• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Bosch 0 280 155 811 Injectors

I'm trying to devise a test to check the Bosch 0 280 150 943 injector that I took out for leaks. I know I should have tested the injectors for leak down before pulling them from the B230 fuel rail. From what I've read I can pressurize the injector inlet with air and check for air bubbles from the injector outlet into a container containing something liquid such as rubbing alcohol.

If I find that I have four good 0 280 150 934 injectors out of the six that I have I may put them back in. These injectors are a better match for a B230FT running LH 2.2
 
I pressure tested the four Bosch 0 280 150 934 injectors that I was previously running at 20 psi. Two of the four leaked down within 5 minutes.
 
I pressure tested the four Bosch 0 280 150 934 injectors that I was previously running at 20 psi. Two of the four leaked down within 5 minutes.

Tested the 2 spare 0 280 150 934 injectors. They passed, so I now have 4 good injectors out of 6.

Now the big question...Do I keep running the GEN III 0 280 155 811 White-top injectors flowing 346.89 cc/min @ 2.5 Bar (380.0 cc/min @ 3 Bar) or do I swap back to the 0 280 150 934 white-top injectors flowing 315 cc/min @ 3 Bar (300.1 cc/min @2.5 Bar)? The LH 2.2 AMM has to be adjusted quite low for the higher flow 0 280 155 811 injectors, even at 2.5 Bar. The 0 280 150 934 injectors work just fine on LH 2.2 at 3 Bar.

Minimum pressure for Bosch GEN III injectors is 30 psi (2.0689 Bar), Maximum is 100 psi 6.8964 Bar.
 
Still looking for comments on reinstalling the 0 280 150 934 - 30 lbs/hr @ 43.5 psi (315 cc/min @ 3 Bar) injectors. These injectors came from a Supercharged Buick 3.8L V6. They are high-resistance 4-hole nozzle injectors with the correct grooves for fuel rail clips. Ballast resistor has already been bypassed.

The 0 280 155 811 - 34.3 lbs/hr @ 43.5 psi (360.5 cc/min @ 3 Bar) injectors came from a Supercharged Buick 3800 V6, The flow rate of these injectors @ 3 Bar appears to be too high for LH 2.2 with stock AMM. Running these injectors @ 2.5 Bar appears to be the only option. I do not have a 2.7 Bar fuel pressure regulator available to try with these injectors. Mpg's seem to be much lower than with the 30 lbs/hr injectors @ 3 Bar, so I'm guessing that these injectors are not atomizing the fuel all that well at 2.5 Bar.
 
Managed to find washer and pintle cap kits at Advance Auto. $1.29 plus tax for 8 kits. Next is a O-ring kit. About $4.49 for 12 o-rings.

My car is being really thirsty with the White Giant injectors. 65 miles on $10 worth of gas. 3.691 gallons at $2.709 per gallon. This was 40 miles highway and 25 miles in town. Averaging 17.6 MPG. My car can average 20 MPG.
 
If the AMM is adjusted to 004 ohms (380 ohms starting point) with Bosch White Giant injectors and 2.5 Bar fuel pressure regulator do I need to do anything with the ignition timing? I'm thinking that I need an LH 2.2 AMM for a PRV V6.
 
Swapping back to the 0 280 150 934 white-top injectors didn't go as planned. One of the injectors was dead. Swapped back to the 0 280 155 811 white giants. Swapped back to the 3 bar fuel pressure regulator and set the AMM to 004 Ohms (which is where it was set for the 2.5 bar fpr). Started it up and the AMM adjustment was close enough to use the LED tool.

Was researching the 0 280 155 811 white giants. They replace the 0 280 150 911 red-top injectors for Porsche 911. Specs for 0 280 150 911 are:

32.55 lbs/hr @ 45 psi
342.1 cc/min @ 3.1 bar

Curiously the 0 280 150 934 white-top and 0 280 155 811 white giants have the same specs at 3 bar:

29.3 lbs/hr @ 43.5 psi
307.9 cc/min @ 3 bar
 
Figured out how to modify pintle caps to work on Bosch GEN III injectors with recessed tips. Use the lower barrel of a Pilot G-2 gel pen. Press the pintle cap onto the threaded part of the barrel. Place used injector 0-ring onto pintle cap. Use belt sander to take the tip off the pintle cap down to the o-ring. Clean up the edge of the pintle cap. It's now ready to use on GEN III injector. Takes about 15 minutes per pintle cap.

Yesterday I made a run in windy, rainy, 55 degree conditions with my 88 765 on these injectors with the AMM set to 24 ohms. Averaged 19 MPG. Today I purchased new injector 0-rings. Next up is pulling injectors to install the pintle caps and new o-rings.

Next question is this...As long as I still have adjustment on the LH2.2 AMM do I need to add a resistor between the AMM and the ECM?
 
I checked the AMM between pins 2 and 3 with my multimeter and came up with 4.5 ohms. According to LH2.2/2.4 Fuel Management Information **Updated** from Bentley Manual the resistance between pins 2 and three should be:

LH2.2 3.5-4.0 Ohms
LH2.4 2.5-4.0 Ohms

According to this info my AMM resistance between pins 2 and 3 is off by 12.5%. Is this correct?
 
You may have already seen this web page but found some of the info interesting and Volvo specific.

http://people.physics.anu.edu.au/~amh110/Injectors/bosch_injector_028050403.htm

"Larger Injectors on a 740 Turbo ?
A number of people have tried larger (eg. 370 cc/min (std 300)) injectors with little success using the standard LH-Jet 2.2 Turbo factory fuel computer and separate EZK ignition. It seems the engine sensor / mapping parameters cannot compensate enough for the increased injector flow and the system runs very rich both during idle and running - Probable reason for rich running - the computer still delivers the same mapped injector pulse width, it doesn't know your using a 66% larger injector. Bill Watson reports that at 11 psi boost in his 87 745, he measured no more than 82% duty cycle. Juha in Finland reports no rich problems with his B230ET model, but the ET uses an early Motronic system where ignition and EFI talk to each other.

Peter Linssen writes: Bosch / Volvo LH 2.2 cannot deal with injectors larger than 310cc. Bad idle and poor drivability is the result.
LH 2.4 however will adapt for injectors up to 370cc and offer good performance. However because the LH 2.4 system is adaptive it will trim itself to compensate for the richer mixture it offer very little if any advantage. If you want to run larger injectors with the stock fuel system you have to modify the signal from the MAF sensor to compensate."
 
You may have already seen this web page but found some of the info interesting and Volvo specific.

http://people.physics.anu.edu.au/~amh110/Injectors/bosch_injector_028050403.htm

"Larger Injectors on a 740 Turbo ?
A number of people have tried larger (eg. 370 cc/min (std 300)) injectors with little success using the standard LH-Jet 2.2 Turbo factory fuel computer and separate EZK ignition. It seems the engine sensor / mapping parameters cannot compensate enough for the increased injector flow and the system runs very rich both during idle and running - Probable reason for rich running - the computer still delivers the same mapped injector pulse width, it doesn't know your using a 66% larger injector. Bill Watson reports that at 11 psi boost in his 87 745, he measured no more than 82% duty cycle. Juha in Finland reports no rich problems with his B230ET model, but the ET uses an early Motronic system where ignition and EFI talk to each other.

Peter Linssen writes: Bosch / Volvo LH 2.2 cannot deal with injectors larger than 310cc. Bad idle and poor drivability is the result.
LH 2.4 however will adapt for injectors up to 370cc and offer good performance. However because the LH 2.4 system is adaptive it will trim itself to compensate for the richer mixture it offer very little if any advantage. If you want to run larger injectors with the stock fuel system you have to modify the signal from the MAF sensor to compensate."

Yes, I've read this.
 
Not a good idea to install Bosch GEN III injector using pintle caps. The injectors are shorter requiring a yellow spacer leaving no possibility to install the pintle caps. Installing the injector without using the yellow spacer possibly allows the fuel pressure to push the injector further into the intake manifold resulting in a fuel leak at the rail. I learned this yesterday when I tried to push the injector further into the intake with the engine running. The result was fuel spraying from the top o-ring.

Today I pulled the injectors, removed the pintle caps, and installed the yellow spacers (which were included in the pintle cap kits) on the bottom of each injector using the same new o-rings that I installed yesterday. The injectors now have a snug fit. The yellow spacers are 2.05 mm thick. So the spacer is 1 mm thinner than installing a second o-ring on the bottom of the injector.
 
Last edited:
Today I swapped the BMW engine temperature sensor [0 280 130 023] back to the correct OE sensor [0 280 130 026]. The engine then ran so rich that I couldn't adjust the AMM baseline idle setting. But now there were no cold start issues with this temp sensor. So to compensate for the rich idle mixture I swapped in the BMW 326e 2.5 Bar FPR. I was then able to adjust the AMM baseline setting.

So it seems that LH 2.2 will not run correctly on bigger injectors without lowering the fuel pressure.
 
0 280 155 811 specs from Bosch...
3.5 bar operating pressure
282 grams/min @ 3.5 bar
261.1 grams/min @ 3 bar
373 cc/min @ 3 bar
15* spray angle
8*-24* spray area amount
92 Design type
Jetronic electrical connector
No locating lug
O-rings standard
60.3 mm between 0-rings
73 mm total length

Original injectors are 75 mm total length. This is why the 2 mm spacers were needed.

0 280 155 811 injectors would flow 32 lbs/hr at 38 psi (337 cc/min at 2.65 bar).
 
Last edited:
Yesterday I tried advancing the ignition timing a bit. The idle improved. I then adjusted the AMM baseline setting until the LED was almost constantly lit, but still blinking. I then hooked up a vacuum gauge and turned the AMM screw clockwise to get the highest vacuum reading. Resistance between pins 2 and 6 of the AMM ended up at 345 Ohms, which is good being the starting point should be 375 Ohms.

Engine is running leaner as the interior of the muffler is more gray in color than previously.

This is all with 0 280 155 811 injectors from Buick 3800 Supercharged V6 and 0 280 160 225 2.5 Bar (38 psi?) fuel pressure regulator from 1987(?) BMW 325e (e being economy model).
 
Finally got the Schrader valve hose replaced on my fuel pressure tester. 0 280 160 225 - 2.5 Bar fuel pressure regulator from BMW 325e pressure test results:

39 psi w/o vacuum hose connected
30 psi w/ vacuum hose connected

These test results indicate that this BMW FPR's pressure specification is similar to Ford specs.
 
Ive been running these injectors for years. Stock amm too. Just got a cheap Ebay adjustable regulator and made some bracket and fitting to adapt it to the factory rail. I can check the pressure its set at but im pretty sure its higher than 38 (i set it for full boost @wot and the wideband shows its happy everywhere else too). For spacers i was lazy and just used extra orings.

Now you mention it my mpg isnt awesome but it never has been. No working odometer so the effort is too great to get actual mpg numbers. All i know is boost makes me happy so burning gas to get there dont bother me.
 
These are my calculations:

0 280 155 811 injectors:
34.3 lbs/hr @ 43.5 psi
360.5 cc/min @ 3.0 bar

32.48 lbs/hr @ 39 psi
341.36 cc/min @ 2.7 bar

Idle pressure with 2.7 bar fpr: 30 psi
28.49 lb/hr @ 30 psi
299.4 cc/min @ 2.0 bar

If LH 2.2 AMM baseline setting is 375 ohms between pins 3 and 6, my calculations indicate that I need to have a baseline of 300 ohms. 300 ohms is what my current setting is:

Fuel flow increase of 20% (360.5/300=1.20)(+20%)
341.3/2.7=126.43
300.0/3.0=100
100/126.43=.79 (21% increase)

375 ohms baseline setting with 300 cc/min injectors @ 3 bar
300 ohms baseline setting with 341.36 cc/min injectors @ 2.7 bar

375(ohms)x0.80=300 ohms

Someone let me know if this makes no sense.
 
Last edited:
Back
Top