Hard Start Issue, AND a CEL!

[m20technik AZ]

Hey everyone. New to the site.

My new(to me) E30 is giving me grief! Ever since I've had it, It cranks longer than it should in the morning, and sputters to life, and eventually settles at a nice idle. I don't know what would cause this. I've been looking into it, and seems to be a dirty injector issue? I'd like to pinpoint it soon, I have a limited budget. Any help or similar stories and fixes would be awesome.:D

Also, on my way home tonight, she threw a CEL at me. Checked the flashes, and got 2. O2 sensor problem IIRC? It still runs fine. No change in performance when I got it. Will have to see if any change tomorrow, but seems to be fine at the moment. How long do I have before it starts acting up?

That seems to be it at the moment!

Thanks for any insight, fellas!

Mike

[bcrdukes]

Does it run rich at startup? You might have a leaky injector. Check your fuel rail pressure and let it sit for an hour to see if pressure drops. Take a look at your spark plugs and see if any of them are wet. I found out my leaky injector caused this problem. Your DME is probably running in limp mode right now.

Also, what codes are you throwing?

[jlevie]

Idle or hard starting problems are most commonly caused by intake leaks and/or
a sticky or defective Idle Control Valve (ICV). The only reliable method of
locating intake leaks is to have a smoke test run on the intake and crank case
and to test the brake booster with a gage and vacuum pump. The complete list
of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hose and valve
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

While leaks in some of those can be found by inspection or by spraying carb
cleaner on suspect areas, not finding leaks that way doesn't eliminate the
possibility. Only a smoke test will really work.

Once the possibility of intake leaks is eliminated, the ICV needs to be
removed and cleaned with carb cleaner until the vane inside moves freely. When
the ignition is switched on you should be able to feel vibration from the
ICV. If no vibration the ICV is bad, there's a problem with its wiring or
connector, there's a problem with the TPS, or the DME (or Idle Control Module
(ICM) on an ETA car) is faulty.

For the DME (or ICM) to control idle, the idle switch in the TPS must work
correctly. The switch should close when the throttle stop is 0.020-0.060" off
the idle stop screw.

The fuel system should be tested via the suite of tests in the Bentley manual
as invalid rail pressure can be a contributor to idle and starting problems. A
simple injector check is to pull the injectors, jumper the fuel relay to run
the pump, and see if the injectors are leaking. You can also point the
injectors into a towel, remove the coil wire, and crank the engine to see if
all of the injectors appear to be spraying in a similar fashion. The best
approach to possible injector problems is to have the injectors cleaned and
flow tested. Since raw fuel can or will be released in these tests, have a
fire extinguisher handy.

The O2 sensor can be a contributor to idle problems. The O2 sensor is a
scheduled maintenance item with a useful life of no more than 100k. If the
sensor has that mileage or more (or is of unknown age), replace it.

The AFM can be a contributor. If the vane doesn't move freely or the
resistance track is worn the DME may be receiving invalid data from the
AFM. And if someone has fiddled with the bypass air adjustment the DME may be
unable to stabilize idle. The bypass air adjustment should only be adjusted
per the procedure in the Bentley and with an exhaust gas analyzer. And even
then everything else associated with engine management has to first be
operating properly. If the AFM becomes a suspect, replacement with a good used
unit is the best approach.

Improperly adjusted or malfunctioning valves will affect idle and starting. As
can compression issues from ring or cylinder wear. A valve adjustment is
called for every 15k. A useful diagnostic is to run compression and leak down
tests on the engine. And aged ignition wires, plugs, distributor cap, or
rotor can cause problems. Insulation does break down with time and heat. And
since the youngest E30 is going on 19 years old, if the ignition system is
original or the plugs are old replacement is indicated.

Although not usually a problem, a bad DME temp sensor is a possibility. That
generally won't cause an unstable idle, but can cause hard cold or hard hot
starts and/or a rough idle. As can problems with the timing reference sensors.

When all other possibilities have been eliminated and idle or starting
problems persist, replacement of the DME, or if applicable the ICM, is
indicated.

[m20technik AZ]

First off, thank you both for the replies.

It seems (and smells) like it may be running rich at start-up. I think this will be an injector problem, all the help I get online pretty much points to that. I'm going to have to have them cleaned, and replace all the seals. It should be done anyways, theres a coating of oil/grime on the top of them...

As far as codes go, since it's only Motronic 1.1, I get a vague code.. It blinked twice. That's an o2 problem, correct? Is there anything else besides the o2 that would cause that CEL?

[m20technik AZ]

Update on the CEL... It went away. I don't know what I did, but after messing with the plugs, and generally cleaning up the bay, it seems ok... Still hard to start though. Would running on almost no gas make that light come on? I was below the white empty line last night. (forgot wallet at home, d'oh!)

[bcrdukes]

OP,

I replaced my injectors today. My problem is still active.

[PeaveyBassist]

A fuel problem would make the CEL come on. Maybe fuel pump giving low pressure, maybe fuel pressure regulator giving low fuel pressure. My guess is low pressure and also the fuel pressure regulator. It takes a long time to start in the morning because the fuel system has to build up fuel pressure again before it has enough fuel to start. The CEL came on because with the low pressure, the computer tells the injectors to give more fuel so it opens the injectors longer, however it probably tried opening them so long that they were always open (100% duty cycle) and the computer saw the problem. The only code it knows is o2 sensor to throw for that IIRC. Try jumping the fuel pump or fuel pump relay with the car off, and the key on for about 30-45 seconds before starting the car in the morning or after it has sat at least 4-5 hours. That should give it a chance to build up fuel pressure before starting the car. If the car starts like normal, then you probably have a bad fuel pressure regulator that bleeds off pressure over night. If you can get a hold of a fuel pressure gauge, even better. Hook that up at night when you put the car up for the night and record the fuel pressure after you run the car at idle for a couple seconds. Then in the morning see what kind of difference there is in pressure. If it has bled off a lot, then replace the fuel pressure regulator. Let us know if this helps!

http://www.bmaparts.com/ShopByVehicle.epc?q=1989-BMW-3--5is--/--L6--494cc--.5l--Gas--Fi--m--0--15---Fuel--Injection&yearid=1989%40%401989&makeid=BMW%40%40BMW%40%40X&engineid=1011845%40%40325IS++%2F+L6-2494cc+2.5L+GAS+FI++%28M20%29+152%40%40325IS&catid=Fuel+Injection%40%40Fuel+Injection&subcatid=Fuel+Pressure+Regulator@@Fuel+Pressure+Regulator&mode=PA

^^^ new one at BMA is $72.

[m20technik AZ]

Ok, I will let you guys know what happens. I will try this out on Tuesday, I'm probably going over a friends house to do some routine maintenance to our cars, should be fun! I may pick up one of these regulators from a junkyard when I go here in the next couple of days, and see if another one makes a bit of difference.

Thanks for all the help, guys

[jlevie]

Running through the suite of fuel system tests in the Bentley will tell once and for all wheter the fuel system is at fault. And if it is those tests will tell which part(s) are bad. That is a far better approach than throwing parts at the problem and hoping for a favorable outcome.

[FREE30]

Did I see you at Pavillions awhile back? Hmmm.....I drive the slammed blue and white Mini Cooper. I might be there this weekend. Gotta take time from pulling my busted ass M2O....:hitler:

[m20technik AZ]

Did I see you at Pavillions awhile back? Hmmm.....I drive the slammed blue and white Mini Cooper. I might be there this weekend. Gotta take time from pulling my busted ass M2O....:hitler:

Hey man, I havent been at the Pavillions in a while, I was there with my Volvo though. I was showing it with my other Volvo buddies about 2 months ago. I may turn up soon though. Love that show:D

[Red88]

If you were in Tucson I'd say I've got a known working FPR you could try, and if you still had a CEL I've got a 173 DME you could throw in and look into it further if it still was gonna throw a code.

[bcrdukes]

OP,

Did you ever resolve this issue?

[m20technik AZ]

Hello, I finally figured out my issue. I got both pumps replaced after the car died on me, and it drove fine, but still had that starting issue. It would take longer than it should. Well, I got a new fuel pressure regulator, and it's fine now! So happy to have it back to normal. I though the fuel pumps and the starting were related directly, turns out they were 2 separate problems!

Thanks for all the help :)