Is there a difference between L-Jet brains |
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Is there a difference between L-Jet brains |
jd74914 |
Jan 24 2007, 10:12 AM
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#1
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Its alive Group: Members Posts: 4,782 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
My brain seems to be toast, and I'm looking at buying a spare known good one to swap in to test out this theory. I have a 74 1.8L with L-Jet; can I use a '75 brain? Are there any important differences between the 2 years?
Thanks. |
SLITS |
Jan 24 2007, 02:10 PM
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#2
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
According to Bosch, the brain is the same from 11/73 - 07/75 on the 1.8L
Bosch Part # 0 280 000 103 VW Part # 022 906 021 G |
JeffBowlsby |
Jan 24 2007, 02:19 PM
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#3
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914 Wiring Harnesses Group: Members Posts: 8,549 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
I don't have access to my references here at work, but I can say with certainty that there are two different L-Jet ECUs for the 914, a 1974 and a 1975 version. I dont not know what the internal differences are, but one has a 6-pin connector the other has a 7-pin. Contact Jim Hoyland, he may know the specifics.
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ClayPerrine |
Jan 24 2007, 04:14 PM
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#4
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Life's been good to me so far..... Group: Admin Posts: 15,541 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
The differences in the L-Jet systems were all in the air flow meter and the wiring harness. The "brains" are identical.
In 74, they used a common wire for both the AFM and Air Temp sensor that is co-located in the AFM assembly. In 75, they split out the wiring, separating the AFM and Temp sensor. Seems there was some feedback issues with the common wire. I have never seen one of these "brains" fail, its usually something else causing it. |
Brando |
Jan 24 2007, 04:19 PM
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#5
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BUY MY SPARE KIDNEY!!! Group: Members Posts: 3,935 Joined: 29-August 04 From: Santa Ana, CA Member No.: 2,648 Region Association: Southern California |
[...] I have never seen one of these "brains" fail, its usually something else causing it. Usually it's the heating element inside the Air Flow Sensor. The only reason you would need a new ECU is if the one in question has been opened (exposed to the elements and is corroded or broken) or has been physically damaged due to impact or some other trauma. 1.8L L-Jet ECUs are interchangeable. |
ClayPerrine |
Jan 24 2007, 04:23 PM
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#6
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Life's been good to me so far..... Group: Admin Posts: 15,541 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
[...] I have never seen one of these "brains" fail, its usually something else causing it. Usually it's the heating element inside the Air Flow Sensor. The only reason you would need a new ECU is if the one in question has been opened (exposed to the elements and is corroded or broken) or has been physically damaged due to impact or some other trauma. 1.8L L-Jet ECUs are interchangeable. Heating element?? What heating element? This is a vane air meter, not a mass airflow sensor. |
SLITS |
Jan 24 2007, 04:26 PM
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#7
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
Ok, I had included in the post but erased it that there were different air flow sensors (VAF) but didn't think it was germain to what was asked ..... silly me
To 07/74 - 0 280 200 001 Porsche & VW Part Number 022 906 301 From 08/74 - 0 280 201 002 Porsche & VW Part Number 473 906 301 |
Brando |
Jan 24 2007, 04:28 PM
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#8
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BUY MY SPARE KIDNEY!!! Group: Members Posts: 3,935 Joined: 29-August 04 From: Santa Ana, CA Member No.: 2,648 Region Association: Southern California |
MY MISTAKE, was confused for a moment. There's no heating element, there is a temperature sensor though.
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jd74914 |
Jan 24 2007, 06:00 PM
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#9
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Its alive Group: Members Posts: 4,782 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
I know my box has been opened by the PO, and had extra wires soldered into it . . . I cut a bunch out, but I would just like to put in a new unopened box.
My real problem is that I went of vacation. The car was running before I left. Then I came back to start it, and it wasn't getting any fuel (i think) or spark. The coil was so hot I burned myself, and I have yet to replace that, and know I definately need to. I found a brain locally that I figured I might swap in as to be garanteed an untampered with box. Anyone have any ideas what could be the problem preventing the car from getting fuel? I think I can hear the coldstart valve shooting gas, but I'm not sure. The injectors definately aren't starting? Are the injector pulses times off of the coil? Thanks for any help. |
Dave_Darling |
Jan 24 2007, 08:08 PM
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#10
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914 Idiot Group: Members Posts: 14,991 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
The injector pulses come off the coil--the same connection as the ignition points. Without that one white wire connected, the injectors will never open.
Are they opening? --DD |
jim_hoyland |
Jan 24 2007, 08:26 PM
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#11
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Get that VIN ? Group: Members Posts: 9,328 Joined: 1-May 03 From: Sunset Beach, CA Member No.: 643 Region Association: Southern California |
Don't know the answer; but I do have spare 6 and 7 pin AFMs and a spare brain that came out of one of Joe Sharp's late 1.8L L-Jet cars. They say the brain is the last thing to go.
I don't have access to my references here at work, but I can say with certainty that there are two different L-Jet ECUs for the 914, a 1974 and a 1975 version. I dont not know what trhe internal differences are, but one has a 6-pin connector the other has a 5-pin. Contact Jim Hoyland, he may know the specifics. |
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