I have an 88 gt convertable. It starts fine cold. But it Does not restart hot unless I either wait 20 minutes or push the accelerator all the way down wot. I have replaced the tps, tfi, ignition coil, plugs and wires, all vac lines ect. This is my firdt car ive ever worked on so please bare with my ignorance. Any info would be appreciated.
Hot Start Issue.
- Thread starter joshthebarber
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Hey John,
Your issue is generally caused by starter heat soak. Over time, your starter has been getting cooked by exhaust heat and it's probably on it's way out. A couple of thing you can try. You can wrap the starter, or the exhaust pipe on that side with some exhaust wrap, or you can install a heat shield between the starter and the exhaust pipe to reduce the amount of radiant heat it's seeing?
How much ignition timing are you running? Excessive ignition timing will also make a car hard to start after it's warm.
Your issue is generally caused by starter heat soak. Over time, your starter has been getting cooked by exhaust heat and it's probably on it's way out. A couple of thing you can try. You can wrap the starter, or the exhaust pipe on that side with some exhaust wrap, or you can install a heat shield between the starter and the exhaust pipe to reduce the amount of radiant heat it's seeing?
How much ignition timing are you running? Excessive ignition timing will also make a car hard to start after it's warm.
Good point jrichker. I just assumed this was a no turn over when hot issue. Turn over, but no start when hot screams bad TFI module though.
rockstarwb
Member
One thing that kinda stands out here is the pedal being pushed to the floor.When you mash the gas pedal to wot while tryin to start the car,the computer shuts the injector pulse off.If it starts with the injectors not spraying fuel,this is sometimes caused by a defective fuel pressure regulator.The no start condition always occurs after the vehicle has been driven for 20-30 minutes and its warmed up to operating temperature.You could rent a fuel pressure gauge,attach it to the shrader valve(near the end of metal fuel lines right before they attach to the fuel rail)check pressure when vehicle is first started(should be 30-40psi)then let the vehicle run for 20 minutes or so,turn the key off,then try to restart.If it won't start,check the fuel pressure to see if its below 35psi or above 45psi with key on/engine off.Low to zero pressure would indicate the regulator is stuck open.Its also possible that the regulator is sticking closed causing the injectors to dump too much fuel into the chamber while you're tryin to start vehicle.Then when you mash the pedal to the floor and the injectors stop spraying fuel,the car will then start.
Simple things first....
Have you run the codes. You have replaced a bunch of parts, but didn't indicate if there were codes that suggested this, or just random guessing.
1988 mustangs do not have a working check engine light, but they do generate codes that must be read pretty much whenever you feel something is wrong. I would start here.
Now personal experience. engine coolant temp sensor. This would generate a code 21 and cause the symptoms you are having. The engine basically floods when warm and only way to start the engine is to press pedal to the floor to turn off injector pulses and allow it to clear and flood. I would warm the engine up fully, run the codes and see if you have a code 21
Have you run the codes. You have replaced a bunch of parts, but didn't indicate if there were codes that suggested this, or just random guessing.
1988 mustangs do not have a working check engine light, but they do generate codes that must be read pretty much whenever you feel something is wrong. I would start here.
Now personal experience. engine coolant temp sensor. This would generate a code 21 and cause the symptoms you are having. The engine basically floods when warm and only way to start the engine is to press pedal to the floor to turn off injector pulses and allow it to clear and flood. I would warm the engine up fully, run the codes and see if you have a code 21
Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.
Dumping the computer diagnostic codes on 86-95 Mustangs
Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.
Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.
Here's the way 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.
Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.
Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.
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.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.
What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems
Some 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.
Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10
Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® 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 www.midwayautosupply.com/Equus-Digital-Ford-Code-Reader/dp/B000EW0KHW Equus - Digital Ford Code Reader (3145It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.
Dumping the computer diagnostic codes on 86-95 Mustangs
Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.
Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.
Here's the way 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.
Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.
Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.
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.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.
What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems
Some 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.
Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10
Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® 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 www.midwayautosupply.com/Equus-Digital-Ford-Code-Reader/dp/B000EW0KHW Equus - Digital Ford Code Reader (3145It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.
rockstarwb
Member
Here is a thread I found on another site which will help you further diagnose your problem if its related to a defective fuel pressure regulator or leaking injectors
http://sbftech.com/index.php/topic,36469.0.html
http://sbftech.com/index.php/topic,36469.0.html
Blown88GT
Founding Member
Ignore electrical issues, it's not any of that. There are no codes, don't bother with that.
Since it does start when you override with pedal to the floor, it's a fuel issue.
Do what rockstarwb says above, ignore all the others.
Most of these guys on Stangnet think every problem is electrical. I learned my lesson the hard way.
Since it does start when you override with pedal to the floor, it's a fuel issue.
Do what rockstarwb says above, ignore all the others.
Most of these guys on Stangnet think every problem is electrical. I learned my lesson the hard way.
He got the info he got because he was non specfic about the conditions in his initial posts. Had he provided ALL of the details from the get go, he might have gotten different answers.
Running the ECU for codes should always be ones first step. 9/10 times, most simple issues can be found by doing this. I don't care what you think the car is doing, unless you run the car for codes first, you're throwing darts! It could potentially save you from chasing your tail, or spending money needlessly. You telling him not to bother at all is piss poor advice frankly. It costs nothing and takes no time to do.
....but hey, you seem to have all of the answers. You may as well take over.
Did you replace the one on the heater tube...or the one bolted into the lower intake.
modulistic
Active Member
- Nov 26, 2002
- 383
- 30
- 29
yep, he might have only changed the temp sender and not the coolant temp sensor.
Sounds like you've replaced a lot.
I still gotta ask though, have to dumped the codes as outlined in post #7.
I still gotta ask though, have to dumped the codes as outlined in post #7.
The car is not obd2. There is no plug under the dash.
The EEC-4 plug is under the hood, on the drivers side next to the windshield wiper plug. It might be tucked down in the harness but it should be there.
I hate sounding like a broken record, but it will make diagnosing the issue much easier than just throwing parts at the problem
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