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Request clarification Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Mon, 13 Sep 2004 06:01:45
In Reply to: Too Much Boost, Sam, Sun, 12 Sep 2004 20:06:43 Members do not see ads below this line. - Help Keep This Site Online - Signup |
There are a few different possible issues here, and more detail would help.
When accelerating under load, does the needle go To the red, or does it go beyond the red? Is it going deep into the red on the boost gauge?
Does the engine feel like it is studdering, like a 'miss', or does the engine smoothly accelerate up until it suddenly starts to buck violently?
Is it consistent or intermittent?
My thoughts - if the engine feels like a 'miss' the classic issue would be spark plug gap. Too big a gap can cause missing. Hard to believe that with all the engine work that could be the issue, but ALWAYS go for the simple stuff. Always use the specified NGK's from the manual, gapped per the manual.
If the problem is a true overboost, where you boost well into the red, two things come to mind, and it can be a combination of both. First, a vacuum leak in the hoses between the intake manifold, BPC, and wastegate actuator. Any loss of pressure in that path, and you can overboost. Pull off the hoses at BOTH ends and make sure you can blow easily through them - a blockage, even a partial one, can cause some strange pressure issues.
Is Base Boost level set correctly? Did someone at some time mess with the wastegate actuator rod length? Many times folks do that to quick-cure some other issues when they get base boost only, and once that is resolved, you get overboost. Always good to make sure they easy stuff is checked.
Lastly, I'd look at your MAP sensor (Manifold Absolute Pressure), including the hose from the intake manifold to the sensor. The Trionic system uses the MAP to measure pressure, and if it's reading the wrong pressure, you can get overboost. Or, if the MAP is reading too high, the Trionic may be trying to cut back boost, or even getting into the fuel-cutoff way too soon.
posted by 192.249....
, Mon, 13 Sep 2004 06:01:45 <-- Viewing This Message, Mon, 13 Sep 2004 13:04:56
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