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BENBRO02 |
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#1
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Member ![]() ![]() Group: Members Posts: 483 Joined: 6-March 15 From: Nokesville, Virginia Member No.: 18,493 Region Association: MidAtlantic Region ![]() ![]() |
It starts okay when cold and only has a slight miss but as it warms up it starts to miss more frequently, bucks, and if hot and idling may cut off completely. If I'm on the highway it may lose 20 mph before it starts running well enough to maintain speed or accelerate. I have recently had the following replaced:
fuel tank fuel pump fuel lines and hoses fuel sending unit vacuum hoses large and small injector seals The shop also checked the vacuum advance and cleaned the injectors. I emptied my bank account with the repairs so now it's time for me to find the problem. Any Ideas? The car has a Pertronics ignition. |
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Dave_Darling |
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#2
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914 Idiot ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 14,991 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California ![]() ![]() |
What does the tach do when the engine starts missing? If the needle jumps all over, you definitely have an ignition system problem. (A lack of jumping around doesn't rule out ignition, so this is can only confirm one possibility but it will not deny any.)
Intermittent problems are usually electrical. If it runs fine for a while then runs crappy, there's a very good chance that the problem is an electrical connection.... somewhere. If it runs crappy all the time, it could be a lot of different things. Do you have an IR thermometer? If so, run the motor for a while and then zap each exhaust tube near the head. If you find one is rather cooler than the others, that says you have one cylinder that isn't firing or is intermittently firing. If the pipe is dead cold, you have a "dead hole" and you can start checking stuff for that one cylinder. You may be able to tell large variations in temperature by holding your hand NEAR each pipe in turn, but DO NOT TOUCH THEM unless you enjoy second-degree burns. Good luck! --DD |
BENBRO02 |
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#3
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Member ![]() ![]() Group: Members Posts: 483 Joined: 6-March 15 From: Nokesville, Virginia Member No.: 18,493 Region Association: MidAtlantic Region ![]() ![]() |
What does the tach do when the engine starts missing? If the needle jumps all over, you definitely have an ignition system problem. (A lack of jumping around doesn't rule out ignition, so this is can only confirm one possibility but it will not deny any.) Intermittent problems are usually electrical. If it runs fine for a while then runs crappy, there's a very good chance that the problem is an electrical connection.... somewhere. If it runs crappy all the time, it could be a lot of different things. Do you have an IR thermometer? If so, run the motor for a while and then zap each exhaust tube near the head. If you find one is rather cooler than the others, that says you have one cylinder that isn't firing or is intermittently firing. If the pipe is dead cold, you have a "dead hole" and you can start checking stuff for that one cylinder. You may be able to tell large variations in temperature by holding your hand NEAR each pipe in turn, but DO NOT TOUCH THEM unless you enjoy second-degree burns. Good luck! --DD Thanks it's great hearing all these ideas. |
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