M62 slow throttle response

[Deadwake]

Hi guys! So my friend just bought a 97 740i with the m62 non tu engine.

We got it super cheap, 500 bucks, it had a dead battery but started right up when we jumped it. Motor sounds great, honestly probably the best sounding m62 I've heard with over 120k miles.

However, it came with some fun stuff to fix before it can be fully enjoyed:

Engine codes as read by a OBD2 reader (all I have unfortunately) are P0173 and P0170, fuel trim malfunction on both banks, most likely related, the throttle is suppppppppper slow to respond, like it gets up to speed and it has power but the power isnt that great and is delivered 2-3 seconds after applying pressure to the gas, however the throttle cables look right, I see them open the throttle body when my friend gives it gas, but the power kicks in late.

There are new hose clamps all over the vacuum system, someone was trying to hunt this down before it would seem, I hear a loud vacuum sound from the back of the engine, so in the meantime I'm gonna replace the CCV with a spare I have lying around and get a fuel pressure tester to see if the fuel pressure is right but any advice or suggestions would be great.

Also, I noticed it has a second cable connecting to a throttle plate closer to the maf, super weird but that cable is crazy loose and the plate is always open, when my friend presses the gas, that cable doesnt move at all. I personally drive a 540i with a m62tu, so electric throttle body and no ICV, so this stuff is all pretty foreign to me.

Thanks a bunch for any guidance!

[Timm]

The other cable and throttle butterfly is for the ASC+T, it reduces the power by controlling the secondary throttle plate - it should be reasonably loose. A failed PCV (the device on the back of the manifold) may give problems with idle - but not full-power, the problem is somewhere else - and that could be blocked cats - a back-pressure test would confirm or rule that out.

There are loads of other possibilities, but a fuel-pressure test would be top of the list....

[Deadwake]

The other cable and throttle butterfly is for the ASC+T, it reduces the power by controlling the secondary throttle plate - it should be reasonably loose. A failed PCV (the device on the back of the manifold) may give problems with idle - but not full-power, the problem is somewhere else - and that could be blocked cats - a back-pressure test would confirm or rule that out.

There are loads of other possibilities, but a fuel-pressure test would be top of the list....

Thanks for the info Timm, I took a video of the loud vacuum sound coming from the CCV. It looks like a vacuum hose on the driver side of the(US) CCV is completely disconnected or cut. On my e39 the driver side(US) vacuum hose goes from the CCV to the firewall or maybe under the brake booster... I don't see any hose at all to connect to it, any ideas where its supposed to go?

https://youtu.be/I-g3sninoLY

[Mayorchuck]

From Timm's site:

https://www.meeknet.co.uk/E32/PCV/Index.htm

[acspecialists]

large lower left goes to the brake booster, small upper left goes the the intake hose, small upper right connects to a hose along the firewall. On my TU anyway. Look under the manifold and see if the main line to the oil return is connected.

[Deadwake]

large lower left goes to the brake booster, small upper left goes the the intake hose, small upper right connects to a hose along the firewall. On my TU anyway. Look under the manifold and see if the main line to the oil return is connected.

Thanks for this, thats how my TU is set up too. My friends older 740i with the non TU m62 is not set up like that though so I'm a bit lost. The larger lower still goes to the brake booster, the small upper left goes to the fuel pressure regulator I believe and the upper right is capped off, which looks factory.

I won't have access to the car for another week or so which is driving me crazy (its not even my car!) but I'm wondering if the vacuum hose from the CCV to the fuel pressure regulator being damaged could cause some of these issues?

[SwallownAmazon]

Stethoscope or small rubber tube in one ear and used to probe where the sound seems to be coming from might narrow it down.