Mechanics

ENGINE TURNS OVER BUT WONT START. WHITE SMOKE IS BLOWING FROM AIR INTAKE WITH A BANG. CHECKED NEARLY EVERYTING

1996 Subaru Impreza • 110,000 miles

Car: Subaru Impreza 1996 GL 2.0i EJ20 MT

Preamble:
Body/engine driven 250.000 km
Body nearly rust free, clutch, drivetrain and electronics in good condition.

1 month ago the car began to idle badly, misfire, stalling aswell as having lost a lot of compression with vigourisly higher fuel consumption and oil burning.
I put a new MAF in it wich helped a tiny bit but not enough

Instead of opting for an expensive repair I bought an engine with 110k on it from a carparts dealer wich included the engine swap.

After the engine swap the car had a small misfire problem on 1 cylinder.
The carparts dealer booked a repair with a Subaru certified workshop.
They sorted out the misfire (new spark plugs, ECU fiddle) and the car was running beautifully.

Problem:
1 week after they sorted the car out, I ran out one morning late for work, put it in reverse to back out of the driveway. Engine fired straight up but stalled right away after 2 meters of backing. (If relevant the driveway is in an incline and it was raining outside and temperture was about 1-2°c)

I tried to start it again but it just turned over and over without firing up. A quick look at the fuel gauge showed an nearly empty tank so I jogged to the nearest gas station and put 5 liters of gas on it. Tried to start it again 3 or 4 times but it just turned over without firing up.

The next day I pushed the car into my garage and started out by changing the starter since I first thought it wasn't releasing fast enough.
Well that didn't work so I rang a workshop that told me the engine was probably flooded.

What I did next was:
#Checked for compression - Engine compresses as I turn the crank
#Check fuel pump - Buzzes with ignition on, fuel pressure normal on "out" line of fuel filter
#Semi-checked injectors - Clicking noise and vibrations on fuel line when cranking
#Removed spark plugs (new NGK's) - They were wet with fuel, cleaned them and dried them out. One plug was dark and sooty.
#Checked for spark on HT Leads, top right looking on top of coil pack didnt spark, measured resistance on lead wich was ok so I got a new coil pack from the carpart dealer wich sorted out the missing spark.
(Before putting in the new coilpack I tried starting with the HT Leds disconnected and the old coil was arcing from bottom right plug onto manifold)
#Checked Cam angle sensor - Had bit of dirt on it, cleaned it up.
#Charged battery to full capacity and checked alternator wich is good
#Checked all ground connections and fuses - All ok
#Checked ECU codes by connecting the black connectors under dash - No codes in memory
#Cleared ECU by having + and - disconnected for 5 hours

Thinking I was good to go I put the plugs back in, went over all connections, hooked the battery up to a battery on a running car and tried starting it again. (Had black "ECU read connectors" connected wich is recomended for cold starts and didn't touch the throttle pedal while starting)

It still doesn't fire up and to make matters worse white smoke blows out of the air intake with a bang when I try to start it
Avatar
Techhead
March 11, 2012.



You checked for compression, but did you measure its pressure?

Try changinf the spark plugs and retest.

KHLow2008
Mar 11, 2012.
The car starts now, but is still misbehaving

I got the timing and HT leads checked out at a workshop and they found out it was the cam sensor that was causing it not to start. Replaced the sensor and now it starts up.

But a new problem has arisen.

Now the car idle's very badly, and when in 3rd, 4th or 5th gear over 2000rpm when I pull off the throttle even mildly, the rpms drop unusully fast and the car jerks down, its like extreme engine braking

I filled the tank, reset the ECU and drove it sensibly for over 2 hours but no difference. Ideas?

Tiny
Techhead
Mar 13, 2012.
Do you have any trouble codes now?
Have you checked if any cylinder is misfiring?

KHLow2008
Mar 15, 2012.