Hesitates/backfires - why?
08-17-2006, 04:18 PM
#16
Burning Brakes
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Originally Posted by 944CS
do you have platinum +4 plugs?
I just saw a post on resoldering some points inside the DME. Maybe I should inspect the DME?
08-17-2006, 06:07 PM
#17
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Ok I see you have altered the symptoms. Let's review...How does the J boot look? Cracks? Not snug at the hose clamps? Underside has a vacuum line, is the rubber port there not cracked? Physically look at the wiper in the AFS to rule out then dig into the DME (which is usually a no/hard start issue) related but not exclusive.
Let's make this more fun for you. Jump in the car and go for a spirited ride and note if you feel the car burp or a feeling of lurching forward in the seat. Then when you get up around redline and upshifting listen for a backfire the second you let up on the gas.
If this is the case I have the cure.
Dal
Let's make this more fun for you. Jump in the car and go for a spirited ride and note if you feel the car burp or a feeling of lurching forward in the seat. Then when you get up around redline and upshifting listen for a backfire the second you let up on the gas.
If this is the case I have the cure.
Dal
08-17-2006, 06:18 PM
#18
Burning Brakes
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Originally Posted by dgz924s
Ok I see you have altered the symptoms. Let's review...How does the J boot look? Cracks? Not snug at the hose clamps? Underside has a vacuum line, is the rubber port there not cracked? Physically look at the wiper in the AFS to rule out then dig into the DME (which is usually a no/hard start issue) related but not exclusive.
Let's make this more fun for you. Jump in the car and go for a spirited ride and note if you feel the car burp or a feeling of lurching forward in the seat. Then when you get up around redline and upshifting listen for a backfire the second you let up on the gas.
If this is the case I have the cure.
Dal
Let's make this more fun for you. Jump in the car and go for a spirited ride and note if you feel the car burp or a feeling of lurching forward in the seat. Then when you get up around redline and upshifting listen for a backfire the second you let up on the gas.
If this is the case I have the cure.
Dal
2. well, about you spirited driving: I do get a significant loss of power above about 5500 rpm, and the engine become very noisy. I don't know if it's related... The car is noisy enough above 3000 rpm, so I wouldn't hear any backfiring, unless it was super loud.
What do you have on your mind?
08-18-2006, 02:23 PM
#19
Burning Brakes
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Originally Posted by dgz924s
Let's make this more fun for you. Jump in the car and go for a spirited ride and note if you feel the car burp or a feeling of lurching forward in the seat. Then when you get up around redline and upshifting listen for a backfire the second you let up on the gas.
If this is the case I have the cure.
Dal
If this is the case I have the cure.
Dal
08-18-2006, 04:26 PM
#21
Drifting
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I would not put in platinum plugs, while they may last longer the resistivity is much higher than copper or silver.
Material Resistivity (ohms per meter)
Silver 1.62*10^-8
Copper 1.69*10^-8
Platinum 10.6*10^-8
The temperature coefficients of Resistivity are close enough that they are negligible
I believe for an '83 Bosch WR8DS are the correct plug as listed in the owners manual. I use this plug with great success, and I would index them as well
Material Resistivity (ohms per meter)
Silver 1.62*10^-8
Copper 1.69*10^-8
Platinum 10.6*10^-8
The temperature coefficients of Resistivity are close enough that they are negligible
I believe for an '83 Bosch WR8DS are the correct plug as listed in the owners manual. I use this plug with great success, and I would index them as well
08-18-2006, 05:02 PM
#22
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I would suggest inspecting the condition of your ignition wires, check to see if there is arching between any two wires.
One way I like to check, is to disconnect and ground one ignition wire at a time.
If there is no change in engine RPM, then you have found the guilty one.
If the RPM drops, then that only means that sparkplug IS working in that cylinder. So now you need to test for crossfiring, so give it the rev test, to see if it still backfires in your 2K-3K range. If it no longer backfires, you have found one of the two bad wires. Good luck.
One way I like to check, is to disconnect and ground one ignition wire at a time.
If there is no change in engine RPM, then you have found the guilty one.
If the RPM drops, then that only means that sparkplug IS working in that cylinder. So now you need to test for crossfiring, so give it the rev test, to see if it still backfires in your 2K-3K range. If it no longer backfires, you have found one of the two bad wires. Good luck.
08-23-2006, 03:52 PM
#23
Burning Brakes
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Update: Those who thought it was ignition related were right. I used a neon-light based tester that you run along the ignition wires, and it blinked much weaker on cylinder 1. So I tooked the spark plug out, and it was completely bridges with dry ashes. I put another one instead, and it's much better now.
Next, I'll replace all ignition components together: all plugs, wires, cap and rotor.
Next, I'll replace all ignition components together: all plugs, wires, cap and rotor.
