miss fire ????????????????????

[e30euro]

ok i had everything checked mass af is good coil is a msd and i know is good a have a new cap and rotor fuel pump is good and i just put a new fpr from bav auto and thats good the injectors i know are good and the timing is good and i just put new NGK r's and they should be good i have wires on the way but could it be the wires it is missing on the same cylinders any one????? btw im not stupid i am an ase tech but i can not figure this out and its stuck at my house wanted to see what people thought thanks.:hitler:

[jlevie]

There are a number of things that can cause misfires, but in my experience the list starts (in order of probablility) with:

intake leaks
fuel delivery or injector problems
bad distributor cap, rotor, wires, plugs

A smoke test is the only sure way of finding all intake leaks. Running through the suite of fuel system tests in the Bentley manual will tell if there's a problem with fuel delivery and having the injectors cleaned and flow tested is really the only way to be sure that the injectors aren't part of the problem. The ignition system is easy. If old, just replace the components.

[e30euro]

i had the fuel tested at the bmw dealer ship my friends a tech there and the maf too it is getting spark but maybe not like it should be i will be pulling the car apart tomorrow so i will check but the other things, this i forgot to say is it sometimes it runs great and than bad than great than bad now its just bad.

[2.5-12]

my vote is intake vacuum leak

[metalix1021]

What are the circumstances in which it runs poorly? i.e. its humid outside?

Does it do it at start up on a cold engine or a warm engine? etc...

[e30euro]

its been real cold but it starts but sometimes real bad or right away i think the vacuum leak is something i will look at bc it will rev high and low i didnt even think about it but even when its warm up it will run bad and than great than bad again

[Disaster Inc]

I had a similar problem with an interment misfire, and it turned out to be a defective plug wire on a fairly new set.

[2.5-12]

its been real cold but it starts but sometimes real bad or right away i think the vacuum leak is something i will look at bc it will rev high and low i didnt even think about it but even when its warm up it will run bad and than great than bad again

exactly like my ic. i replaced a IM gasket, runs perfect.

check for leaks first.

[e30euro]

yea im going to check it tomorrow morning and places to really look at this is my first bmw e30 ive ever had so not too sure what to look at for leaks it had just started out of no place and its been doing it on and off for the past month

[metalix1021]

yea im going to check it tomorrow morning and places to really look at this is my first bmw e30 ive ever had so not too sure what to look at for leaks it had just started out of no place and its been doing it on and off for the past month

intake boot, intake manifold gasket, the hose that runs from the throttlebody to the valve cover, all the other damned vacuum hoses. Some are obviously easier than others. I'd check that intake boot first, they like to crack on the bottom side so it can be difficult to see. Take it off and look at it.

[e30euro]

kk i will post tomorrow what i find and if anyone else has any other ideas let me know thanks guys

[e30euro]

its wires and or the new plugs failed i will pull them off in about an hour and check all the hoses and piping are perfect almost new so thats the only thing thats left i will post more with what i see

[e30euro]

yup guys its the wires waiting for my new set

[catchuk]

im waiting for my new ones to comes in too, I did the IM gaskets and fuel injector o rings and still have the same problem, I decided to order new wires, rotor, ICV, Temp sensor and oxygen sensor. It'll be here monday, hopefully its fixes it.

[e30euro]

im sure i had a new cap, rotor, coil (msd), and new 8 mil wires(on the way)(tomorrow i hope) but i believe it was the resistor type wire i dont remember what its called it was loose as a goose lol but i also ordered a new dme but i just need to keep this motor running for a few more months till my built motor is ready to go in. let me know how yours goes i learn alot from other peoples problems