Question about ECU's, ECU upgrades, any benefit

Hey guys,

I have a 97' jetta, 1Z with the 028 906 021 ED ECU. I was just wondering if there was any benefit to swapping to a different ECU at some point. The reason I ask this is that I will be doing some power upgrades in the future, getting a chip, probably VNT, etc. My EGR is also deleted and I have the CEL for it.

The reason I ask is because another member is selling the exact same ECU I have. I was thinking of buying it for the future if I ever had the need to send it out for programming but still needed to drive the car.

The ED ECU has a proclivity for dumping it's ROM memory and failing. If you're going to keep using it, have Jeff upgrade it to JB programming.

If you're going to buy a spare ECU, find one with the JB suffix.

paramedick said:

The ED ECU has a proclivity for dumping it's ROM memory and failing. If you're going to keep using it, have Jeff upgrade it to JB programming.

If you're going to buy a spare ECU, find one with the JB suffix.

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Sounds decent. So a JB branded ECU will be more reliable than the ED with JB programming?

IIRC, the software itself in the ED was unstable. I don't know what Jeff does, but he assured me that I would have no problems when he updated my ED unit on the old Jetta.

question about an ECU upgrade?

I purchased a 1996 passat TDI with the ECU code of 028 906 021 BK. I was checking around for the chip upgrades and Neuspeed has a drop in specifically designed for this ECU.

As i am new to this what are your toughts on the Neuspeed chip?

Thanks.

Be aware that the BK and GQ for the 1Z Passat are designed to operate with an engine harness wired differently for the changes in the glow plug monitoring system added in November 1996 build date cars. These 1996 and early 1997 models use a 103 glow plug relay in position 12 of the relay mounting block.
The FA for the 1Z Passat is designed for use with the different harness and the 180 glow plug relay with monitoring. This relay 180 is remotely mounted above the relay mounting block and the harness changes are used to connect it.

The 1997 Jetta with the 1Z / AHU also has a November 1996 change in the 1997 models that also affects the glow plug relay circuit and wiring. The ED is an earlier ECU version than the JB and my concern is that a similar incompatibility of proper glow plug operation might exist in that model if the JB is used with the ED compatible wiring.
Not that a later version of ECU won't work with an early version wiring harness, but be aware that there is a wiring harness change from November 1996 build date TDI that might, might, make problems with the A3 as it does with the B4.
The 98 A3 I had suffered serious wiring meltdown issues when a prior owner's mechanic used an early relay with the later (JB) ECU and harness. It took weeks for me to splice in replacement wiring segments and undo the problem.

Jon, the JB is a direct replacement for the ED. VW put these out when the EDs started failing. No issues swapping back and forth.

paramedick said:

Jon, the JB is a direct replacement for the ED. VW put these out when the EDs started failing. No issues swapping back and forth.

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Hey Paramedick, that is some really great info. At what point does the ED cpu develop a fail (km/yr wise). I have pretty much the same setup with my A3. I'm pretty sure my ECU was changed as i see yellow paint on it from the wrecking yard. I'm not sure when the change occured, as i purchased the car a few months back.

Is the ROM chip soldered onto the mainboard, or is it socketed. If socketed, maybe Jeff is hot flashing the rom chip and all else is good. Is there someone locally in Ontario/Canada that might sell these socketed chips?

thanks

As I understand it, the hard chips on the ECU motherboard contains the unstable programming that deletes itself. Not the socketed chips. AFAIK, only the 97 Jettas got this ECU.

Jeff can speak to this better than I can. He resurrected mine.

As far as mileage vs failure, no clue. I was just driving down the road, and the car turned off like with a key. Never restarted.

paramedick said:

As I understand it, the hard chips on the ECU motherboard contains the unstable programming that deletes itself. Not the socketed chips. AFAIK, only the 97 Jettas got this ECU.

Jeff can speak to this better than I can. He resurrected mine.

As far as mileage vs failure, no clue. I was just driving down the road, and the car turned off like with a key. Never restarted.

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Thanks again, looks like i'll be looking into getting a spare ECU until i get the same thing done to mine as you advised Blake. Same car, same year, pretty much same issues.

Hmm, I am fairly certain my ED ECU is socketed, will have to take pictures next time I have it open. We'll see.

blizzak said:

Hmm, I am fairly certain my ED ECU is socketed

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When you open it, you will see both socketed and soldered chips.

paramedick said:

When you open it, you will see both socketed and soldered chips.

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Ah, my bad. I didn't see your earlier post about how the hard chips were the ones that cause trouble. Good to know.

blizzak said:

Ah, my bad. I didn't see your earlier post about how the hard chips were the ones that cause trouble. Good to know.

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I was hoping Jeff might chime in regarding his ED to JB upgrade - I'm puzzled since none of the soldered chips appear to be ROMs.

Simon

I've invited him to comment.