1984 Delta 88 Stalling at stops/ Sluggish when Accelerated??
April 3rd, 2018, 07:47 PM
#1
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1984 Delta 88 Stalling at stops/ Sluggish when Accelerated??
Hey gentleman. My 84 is in the back burner until I can figure out why it's stalling after running a few minutes at stops. Seems also to delay in acceleration. Cat convertor? Carb issue?? Please help I miss the 84.
April 8th, 2018, 08:15 AM
#6
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you established that the choke is fully open warm?next i would see if there is any fuel in the bowl vent tube(large hose top above inlet)if there is plug the hose or replace purge valve.you still have q-jet?
May 6th, 2018, 11:38 AM
#8
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Are you getting any MIL codes when it stalls? As noted, there are about a bazillion potential causes for this on the CCC 307. Idle speed controller, vacuum connections to the ILC, leaking vac line anywhere, stuck EGR, mis-adjusted carb, A.I.R diverter valve stuck open, etc, etc. I've even had one of the idle mixture screws vibrate out of my CCC carb, causing this sort of driveability problem. The only solution is to curl up with the Chassis Service Manual (specifically Chapter 6E) and chase down every branch of the fault tree. Simply replacing parts is a good way to spend a LOT of money and still not fix the problem.
August 20th, 2018, 05:17 PM
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December 2nd, 2018, 07:12 PM
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Conventional wisdom for mechanical diagnosis states:
First - Check spark: The old adage goes "80 percent of carb problems are spark". Essentially do not rule out spark/timing issues. Check timing and advance (or if the engine has a vacuum retard, that it is working) and the silly things like making sure the distributor is not loose and affecting timing.
Second -- Check fuel: As was pointed out, if it runs fine until warm and then stalls and runs sluggish, the choke is a good place to look. You can also pull one of the spark plugs and look to see if it is black with soot, which would indicate a rich condition. It is also possible that you have an air leak in or near the carb. If you have air leaking into the intake manifold or through the throttle shaft/plates, when the car comes to a stop there is not enough fuel to offset the lean condition. Again, the plugs might indicate a lean condition with white dots or burning on the electrodes.
It is probably not exhaust related.
First - Check spark: The old adage goes "80 percent of carb problems are spark". Essentially do not rule out spark/timing issues. Check timing and advance (or if the engine has a vacuum retard, that it is working) and the silly things like making sure the distributor is not loose and affecting timing.
Second -- Check fuel: As was pointed out, if it runs fine until warm and then stalls and runs sluggish, the choke is a good place to look. You can also pull one of the spark plugs and look to see if it is black with soot, which would indicate a rich condition. It is also possible that you have an air leak in or near the carb. If you have air leaking into the intake manifold or through the throttle shaft/plates, when the car comes to a stop there is not enough fuel to offset the lean condition. Again, the plugs might indicate a lean condition with white dots or burning on the electrodes.
It is probably not exhaust related.
December 3rd, 2018, 10:24 AM
#12
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Unfortunately, this is a 307 with the CCC system. Conventional wisdom doesn't necessarily apply. There are literally dozens of possible failures that can cause these symptoms. The only way to really troubleshoot this is to get a CSM and READ it thoroughly for troubleshooting steps, as pointed out back in Post #8.
December 3rd, 2018, 10:43 AM
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Don't get me wrong, as I'm not a CCC expert in any way shape or form. I was simply pointing out that any "it dies" situation requires identifying spark vs fuel and conventional wisdom seems to still apply here, because the parts might be slightly different (electronic vs. pure mechanical actuation) but the theory is still the same. If memory serves, CCC simply uses a basic throttle position sensor (along with O2 sensors, coolant sensors -- the normal stuff you'd find on EFI cars) to control timing advance/retard, the carb idle circuit and the off-idle progression. (It probably also deals with emissions and A/C idle, but those likely aren't the issue.) Instead of just being a mechanical failure/wear situation, it can also be TPS or ECU failure and/or mechanical failure/wear out.
Sensors do wear out...and things like a bad O2 sensor will cause a car to die if the computer starts getting incorrect info from it. (Joe can probably confirm if this is definitely the case with the CCC, but many O2 sensor cars release to the info from the O2 sensor only after it is warm...so a bad sensor car will run on a set program until the computer senses the O2 sensor is warm enough and then start varying based on the data stream. If the O2 says "hey, I'm warm and sending you data" but the data is wrong, the car won't have a correct mixture or timing.
Sensors do wear out...and things like a bad O2 sensor will cause a car to die if the computer starts getting incorrect info from it. (Joe can probably confirm if this is definitely the case with the CCC, but many O2 sensor cars release to the info from the O2 sensor only after it is warm...so a bad sensor car will run on a set program until the computer senses the O2 sensor is warm enough and then start varying based on the data stream. If the O2 says "hey, I'm warm and sending you data" but the data is wrong, the car won't have a correct mixture or timing.
Last edited by classwinners; December 3rd, 2018 at 10:51 AM.
December 3rd, 2018, 10:53 AM
#14
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Don't get me wrong, as I'm not a CCC expert in any way shape or form. I was simply pointing out that any "it dies" situation requires identifying spark vs fuel and conventional wisdom seems to still apply here, because the parts might be slightly different (electronic vs. pure mechanical actuation) but the theory is still the same. If memory serves, CCC simply uses a basic throttle position sensor (along with O2 sensors, coolant sensors -- the normal stuff you'd find on EFI cars) to control timing advance/retard, the carb idle circuit and the off-idle progression. (It probably also deals with emissions and A/C idle, but those likely aren't the issue.) Instead of just being a mechanical failure/wear situation, it can also be TPS or ECU failure and/or mechanical failure/wear out.
Here's a personal example. On one of my 307 cars, the check valve in the air injection pipe to the catalytic converter went bad and stuck open. This allowed hot exhaust to reach the diverter valve in the A.I.R. system. The heat destroyed the rubber seals, so now the diverter valve was fully open. This allowed the full output of the A.I.R. pump to reach the O2 sensor even after the car was in closed loop mode. The result was that the ECU saw this fresh air as an overly lean condition, set that MIL code, and ran the carb full rich. Every indication I had was that the plugs were sooty black from being too rich, yet the code said too lean. That is NOT "conventional wisdom". By the way, the CSM actually suggests a failed diverter valve as one possible cause in this situation. You must read the CSM and not rely on conventional wisdom.
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