Catalytic Or Fuel

[idanity]

heres my problem

when im driving , sometimes my car "sputters- jerks" like i let off the gas 1 second and its always
on- off on -off -on-on-off-ononon- as one breath out of 500 was nananana ,,, that fast that bumpy-jerky-pulsatingly bad...

it occurs 2-4 times in a row then all is well for a while.
starts okay and climbs speed or hills okay too

this mostly happens when im keeping pace or cresting a hill and slowing down.

when i did the HOT SOAK i noticed a tiny bit of smoke from my catalitic conv-or somewhere close to that. does that indicate a crack?

and would a crack have my back pressure ruining my smooth ride to a jerking one momentarily

[guywithblack88e30]

is all your air intake to throttle body ok maybe the car isn't geting enough air to engine, sometimes thats why they sputter

[idanity]

Originally posted by guywithblack88e30@Dec 3 2004, 11:32 AM
is all your air intake to throttle body ok maybe the car isn't geting enough air to engine, sometimes thats why they sputter

[snapback]242719[/snapback]

ive looked over the outside and it all appears ok,
6 months ago i changed the air filter and it needed that
however i will check the intake but theres some hoses that have this crimp on them like NON-ADJUSTABLE or at least no-screw

they come in 2 peices and (at the junkyard) i had to stretch the "over" part and the "under" part was a rounder U witha O crimped over it, seems to have NO_WAY to re-tighten them...

should i buy new clamps?
where do i get these "crimp-clamps"?
photos of the 'under'part of 2 defferent clamps i got from junkyard, tops are trashed.
im doing a injector cleaning today, i cleaned out the engine yesturday and bought seals for the process...[attachmentid=15787][attachmentid=15788][attachmentid=15789][attachmentid=15790]

[87 325iS]

Fuel filter.

[idanity]

5 months ago i went to Autozone and replaced the fuel filter too... same problem persists.
also changed
spark plugs to autolite copper cores
timing belts and all belts
fuel regulator
gas cap


checked
fuel pressure from pump
fuel tanks, (removed pump and looked for dirty tank, pump strainer looks new)
tank for dirt, saw very little dirt spots, the 1 gallon in there seemed clear
rotor
cap
wires
oxygen wires but not checked its voltage/ohm whatever.(should i un-plug?)

[rw685]

Sounds more like a DAC motor then anything. It's that round cylinder-looking device behind the 7th injector (attatches to a cam cover bracket). The DAC computer is beside the engine computer in (above) the glove box. You can take the motor itself off and look at it. See how crusty it is inside there and clean it up a little. You have to be carefull how you hold it if your going to spray cleaner inside it. Hold the end up so cleaner doesn't run inside the electrical part of it and run things. I use carburetor cleaner on mine about once a year. Oil & whatever, builds up inside it and makes the cylinder inside it stick. How you describe your problem, sounds like what a DAC does. It's basically your idle control device. Anytime the engine rpm's get low enough, the DAC takes over to control engine speed. For instance when the A/C kicks on, the DAC raises engine rpm. If you let the clutch out without touching the gas peddle, the DAC is doing the accelerating, slowly but shurely anyway. Clean the varnish out of the workings with carb cleaner then spray some WD40 or light lubricant in it and see if that doesn't help.

[idanity]

ooo i dont have a 7th injector, (the cold start one)

also everything looks new, at least on the outside.

i was going to pull out the injectors and clean them today but was afraid to break the plastic (2) bars that hold the injectors in ... i couldnt find any screws or bolts holding them down.

plus i couldnt disconnect the electrical plugs from the injector housing..
any help?

[idanity]

Originally posted by rw685@Dec 3 2004, 02:24 PM
Sounds more like a DAC motor then anything. It's that round cylinder-looking device behind the 7th injector (attatches to a cam cover bracket). The DAC computer is beside the engine computer in (above) the glove box. You can take the motor itself off and look at it. See how crusty it is inside there and clean it up a little. You have to be carefull how you hold it if your going to spray cleaner inside it. Hold the end up so cleaner doesn't run inside the electrical part of it and run things. I use carburetor cleaner on mine about once a year. Oil & whatever, builds up inside it and makes the cylinder inside it stick. How you describe your problem, sounds like what a DAC does. It's basically your idle control device. Anytime the engine rpm's get low enough, the DAC takes over to control engine speed. For instance when the A/C kicks on, the DAC raises engine rpm. If you let the clutch out without touching the gas peddle, the DAC is doing the accelerating, slowly but shurely anyway. Clean the varnish out of the workings with carb cleaner then spray some WD40 or light lubricant in it and see if that doesn't help.

[snapback]242860[/snapback]

would this be the "DAC"

the pics at the bottom are from what i just took off and cleaned . however

the pics are Pre-Cleaning so if yours is worse was mine just fixed???or cleaned by previouse owner.?[attachmentid=15804][attachmentid=15805][attachmentid=15806]

[rw685]

Sorry, Wrong engine. I'm always thinking of the e engines. The i also has a DAC which you show. It looks very clean, write that off your checked list.

Stumbling at part throttle, could be several possibuilities. You say it rev's out without a glitch? Runs smooth otherwise?

Keep in mind I'm not that familier with the i engines. I would blame spark plugs first. I run NGK Gold Palidium's from O-reilley's. It's a thin wire electrode. After almost two years of use they run better then the Bosch's would have.

Then I would blame a possible bad throttle position switch. These seem to make a noticable difference when changed if your having simptoms like this. An airflow sensor could also cause low-speed trouble. This would be the last part I would replace as they are over $300.00. If you can try a known good air-flow meter, that could rule it out without spending anything.

[idanity]

does anyone know of the catalytic converter doing this?
fuel injectors?

can i clean the air=flow meter? or make one ?or by[pass] it ?

btw the exhaust manifol is rusty and the bolts will probably have to be cut off.