4agze Aw11 Engine Idle and Hesitaion Issues
Good day to you all.
I recently have had a series of engine idle and hesitation issues I was wanting some advice on.
Originally the car would cold start fine and continue to run like a dream while the engine was warming up. As soon as the engine was warm and the idle dipped below 1000rpm is when my idle issues would begin. The idle would start to get rather rough and the idle would hunt between around 1400 and 850 intermittently. Plus if you would step on the gas quickly then let go the idle would settle below 850 and the engine would strain to stay running. Eventual the engine would settle back to 850 but it may take a while.
The car as well will intermittently hesitate under acceleration. Slow/ linear acceleration is fine and the engine under load seems to perform well. However if for example you down shift and floor it for a second the engine dosnt rev its like its lost all power. Once the SC kicks in suddenly all the power in the world is available and the engine accelerates without an issue through out the rev range. As stated above this intermittently occurs and I can be driving for 30 minutes plus sometimes before this happens.
My theory was that the engine was running rich and didnt have the correct fuel/ air mixture till the SC kicked in and gave it the needed air to breath.
I studied the BGB and followed what I could to resolve this. Below is a list of what I did to try and resolve this:
- Found a leak in a dodgy boost gauge installed by a previous owner. I removed the gauge from the system and replaced the piping.
- Checked and couldn't find any other boost leaks
- Checked and have found no vacuum leaks
- Found the O2 sensor cable was damaged and not making a solid connection to the sensor. I replaced both the cable and sensor and have found no issues with it.
- Flushed and replaced the coolant. Checked and found no air in the system.
- Replaced and ensured spark plugs had the correct gapping
- Checked the ignition system with a multimeter and found no issues
- Replaced the air filter
- Checked and no engine error codes were being reported
After doing this I found that the engine hunting at idle has stopped completely. I have also found only once since performing all the above steps the engine struggling to retain idle after a quick step on the gas. Plus when the one struggled occurred it was over in a matter of moments and wasn't as severe. However the idle is still rough below 1000rpm and not Toyota perfect. The power hesitation issue has still remained unchanged as well.
From what I see the car is possibly running rich still, but I cant see why? I know possibly either a cam or ignition timing issue could cause this. I however dont have the tools to test this and i'm trying to prevent having to take the car to a garage for cost and pride reasons.
I was then wondering does anyone have any advice on anything else I can do to test the engine, or any ideas on what could be doing this?
Thanks
post edited by dwoodcob . - 2014/04/30 15:39:29