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Low Boost Indication after Turbo Replacement

823 views 4 replies 3 participants last post by  MoreBoost 
#1 ·
I replaced my turbo because it was worn out. I had it rebuilt and I re-installed it. No more smoke out the back, but since I replaced it I'm not sustaining boost from idle as I add power while still stationary.

Initially on start up, it idles fine but after I have let it warm up a few minutes it starts hesitating and running rough when power is applied, like a misfire or no boost.

I notice that the turbo indicator doesn't respond beyond the yellow band when power is applied indicating no boost action or cut-out.

I am fairly certain I got the turbo vacuums back on correctly on the underside of the turbo, but I'm not 100% certain. I was going by the natural run of the hose and length since I didn't mark them. I also took one hose off the waste gate control atop the radiator so that shouldn't be an issue. I suspect the issue might be down below or the rebuild might be in question. All other hoses appear to be okay. Any suggestions. I'm anxious to get back on the road.

91 SAAB Turbo 2.3L
 
#2 ·
more data gathering on the problem

I swapped the vacuum hoses on the wastegate unit and it seems to idle smooth now but when I go from 1st to 2nd gear I'm still getting hesitation and rough transition into to 2nd and 3rd gear. Boost seems responsive now, but it still seems as though it is misfiring.
 
#4 ·
Idle is Okay now

Been away for awhile. The new plugs did the trick. Thanks Mate

Git two other issues with the car:

1. Low Boost. Turbo was bad, rebuilt and re-installed. Car drives fine in the city but not getting the acceleration I'm used to from idle and on the highway to get out of traffic trouble. I can get up to about 85mph but the acceleration is weak. Turbo gauge show midrange when acceleration is applied.

2. Having trouble keeping the car cool. Have factory coolant and expansion tank filled. Car idles at 3/4 on temp gauge and increases if idle for a long time. When driving or moving, temp gauge shows 3/4 and stabilizes there. Cant seem to get it cooler or back to normal range. Thermostat was replaced also. No change in results. This may be also be related to turbo seemingly reduced performance or low boost.

Any ideas?
 
#5 ·
The type of oil you use makes a huge difference. When was the last time you changed the oil?? What kind of coolant are you using?? My 9000k was running real hot, then i changed the oil and i flushed the cooling system and i used this other type of coolant from pepboys, comes in a tin can with neon colors, it says it drops the temp 20 degrees, and it really did, before i was reading anywhere from 3/4 and up, almost to the red, now after the oil change and coolant flush and the new coolant, it runs between 1/2 and 3/4 much cooler.
 
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