Getting codes 1261, 1251, 1252

[throttle]

I recently got my e30 back up and running again, however whenever I drive it it keeps dying out and losing power, could use some guidance on how to diagnose this issue, thx :)

Situation:

Getting codes 1261, 1251, 1252

Description:

Whenever I drive it in gear it tends to shut off, doesn't matter if its in the low rpm or the high rpm band. It seems to happen more often if torque is applied it seems. (i.e 2nd gear and sometimes first from start.). It idles fine, I'm able to drive it, until that happens.

What I have checked:

- Vacuum leaks
- Cables (Checked OHM resistance and shook the cables around while the car was on)
- Switched O2 sensor relay with fuel pump relay
- I do have a 'new' used ECU I swapped in

I suppose I could recheck everything, but want to confirm a sanity check on what I have checked.


EDIT / NOTE: I have read that it could be the harness, rather than buying a new one, could it be refurbished by myself, or is it just better to buy it new?

[It's Soda Not Pop]

Check your C101 connector under the intake manifold for corrosion. Also how old are your relays? Because those codes are bank injector banks and fuel pump relay related.

[throttle]

Check your C101 connector under the intake manifold for corrosion. Also how old are your relays? Because those codes are bank injector banks and fuel pump relay related.

No corrosion, still a gold color, peeled back the weather guard and same, no green. Even bent the pins to see if it was a contact issue, no change. Will double check again.

As for the relays, probably original, (car has 130k - 150k miles on it)

[It's Soda Not Pop]

Could also be the Main relay acting up. I had this happen to me. I also just rewired my fuel pump to only get a signal from the FP relay and power directly from the battery which help me out greatly as well.

[throttle]

Could also be the Main relay acting up. I had this happen to me. I also just rewired my fuel pump to only get a signal from the FP relay and power directly from the battery which help me out greatly as well.

Interesting, I'll do that temporarily and see if that works.

Darn, I just put in a new main relay as well. Still have the old one I can try.

[It's Soda Not Pop]

Check your grounds as well. Replace them if you need to

[It's Soda Not Pop]

Read through this as well it may help. A lot of knowledge.

https://www.r3vlimited.com/board/forum/e30-technical-forums/e30-faq-and-diy/333798-diagnostics-tips-tricks-by-jim-levie-e30-jedi-master

[throttle]

Check your grounds as well. Replace them if you need to

Will do, do you think the O2 sensor could be an issue? I'd assume not but it does affect fuel.

Also will be checking the TPS, im wondering if the idle one is somehow clicking on and trying to stall it out if that's possible

[It's Soda Not Pop]

I don't think your O2 is causing this. Could be the CPS.

[It's Soda Not Pop]

Again read through that link I sent He knows way more than me.

[It's Soda Not Pop]

Any update?