constant misfiring... need help

[Angus]

constant misfiring... need help *vid added

So my bmw is constantly misfiring. it's the 1.8 e36 coupe w/ 5-speed. AND 200k

after some time trying stuff out, cylinders 2 and 4 are not firing (IIRC) but getting spark.

So I just replaced all the injectors and the same misfiring is still there...

I believe that I had a misfire before I got it and just didn't really notice, just thought it was really slow... then I think i lost another cylinder and it'll BARELY accelerate...

What else should I check for? And as I have going on the bimmer forum, anyone that helps me figure out the problem will be payapled some beer $ and you can have all my casino cash!

haha thanks guys


EDIT: vid added of it trying to run...

http://www.youtube.com/watch?v=dIR6Z8s7_co

Click to read more...

 

[bikrboy128]

check the injector pulse. you can get a kit at your local parts store.

after that you probably have a bad ECM.

 

[02BlueGT]

Does it have a Distributor??? Is timing off, How old are plugs/wires, a bad wire may spark normal through a tester(not as much resistance as inside the cylinder).....and is it only at idle, or all speeds??? more data please!!!

 

[Angus]

we can pull the wires off of cylinders 2 and 4 and it'll still run crappy. it'll misfire the entire rpm range.

and we tested spark but pulling the plug out and running it completing the circuit to the valve cover (ground). there is a good spark.

the code that popped up (even though no ses light) was coil #1 was bad. so we swapped it and it worked on a good cylinder.

we also traced back all the wiring to the ecu an checked the signal wires and they were all fine.. so that's why we turned over to the fuel side... could a pump cause this or clogged fuel filter?

TIA

 

[OffshoreDrilling]

new car time?

 

[epik_x]

200k huh? 1st thing I would do is a compression test.

 

[Angus]

new car time?

nope. ran just fine and I just put a lot of work, time and money into making this a nice DD.

just gotta fix this... haha

 

[Angus]

200k huh? 1st thing I would do is a compression test.

just wondering but where and/or how do i do this? any cheap way other than a shop?

 

[02BlueGT]

ing the plug out and running it completing the circuit to the valve cover (ground).

This is why I said it isn't the same as in the cylinder.....try switching the wires around, or the injectors, see if the problem follows your part moving

 

[E]

just wondering but where and/or how do i do this? any cheap way other than a shop?

You need a pressure gauge, a strong hose and a fitting that will fit the tread for the spark plug. Take all the spark plugs out and test each cylinder with one crank on the starter.

 

[bikrboy128]

meet up? i have a compression tester and just about any other tool you would need :smile:

i also have injector pulse testers.

 

[epik_x]

^^^^^^^^^

You need a pressure gauge, a strong hose and a fitting that will fit the tread for the spark plug. Take all the spark plugs out and test each cylinder with one crank on the starter.

and

I beileve you can also rent one at Autozone, or Murrays.

 

[Angus]

This is why I said it isn't the same as in the cylinder.....try switching the wires around, or the injectors, see if the problem follows your part moving

did switch the wires around. And it stayed with the cylinders.

 

[Angus]

I'll see if advance has a compression tester i can rent...

thanks for the help.

 

[TonzKnock-G]

OLD ASS LUXURY IMPORTS FTL!

 

[Angus]

OLD ASS LUXURY IMPORTS FTL!

it's a good car and it's not very luxurious... But funny thing I've noticed is that my car has options on it that other auto manufacturers are just now putting on cars...
for example, when i was looking at the new mustangs a bit ago, i had a salesperson show me how the window will move a bit when opened to let out air pressure when being closed and said that was a new technology. my 93 does that.
Also, I saw an article in C&D show off the new acura RL and the caption in the picture was that the new front fascia design had functional air ducting to the brakes... so does my 93.

I just found this all funny...

but back on topic...

Today, my pop's is going to throw his scope on the injector signal wires and see if that's the problem...

 

[02BlueGT]

^^^Good luck

 

[Angus]

haven't gotten the scope on the injector wires yet, but did post up a vid of it running.

well it runs like crap. It'll start up and for a fraction of a second would seem fine but then go back to its old ways....

 

[LSx S10]

when you do the compression test, do it dry one time and then add a little bit of oil into the cylinder and retest. if your numbers go way up..then you know youve got a ring issue. And im not sure if you can get it or not, but a leakdown test i think would be a better test for this. I can pull some specs for both off my schools computer if you want.

stupid question but..i dont see anything about the condition of the plugs? are they gapped correctly? what do the plugs look like in the misfiring cylinders?

 

[Angus]

wow that info would be great.

the plugs are brand new and were gapped correctly. They were switched out with the old (good condition) ones too and didn't fix it either.

 

[LSx S10]

did some research in class today for you, from what i found it looks like the crank position sensor could be the cause for your misfires. but i forgot to get the spec so you can test it, my bad. but ive got lab in an hour so ill just do it then.

EDIT: i just looked through some forums too and guys with the same problem after doing all the same things you did (tune up, filters, etc..) still had the misfire, but the cps took care of it. If you decide to replace it, napa has them listed for 171$ but if you go to the napa of libertyville and say your from NTB of mundelein youll get it for 81$, they dont check i did that all summer and i only worked at ntb for like a week

 

[Angus]

huh, ill look into that. thanks a lot!

edit: is it really possible for a bummed cps to cause my #2 and #4 cylinders to just not fire? I pulled the wires yesterday and it ran the same just on 1 and 3.... so a cps can cause certain cylinders to just not fire at all?

 

[LSx S10]

thats your cps plug, check the resistance between pins 1 and 2. it should be within 50ohms of 540ohm...so 490-590ohms.

then measure between pins 1 and 3. should be over 100k ohms.

if you have that scope you were talking about, hook it up between pins 1 and 2. it should produce a wave pattern.

and as for your compression tests, all cylinders should be within 145-159psi and shouldnt deviate much more than 6psi. but again like i said, try putting oil in the cylinder during one of the tests.

i couldnt find the leak down specs, but by the sounds of it you dont have the tool to do it.

 

[Angus]

crank position sensor checked out ok...

 

[Angus]

ok put a scope on the injector wires/connectors. no pulse for injectors 2 and 4, but strong, visible pulse for 1 and 3 as those are the only ones firing.... BUT thing is, right at start-up, all injectors fire, but then 2 and 4 instantly stop firing...

any more ideas? thanks guys.