Hi guys,
Have a 2001 Holden Astra (TS)/Opel Astra. Running the Z18XE engine. Had been in storage for 12 months and never started until a week ago. The issue for the customer is when cold it is hard to start and takes several attempts to get it running and staying running. It also won’t rev until the engine warms up a little.
I confirmed the hard start and had a long crank then fire and stall after a second or two. 2nd start was fairly normal but once again stalling after a couple of seconds. Third attempt was similar except when trying to get the revs up to keep engine running there was little response and engine stalled after around 15 secs. On the 6th attempt it started normally but not wanting to rev for about a minute or two but didn’t stall then was able to use the throttle to increase revs which smoothed the engine.
Codes initially were P0136 P01130 P01140 P0170 P0110 and P0100. The only one current at time of testing though was the P1130. After viewing data pids on the scan tool (Autel ms908P) I found the 2nd O2 sensor to be unresponsive and pegged high (1900 to 2100mv). I then cleared the codes to see what would return once I returned to testing once engine was cold again. The code that returned was the P0136. I also noticed that the heater circuit on O2s2 was inactive.
Thinking about what could affect a cold start I looked at the ECT IAT MAF APP and Throttle body signals. All tested ok. A bit of investigation found that the ECT is a common problem for hard start and rough running and is caused by vibration in the connector. Something to keep in the back of my mind. I checked fuel pressure only to find that there was no prime when the key was turned on. Fuel pressure did reach 52 psi very quickly once started and only dropped to 51 psi after turning the engine off. I checked the heater circuit on the O2 sensor and had 12v both side with KOEO. Which is where I stopped testing as the customer required the car for work the next day.
I have asked them to bring the car back when they get a chance. Something I would like to test is how the car starts with the ECT unplugged as the ECM reports -40. I also need to test the rest of the O2 wiring. But after that I am running out of ideas. Any thoughts from anyone else?
I have included a wiring diagram to help.
Cheers
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