Eta stumbles after throttle bump; also low oil to cam?

[shaferbm]

Bought the car yesterday as a daily. Idles around 1000 rpm and when I bump the gas it will rev then drop way below 1000 rpm and seem like it wants to stall then come back up. What could be causing this? PO had the car sitting in his barn for quite a while.

Also, idle changes when I open the oil cap on the rocker cover, but I'm guessing thats normal? Either way when I do and look inside it doesn't seem like there is much oil getting to the cam, rocker, etc. I don't want to run it like this. Oil light is also on.
Hopefully I can get this thing running by the end of the week.

[ANDRÜ]

Sounds like the fuel pump. Mine had a slight whine when I had an eta, and would do this. I would change the filter, and put your ear close to the pump to hear if it is struggling. You may be able to hear it at idle just infront of the drivers side rear wheel.

[TurboJake]

Also, idle changes when I open the oil cap on the rocker cover, but I'm guessing thats normal?

Very normal. The valve cover is connected to the intake manifold, and is not governed by the throttle body or intake tract. Unmetered air entering the system = idle change.

Oil light is also on.

Get that looked into. But above all, make sure there is enough oil (I'm sure you did the moment you saw the light though)

Either way when I do and look inside it doesn't seem like there is much oil getting to the cam, rocker, etc.

If you see oil in there, and everything is nice and lubricated, it's probably fine. You don't really want too much oil in there. But the overhead rail than runs along the head can and sometimes does clog up. Good place to start.

I'd diagnose the high idle to begin with. Sounds like the car is trying to return to a normal idle after you bump the throttle, which is not 1k rpm.

[shaferbm]

Also, I just pulled the valse cover and literally found this floating around in there. What is it?
The car has plenty of oil. Everything under the valve cover seems to be pretty dirty and sludgy.

Think the idle could be caused by the idler control valve?

[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 hoses, valve, and expansion tank
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 0.030-0.060" 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.

While a bad check valve in the high pressure pump can result in longer than
normal cranking, if the fuel system is working as it is supposed to the rail
will reach normal pressure in a few turns of the engine. A weak pump, clogged
filter or leaking FPR in conjunction with a failed check valve can result in
longer cranking.

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 (dry and wet)
and leak down tests on the engine. 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 20 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. Although not commonly encountered, a bad harmonic balancer on an
M20B25 or M30 engine will cause problems.

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

[paperplane94]

Random trim clip for O2 sensor wire above I think^

[shaferbm]

Jlevie thanks for the great info. I'll see if I can run trough the list and resolve the issue. The first thing that comes to mind is lines and connection to the brake booster( which seems really weird that that would affect it) because the brake fluid is low and there is a bad line.

Edit: what's normal idle for an eta?

[shaferbm]

It is idling nicely now. There is a tear in the rubber that goes from the intake manifold to the mad sensor and box, as well as a leak between the intake manifold and the head. Next a valve adjustment will be in order. It also seems the airbox had some visitors.

[5Toes]

Not to threadjack, but how does one figure out if a harmonic balancer is bad?

[jlevie]

Not to threadjack, but how does one figure out if a harmonic balancer is bad?

Separation or mechanical damage are the likely failure modes, which can be detected visually.

[shaferbm]

If you see oil in there, and everything is nice and lubricated, it's probably fine. You don't really want too much oil in there. But the overhead rail than runs along the head can and sometimes does clog up. Good place to start.

Alright, idle issue was a simple vacuum leak. Oil issue still persists though. I gave the car fresh oil(old oil was pretty sludgy) and filter, pulled the oil rail that runs over the cam and rockers, ran brake parks cleaner though and blew it out with compressed air. All openings were clear. Could I have an issue with the sensing unit for oil pressure? I know oil pressure is vital and don't want to ruin anything.

Edit: There is alway a little bit of oil in there, but not what seems like enough to me. Also when I open the oil cap after driving, just a little bit of smoke comes out.
This makes me concernicus.

[TurboJake]

Take off your valve cover and get a pic.

A nice, well lit one.

[shaferbm]

I'll see if I can get one tomorrow. This is my only dd right now since the audi is not running(naturally).

I also tried revving it up a bit while driving and after 4k rpm the flickers, go out, then comes back on when under.

[I got it, yes!!]

Then most likely your oil pressure sensor is fine and you have poor oil pressure. Does your engine make any other noises(knocking, etc)

[shaferbm]

It knocks a bit but I was under the idea that all m20s knocked or ticked. Where would I look first? Check oil pump?