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Discussion Starter · #1 ·
I'm troubleshooting my 1985 900T. She sat for approximately 10-years. I completely updated the entire fuel system (new fuel pumps, fuel lines, filter and new 2.5 Bar FPR. Cleaned and tested the fuel injectors. Engine runs good but causes excessive fouling of the plugs (black soot). Checked all vacuum lines. I removed and checked the Air Mass Meter. The filaments are intact. I have 12VDC on pins 2&4 but don't get the 4VDC on pin#1 after running the RPM up to 2500 and they don't glow as outlined in the Bentley manual. Looks like the signal comes from the ECU. Does anyone have a write up on the 2.2 Jetronic and a pin out diagram? Thanks, Paul
 

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The factory manuals are in the stickies on this board, although searching through to find the links that still work is a royal PITA. I would highly encourage you to pick up the Bentley manual from Amazon - it has a distillation of the factory manual that's to the point and easy to follow, including full wiring diagrams. When it comes to LH Jetronic, it's literally the only thing I have ever used.
 

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Thanks. I do have the Bentley manual bit didn't find any detailed information regarding the inputs and outputs on the Bosch Jetronic 2.2. However, I did find two breaks in the vacuum line from the intake manifold to the PCV. I'll fix that and see if that contributed to the excessive plug fouling. Stay tuned.
 

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Real wiring diagrams are in Section 3.2 in the factory manual.
Very rich running can only be a few things. Air Mass Meter, ECU, leaking Fuel Pressure Regulator, large vacuum leak, NTC resistor.
 

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Thanks. I do have the Bentley manual bit didn't find any detailed information regarding the inputs and outputs on the Bosch Jetronic 2.2. However, I did find two breaks in the vacuum line from the intake manifold to the PCV. I'll fix that and see if that contributed to the excessive plug fouling. Stay tuned.
Look in wiring diagrams, fuel system. The factory diagram is there showing every terminal and what it's connected to. There is also a detailed pinout in the troubleshooting section.
 

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Discussion Starter · #8 ·
If you end up narrowing it down to the Air Mass Meter send it out and have it repaired. Do not buy buy one of the reman'd ones out there, they usually work worse than your old one.
I ordered an old original AMM from Ebay. The wire elements look intact and the resistance measured 360 ohms. I'll install it tomorrow morning and see if that takes care of the plug fouling.

Do you have any recommendations for a rebuild shop for the AMM?
Thanks
 

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Injection Labs if they're still doing the work -


Their website is trash but their product is The Best.

You might consider bailing out of LH 2.2 and swapping to LH 2.4 or even Trionic. It's probably $500 to do LH 2.4 and $2000 for Trionic ... it can be done for less, but assuming you just wanna buy vs build as much as possible. By the time you stock up on old 2.2 parts and have MAFs rebuilt, the swap options start looking more and more appealing. I've ditched 2.2 on every car I've owned for 20 years and never once regretted it.
 

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Discussion Starter · #10 ·
Injection Labs if they're still doing the work -


Their website is trash but their product is The Best.

You might consider bailing out of LH 2.2 and swapping to LH 2.4 or even Trionic. It's probably $500 to do LH 2.4 and $2000 for Trionic ... it can be done for less, but assuming you just wanna buy vs build as much as possible. By the time you stock up on old 2.2 parts and have MAFs rebuilt, the swap options start looking more and more appealing. I've ditched 2.2 on every car I've owned for 20 years and never once regretted it.
I think I'll consider doing an upgrade after I get her running to a point that I'm comfortable investing more time and $$$$. What's the advantage to doing an upgrade to 2.4? How difficult is the upgrade?
Thanks for your help!
 

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I think Fuel Injection Corp rebuilds the AMM as well. I believe the person told me about them said they were not able to get in touch with Injection Labs.But the only place I have ever used is Injection Labs. But I haven't needed the service for a few years.
 
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