a gslse idle problem!
04-23-10, 01:09 PM
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a gslse idle problem!
So ive been searching around the forum on what my problem could be and i havent found anything. When i start my car occasionally it will rev up to about 3000rpm, BUT most of the time it will start off at 1000 and continuously bounce down to almost 0 and then raise its self back up to 850 or 1000. It does this all the time and continuously. But at other times it will stay at 1000 or 1500 when its supposed to idle. I have a feeling i might have to clean the throttle body but im not sure.
any suggestions?!
any suggestions?!
04-23-10, 01:22 PM
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First of all check your TPS, make sure it's set correctly.
If that's good, see if you have a vacuum leak somewhere.
Does it do it when it's cold, or after warm up?
If that's good, see if you have a vacuum leak somewhere.
Does it do it when it's cold, or after warm up?
04-23-10, 01:41 PM
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i thought when theres a vacuum leak it only revs high all the time?
and usually when its cold and after warm up to. but sometimes it stays steady after warm up and other times it starts steady and then after it warms up the rpms start bouncing
04-23-10, 03:38 PM
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Still sounds like an incorrectly set TPS. Double check it. Make sure you set it when the engine is fully warmed up.
If there's a vacuum leak, it'll cycle the RPMs, but usually it'll be up higher. If yours drops so low, then it's an upset mixture. Either your fuel or your air are getting too low, due to not being metered correctly.
You could try cleaning and lubing your throttle body, to make sure nothing is sticking. And also try cleaning your bypass air control valve, make sure it doesn't stick.
If there's a vacuum leak, it'll cycle the RPMs, but usually it'll be up higher. If yours drops so low, then it's an upset mixture. Either your fuel or your air are getting too low, due to not being metered correctly.
You could try cleaning and lubing your throttle body, to make sure nothing is sticking. And also try cleaning your bypass air control valve, make sure it doesn't stick.
04-24-10, 04:49 AM
#5
84SE-EGI helpy-helperton
Search: "SE Idle Surge" - everything you ever wanted to know, including how to fix it.
And, it's not a vacuum leak or a bad, or maladjusted TPS, either.
And, it's not a vacuum leak or a bad, or maladjusted TPS, either.
04-24-10, 09:18 AM
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hmmm longduck im guessing your talking about this one ?
thanks for the help! i plan to take off the throttle body either sunday or wednesday and i'll let you guys know if it works!
thanks for the help! i plan to take off the throttle body either sunday or wednesday and i'll let you guys know if it works!
'Surging' is a specific description of what happens when a 13b EFI engine (cold or warm, but usually when cold) idles at 1500rpm reving to 3000rpm and then back down to 1500rpm (and then back up to 3000rpm). Over and over with about a second interval at the higher rpm setting.
This phenomenon is due to the throttle body rods which control the butterfly valves 'sticking' in their holes and causing a feedback loop between the Idle Air Compensator valve and the Bypass Air Control valve. This feedback loop is what causes the surge in engine rpm at idle. Once you get on the throttle, it changes the TB plate position and you don't notice the surging because you've got considerably more airflow going under acceleration or off-idle driving.
The fix; remove the air pipe going from the AFM to the TB with the 2x12mm cap head nuts (chrome), and then remove the throttle linkages going from the gas pedal and Cruise Control to the TB. Remove the heater hoses from the back of the water pump and then going to the rear housing of the block. Remove the TB (4x12mm nuts), and use a light oil (teflon, PTFE, or equivalent) on the outsides and insides of the throttle shafts where they enter the TB. The reason why you've removed the TB from the DEI chamber is so that you can rotate the TB 90degrees Left and then Right - lubing the left side rods, and then letting the lube run down into the TB, then turning to the right 90degrees and doing the same for the other side.
The problem is that the TB rods are steel and the TB is aluminum. This difference in construction materials results in aluminum 'galling' where the steel rods pass through the TB. This galling results in 'stiction' (friction) of the rods when they're under the control of the cold start system for the Secondary Throttle Plates, and the ACV/Idle Compensator. Lubing the rods will remove the problem for awhile, but the problem will arise when the lube dries out (usually lasts about a year or so between lubing).
Consider it your indoctrination into the joys of owning an SE! HTH,
This phenomenon is due to the throttle body rods which control the butterfly valves 'sticking' in their holes and causing a feedback loop between the Idle Air Compensator valve and the Bypass Air Control valve. This feedback loop is what causes the surge in engine rpm at idle. Once you get on the throttle, it changes the TB plate position and you don't notice the surging because you've got considerably more airflow going under acceleration or off-idle driving.
The fix; remove the air pipe going from the AFM to the TB with the 2x12mm cap head nuts (chrome), and then remove the throttle linkages going from the gas pedal and Cruise Control to the TB. Remove the heater hoses from the back of the water pump and then going to the rear housing of the block. Remove the TB (4x12mm nuts), and use a light oil (teflon, PTFE, or equivalent) on the outsides and insides of the throttle shafts where they enter the TB. The reason why you've removed the TB from the DEI chamber is so that you can rotate the TB 90degrees Left and then Right - lubing the left side rods, and then letting the lube run down into the TB, then turning to the right 90degrees and doing the same for the other side.
The problem is that the TB rods are steel and the TB is aluminum. This difference in construction materials results in aluminum 'galling' where the steel rods pass through the TB. This galling results in 'stiction' (friction) of the rods when they're under the control of the cold start system for the Secondary Throttle Plates, and the ACV/Idle Compensator. Lubing the rods will remove the problem for awhile, but the problem will arise when the lube dries out (usually lasts about a year or so between lubing).
Consider it your indoctrination into the joys of owning an SE! HTH,
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