help rough idle, bad acceleration still
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Instructor
Joined: Dec 2006
Posts: 213
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From: sparta michigan
help rough idle, bad acceleration still
85 tpi, wont idle below 1,000 rpm +bad acceleration.
new plugs, cap, rotor and wires.
idle/IAC adjusted to stock
ignition timing adjusted to stock with est disconnected 6 deg.
cat not plugged
injectors cleaned, should i have just bought new ones?
no check engine light???
cant find any vacuum leaks, are there any good methods to check this?
replaced fuel filter, checked regulator and checked fuel pressure (around 28psi)
acts like the ignition timing is off, but i corrected it and the balance is not spun.
this engine is stock with 52mm TB
whats next. ecm?? like most of you i dont want to spend $800 on parts i dont need to fix the problem.
help would be awesome
updated..... new IAC and EGR valve..... same problem
new plugs, cap, rotor and wires.
idle/IAC adjusted to stock
ignition timing adjusted to stock with est disconnected 6 deg.
cat not plugged
injectors cleaned, should i have just bought new ones?
no check engine light???
cant find any vacuum leaks, are there any good methods to check this?
replaced fuel filter, checked regulator and checked fuel pressure (around 28psi)
acts like the ignition timing is off, but i corrected it and the balance is not spun.
this engine is stock with 52mm TB
whats next. ecm?? like most of you i dont want to spend $800 on parts i dont need to fix the problem.
help would be awesome
updated..... new IAC and EGR valve..... same problem
Last edited by thumper823; Jul 16, 2007 at 08:29 AM. Reason: add info
Thread Starter
Instructor
Joined: Dec 2006
Posts: 213
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From: sparta michigan
Thread Starter
Instructor
Joined: Dec 2006
Posts: 213
Likes: 0
From: sparta michigan
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
To find vacuum leaks:
1)Find someone who smokes (if you smoke then your set)
2)Buy a section of clear tubing (5 ft minimum)from Lowes/Home Depot ($3)
3)Remove the snorkle from the air filter to the throttle body
4)Slip one end of the tubing under the throttle plates
5)Tape up the throttle body and tubing with duct tape so it is sealed
6)Have the smoker exhale smoke in the tube. it will take a few minutes for the intake to fill with smoke. If there is a vacuum leak, smoke will appear
7)Use a flashlight to pinpoint the source of the leak.
P.S. for lower runner/base manifold leaks (L98 engine), it may be necessary to remove the valve covers and wiring harnesses to see exactly where the leak is coming from. If you do this, make sure you unplug and tape up the PVC system. otherwise the smoke billow out of the open valve cover and cause confusion.
I have used this system successfully several times.
I got this idea from the forum here.
HTH!
1)Find someone who smokes (if you smoke then your set)
2)Buy a section of clear tubing (5 ft minimum)from Lowes/Home Depot ($3)
3)Remove the snorkle from the air filter to the throttle body
4)Slip one end of the tubing under the throttle plates
5)Tape up the throttle body and tubing with duct tape so it is sealed
6)Have the smoker exhale smoke in the tube. it will take a few minutes for the intake to fill with smoke. If there is a vacuum leak, smoke will appear
7)Use a flashlight to pinpoint the source of the leak.
P.S. for lower runner/base manifold leaks (L98 engine), it may be necessary to remove the valve covers and wiring harnesses to see exactly where the leak is coming from. If you do this, make sure you unplug and tape up the PVC system. otherwise the smoke billow out of the open valve cover and cause confusion.
I have used this system successfully several times.
I got this idea from the forum here.
HTH!
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Thread Starter
Instructor
Joined: Dec 2006
Posts: 213
Likes: 0
From: sparta michigan
To find vacuum leaks:
1)Find someone who smokes (if you smoke then your set)
2)Buy a section of clear tubing (5 ft minimum)from Lowes/Home Depot ($3)
3)Remove the snorkle from the air filter to the throttle body
4)Slip one end of the tubing under the throttle plates
5)Tape up the throttle body and tubing with duct tape so it is sealed
6)Have the smoker exhale smoke in the tube. it will take a few minutes for the intake to fill with smoke. If there is a vacuum leak, smoke will appear
7)Use a flashlight to pinpoint the source of the leak.
P.S. for lower runner/base manifold leaks (L98 engine), it may be necessary to remove the valve covers and wiring harnesses to see exactly where the leak is coming from. If you do this, make sure you unplug and tape up the PVC system. otherwise the smoke billow out of the open valve cover and cause confusion.
I have used this system successfully several times.
I got this idea from the forum here.
HTH!
1)Find someone who smokes (if you smoke then your set)
2)Buy a section of clear tubing (5 ft minimum)from Lowes/Home Depot ($3)
3)Remove the snorkle from the air filter to the throttle body
4)Slip one end of the tubing under the throttle plates
5)Tape up the throttle body and tubing with duct tape so it is sealed
6)Have the smoker exhale smoke in the tube. it will take a few minutes for the intake to fill with smoke. If there is a vacuum leak, smoke will appear
7)Use a flashlight to pinpoint the source of the leak.
P.S. for lower runner/base manifold leaks (L98 engine), it may be necessary to remove the valve covers and wiring harnesses to see exactly where the leak is coming from. If you do this, make sure you unplug and tape up the PVC system. otherwise the smoke billow out of the open valve cover and cause confusion.
I have used this system successfully several times.
I got this idea from the forum here.
HTH!
i tried it and i think its leaking from either the iac, or the bottom cover on the TB. i will look at closer tonight. thanks
Thread Starter
Instructor
Joined: Dec 2006
Posts: 213
Likes: 0
From: sparta michigan
Thread Starter
Instructor
Joined: Dec 2006
Posts: 213
Likes: 0
From: sparta michigan
i have replace the o2 sensor when i bought the car. i would like to buy injectors seems a couple had some gunk in them. which does'nt suprise me at 116k
Team Owner
Joined: Jan 2003
Posts: 20,322
Likes: 249
From: Summerland B.C. Canada
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
To find vacuum leaks:
1)Find someone who smokes (if you smoke then your set)
2)Buy a section of clear tubing (5 ft minimum)from Lowes/Home Depot ($3)
3)Remove the snorkle from the air filter to the throttle body
4)Slip one end of the tubing under the throttle plates
5)Tape up the throttle body and tubing with duct tape so it is sealed
6)Have the smoker exhale smoke in the tube. it will take a few minutes for the intake to fill with smoke. If there is a vacuum leak, smoke will appear
7)Use a flashlight to pinpoint the source of the leak.
P.S. for lower runner/base manifold leaks (L98 engine), it may be necessary to remove the valve covers and wiring harnesses to see exactly where the leak is coming from. If you do this, make sure you unplug and tape up the PVC system. otherwise the smoke billow out of the open valve cover and cause confusion.
I have used this system successfully several times.
I got this idea from the forum here.
HTH!
1)Find someone who smokes (if you smoke then your set)
2)Buy a section of clear tubing (5 ft minimum)from Lowes/Home Depot ($3)
3)Remove the snorkle from the air filter to the throttle body
4)Slip one end of the tubing under the throttle plates
5)Tape up the throttle body and tubing with duct tape so it is sealed
6)Have the smoker exhale smoke in the tube. it will take a few minutes for the intake to fill with smoke. If there is a vacuum leak, smoke will appear
7)Use a flashlight to pinpoint the source of the leak.
P.S. for lower runner/base manifold leaks (L98 engine), it may be necessary to remove the valve covers and wiring harnesses to see exactly where the leak is coming from. If you do this, make sure you unplug and tape up the PVC system. otherwise the smoke billow out of the open valve cover and cause confusion.
I have used this system successfully several times.
I got this idea from the forum here.
HTH!
if the engine is in a situaation where (at least 1 of 8 combustion chanbers are in this situation..) there is overlap (intake and exhaust valve open), the smoke can go in the exhaust...
,...And the smoke that goes in to open intake valves? are we sure about the ring seal?
I don't think it's a good way to test leaks...unless it is made under pressure. A leak can't be detected (even if it's present a noticeable hole) if there is not a difference of pressure.
-Beppe-
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
...and what about the smoke going in the open valves?
if the engine is in a situaation where (at least 1 of 8 combustion chanbers are in this situation..) there is overlap (intake and exhaust valve open), the smoke can go in the exhaust...
,...And the smoke that goes in to open intake valves? are we sure about the ring seal?
I don't think it's a good way to test leaks...unless it is made under pressure. A leak can't be detected (even if it's present a noticeable hole) if there is not a difference of pressure.
-Beppe-
if the engine is in a situaation where (at least 1 of 8 combustion chanbers are in this situation..) there is overlap (intake and exhaust valve open), the smoke can go in the exhaust...
,...And the smoke that goes in to open intake valves? are we sure about the ring seal?
I don't think it's a good way to test leaks...unless it is made under pressure. A leak can't be detected (even if it's present a noticeable hole) if there is not a difference of pressure.
-Beppe-
Well, what I can tell you is that the force of a person exhaling is enough to push smoke out of a leak point in the intake. I usually have to ask my smoker to exhale slowly in order to pin point the leak.
As for smoke making it way into the exhaust, I am sure that does occur, but it still comes out of the vacuum leak as well.
There may be a better way, but I have used this method successfully on several occasions.
Thread Starter
Instructor
Joined: Dec 2006
Posts: 213
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From: sparta michigan
Thread Starter
Instructor
Joined: Dec 2006
Posts: 213
Likes: 0
From: sparta michigan