The comprehensive DOHC engine swap thread.

[Vtec?lol]

thanks for your help!
I will try to grab a new ecu and see if that helps.

[Jand3rson]

It sounds to me like you might have a bad ECU. Try a new one and see if it helps. Easier said than done, I know, but that's what it sounds like to me.

[Vtec?lol]

still nothing.. I'm still hitting a rev limiter at 2.5-3k max and it cuts in between that and idle

[Vtec?lol]

won't stay alive when I unplug it.
The charcoal canister is supposed to have air sucked through the bottom right?

I'm searching for all sorts of vacuum leaks.

[bimerok]

Don't disconnect it while the car is running. Disconect the maf then stert the car and see if it runs better

[Vtec?lol]

disconnecting the maf kills it

[bimerok]

Check engine is flashing means you're dumping raw fuel into your cats. It tells you the danger of melting them.

Try disconnecting the MAF sensor and see if there is improvement.

[Vtec?lol]

Thanks again for your help guys.
So I got the o2 sensor in and now I have some running issues.

When I hit the gas and hold it at part or full throttle, It will r3v to a certain rpm and then cut fuel and spark then rev then cut, then rev then cut. over and over like an idle surge if you had bad vacuum lines but all mine are good.

I unhooked the TPS and noticed no difference at all, I also tried messing with the tps off the throttle and it didn't effect the engine at all.

I noticed if I restrict the intake/MAF then I can rev it a lil higher but still rev then cut.

Then after try to rev it the check engine light starts flashing so I cut it off.

When I try to do the stomp test I get nothing.

91 318is M50nv help

[JGood]

Regarding the O2 sensor connector location, there are 4 main branches coming out of the harness 'box' (the black plastic box that sits against the firewall and houses all the wires). One goes to the DME, one goes to the coil packs, one goes to the diagnostic connectors/MAF sensor, and finally the last one goes under the intake manifold to all the other sensors: ICV, temp sensor, crank position sensor, etc... And that is where the larger round O2 sensor connector is, bundled with those. So it is likely tucked up under the intake manifold somewhere.

[Jand3rson]

It has to be there. The car it came from had an 02 sensor, so it's there, you're just not seeing it.

[Vtec?lol]

I don't know the wire color off-hand, but it's the only connector like it in the harness, you should be able to find it fairly easily.

If you don't have it, that's worrying...

ok lol. Thanks again! It might be tucked somewhere. Checking for it now.

[Jand3rson]

I don't know the wire color off-hand, but it's the only connector like it in the harness, you should be able to find it fairly easily.

If you don't have it, that's worrying...

[Vtec?lol]

It's a round twist-lock connector.

Thanks for taking your time to add pix. I can't seem to find it in my harness.
Does it come out from the harness near the starter? and do you know wire color?

[Jand3rson]

It's a round twist-lock connector.

[Vtec?lol]

can someone help me locate where the o2 sensor plug wire is for my m50nv from an e34 harness?
is it a round connector or squared? and what colored wires?