1996 850 2.0 GLT won't start, please help

danielb314 · Post by **danielb314** » 29 Aug 2023, 09:29

Hello all! After sitting for a few days, my car refused to start. Cranks, seems like it wants to start but then dies almost immediately. I checked all the sensor signals right to the ecu connector, I have spark, I have fuel pressure, but the motronic 4.3 is not activating the injectors.

My suspicion was the immo 2 box being unhappy, because if I load an older '94 2.0T program into the motronic eprom, the injectors are firing and the car starts up. However I have also replaced the immo box now and the chip in the key, but the car still won't start up (at least with the original firmware).

What am I missing, what could I try next? Please help, I'm about to set this beautiful white brick on fire..

5rivers · Post by **5rivers** » 30 Aug 2023, 06:26

Hey there!
In this forum there are lots of similar posts, many of which say start checking your relays and sensors. I would recommend reading the posts. And check out the repair database as well, there is a "no-start" page that might help. In your case, the fuel relay, cam sensor, rotor, and fuses would be top of my list.
I am not familiar with anything ECU related, sorry!
Keep posting your progress and those with much more experience than I will chime in!

danielb314 · Post by **danielb314** » 30 Aug 2023, 10:18

Hey 5rivers, thanks for the reply! I have read a lot of no-start posts, and checked and ruled out the relays and sensors by now.

At the moment I am able to start the car with a different ECU program that does not have immo check, the biggest issue is that it seems to be a manual ecu program my automatic transmission shifts are very rough..

If anyone happens to have a US or pre-immo ('95?) 2.0 GLT 132KW .bin file, that would be super helpful!

danielb314 · Post by **danielb314** » 30 Aug 2023, 14:14

Ok I managed to solve it! Seems like the automatic transmission is handled inside the ECU but not within the eeprom program, so I uploaded the older (non-immo) program to my own ECU (I've been using a spare one previously, from a manual car), and lo and behold the car starts up and shifts perfectly. This issue was the biggest headache my 850 caused so far..

jmartin919 · Post by **jmartin919** » 30 Aug 2023, 14:23

Why not replace the immobilizer, or am I missing something?

Post by **misha** » 31 Aug 2023, 02:23

Because EU market '96 have chipped keys.

5rivers · Post by **5rivers** » 31 Aug 2023, 06:04

I'm glad you figured out a solution to your problem!!! I still have lots to learn about ECU's...

Post by **misha** » 31 Aug 2023, 14:36

danielb314 wrote: 30 Aug 2023, 10:18 ...2.0 GLT 132KW...

In '96?
...and '94 2.0 T?

Those engines didn't existed for 850.

Engine is swapped from s,v70(B5204T2).