi, 3 bar
30.72 lb/hr 31.27 lb/hr
322.56 cc/min 328.34 cc/min

Not much lower than 0 280 150 804 specs:
32.05 lb/hr
336.8 cc/min
242.3 grams/min
43.5 rated psi
3.0 bar
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Old 10-04-2017, 06:48 PM   #6
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I've come to the conclusion that the White top Bosch 0 280 150 934 (28.05 Lbs/hr at 2.5 Bar) injectors just don't like being run at 3 Bar. At 3 Bar I have an issue with oil/fuel? coming out of the tail pipe at anything faster than 55-60 mph. I have oil spots on the back of my 765 and oil around the tip of the tail pipe. But the oil is thin, as if containing fuel. Running a BMW 2.5 Bar fuel pressure regulator doesn't have the same result but the power output is quite a bit lower.

I'm thinking I need a Ford 4 hole injector that flows at least 30 Lbs/hr at 2.5 bar.

Last edited by lummert; 10-04-2017 at 08:50 PM..
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Old 10-05-2017, 03:51 PM   #7
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May have come up with an adjustable fuel pressure regulator that I could use for tuning between 2.5 and 3.0 Bar. Holley Adjustable Fuel Injection Regulators 515-503-5. Adjustable 35-65 psi. Fits 1984-1987 Buick Turbo (GN/Regal). Direct bolt on for Volvo.
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Old 10-05-2017, 08:09 PM   #8
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Got to wondering what ECT I was running. Go to checking and I was still running the white-connector BMW ECT. Took it out and put in the blue-connector Volvo ECT. Now the car is running fine with the 2.5 Bar BMW FPR.
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Old 10-12-2017, 06:28 PM   #9
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I may have been running a bad 3.0 Bar FPR. It was the only 3 Bar FPR that I had that wasn't leaking fuel. Or so I had assumed that it wasn't leaking fuel. I found a Bosch 3 Bar FPR from an 80's Buick 3.8 V6. While searching through my box of brass fitting I found that I still had the same 0 280 160 237 FPR in the box of parts. This fuel pressure regulator uses A GM o-ring fuel return line with a M14x1.5 male fitting. I had adapted the Buick FPR for use on my 88 765 and got busy and had forgotten about it. I put the Buick FPR on yesterday and adjusted the AMM baseline setting again. The engine is idling well, the power output is back, and I'm not noting the telltale signs of smoke from the exhaust at highway speeds.
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