cyclinder with 60lbs
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Fleet Mechanic
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From: va
cyclinder with 60lbs
Hi, my engine number #2 cyclinder has only 60lbs, I think it has bad piston rings. I added some oil and the pressure jumped to 190 psi. It does burn oil. Most of time it runs great. Then there has been few days lately that the engine started to run fast, at 5 grand. Sometimes it will idle bad. Does the engine computer adjust the fuel because there is a cyclinder with low pressure? Is that why it runs bad sometimes. I have the one general missfire code. Everything thing else tested ok.
93 f150 5.0
93 f150 5.0
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Joined: Jul 2009
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From: Lansdale, PA
The computer has no idea that one cylinder isn't up to par.
Bad rings will cause low pressure, and with oil increase its output. I think you're on the right track.
The 5k rev could be idle air valve. Seems high but its possible.
Bad rings will cause low pressure, and with oil increase its output. I think you're on the right track.
The 5k rev could be idle air valve. Seems high but its possible.
Logistics Pro
Joined: Jul 2009
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From: Lansdale, PA
Your first post says it does burn oil.
But it could be compression ring, or bad valve seats causing low compression.
Give it some seafoam and let it sit for 20 min. See if that helps.
If not I'd mist a bunch of water into it so un-gum most everything in the engine. But don't try that unless you know what you're doing. You can hydro lock the motor and hurt stuff.
Your hanging idle, clean iac with carb cleaner or get a new one.
Check your PCV valve. Check egr valve.
But it could be compression ring, or bad valve seats causing low compression.
Give it some seafoam and let it sit for 20 min. See if that helps.
If not I'd mist a bunch of water into it so un-gum most everything in the engine. But don't try that unless you know what you're doing. You can hydro lock the motor and hurt stuff.
Your hanging idle, clean iac with carb cleaner or get a new one.
Check your PCV valve. Check egr valve.
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Fleet Mechanic
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From: va
Engine speeding up while driving
Thanks, sorry it does NOT burn oil. Yesterday the engine started something new. It started to speed up by it's self while driving. It went to 5 grand maybe higher without my foot off the pedal. When I used the brake it jerked, then I was in control again. But only for a few minutes. Then it repeated again and again for about 15 minutes. Today, first thing in the morning I tested the car for 20 minutes, ran ok no problems at all. It felt like a sticking throttle cable. ???? The problem is off and on, no trouble codes. Besides the miss fire compression code.
Logistics Pro
Joined: Jul 2009
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From: Lansdale, PA
I had a problem once where the cruise control actuator lost its mind.
It would randomly give it throttle. Unhook the vacuum line to the cruise control and see if it stops.
It would randomly give it throttle. Unhook the vacuum line to the cruise control and see if it stops.
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Fleet Owner
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Ford stopped using the vacuum servo speed control system after 1992. The OP's '93 uses the electro-mechanical system.
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From: Lansdale, PA
Yup. You're right. Hmmmmm
Unhook the wiring anyway.
When the truck is accelerating on its own, does the gas pedal feel like its being pulled down like the cruise is on. Or that the throttle butterfly's are sticking open.
Unhook the wiring anyway.
When the truck is accelerating on its own, does the gas pedal feel like its being pulled down like the cruise is on. Or that the throttle butterfly's are sticking open.
Postmaster
Joined: Nov 2011
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From: SW Florida
I have a hard time believing a stuck idle air valve can make it rev to 5K. I backprobed the connector on mine (experimenting with an idea/mod) and grounded the signal wire, which drives the valve wide open. RPM's were ~1600 with no load on a warm engine.
I'd say your problem is mechanical...
I'd say your problem is mechanical...
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Fleet Mechanic
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From: va
throttle body hose air leak
It caused high rev. bad idle. It also caused the engine to stay stuck at 42 mph yesterday and it would not go any slower. A ROLL of duck tape worked until I got home, there sure is a lot of air pressure.
Fixed thanks!
Fixed thanks!
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Fleet Mechanic
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From: va
cyclinder low psi, normal when added oil
Put some into the oil filler hole, and then add some slowly threw the pvc hose?
Into the gas tank to?
So after 20 minutes do I change the motor oil?
Do I need to get a leak down test done, it must by the compression ring? Doesn't burn oil.
Thanks
Logistics Pro
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From: Lansdale, PA
Suck the seafoam through the port in the throttlebody used for the canister purge solenoid.
I think that will evenly distribute the seafoam pretty decent.
It will get at both intake and exhaust valves because the engine is consuming the liquid.
I used to take a garden hose and mist water into the gasser school busses throttlebody. It cleaned the carbon out really well and made the engines run great afterwards. Gotta be real careful like I said though. The seafoam is different in that there isn't much of it, and it reacts with a hot engine by foaming up and getting into all the cracks and loosens all the crud (supposedly).
If you put seafoam in the oil, you can run it for 50-100 miles. It won't hurt anything.
Put it in the gas because its a great injector cleaner and water remover.
Great trans flush additive before you change the filter.
And it cleans valves and catalytic converters when sucked into the intake.
I think that will evenly distribute the seafoam pretty decent.
It will get at both intake and exhaust valves because the engine is consuming the liquid.
I used to take a garden hose and mist water into the gasser school busses throttlebody. It cleaned the carbon out really well and made the engines run great afterwards. Gotta be real careful like I said though. The seafoam is different in that there isn't much of it, and it reacts with a hot engine by foaming up and getting into all the cracks and loosens all the crud (supposedly).
If you put seafoam in the oil, you can run it for 50-100 miles. It won't hurt anything.
Put it in the gas because its a great injector cleaner and water remover.
Great trans flush additive before you change the filter.
And it cleans valves and catalytic converters when sucked into the intake.
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Fleet Mechanic
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From: va
Using mystery oil
Suck the seafoam through the port in the throttle body used for the canister purge solenoid.
I think that will evenly distribute the seafoam pretty decent.
It will get at both intake and exhaust valves because the engine is consuming the liquid.
I used to take a garden hose and mist water into the gasser school busses throttle body. It cleaned the carbon out really well and made the engines run great afterwards. Gotta be real careful like I said though. The Seafoam is different in that there isn't much of it, and it reacts with a hot engine by foaming up and getting into all the cracks and loosens all the crud (supposedly).
If you put Seafoam in the oil, you can run it for 50-100 miles. It won't hurt anything.
Put it in the gas because its a great injector cleaner and water remover.
Great trans flush additive before you change the filter.
And it cleans valves and catalytic converters when sucked into the intake.
I think that will evenly distribute the seafoam pretty decent.
It will get at both intake and exhaust valves because the engine is consuming the liquid.
I used to take a garden hose and mist water into the gasser school busses throttle body. It cleaned the carbon out really well and made the engines run great afterwards. Gotta be real careful like I said though. The Seafoam is different in that there isn't much of it, and it reacts with a hot engine by foaming up and getting into all the cracks and loosens all the crud (supposedly).
If you put Seafoam in the oil, you can run it for 50-100 miles. It won't hurt anything.
Put it in the gas because its a great injector cleaner and water remover.
Great trans flush additive before you change the filter.
And it cleans valves and catalytic converters when sucked into the intake.