Smoke at idle
03-11-2015, 04:03 PM
#152
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Update !
I've spent a bit more than 2 hours in stop-start traffic on last sunday. Great...
To keep the focus on the bright side, the car hadn't smoked at idle with the PCV.
I put a 1/32" restrictor in the line running between the cam tower and the OCC to avoid oil succion and it looks to work. See pics here
https://rennlist.com/forums/944-turb...essure-12.html
I've spent a bit more than 2 hours in stop-start traffic on last sunday. Great...
To keep the focus on the bright side, the car hadn't smoked at idle with the PCV.
I put a 1/32" restrictor in the line running between the cam tower and the OCC to avoid oil succion and it looks to work. See pics here
https://rennlist.com/forums/944-turb...essure-12.html
09-06-2015, 01:53 PM
#154
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Well for now I'm a new involuntary member of the smoke at idle club, but with a peculiar twist. It's sort of bluish and definitely smells like oil. This follows a recently installed a stock M52 short block and Vitesse Stg ll. From the get go had smoke at idle. The short block had perfect bores, and the turbo had no shaft play. Had the entire engine resealed before it was installed.
This past week the AC went on the blink. Works sporadically, more off then on, (still sorting that out). The strange thing that happened is I noticed when the AC compressor stops engagement, the smoke at idle almost completely ceases. I very tiny bit still comes out, but almost undetectable. Little enough that I wouldn't qualify to be a member of the club.
When the compressor stops, it takes about 1:30 to 1:45 seconds to clear out. When the compressor re-engauges, it begins to smoke in about 15 seconds.
I do not have a oil restrictor on the turbo, catch can or PCV on the car, at least not yet anyway. My prior setup was virtually identical except the Vitesse turbo was a Gen-1 and this one is a Gen-2.
The engine is under load with the compressor running, but the wide band shows the fuel mixture to remain relatively constant whether the AC is running or not. Doesn't make any sense that the engine running under AC load would produce oil smoke at idle. Car seems to run pretty good under boost. Makes 1 bar at 3200 rpms. Little puff of blue sometimes, then clear as far as I can see.
I've searched and read almost every post related to this, but no one has posted about any correlation with the AC running. It's a riddle. Any ideas?
This past week the AC went on the blink. Works sporadically, more off then on, (still sorting that out). The strange thing that happened is I noticed when the AC compressor stops engagement, the smoke at idle almost completely ceases. I very tiny bit still comes out, but almost undetectable. Little enough that I wouldn't qualify to be a member of the club.
When the compressor stops, it takes about 1:30 to 1:45 seconds to clear out. When the compressor re-engauges, it begins to smoke in about 15 seconds.
I do not have a oil restrictor on the turbo, catch can or PCV on the car, at least not yet anyway. My prior setup was virtually identical except the Vitesse turbo was a Gen-1 and this one is a Gen-2.
The engine is under load with the compressor running, but the wide band shows the fuel mixture to remain relatively constant whether the AC is running or not. Doesn't make any sense that the engine running under AC load would produce oil smoke at idle. Car seems to run pretty good under boost. Makes 1 bar at 3200 rpms. Little puff of blue sometimes, then clear as far as I can see.
I've searched and read almost every post related to this, but no one has posted about any correlation with the AC running. It's a riddle. Any ideas?
09-06-2015, 02:42 PM
#155
That's a funny coincidence - I was having a beer just 15 min ago with marcoturbo who noticed the smoke went away when disengaging A/C.
However, in his case he uses a standalone A/C system with an aftermarket compressor and since his DME ignores when A/C is engaged, he adjusted his idle speed at 1200 rpm with the A/C off. It makes sense to us that the engine pulls enough air from the crankcase to avoid oil to slip through turbine seals at that speed, but not at speeds below 1000 rpm, which is where his idle speed sits with A/C engaged.
How much does your idle speed vary with the A/C engaged/disengaged?
However, in his case he uses a standalone A/C system with an aftermarket compressor and since his DME ignores when A/C is engaged, he adjusted his idle speed at 1200 rpm with the A/C off. It makes sense to us that the engine pulls enough air from the crankcase to avoid oil to slip through turbine seals at that speed, but not at speeds below 1000 rpm, which is where his idle speed sits with A/C engaged.
How much does your idle speed vary with the A/C engaged/disengaged?
09-06-2015, 03:25 PM
#156
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Idles at 900. I'll have check again to be certain, but after the compressor engages I think the idle dips momentarily, but resumes fairly consistently at 900. Definitely not much of a deviation.
09-06-2015, 03:40 PM
#157
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Tech who installed the engine smoke tested and did say I had a noticeable leak at the throttle body. Having gotten the car back from the shop a few weeks ago, and since it runs decent otherwise, I have not addressed it yet.
Tomorrow I'll bump the idle up some to see if it changes anything. Think I'll go ahead and order the throttle body reseal Kit from Arnworx. Maybe under load the leaky TB is enough to affect vacuum and crankcase ventilation.
Tomorrow I'll bump the idle up some to see if it changes anything. Think I'll go ahead and order the throttle body reseal Kit from Arnworx. Maybe under load the leaky TB is enough to affect vacuum and crankcase ventilation.
