Revdoc
Probationary Member
- 3
- 0
- Feb 3, 2004
-
Columbia,
Missouri
This has just recently started happening to my 91 Eclipse GSX automatic. It is completely stock other than the addition of a boost gauge, and I redid all the vacuum lines and removed the EGR.
I start the car in the morning and drive about a mile before I get on the on ramp to the highway. I usually baby it because it's cold, however when I go to get on the highway I have to give it some throttle to get up to 60-65 before the end of the ramp. This is where the problem happens, I will slowly increase throttle to maybe 20-25% and I can watch my aftermarket boost gauge increase to about 5 psi, but I don't get the increase in power that I usually feel at 5 psi. I hold the throttle steady and the car makes a hollow popping noise from up front, at the same time the boost gauge jumps, but it's so quick I can't tell if it's dropping to 0 psi or what. The noise happens once every 2-3 seconds, when this happens I usually give it more throttle and it boosts up to 10 psi and gains power and runs correctly. I have noticed that the stock boost gauge on the tach reads steadily when the noise happens and the aftermarket gauge jumps.
Once the car is warmed up the problem seems to go away. There is a smooth transition into boost and it pulls fine at low throttle, low boost conditions. I have had loose intercooler hoses before and it would boost to 5 psi or more and then the boost would blow out through the loose connection, the current problem does not sound the same, plus I can hold 10-12 psi just fine if I give it more throttle so it can't be a loose hose. I am going to double check vacuum lines today and I will have a data logger before too long, so hopefully that will help with the diagnosis. Any ideas? I have searched and found threads about phantom knock and crankwalk, I don't think it's crankwalk because I have a 1G, I don't think it's phantom knock because it seems to affect the boost gauge.
I start the car in the morning and drive about a mile before I get on the on ramp to the highway. I usually baby it because it's cold, however when I go to get on the highway I have to give it some throttle to get up to 60-65 before the end of the ramp. This is where the problem happens, I will slowly increase throttle to maybe 20-25% and I can watch my aftermarket boost gauge increase to about 5 psi, but I don't get the increase in power that I usually feel at 5 psi. I hold the throttle steady and the car makes a hollow popping noise from up front, at the same time the boost gauge jumps, but it's so quick I can't tell if it's dropping to 0 psi or what. The noise happens once every 2-3 seconds, when this happens I usually give it more throttle and it boosts up to 10 psi and gains power and runs correctly. I have noticed that the stock boost gauge on the tach reads steadily when the noise happens and the aftermarket gauge jumps.
Once the car is warmed up the problem seems to go away. There is a smooth transition into boost and it pulls fine at low throttle, low boost conditions. I have had loose intercooler hoses before and it would boost to 5 psi or more and then the boost would blow out through the loose connection, the current problem does not sound the same, plus I can hold 10-12 psi just fine if I give it more throttle so it can't be a loose hose. I am going to double check vacuum lines today and I will have a data logger before too long, so hopefully that will help with the diagnosis. Any ideas? I have searched and found threads about phantom knock and crankwalk, I don't think it's crankwalk because I have a 1G, I don't think it's phantom knock because it seems to affect the boost gauge.
