M30E30 rough idle, backfiring when getting on the throttle

[Psygo]

I finished up my m30b35 swap a while ago, ran with a m30b30 DME for a while, made sense to me it ran like shit then, ordered a 179 DME, plugged it in, still ran like shit.
say I need to keep the speed at 80km/h in traffic, I can't sit on the throttle in the low end without it bucking like mad, so I have to get on the throttle and get off it again, when getting back on it, it backfires around 50% of the time.

I tried changing the coil and one spark plug that I accidentally snapped, took another one off of my old dirty m20, and that made the bucking a bit better, but the backfiring is still happening and the idle is absolute shit.

how is the power on this supposed to be?
if I floor it in second from 20km/h it should just smoke the tires with a 4.10 diff right?

oh, and also the injectors tick like hell, not sure if they're supposed to tick this much, but I don't know how to go about cleaning them the best way.

also does anyone know the number for the little rubber disks for an e28 cooler?
My radiator is starting to fall off and I only have zip ties.

[Bearmw]

Recheck all your wiring for excess resistance.

[Jaxx_]

try unplugging the TPS, idle might get better.

My E34 M30 ran like shit with a TPS that randomly went when I was replacing the head gasket. At full throttle it would stumble hard and at idle it would nearly die, especially if trying to move away from a stop.

I'm also assuming that you have already checked the obvious culprits--vac leaks, bad spark, good fuel pressure etc

[Psygo]

I already tried changing the TPS, to one off of an m30b30 I have sitting around, I looked at the spark plugs and they look okay to me, also checked the ignition cable ends visually and they all looked okay, I know that one of the fuel lines leak a tiny bit right under the middle of the car, but it doesn't make sense if it was that, as it runs perfect when gunning it.

or maybe it does make sense, because I've only been able to do wheel spin in the rain in it.
maybe I should look at that fuel leak a bit more.

[george graves]

Assuming you have good spark, fuel and air. And that your ECU is not gone full retarded....it has to be a sensor that is reporting bad info back.

Lots of ticking? Adjust your valves.

Smoke ties in 2nd gear with a 410? Depends on the tires. 185's econo pep boy specials. Sure. Sticky 235s? Not a chance.

Sound like your engine/car is a bit of a mess. Is your O2 sensor hooked up? Cars generally backfire on excess about of fuel. And running with out a good O2 sensor will do that.

BTW! Stop using zip ties to mod your car!

Recheck all your wiring for excess resistance.

I don't even know what this means? Good thing I don't know anything about car electronics!

[Alpina]

This sound just like a worn cap and distriputer

[lukeADE335i]

I was going to suggest the distributor cap & rotor too (and new plugs by the opening post!)

[Psygo]

BTW! Stop using zip ties to mod your car!

didn't have anything better at hand, it's why I asked for the parts number for those little rubber disks for the e28 rad.

my car definitely is a mess though, whole build for 2200 USD, and I have two complete m30 engines with transmissions.

I guess I'll try to take the distributor apart when I have a little more time to mess around with things.

and I do not have the O2 connected because half the wires the plastic has burned on, and I believe that gives wrong signal?
Also I read in quite a few places that it shouldn't have much effect on the m30, but I suppose it might.

[CorvallisBMW]

and I do not have the O2 connected because half the wires the plastic has burned on, and I believe that gives wrong signal?

DING DING DING we have a winner!

Yes, an O2 sensor is absolutely required for the engine to run properly. Without it the engine has no idea if it's running rich or lean, so will automatically set itself to full-rich. It's the default setting. Not bad for the first 60 seconds of a cold start, but super-duper shitty 99.9% of the time. All the symptoms you mentioned indicate too much fuel and a too-rich burn.

You will cause damage to your engine if you continue to drive it without an O2 sensor.

Also I read in quite a few places that it shouldn't have much effect on the m30, but I suppose it might.

Please tell me who said this so that I can c*nt-punch them.

[Psygo]

well fuck, don't seem to be able to find one in any online stores over here, what's the part number?
I might have one from an m20 somewhere, will that work?
Also I don't seem to be able to find it now, I looked through 4 months worth of different pages on this thing while doing the swap.
I do remember when I picked up my m30b30 the guy said it only ran a little less per liter.

guess I'm off to find a new o2 sensor :(

actually I did fine one... and I simply can't afford one right now.
fuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuck.

would it work to reisolate the wires? probably not lol.

[CorvallisBMW]

If the wires on the O2 sensor harness are damaged, you will need to make a new harness and/or repair the wires, then attach them to a new O2 sensor.

[Psygo]

it's the wires from the o2 sensor that are melted, since they lie so close to the exhaust when using an m20 harness.

[CorvallisBMW]

If you still have the O2 sensor, start be re-running the wires. You'll have to do it anyway even with a new sensor. You can add heat-shrink tubing and even reflective tape once they're done, then secure them to the underside of the car away from the exhaust. Since you're running new wires you can add length, and they won't have to be anywhere near the exhaust.

[Psygo]

aaaaand there went the headgasket.
yay.

I think that's the end of the e30 for me for now.
I learnt quite a bit, it was some what fun, but I only got 1000km out of it.
too illegal to run where I live, too expensive with fuel etc.

[CorvallisBMW]

Sorry to hear, but it was probably as a result of running it for 1000km with no O2 sensor :/