hey guys my name is Chris and i have been in the classic forums for quite a little while now but i also have a 5.0 convertible 89 with an aod and a few mods like headers high flow h-pipe, exhaust, cold air intake, and under drive pullies. well anyways i have quite a big problem i was driving one day and the car overheated..crap...so since that day the car has been running INCREDIBLY rough. what could have happened, i have heard a few things but nobody has been sure its almost as if a cylinder is dead, could it have just killed a spark plug or is it more serious like a burned up cylinder or something just let me know thanks agian
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bill302
Active Member
welcome to 5.0 few things you can do...cylinder balance test, compression test,pull codes...to locate problem...alot of times a cylinder balance test will give you all the info. you need it will tell you which cylinder is the culprit ...
bill302
Active Member
i usually do the cylinder balance test the old fashion way:
One way you can find a weak or dead cylinder is to momentarily disconnect each of your engine’s spark plug wires one at a time while the engine is running. When the plug wire is removed from the spark plug, there should be a big drop in idle speed and idle smoothness. When you pull a wire and there’s little or no change in idle speed or quality, you’ve found the bad cylinder.
you can also do this thru the KEY ON ENGINE RUNNING (KOER) TEST
1. Make sure engine is fully warmed. If in doubt, run engine at 2000 rpm for 2 minutes.
2. Turn ignition off and wait 10 seconds for system to shut off. Make sure A/C is off and transmission is in Park (automatic) or Neutral (manual).
3. Hook up light and jumper (or tester if you have one).
4. Make sure vehicle is safe to run and start engine.
5. Engine I.D. should be output.
6. Step on brake and turn steering wheel 1/4 turn.
7. If a "Goose" pulse is received, move throttle quickly 1/2 way down and release.
8. Fast Codes are output (ignore).
9. Read codes.
10. See code explanations and check components as necessary.
Use FIRST CODE OUTPUT and retest after any repairs are made.
CYLINDER BALANCE TEST
NOTE: This test is only available on Sequential Fuel Injection (SFI) Engines.
Start an engine running test and press the accelerator lightly within 2 minutes after the last code is output. The PCM will cancel each cylinder in turn and measure the RPM drop. If any weak cylinders are noted their number will be output as a multiple of 10 (e.g. 30, 40). The output is the actual cylinder number, not the number in the firing order. NOTE: Will not always pinpoint bad injectors.
copied from:http://www.muscularmustangs.com/test1.php
One way you can find a weak or dead cylinder is to momentarily disconnect each of your engine’s spark plug wires one at a time while the engine is running. When the plug wire is removed from the spark plug, there should be a big drop in idle speed and idle smoothness. When you pull a wire and there’s little or no change in idle speed or quality, you’ve found the bad cylinder.
you can also do this thru the KEY ON ENGINE RUNNING (KOER) TEST
1. Make sure engine is fully warmed. If in doubt, run engine at 2000 rpm for 2 minutes.
2. Turn ignition off and wait 10 seconds for system to shut off. Make sure A/C is off and transmission is in Park (automatic) or Neutral (manual).
3. Hook up light and jumper (or tester if you have one).
4. Make sure vehicle is safe to run and start engine.
5. Engine I.D. should be output.
6. Step on brake and turn steering wheel 1/4 turn.
7. If a "Goose" pulse is received, move throttle quickly 1/2 way down and release.
8. Fast Codes are output (ignore).
9. Read codes.
10. See code explanations and check components as necessary.
Use FIRST CODE OUTPUT and retest after any repairs are made.
CYLINDER BALANCE TEST
NOTE: This test is only available on Sequential Fuel Injection (SFI) Engines.
Start an engine running test and press the accelerator lightly within 2 minutes after the last code is output. The PCM will cancel each cylinder in turn and measure the RPM drop. If any weak cylinders are noted their number will be output as a multiple of 10 (e.g. 30, 40). The output is the actual cylinder number, not the number in the firing order. NOTE: Will not always pinpoint bad injectors.
copied from:http://www.muscularmustangs.com/test1.php
Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
See http://www.troublecodes.net/Ford/
IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.
Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
See http://www.troublecodes.net/Ford/
IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.
Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
so if i find a bad cylinder by pulling the plugs what could that mean is bad about the cylinder what could i have done from the overheating? and how hard would it be to fix would it be a pull the motor type of thing or what im kinda intimidated by the 89 because of the electronics im not very good with them.
bill302
Active Member
after the test when you find the bad cylinder most of the time it will be a fouled or even a loose plug or burned wire causing a short..but it could also be something major like a blown headgasket or warped head which all of the above can be linked to overheating...find the bad cylinder and repost.
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