Lower Power and Stumbling

[floatinghead]

Sorry this is a bit long, but i've looked on the boards for a while and haven’t quite seen the same symptoms like what i’m experiencing. I’m a novice mechanic, but have been working on my cars for a few years fixing what needs fixing. My 1982 320i hasn’t been running great since I bought it. I didn't pass DEQ emissions the first time but with some high octane fuel adds from a mechanic, we got it through. And while a house project is keeping me from working on the car at the moment, I thought I'd get some feedback on how I should approach it when i have time next month.

Car starts up easily every time and idles smooth. Idles a bit high (1100) as I adjusted it after I bought it as it had been randomly cutting out while driving. No problems since. List of things i’ve done to the car since I bought it last year:

• New Spark plugs
  
• New Plug wires
  
• New Ignition Coil as the plug connection snapped off
  
• New Battery
  
• Oil change and filter
  
• New Vacuum hose to Distributor
  
• New Air Filter
  
• New Air intake bellows ( no vacuum leaks )
  
• New coolant hoses ( except for water pump hose) and new thermostat (80deg)
  
• New Hazard switch
  
• New light switch
  
• New fuel filter
  
• 3 new braided hoses from tank to fuel pump/filter.

This is the general sequence of events:

1. Starts up great.
   
2. If I pull away shortly after start up it pulls decently and feels kinda strong, but I don’t want to rev it too much as it's not warmed up yet.
   
3. After a minute or two, I’ll get some strong stutters when driving. It will kind of bog and then surge. If I’m higher RPM ( over 2 or 3k) it will be a bit better, but not smooth at all.
   
4. Once it's warmed up, it will run smoother, but doesn’t have the same power as after i first started the car. And I can feel some light stuttering through the range.
   
5. Idle is flat and quiet.
   
6. Slow acceleration, but i’m new e21’s ( 1.8L) so not sure what it should feel like, but getting on a freeway is tough.
   
7. Any incline is a struggle. Cruises fine on flat and I can get to 65mph without much problem. If going up a slight incline, I’ve had it floored and dropped a gear and barely keeps up with traffic.
   
8. Car runs better the warmer it is outside. Cool weather, more bogging and bucking and when it’s above say 65F, it will run smoother off the bat. Still has low power on inclines, just a bit smoother.

Looking for logical (easiest first) way to solve this issue.

1. Replacing fuel filter again?
   
2. Checking fuel pumps for pressure? Never done this
   
3. Timing? Could timing be off? Havne’t done this either.
   
4. Injector O rings. Bought, but haven’t replaced
   
5. WUR? Fuel distributor? Unknown terroritory for me but seems like there’s lots of info here.

Any tips would be appreciated. Really want to get this car running smoother so i can tackle some of he body issues.

Thanks,

Baron

[autox320]

Definitely check ignition timing first, then dive in and tidy up testing fuel pressures etc. Sounds like ignition timing issue just from your description. Theres always WUR and kjet issues as another layer but start with timing.

[goinstrong]

+1 for the timing first. Other thoughts: cold start injector not shutting off? Warm up regulator as mentioned above? Coolant temp sensor bad? Let us know what you find! Best of luck!

[floatinghead]

thanks for the comments, I appreciate it. Had me thinking if the vac advance on distributor is working as well. These seem easy to try so will check hopefully this week ( car isn't at home) and will report back.

[epmedia]

Originally, there are tiny cone-shape filters under the injector line banjo bolts on the fuel distributor. Debris can settle in the fuel ports when the filters are installed, may need to flush the fuel ports too.

[OLD MAN]

As far as fuel issues go - pull the plugs and look at them, they will let you know if you are running lean or rich or good.

Over the years I have had a couple distributors go bad and ignition module, so an ignition issue can be more then just plugs, wires, cap and rotters. Your vac advance my be sticky or not working.

Also with as old as your E21s are, unplugging and - messing with the wiring harness can break things. They are old and brittle like some of us.

[320iAman]

"WUR? Fuel distributor? Unknown terroritory for me but seems like there’s lots of info here."

I'd check the WUR Cold and Warm Control pressure,,low power can be from an WUR out of adjustment. 20/50 psi is standard pressures.

Tool Aid 33800 can test the Fuel pump, the WUR , and Fuel Distributor pressure relief valve o-ring which gives rest pressure.

Randy

[floatinghead]

Thanks for the added the responses. I drove the car home tonight and attempted to check the timing ( which I've never done). I have a crappy adjustable timing light from HF ( going to get a real one soon!) and when I used the light at 2200RPM at 0 degrees I saw the ball in the trans hole. I was expecting it to see it at 25degrees. Is this right or do I need to advance it to 25?

Sorry if this seems rudimentary, but this is new to me.

thanks,

Baron

[OLD MAN]

Thanks for the added the responses. I drove the car home tonight and attempted to check the timing ( which I've never done). I have a crappy adjustable timing light from HF ( going to get a real one soon!) and when I used the light at 2200RPM at 0 degrees I saw the ball in the trans hole. I was expecting it to see it at 25degrees. Is this right or do I need to advance it to 25?

Sorry if this seems rudimentary, but this is new to me.

thanks,

Baron

With the RPMs at 2200 - you should set the timing light to 25 degrees of advance (if this is how yours works) then adjust timing till you see 1/2 of the ball. At least that is how I do it.

[floatinghead]

Well I looked at the directions to my
timing light and it appears that if I set the dial to 0 advance and the ball lines up I’m at 25 btdc, so it appears my timing is about right. I’ve never done this, but the ball certainly wasn’t steady, but was visible in the hole. I’ll probably do another check to make sure tomorrow....


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[epmedia]

Under the dist rotor, is originally a felt material pad on-top of the shaft. This felt pad is to be lubricated routinely with a couple drops of engine oil. This lubrication is to assist with smooth function of the centrifugal ignition timing advance.

[floatinghead]

Under the dist rotor, is originally a felt material pad on-top of the shaft. This felt pad is to be lubricated routinely with a couple drops of engine oil. This lubrication is to assist with smooth function of the centrifugal ignition timing advance.

I pulled the rotor this morning and it was quite dry. added some oil and found a new rotor and cap, even though the current one wasn't so bad. ran it this afternoon, and not sure if it was cause it was in the 60's out, but it ran a bit smoother. I still think there's more going on, but every little bit helps.

[epmedia]

I should have said: 'remove the felt pad and put a couple drops of engine oil in there, then re-install the felt pad'. sorry about that

[autox320]

Well I looked at the directions to my
timing light and it appears that if I set the dial to 0 advance and the ball lines up I’m at 25 btdc, so it appears my timing is about right. I’ve never done this, but the ball certainly wasn’t steady, but was visible in the hole. I’ll probably do another check to make sure tomorrow....


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Least you know it's not super out of spec. If not needing a fancier light then the HF one is probably fine. If want a better one though i recommend INNOVA https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I also make bright paint marks on the front pulley and scribe on the timing cover @TDC. Makes much easier to be accurate setting timing. Set light at advance number what you want/should be and the lines will line up when throttle held for target rpm. Digital light gives a nice rpm readout and advance to make this easiest possible one man job.

Maybe see if can hear any "bees in a can" buzzing sounds from the main fuel pump. If it's excessive it can mean a in tank pump failure or it's dying putting strain on the main pump. Just thinking out loud, sorry if can't be much more help. Timing is a biggie so your half way there.

[floatinghead]

I’ve seen that innovo light and was thinking about getting a better one anyway.

Im a few weeks out from really spending time digging into this issue, so I’ll report back once I get back into it.


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