New member with M10 troubleshooting question

[CHZBRGR]

Hello all, new member with his first BMW and with that...issues, lol. I recently acquired an 85 318i 5 sp off a friend of mine. He had to relocate and couldn't take the car and I daily a 4x4 v10 Excursion with a drinking problem, lol. The car starts and idles decent, but at about 3k rpms it begins to drastically lose power. It's able to wheeze up to almost 5k rpm where it just falls on its face. It sounds like anti-lag, lol. I went ahead and gave it a basic tune-up just to see if it helped (cap, rotor, plugs, battery, air and fuel filters). PO said he had no service records and hadn't done anything but change the oil in the 2 yrs he owned it. Wires and coil looked to be in real good condition. Anyways, he was assisting and managed to cross the front 2 wires and when he got them switched back, it backfired through the intake and obliterated the intake boot, lol. So, I replaced it as well. Afterwards, the car would start and idle at about 800 rpm, then climb to about 1,500 and just stay there. I tried spraying down all the intake area with some starter fluid and it didn't react like it was a vac leak. He made mention that he had fiddeled with the idle valve, so I went ahead and turned the idle set screw and idle is back to 800ish. The plugs we plugged weren't particularly bad, maybe just a bit fouled. I have a feeling that my issue may be an overfueling problem. When I lift off the throttle, even just cruising, it backfires and burbles. When it hits it's "wall" around 5k, it cracks and bangs out the back end. He says the fuel pump was just replaced when he bought the car, but he didn't know there was 2. Either way, overfueling wouldn't be a pump issue. I'm kinda at a loss at this point, aside from shot-gunning expensive parts at it. Working with OBD cars has dummed me down, I guess. I'm particularly interested in knowing if it could be the valves being out of adjustment. The odo doesn't work, so the 15k mile service has likely come and gone, w/o him having had a clue. My valve cover is a bit leaky anyways, and the lifters a bit noisey, so I may just dig into that anyways. But this is quicjly losing it's "economy" purchase, lol. Thank you all, and thank you for including me in your resourceful forum.

[e30davie]

Welcome, we dont charge extra for paragraphs:)

Hello all, new member with his first BMW and with that...issues, lol.

I recently acquired an 85 318i 5 sp off a friend of mine.

He had to relocate and couldn't take the car and I daily a 4x4 v10 Excursion with a drinking problem, lol.

The car starts and idles decent, but at about 3k rpms it begins to drastically lose power. It's able to wheeze up to almost 5k rpm where it just falls on its face.

It sounds like anti-lag, lol.

I went ahead and gave it a basic tune-up just to see if it helped (cap, rotor, plugs, battery, air and fuel filters). PO said he had no service records and hadn't done anything but change the oil in the 2 yrs he owned it. Wires and coil looked to be in real good condition.

Anyways, he was assisting and managed to cross the front 2 wires and when he got them switched back, it backfired through the intake and obliterated the intake boot, lol.

So, I replaced it as well. Afterwards, the car would start and idle at about 800 rpm, then climb to about 1,500 and just stay there. I tried spraying down all the intake area with some starter fluid and it didn't react like it was a vac leak.

He made mention that he had fiddeled with the idle valve, so I went ahead and turned the idle set screw and idle is back to 800ish. The plugs we plugged weren't particularly bad, maybe just a bit fouled. I have a feeling that my issue may be an overfueling problem.

When I lift off the throttle, even just cruising, it backfires and burbles. When it hits it's "wall" around 5k, it cracks and bangs out the back end. He says the fuel pump was just replaced when he bought the car, but he didn't know there was 2. Either way, overfueling wouldn't be a pump issue.

I'm kinda at a loss at this point, aside from shot-gunning expensive parts at it. Working with OBD cars has dummed me down, I guess. I'm particularly interested in knowing if it could be the valves being out of adjustment.

The odo doesn't work, so the 15k mile service has likely come and gone, w/o him having had a clue.

My valve cover is a bit leaky anyways, and the lifters a bit noisey, so I may just dig into that anyways. But this is quicjly losing it's "economy" purchase, lol.

Thank you all, and thank you for including me in your resourceful forum.

[CHZBRGR]

Lol, sorry. I had been typing that out for a few hours off my phone between errands.

[rommaster2]

Have you verified ignition timing? The procedure on this is kinda weird but it goes like this. Make sure you have a timing light.

1. Unplug the vacuum hose from the distributor

2. Rev engine to 4,000 rpms and hold it steady there

3. Shine timing light on the bell housing there should be a hole that is visible on top of it allowing you to see the flywheel spinning. Shine the timing light into that hole and you should be able see both a tooth and a mark that looks kinda like a bulls eye or a hatch mark. if you see them and they are lined up your timing is good. Most likely you will at least be able to see the mark because the engine is running already if it is not lined up with the tooth proceed to step 4.

4. Loosen the bolt that is holding the distributor clamped on the shaft. IIRC this is a 10mm bolt and nut so use two 10mm sockets or wrenches.

5. Turn distributor slowly while holding timing light clockwise should be advancing it, counter clockwise would be retarding it. Try advancing it a little and see if you can see the mark now. If that doesn't work try retarding it a little. Once it is lined up just tighten up the 10mm bolts, plug the vacuum advance line in, and take her for a spin.

Did you check all the vacuum lines connected to the idle air control valve when the intake boot got obliterated? Theres a plastic adapter that goes into it that has a small vacuum line reference going off of it that could be that it was broken if not paying attention or can easily be broken reinstalling (I broke two of them in the process of repairing my car years ago).

One thing you can check for over fueling as well is the cold start valve as these can be stuck open and the o2 sensor as well. An o2 sensor thats bad can cause the engine to think its running lean and overcompensate by enriching the fuel.

[TobyB]

Might check fuel pressure, too, for grins-
the regulators can mess up, the return line get plugged, etc.

It's quick and easy to rule out.

t