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Bosch 0 280 155 811 Injectors

Do you have any info on making one of those led tools? I remember a thread years back but 15 min on google and i cant find anything about making one just using one.

Cause you have me wondering now... i havent touched my amm and we have the same injectors (well basically, mine are 363@3bar). All i did was adapt an adjustable fpr to the rail and set that. Idles fine and afrs are perfect in boost and cruising so i didnt think anything of it.

Also amm adjustment only effects (affects?) Idle right? Or am i mistaken
 
Do you have any info on making one of those led tools? I remember a thread years back but 15 min on google and i cant find anything about making one just using one.

Cause you have me wondering now... i havent touched my amm and we have the same injectors (well basically, mine are 363@3bar). All i did was adapt an adjustable fpr to the rail and set that. Idles fine and afrs are perfect in boost and cruising so i didnt think anything of it.

Also amm adjustment only effects (affects?) Idle right? Or am i mistaken

I made my LED tool with a large 12 volt LED from Radio Shack. This LED has a built in resistor, so addingbresistors isn't needed. It has been my experience that adjusting the AMM pot screw effects more than just the isle mixture. I think you can find info on making your LED test tool by searching for LH 2.2 setting baseline isle mixture.
 
I used a dwell meter to check for injector duty-cycle using the 6 Cyclinder scale. got 21 degrees or 35% duty-cycle at idle. This is with adjusting the AMM pot screw to just a hair rich (LED constantly lit, turn counter-clockwise just a hair and the LED is on more than off) on the LED tool. Adjusting the AMM pot screw in or out has no effect on the dwell meter with the exception that the meter dithers at the same time that the LED blinks. Is 35% anywhere in the ball park? 30 degrees would be 50%, 39 degrees would be 65%, and 60 degrees would be 100% duty-cycle.

Specs that I find indicate latency (dead time) at 12 volts: 0.605 ms; 14 volts: 0.305 ms.

Pulse width of 0.605 ms @ 12 volts calculates to 0.38% duty cycle.
Pulse width of 0.305 ms @ 14 volts calculates to 0.19% duty cycle.

Some specs for Bosch
0 280 155 737
0 280 155 811
0 280 155 868
36 lb/hr @ 43.5 psi
380 cc/min @ 3 Bar
Gain: 0.12 ms/MG
Offset: 0.055 ms
Turn on time @ 14 vdc: 1.14 ms
Turn off time: 0.85 ms @ 3 Bar
Amperage: 1.0 amps
Pressure: Minimum: 30 psig; Maximum: 100 psig
Accuracy: 2.5%
 
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Okay sounds good, thanks.

One other question though. Why did you check dwell on the 6cyl scale for a 4cyl engine?





Edit for another question. You do have a fresh o2 sensor in there right? Cause otherwise all this adjustment is for naught. And thanks for the search suggestion i used those terms and found a schematic. Now to build one and try it out myself to see if our results correlate
 
Okay sounds good, thanks.

One other question though. Why did you check dwell on the 6cyl scale for a 4cyl engine?

My old dwell meter only has 6 and 8 cylinder scales. The 6 cylinder scale is easier to read than the 8 cylinder scale. Duty cycle conversion charts are available for 2,3,4,6,and 8 cyl. 50% duty cycle is 45* on a 4 cyl scale, 30* on a 6 cyl scale, and 22.5* on an 8 cyl scale. 100% duty cycle is 90* on a 4 cyl scale, 60* on a 6 cyl scale, and 45* on an 8 cyl scale. How many cylinders the engine has has to bearing in this case.




Edit for another question. You do have a fresh o2 sensor in there right? Cause otherwise all this adjustment is for naught. And thanks for the search suggestion i used those terms and found a schematic. Now to build one and try it out myself to see if our results correlate

I don't have a fresh O2 sensor, but I have 2 spare OE O2 sensors, The O2 sensor is switching, I've checked for that.
 
Oh okay i got ya, carry on lummert ill join you when i get the chance. Probably this weekend cause now that i think about it, i quit driving that car cause mpg sucked idling in traffic to work every day. I figured i was just used to my 30mpg 1.8t but now youve got me thinking the idle mixture is just wrong.
 
Went out in the cold ass weather to check duty cycle using a higher quality KarCheck Dwell Meter, Clark engine analyzer, and LED tester. All 3 connected between the ECU test lead and battery positive.

Engine off/key off:
LED tester steadily lit:
5 volts steady
73.8* on 4 cylinder scale (calculated) = 82% duty cycle
49.5* on 6 cylinder scale = 82% duty cycle
37.0* on 8 cylinder scale = 82% duty cycle

Engine warm and in closed loop:
LED on more than off
5 volts on more than off
60* on 4 cylinder scale (calculated) = 67% duty cycle
40* on 6 cylinder scale = 67% duty cycle
30* on 8 cylinder scale = 67% duty cycle

Is this too rich? Should I try running same tests with 3 Bar FPR installed?
 
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Whats the factory duty cycle speced at? Me thinks you could divide the DC into your actual injector flow rate and compare that to the same calculation done with factory specs.

Or just get a wideband and youll know for sure of its too rich instead of all this black magic math and guesstimation.
 
Today I swapped back to the BMW 0 280 130 023 ETC.

Lowered the Idle duty cycle to 61% (36.5* on 6 cylinder scale, 27.5* on 8 cylinder scale) from 67%.

The engine off/key off duty cycle increased to 85% (51.0* on 6 cylinder scale, 38.0* on 8 cylinder scale).

I read on a Corvette forum that increasing fuel pressure will lower injector duty cycle. Since I'm running lower pressure 2.7 Bar (39 psi) FPR, I'm wondering if swapping back to the 3 Bar (43.5) FPR will lower the idle duty cycle. My calculations show that increasing the fuel pressure back to 3 Bar should lower the idle duty cycle to 55%.
 
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Swapped back to Bosch 0 280 160 237 3.0 Bar fuel pressure regulator from 1989 Pontiac Turbo Trans Am.

Fuel pressure test:
40 PSI w/ vacuum hose connected
44 PSI w/o vacuum hose connected and plugged

Duty cycle results at idle in closed loop are:
54* on 4 cylinder scale = 60% duty cycle
36* on 6 cylinder scale = 60% duty cycle
27* on 8 cylinder scale = 60% duty cycle

Duty cycle with engine off:
72* on 4 cylinder scale = 80% duty cycle
48* on 6 cylinder scale = 80% duty cycle
36* on 8 cylinder scale = 80% duty cycle

Now to run wire from test point into the car to check duty cycle at about 6000 RPM.
 
Starting to notice that these injectors work better at 2.7 Bar fuel pressure. Engine idles rough until it warms up at 3 Bar fuel pressure. Duty cycle is nearly the same at either fuel pressure. Idle: 60% compared to 58%. Engine off : 82% compared to 79%. So I take it that the fuel pressure difference has little effect on the duty cycle. So go with the fuel pressure that works best for the injectors?

Info that I found on Mustang Cobra site about running injectors that are too big:
* Lower fuel pressure and increase injector openings.
* Run richer at idle.
* Run a less aggressive injector if ECU allows it.
* Raise the idle speed.
* A combination of a few above...
 
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Swapped to a second BMW 2.5 Bar FPR because car was hard to start this morning (35* F) with the Buick 3.0 Bar FPR. Now to wait for it to warm up a bit outside to do a pressure test with this other BMW FPR.

Looking through my FPR's to see if I have a good OE Volvo type FPR.
 
Today I found a different dwell to duty cycle conversion chart. I retested with the dwell meter on a warm engine and got 36 degrees on 6 cyl scale. According to this chart 36 degrees on 6 cylinder scale = 40% duty cycle. 40% duty cycle at idle in closed loop makes much more sense.

Ground controlled circuit @ 36 degrees on 6 cylinder scale = 40% duty cycle
Feed controlled circuit @ 36 degrees on 6 cylinder scale = 60% duty cycle

Not sure about the voltage reading that I was getting. With dwell meter at voltmeter connected at same time between test point and battery positive showed 5.95 VDC. 5.80 VDC corresponds to 60% duty cycle on same chart.
 
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Found specs for 36 lbs/hr injectors when running at 39.15 psi (2.7 Bars).

34.0 lbs/hr @ 39.15 psi
357.3 cc/min @ 2.7 Bars
257 grams/min @ 2.7 Bars

35.84 lbs/hr @ 43.5 psi
376.7 cc/min @ 3 Bars
.52 BSFC - Estimated HP @ duty cycle
52.3 @ 80%
62.1 @ 95%
 
Duty cycle is calculated by comparing the injector pulsewidth to the time it takes to complete an engine cycle.

For example, an engine idling at 800 rpm takes 150ms to complete one full engine cycle of 720 degrees crank rotation.

If your idle injector pulsewidth is 3ms then your injector duty cycle is 2%. Simple as that.

You’re trying to look far to into this.
 
Duty cycle is calculated by comparing the injector pulsewidth to the time it takes to complete an engine cycle.

For example, an engine idling at 800 rpm takes 150ms to complete one full engine cycle of 720 degrees crank rotation.

If your idle injector pulsewidth is 3ms then your injector duty cycle is 2%. Simple as that.

You?re trying to look far to into this.

One thing I know for sure is that these injectors (Bosch 0 280 155 811) work best at 39.15 psi (2.7 Bars), same as when running these on a Ford Mustang.
 
When you?re trying to patch it into a different application such as this, maybe. When properly controlled they?ll operate just fine with any other common fuel pressure.
 
Running these 0 280 155 811 injectors at 2.5 Bar resulted in an average of 14 MPG with my 1988 B230FT on LH 2.2. Yesterday I dug out another Bosch 0 280 160 237 3 Bar Fuel Pressure Regulator that was in my stash and installed it. This FPR fits 1989 Pontiac TTA (Turbo Trans Am), as well as other 87-92 GM cars with 3.8 L V6.

The specs are:

37-43 PSI with vacuum connected
40-47 PSI with vacuum disconnected and plugged
Buick has it rated at 45 psi.

I installed this fuel pressure regulator without any adjustment to the AMM POT screw. Waiting for the rain to let up long enough to check the baseline fuel mixture adjustment. The engine has a decent idle and good power. The warm starts seem to indicate that the fuel mixture is slightly rich. I also need to hook up the pressure tester and check against the FPR specifications.
 
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