IAC and TPS adjustment heck!
11-01-2003, 03:59 PM
#1
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Car: 1991 Formula
Engine: 5.0 TPI
Transmission: T-5
IAC and TPS adjustment heck!
I've read the tech article and I also have "How to tune and modify GM fuel injected motors" and I'm just a bit curious.
I haven't seen any mention of disconnecting the EST wire and when I try to adjust my minium air, the idle hunts up and down and when it gets to low, it dies.
Also, my TPS was .78 volts. The lowest I can get it down to is .70 volts. I can get it down to .62 if I adjust the minimum air while the IAC is connected but I'm sure that the car wont start if I tried to adjust properly again.
1. Can the car idle at 450 rpm's?
I think one or both CAT's are bad but I want to know if 450 rpm's is possible.
2. Could my TPS switch be going bad?
Full throttle volts are 4.37 and it seems to be smooth getting there.
Thanks!
I haven't seen any mention of disconnecting the EST wire and when I try to adjust my minium air, the idle hunts up and down and when it gets to low, it dies.
Also, my TPS was .78 volts. The lowest I can get it down to is .70 volts. I can get it down to .62 if I adjust the minimum air while the IAC is connected but I'm sure that the car wont start if I tried to adjust properly again.
1. Can the car idle at 450 rpm's?
I think one or both CAT's are bad but I want to know if 450 rpm's is possible.
2. Could my TPS switch be going bad?
Full throttle volts are 4.37 and it seems to be smooth getting there.
Thanks!
11-01-2003, 08:44 PM
#2
Yes, the engien should odle at the specified RPM for minimum air position adjustment (in DRIVE with an automatic).
I'm not sure what article you may have read, but try this procedure:
Throttle Minimum Air Position
Tools needed:
1. Torx driver # T-20
2. Paper Clip
3. Small Punch
4. Tachometer
GENERAL NOTE: The engine should be at normal operating temperature before performing any adjustments. Never rely on the dash mounted instruments for diagnostics and adjustments. The oil pressure and temperature gauges and the voltmeter and tachometer just aren't calibrated accurately enough for diagnosis, but are a relative indication for monitoring the vehicle while driving.
For this adjustment, the transmission will be in DRIVE while you're under the hood. You will need to securely set the parking brake and block the drive wheels. It would also be a good idea to have an assistant hold the service brake while you perform the adjustments.
In order to successfully complete the adjustment, the IAC air passages and pintle need to be clean. The throttle plates and bores need to be clean as well. If this is not the case, you'll need to remove the air cleaner from TBI engines or the intake air bellows from TPI engines to gain access to the area to be cleaned. A spray-type carburetor cleaner works well for this. Cleaning the IAC passages on a TPI/MAF engine will set a DTC, but we'll be clearing that later. With the engine idling, direct the spray cleaner in to the IAC air passages and around the throttle plates. Shut off the engine and continue cleaning the throttle plates by opening the throttle manually. Once everything is satisfactorily cleaned, replace the air bellows on TPI engines. Many times, this alone can solve IAC/idle speed problems.
If this doesn't solve the problem, you may need to remove and clean the IAC stepper motor. If the IAC appears to be clean and functioning properly, continue with the adjustment procedure.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Idle Air Control Cleaning
You can remove the IAC and service it. Remove the electrical connector from the IAC. Unscrew the IAC unit from the throttle body.
You can gently rock the pintle back and forth and allow the spring to extend it until it comes apart in your hands. Clean everything with lint-free cloths and a mild solvent. Harsh solvents can affect the insulation of the stepper motor coils. It's generally the dirt and buildup on this worm shaft that causes sluggish IAC operation.
When the worm gear on the pintle shaft is clean and dry, apply one drop of clean light oil to the shaft and work the pintle back into the rack gears of the motor by the same rocking motion. It takes a while to get the pintle back into the worm gears, but you'll get it. It is important to get the pintle fully retracted into the housing so that the pintle is not forced against the gears when reinstalling the IAC unit in the throttle body.
While the IAC is out, clean the air passages in the throttle body. The orifice in the TB where the IAC resides is the seat that the IAC valve closes against, and it can accumulate a lot of carbon, dirt, and debris. The easy way to do this is with carburetor cleaner and a small stiff brush.
When everything is clean and dry, replace the gasket if it is damaged, apply a little anti-seize to the threads, and torque the IAC to the proper specs. (13 ft/lb for '85-'89 , 30 in/lb for 1990-on.) Proceed with setting the TPS and minimum air position.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Locate the ALDL connector under your dash panel, in the driver's footwell area. Remove the plastic trim cover (if it is still there).
Cut and form a paper clip into a "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' sockets.
Turn on the ignition, but don't start the engine. This will force the ECM into its diagnostic mode. Wait 30 seconds to allow the IAC pintle to fully extend. Under the hood, remove the electrical connector from the IAC, then turn off the ignition and remove the paper clip jumper from the ALDL. With the IAC pintle fully extended (closed) all idle air will be controlled by the position of the throttle plates. Some manuals indicate that the EST bypass connector should be disconnected for this procedure, while some make no mention of it. While timing is a factor in idle speed, the EST should only operate as a function of engine RPM, temperature, and detonation sensor inputs. To remove all doubt, disconnect the EST bypass connector is your car is so equipped. Some TBI and V-6 engines do not have this bypass connector, and therefore must be set with no regard to the EST system. The EST can be bypassed on some cars by grounding the diagnostic terminal at the ALDL and continuing with the procedure, but the fuel mixture will be skewed to the rich side, affecting idle speed as well. In any event, the minimum air position idle speed range is wide enough to allow for some variations. As always, it is best to consult your service manual for the exact procedure for your system.
Locate the Torx screw on the left side of the throttle body. It may be equipped with a protective metal cap from the factory. This was intended to discourage adjustment. If the cap is present, use a small punch to knock it out. Once the screw is accessible, start the engine and place the transmission in DRIVE. Adjust the throttle stop to obtain 400 RPM with the transmission in "DRIVE" on an automatic transmission car, 450 in neutral on a manual transmission car, rotating the Torx screw clockwise to raise speed and counter-clockwise to lower speed. Once the idle RPM is set, place the transmission in PARK and turn off the engine.
Re-connect the electrical connector onto the IAC. Start engine. Idle speed should be governed by the ECM at approximately 600-650 rpm in "DRIVE" (for unmodified cars). Idle speed in NEUTRAL or PARK is less significant, and will be higher.
Throttle Position Sensor (TPS)
Tools needed:
1. Digital Volt-Ohm-Meter (VOM)
2. Breakout jumper wires or probes (make your own)
3. AutoXray, Diacom, or similar scanner will replace the VOM and jumper wires.
Turn on ignition, but don't start the engine.
With a diagnostic scanner: plug in the scanner and read the TPS voltage. It should be 0.54Volts +/- 0.07 VDC.
Connect the VOM to the TPS electrical connector terminals ‘A' and ‘B'.
With a breakout jumper: Disconnect the electrical connector from the TPS. Install the breakout in-line, between the TPS and wiring harness connector. Connect the meter probes to terminals 'A' and 'B' on the connector. (‘B' is the positive connection, ‘A' the signal ground, or negative.)
With probes: If you have very slender probes on your VOM, you can back-probe the TPS connector while it is attached to the TPS. If you have made probes of large dressmakers pins or a similar item, you can back-probe the connector as well. Connect the meter probes to terminals 'A' and 'B' on the connector.
Turn on the ignition to read the TPS output voltage at the idle position. The reading should be 0.54VDC +/- 0.07VDC. The ideal is the center of the range, 0.54VDC for a stock engine. To adjust the output voltage, loosen the two Torx screws holding the TPS to the throttle body, and slightly rotate the TPS up or down, reading the voltage until it comes into specification. Tighten screws. Using the throttle lever, rotate the throttle to WOT (wide open throttle). The TPS voltage should be over 4.0 volts. Close the throttle again, and then slowly open it to WOT, observing the voltage reading. It should increase progressively and in a linear fashion. If it sticks or jumps or falls off at all while doing this check, the TPS sensor may be failing and could be a cause of stumbling and driveability problems.
After achieving the desired setting, turn off the ignition switch. Remove all jumpers or the scanner and reconnect the TPS connector as required.
Reinitializing the ECM
If you set a DTC during the procedure, the SES light should be illuminated on the dash. This ECM retains DTC data for the previous 50 engine starts, so the codes will eventually be cleared. If you want more immediate results, after shutting down the engine disconnect the negative battery terminal for five minutes. This will clear the ECM of all diagnostic trouble codes. Clearing the ECM also clears any data learned about your engine, and clears the radio presets. If you have a Delco-Loc or Theft Loc II radio, make sure you follow the procedure to unlock the radio protection before disconnecting the battery. This five minutes is also just about long enough to clean both battery cables. Reconnect the battery. When you first start the engine after clearing the ECM, the engine will operate with base parameters programmed into the ECM PROM. These parameters may not be optimum for your engine, but the ECM will enter a Block Learn Mode soon after the engine is warm and enters Closed Loop Mode. The ECM will write new data tables specific to your engine and will eventually rely on those tables instead of the base tables of the factory program. You can expedite this process by driving the car for 20 minutes under varying conditions to allow the ECM to initialize. Or you can wait and drive the car normally at your convenience. The BLM tables are constantly being updated as sensor input ranges change, but the greatest change will occur within the first twenty minutes of Closed Loop operation.
I'm not sure what article you may have read, but try this procedure:
Throttle Minimum Air Position
Tools needed:
1. Torx driver # T-20
2. Paper Clip
3. Small Punch
4. Tachometer
GENERAL NOTE: The engine should be at normal operating temperature before performing any adjustments. Never rely on the dash mounted instruments for diagnostics and adjustments. The oil pressure and temperature gauges and the voltmeter and tachometer just aren't calibrated accurately enough for diagnosis, but are a relative indication for monitoring the vehicle while driving.
For this adjustment, the transmission will be in DRIVE while you're under the hood. You will need to securely set the parking brake and block the drive wheels. It would also be a good idea to have an assistant hold the service brake while you perform the adjustments.
In order to successfully complete the adjustment, the IAC air passages and pintle need to be clean. The throttle plates and bores need to be clean as well. If this is not the case, you'll need to remove the air cleaner from TBI engines or the intake air bellows from TPI engines to gain access to the area to be cleaned. A spray-type carburetor cleaner works well for this. Cleaning the IAC passages on a TPI/MAF engine will set a DTC, but we'll be clearing that later. With the engine idling, direct the spray cleaner in to the IAC air passages and around the throttle plates. Shut off the engine and continue cleaning the throttle plates by opening the throttle manually. Once everything is satisfactorily cleaned, replace the air bellows on TPI engines. Many times, this alone can solve IAC/idle speed problems.
If this doesn't solve the problem, you may need to remove and clean the IAC stepper motor. If the IAC appears to be clean and functioning properly, continue with the adjustment procedure.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Idle Air Control Cleaning
You can remove the IAC and service it. Remove the electrical connector from the IAC. Unscrew the IAC unit from the throttle body.
You can gently rock the pintle back and forth and allow the spring to extend it until it comes apart in your hands. Clean everything with lint-free cloths and a mild solvent. Harsh solvents can affect the insulation of the stepper motor coils. It's generally the dirt and buildup on this worm shaft that causes sluggish IAC operation.
When the worm gear on the pintle shaft is clean and dry, apply one drop of clean light oil to the shaft and work the pintle back into the rack gears of the motor by the same rocking motion. It takes a while to get the pintle back into the worm gears, but you'll get it. It is important to get the pintle fully retracted into the housing so that the pintle is not forced against the gears when reinstalling the IAC unit in the throttle body.
While the IAC is out, clean the air passages in the throttle body. The orifice in the TB where the IAC resides is the seat that the IAC valve closes against, and it can accumulate a lot of carbon, dirt, and debris. The easy way to do this is with carburetor cleaner and a small stiff brush.
When everything is clean and dry, replace the gasket if it is damaged, apply a little anti-seize to the threads, and torque the IAC to the proper specs. (13 ft/lb for '85-'89 , 30 in/lb for 1990-on.) Proceed with setting the TPS and minimum air position.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Locate the ALDL connector under your dash panel, in the driver's footwell area. Remove the plastic trim cover (if it is still there).
Cut and form a paper clip into a "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' sockets.
Turn on the ignition, but don't start the engine. This will force the ECM into its diagnostic mode. Wait 30 seconds to allow the IAC pintle to fully extend. Under the hood, remove the electrical connector from the IAC, then turn off the ignition and remove the paper clip jumper from the ALDL. With the IAC pintle fully extended (closed) all idle air will be controlled by the position of the throttle plates. Some manuals indicate that the EST bypass connector should be disconnected for this procedure, while some make no mention of it. While timing is a factor in idle speed, the EST should only operate as a function of engine RPM, temperature, and detonation sensor inputs. To remove all doubt, disconnect the EST bypass connector is your car is so equipped. Some TBI and V-6 engines do not have this bypass connector, and therefore must be set with no regard to the EST system. The EST can be bypassed on some cars by grounding the diagnostic terminal at the ALDL and continuing with the procedure, but the fuel mixture will be skewed to the rich side, affecting idle speed as well. In any event, the minimum air position idle speed range is wide enough to allow for some variations. As always, it is best to consult your service manual for the exact procedure for your system.
Locate the Torx screw on the left side of the throttle body. It may be equipped with a protective metal cap from the factory. This was intended to discourage adjustment. If the cap is present, use a small punch to knock it out. Once the screw is accessible, start the engine and place the transmission in DRIVE. Adjust the throttle stop to obtain 400 RPM with the transmission in "DRIVE" on an automatic transmission car, 450 in neutral on a manual transmission car, rotating the Torx screw clockwise to raise speed and counter-clockwise to lower speed. Once the idle RPM is set, place the transmission in PARK and turn off the engine.
Re-connect the electrical connector onto the IAC. Start engine. Idle speed should be governed by the ECM at approximately 600-650 rpm in "DRIVE" (for unmodified cars). Idle speed in NEUTRAL or PARK is less significant, and will be higher.
Throttle Position Sensor (TPS)
Tools needed:
1. Digital Volt-Ohm-Meter (VOM)
2. Breakout jumper wires or probes (make your own)
3. AutoXray, Diacom, or similar scanner will replace the VOM and jumper wires.
Turn on ignition, but don't start the engine.
With a diagnostic scanner: plug in the scanner and read the TPS voltage. It should be 0.54Volts +/- 0.07 VDC.
Connect the VOM to the TPS electrical connector terminals ‘A' and ‘B'.
With a breakout jumper: Disconnect the electrical connector from the TPS. Install the breakout in-line, between the TPS and wiring harness connector. Connect the meter probes to terminals 'A' and 'B' on the connector. (‘B' is the positive connection, ‘A' the signal ground, or negative.)
With probes: If you have very slender probes on your VOM, you can back-probe the TPS connector while it is attached to the TPS. If you have made probes of large dressmakers pins or a similar item, you can back-probe the connector as well. Connect the meter probes to terminals 'A' and 'B' on the connector.
Turn on the ignition to read the TPS output voltage at the idle position. The reading should be 0.54VDC +/- 0.07VDC. The ideal is the center of the range, 0.54VDC for a stock engine. To adjust the output voltage, loosen the two Torx screws holding the TPS to the throttle body, and slightly rotate the TPS up or down, reading the voltage until it comes into specification. Tighten screws. Using the throttle lever, rotate the throttle to WOT (wide open throttle). The TPS voltage should be over 4.0 volts. Close the throttle again, and then slowly open it to WOT, observing the voltage reading. It should increase progressively and in a linear fashion. If it sticks or jumps or falls off at all while doing this check, the TPS sensor may be failing and could be a cause of stumbling and driveability problems.
After achieving the desired setting, turn off the ignition switch. Remove all jumpers or the scanner and reconnect the TPS connector as required.
Reinitializing the ECM
If you set a DTC during the procedure, the SES light should be illuminated on the dash. This ECM retains DTC data for the previous 50 engine starts, so the codes will eventually be cleared. If you want more immediate results, after shutting down the engine disconnect the negative battery terminal for five minutes. This will clear the ECM of all diagnostic trouble codes. Clearing the ECM also clears any data learned about your engine, and clears the radio presets. If you have a Delco-Loc or Theft Loc II radio, make sure you follow the procedure to unlock the radio protection before disconnecting the battery. This five minutes is also just about long enough to clean both battery cables. Reconnect the battery. When you first start the engine after clearing the ECM, the engine will operate with base parameters programmed into the ECM PROM. These parameters may not be optimum for your engine, but the ECM will enter a Block Learn Mode soon after the engine is warm and enters Closed Loop Mode. The ECM will write new data tables specific to your engine and will eventually rely on those tables instead of the base tables of the factory program. You can expedite this process by driving the car for 20 minutes under varying conditions to allow the ECM to initialize. Or you can wait and drive the car normally at your convenience. The BLM tables are constantly being updated as sensor input ranges change, but the greatest change will occur within the first twenty minutes of Closed Loop operation.
Last edited by Vader; 03-31-2018 at 10:47 AM. Reason: Updated links
11-01-2003, 09:31 PM
#3
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Car: 1991 Formula
Engine: 5.0 TPI
Transmission: T-5
The tech article I read is the one in TGO. Although I didnt see the disconnect the EST part.
I basically did all of that but pinning my idle down is hard, it keeps wandering +/- 50 rpm's. Is that normal?
I basically did all of that but pinning my idle down is hard, it keeps wandering +/- 50 rpm's. Is that normal?
11-01-2003, 11:34 PM
#4
Yanno Vader, you really should publish a book. Maybe poll everyone's knowledge/input and compile an "aftermarket" service manual for the third gens. (just have to give credit to whoever's input you use) I bet a book like that would sell like hotcakes.
11-01-2003, 11:38 PM
#5
One other thing. You may want to soak that idle screw in WD40 or other penetrating oil for several hours before attempting to move it. The screw is a fine thread and made of steel, screwed into alumnium, dissimilar metal corrosion likes to sieze that screw in the throttlebody.
11-28-2003, 12:49 PM
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Car: 1989 IROC-Z
Engine: 350 TPI
Transmission: 700R-4
Scottlb9- Mine was going +/- 50 rpm too when I was trying to adjust min. air, did you ever find out if this is normal? Kind of hard to get a reading....so I just put it way down and when I plugged the IAC back in the idle was alright.
I was thinking maybe since I have an airfoil in the TB that maybe it wasn't letting in enough air at idle, so it was "gasping" for air. It is still surging at idle so maybe I should take out the air foil?
And when I was adjusting the TPS, I was getting a .4 V reading at idle, but at WOT, I was only getting 1 V....is this normal or am I reading the the multimeter wrong? So I went out and bought a new TPS thinking it was bad and the new one was reading the same way. Thanks for the help, I realize this is and old post.
I was thinking maybe since I have an airfoil in the TB that maybe it wasn't letting in enough air at idle, so it was "gasping" for air. It is still surging at idle so maybe I should take out the air foil?
And when I was adjusting the TPS, I was getting a .4 V reading at idle, but at WOT, I was only getting 1 V....is this normal or am I reading the the multimeter wrong? So I went out and bought a new TPS thinking it was bad and the new one was reading the same way. Thanks for the help, I realize this is and old post.
11-28-2003, 01:27 PM
#7
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Car: 1991 Formula
Engine: 5.0 TPI
Transmission: T-5
Mine was going +/- 50 rpm too when I was trying to adjust min. air, did you ever find out if this is normal?
Basicly, my car is a nice looking mess right now. I'm running lean and it sounds like I have an exhaut leak (caused by the cats?)
I'm gutting the cats next week and I'll start up from there again.
I know the TPS reading should be around 0.54 +/- 0.07 for closed throttle and over 4.0 WOT. I don't know how you're measuring it but I used a scanner.
I'll let you know either way on the outcome.
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11-28-2003, 04:25 PM
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Car: 1989 IROC-Z
Engine: 350 TPI
Transmission: 700R-4
I just need to get my notebook computer then I'll be able to hook that program up and scan it....much better than using a multi-meter I think. I am still wondering about the air foil though.
I think next I'm going to pull a few plugs and check on em and then maybe look at the charcoal canister because some of the vacuum lines are cracked and last time I had the canister out, I shook it and it sounded like it was saturated with something....I don't know if it supposed to sound like that or not. It's still surging a litte and I'm getting bad mpg so I need to look elsewhere I guess.
I think next I'm going to pull a few plugs and check on em and then maybe look at the charcoal canister because some of the vacuum lines are cracked and last time I had the canister out, I shook it and it sounded like it was saturated with something....I don't know if it supposed to sound like that or not. It's still surging a litte and I'm getting bad mpg so I need to look elsewhere I guess.
11-30-2003, 02:14 PM
#9
Scott,
Any luck? You're going to have a tough time getting the idle RPM down to 500-550 with a T-5 (no load from a torque coinverter). Make sure the throttle and cruise/TV cables are not holding the throttle open, and clean the TB thoroughly so that there is no leakage around the throttle blades from varnish and carbon. Vacuum leaks will also keep teh idle RPM up. Check the PCV, brake booster, FPR and HVAC vacuum lines, and gaskets and 'O' rings on the intake.
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IROCSTER,
The problem with a data scanner can be the delay between signal change and data update to your laptop. There are also input buffer circuits, so a meter is probably an easier method to set and check the TPS, and may be more accurate.
Any luck? You're going to have a tough time getting the idle RPM down to 500-550 with a T-5 (no load from a torque coinverter). Make sure the throttle and cruise/TV cables are not holding the throttle open, and clean the TB thoroughly so that there is no leakage around the throttle blades from varnish and carbon. Vacuum leaks will also keep teh idle RPM up. Check the PCV, brake booster, FPR and HVAC vacuum lines, and gaskets and 'O' rings on the intake.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
IROCSTER,
The problem with a data scanner can be the delay between signal change and data update to your laptop. There are also input buffer circuits, so a meter is probably an easier method to set and check the TPS, and may be more accurate.
11-30-2003, 02:20 PM
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Car: 1989 IROC-Z
Engine: 350 TPI
Transmission: 700R-4
Well, the car seems to be running better now. The only problem is when I am coming to a stop, right before I come to a complete stop, it surges a little, kinda like it is gasping for air....that seems to be the only problem though. And that only happens after the car is warmed up. I'm thinking that can maybe be from my spark plugs, they are usually fouled when I pull them. Everything else seems a lot smoother though.
I guess I could still go ahead and replace my charcoal cansister and those vacuum lines (charcoal canister sounds saturated when I shake it). Let me know what you think.
I guess I could still go ahead and replace my charcoal cansister and those vacuum lines (charcoal canister sounds saturated when I shake it). Let me know what you think.
Last edited by Irocster; 11-30-2003 at 02:25 PM.
11-30-2003, 05:18 PM
#11
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Car: 2003 Hyundai Tiburon GT
Engine: 2.7L V6
Transmission: 6-speed
Axle/Gears: 4.41
You said your vacuum lines were cracked. Replace them. If the engine does not have adequate vacuum it will act like it is being choked becuase the vacuum is what pulls the air into the engine. My V6 had that problem and I ended up spending about $12 to replace all of the lines from the engine to the canister. If there are crumbs of rubber left in your hand when you handle the lines, they are deteriorating and definitely need to be replaced, like mine were before I replaced them. It takes about $10-15 and about an hour or less of your time, but you end up with a better running engine.
Edit: And the problem with my six only got worse when I applied the brakes, so much so that the engine stalled and could barely be restarted, because the brake booster takes a good portion of what little vacuum the engine is producing, which chokes it even more.
Edit: And the problem with my six only got worse when I applied the brakes, so much so that the engine stalled and could barely be restarted, because the brake booster takes a good portion of what little vacuum the engine is producing, which chokes it even more.
11-30-2003, 11:10 PM
#13
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Car: 1991 Formula
Engine: 5.0 TPI
Transmission: T-5
You're going to have a tough time getting the idle RPM down to 500-550 with a T-5
I tightened it up but I still think one of my cat's are plugged.
I had a rattle in it a few weeks ago and once that happens, it's all downhill from there.
I'm getting them gu--- "changed" this week and I'll post back.
Scott
Last edited by Scottlb9; 12-01-2003 at 07:35 AM.
12-01-2003, 01:11 AM
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Car: 2003 Hyundai Tiburon GT
Engine: 2.7L V6
Transmission: 6-speed
Axle/Gears: 4.41
With the charcoal canister, does it sound like it's full of gas or does it have a sort of rattling sound to it, like there's some small pebbles inside of it that are rattling around? If it sounds full of gas, you might want to search around for a problem with major flooding. I don't remember which forum it was in but someoone mentioned that their engine was flooding itself so badly that it filled the throttle body with gas, and that it was related to the evap can somehow. TomP would be the best one to ask about that in that case. I personally don't think that changing the canister and the filter in the bottom of it would hurt at all, though, if you have emissions check where you live, it might help even.
Oh, and if it sounds like there is something rattling inside of it, that's normal as far as I know because there are little beads that are coated with something or other that help absorb the gas odors and dispense them into the engine when the time is right.
Oh, and if it sounds like there is something rattling inside of it, that's normal as far as I know because there are little beads that are coated with something or other that help absorb the gas odors and dispense them into the engine when the time is right.
Last edited by Maverick H1L; 12-01-2003 at 01:15 AM.
12-01-2003, 04:50 PM
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Car: 1989 IROC-Z
Engine: 350 TPI
Transmission: 700R-4
No, there is no rattling noise. Like I said, it sounds like it is saturated with some kind liquid (I am assuming gas). I'll have to talk to TomP. I will replace the vacuum lines for now and see what happens. Thanks.
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