2nd Generation Specific 1986-1992 Discussion

Detonation Questions

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Old 12-04-2002, 07:49 AM
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For some reason I turned my TPS very rich and because of that I had to open my idle screw all the way.

Q1- Can an open idle screw let in enough air to lean out the engine at near redline?

Q2- Where is a good right up on how to set the TPS with a multimeter

Thanks
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Old 12-04-2002, 09:26 AM
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it has fuel maps you can't blowup a N/A engine running the stock fuel computer....
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Old 12-04-2002, 10:43 AM
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Since he mentioned detonation I have a question along those lines. Can someone please describe tome what a knock and aping sound like when you're driving ? I've probably heard one before but never knew what it was. Also what is the difference between a knock and a ping? Thanks.
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Old 12-04-2002, 11:02 AM
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The TPS sure can be a pain in the ***. I had to set and re-set mine several times to illicit a good idle. Even now when feathering the throttle it will surge a bit, and then work fine. I made one of the TPS checker lights using two LED lights and 3 male connectors. Just head down to radio shack and buy the lights for like .99 cents. Splice the positives together on one male connector. When adjusting the TPS take a paper clip and jump the initial set coupler up by the battery. It is a small green connector that will bypass the computer so it isn't fighting you while you are trying to set the TPS. I put mine out of calibration first and then turned the screw bringing it back to where one light was on. After that I would start it and check the timing, and then mess with the idle speed screw. You should be able to close the screw a bit and put your idle where you want it after the TPS and timing are good. Remember to keep the initial set coupler jumped while doing the timing and adjusting the idle speed screw as well. After I set everything I also disconnected the negative battery cable and layed on the brake for a few minutes clearing the codes out of the computer. I don't know if this made a difference though. I believe it was J9fd3s or someone who said that all the N/A's run way to rich with the stock components.
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Old 12-04-2002, 11:05 AM
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ping and knock are the same thing..... it sounds like a pop or a bang noise from the engine... you will also notice loss of power immediately when it happens....
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Old 12-04-2002, 11:07 AM
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Does it cause the car to hesitate for a split second or so or does the power loss stay around for a while?
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Old 12-04-2002, 11:15 AM
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what happens is the engine will start to knock, you cant really hear it and power will drop off, then it will start detonating where you can hear it, its loud and sounds like someone banging on trash can lids.



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Old 12-04-2002, 11:16 AM
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well, i have had both occur in 2 different motors for my 7.

(un)fortunately, i've never had e.f.i. this is more likely with carbs



1) the ping... a.k.a. the frying eggs sound. notorious in a 80's chrysler/dodge. It comes from an over-advanced timing.



2) the knock...

i do know that the knock is from pre-detonation. it sounds like a woodpecker is drilling the side of the motor. when you hear it, (usually on the initial full throttle kick) back off and try to give it gas gradually again.

also- i have found that turning the ignition counter-clockwise (retard) will help reduce the likelyhood of knocking.



THE BIG TIP... LUCAS- this oil treatment helps keep everything covered by oil. and it allowed me to advance the timing more with less knocks.
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Old 12-04-2002, 11:19 AM
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i've only heard the loud knocks on a car with a weak fuel pump going up a hill



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Old 12-04-2002, 12:50 PM
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use bad gfasoline in most any boinger, and youll hear it under load, metal vs. metal
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