HELP! Cold stall, now no start.

[mrbobian]

The past few days my '88 ix has been acting funny.

I usually let it idle for a while since its usually pretty damn cold here once I start it up, then blip the throttle a few times and shes good to go. This weekend or so, I did do the same thing, it started just fine but I blipped the throttle as usual, it revved to 1200rpm or so then died. I cranked for a bit with no results so I let it sit for a minute or two and then it started fine. Well, this morning it did the same thing but wouldnt start at all and still wont...

My first thought was a vacuum leak, but I really need the car running to test for this...

I pulled a plug (which have about 3000 miles on them) and it looked like this:



I have yet to determine if it has spark yet...

I'm pretty sure its getting fuel but I am unsure how to test this? Any tips?

Just looking for some direction, thanks in advance,

Mike B.

[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.

[shay91]

he pretty much covered it. but check for CEL codes on mine, it was a 1215 which is the AFM your spark plug is greyish which is normal condition that means its been firing correctly.

to check you CEL code depending on the model of the car you can 1. turn the key to the on position and wait for the Check engine light to flash and count them or 2. turn the key to the on and press the gas pedal 5 times and count the flashes. its four digits per code. Good luck friend

[mrbobian]

I pulled a spark plug out and tried to get it to spark to the block but go nothing... Do I have to have one in the whole to get it to fire properly? If not then I would assume at least one problem is no spark... I have also pulled the ICV off and cleaned it briefly with some carb cleaner but it changed nothing... I'm assuming its receiving power because with the key in the on position it is very apparent that it is vibrating...

Where to go next?

Thanks!

Mike B.

[jlevie]

I pulled a spark plug out and tried to get it to spark to the block but go nothing... Do I have to have one in the whole to get it to fire properly? If not then I would assume at least one problem is no spark... I have also pulled the ICV off and cleaned it briefly with some carb cleaner but it changed nothing... I'm assuming its receiving power because with the key in the on position it is very apparent that it is vibrating...

The body of the spark plug only needs to touch the block to have spark. The observation that the ICV is vibrating when the ignition is on says that the DME has power and running. Therefore no spark would be:

No power to the coil
No timing data to the DME
Bad coil
Bad distributor
Broken timing belt
Bad DME

I doubt that the timing belt is the problem, but if you remove the oil fill cap and crank the engine you can tell if the cam is turning. You can eliminate the eliminate the distributor by checking for spark at the coil wire.

[mrbobian]

My timing belt was replaced about 3000miles ago so I can't imagine that would have gone. How do I check for spark at the coil wire? Sorry... ignition is very strange to me...

[jlevie]

Pull the wire that runs from the coil to the distributor and see if a spark will go from that wire to ground when cranking.

[mrbobian]

I could not for the life of me get my coil to spark to a ground... Could a bad coil really cause it to stall out on me like it did???

Also I got a reading of 0.6-0.7ohms for the TPS when closed and I think I got about 506ohm from my CPS. Those seem to be pretty close to spec.?

[mrbobian]

Well I got things figured out...

First I put a whole bottle of dry gas in the tank, let it sit, jumpered the fuel pump and let close to a liter run out the FPR. I hooked things back up and she still would start BUT it sputtered a little.

Then just for grins I disconnected the oxygen sensor and it started right up no problems... I reconnected the sensor and it started too...

So I'm thinking a combination of a corroded O2 sensor connection and some bad gas gave me a no start... Anyway, its back on the roads. Thanks for your help!

Mike B.

[jlevie]

The O2 sensor isn't used by the DME on a cold start. Disconnecting it should have had no affect.

[mrbobian]

Humm must have been completely bad gas... That's strange to me but I kind of makes sense. It was really warm here then dropped to about 10 deg. in a day so I'd imagine there was some condensation in both the station's tank and mine...