HELP m30 running and idling issues

[vic_325]

i got my m30 all finished today. its a b35 and im using the m20 harness.

i first started it without the o2 sensor plugged in at all because my exhaust doesnt have an place for it yet. with the sensor uplugged it wouldnt rev past 2000rpm, it would cut out and rev to 2000 again kinda like it was rev limited.

i plugged the o2 sensor and just kept it sitting in the front battery tray and the engine now reved up but idles like crap and eventually stalls.

all day iv been trying to figure it out.

now, it takes 2 attempts to start it. first it starts and shuts down, second it starts and idles above 1000-1500 rpm. not the smoothest idle but stays running. once i rev it past say 2500 - 3000 and let off the throttle it won't idle and just shuts off.-- then takes two starts to get it to idle again.

when driving, it hesitates and stumbles with no power and never running smoothly at any rpm. and i can;t completely let off the throttle or else it shuts off.

today, i changed afm, icv, fpr, sparkplugs, tps, ran it with o2 plugged and unplugged, i even tried the 173 m20 ecu and that didnt work at all.

just before i called it a day, with it running i noticed tons of smoke from under the car ... the cat was turning RED HOT!! ( with the o2 plugged in but just in the engine bay) why is it so hot ?? Im stumped.

i need help,

Thanks,
Vic

[chadthestampede]

Cat is probably clogged.

[vic_325]

its the same exhaust i used for my m20 and it was fine. could one day of crappy running m30 clog the cat?


also iv read about adjusting the tps... how is that done? just loosen and twist the tps

[chadthestampede]

Maybe. The cat shouldn't turn red hot unless it is clogged.

I will say that I had the exact same problem on my b32, seriously, EXACTLY, and I fixed it by replacing the fpr and ignition coil. Now it was kind of a freak thing with mine so I won't guarantee that will fix yours. Then again the b32's have a cold start valve that I had to plug off to keep it from flooding the engine so that was part of the problem.

Was the car sitting for a long time or something? I know mine had bad gas in it.

[vic_325]

no its my daily lol it has good gas in it... the engine on the other hand. its been sitting over a year but i just did the head new seals and gaskets, reseated teh valves.

[drift]

Looks like this ? : http://www.car-sound.com/04basics/04convBasics.asp

[vic_325]

thanks for that link! i can see why it got red hot now. it could be any one of those because
-its only running with the acc fan
-exhaust does leak
-o2 not reading exhaust
-tps (im not sure how to adjust it)
-m20 harness could have a problem somewhere

today, im going to change both coolant sensors, the coil and plug wires, and do something about the o2 sensor

[vic_325]

changed the coolant sensors, coil, plug wires and adjusted the tps, still idles above 1000 when it does idle its kinda lumpy, and wont idle after i rev it or after any quick change in throttle. still same old thing

[chadthestampede]

changed the coolant sensors, coil, plug wires and adjusted the tps, still idles above 1000 when it does idle its kinda lumpy, and wont idle after i rev it or after any quick change in throttle. still same old thing

You're using an e30 temp sensor to the gauge and a b35 sensor to the ecu right?

The tps is a manual tps, right? Just taking shots in the dark here. Did you have to rewire anything?

Oh, wait a minute. Make sure your main and fuel pump relays are good. I had a bad one that caused similar issues.

You're not that far from me, I wish I had a passport so I could come up and help you.

[vic_325]

i found that i had the icv and the tps plugs backwards so i switched them around and it helped out abit.. it doesnt stall and it runs a little smoother, but now it stays reved up at 2500-3000 when its supposed to be idling. if i pull out the icv and plug the vacum with my thumb , it idles under 1000

[yert315]

sounds like a vacuum leak. Check all vacuum hoses (there aren't a lot). you're icv may be bad as well. If you have access to another one, try it out.

[RickSloan]

sounds like your icv is bad or needs to be cleaned. Do you have the icv in the right direction?

[vic_325]

it tried two icv's, it in the right way or else it would hit the hood. all vacuum lines are good i had to replace the one for the fpr. i do kind of hear a hissing tho,

[vic_325]

alright, i found the vacuum leak. it was the bolt that holds a sensor and the triangular bracket under the intake manifold. it runs smooth now at about 900rpm, but still after driving it stays around 1500-2000 and SLOWLY comes back down. once i get a decent exhaust with a place for the o2 it should be fine. ill clean the icv too.

[vic_325]

have been driving it for a while now. it had a faulty throttle position switch ( thats why it idled high) now it idles at 600 or 700 after adjusting the new tps but it idles really lumpy as if it had a cam. But its just the stock cam. (i am using a 72c thermostat, would that affect idle?)

also feel vibrations when its reving in neutral at a stop light or at any rolling speed. a mechanic told me it feels like it has solid mounts. its on DIY mounts with e24 green motor bushings.