Coolant eruption... car cranks but won’t start... HELP please!

barandw

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Jan 22, 2020
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So I was performing maintenance on my 99 v6 3.8 this past weekend, I replaced the valve cover seals and lower and upper intake manifold gaskets. Reassembled the engine completely and started it up. Car ran for approximately 15-20 while I was bleeding the coolant system. I loosened the upper bleed screw on the return line from the heater core to bleed out excess air, and loosened too far and the screw blew out completely and shot coolant out all over engine on intake, crank and serpentine belt and surrounding areas. Shut the car off as quick as I could and clean all areas of fluid. Replaced bleed screw refilled coolant with what was lost and started car again to repeat the bleeding process. Car ran for a minute and started to bog down then revs came back up bogged down again and eventually stalled out.

Now it will crank but will not start. I monitored the CKP sensor while cranking and it’s registering around 175 rpms, so I don’t believe that was affected by the coolant. I don’t know what else electrical might have been affected by the coolant that is causing the engine to not turn over and would really appreciate some troubleshooting advice. It was running perfectly fine before the coolant explosion so I don’t see it being a fuel or spark issues but more something electrical that either got soaked or shorted out and blew a fuse or something.

Any help you have to give would be appreciated. Thanks!
 
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wmburns

SN Certified Technician
Aug 14, 2009
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First here's some information on how to bleed the coolant system on a V6. From the sounds of it the bleed screw was removed while the motor was hot and maybe still under pressure. Remove the bleed screw only when the motor is COLD.

V6 coolant refilling procedure:

IMO it's a mistake to not confirm spark is present. It seems possible to me that most anything could have been accidentally disconnected during the cleaning processes. So assume NOTHING. But there really aren't that many sensors that will cause a crank with no start. For example:
  • CKP
  • CMP (V6)
  • fuel rail pressure sensor (1999-2004)
  • an out of range MAF sensor

Confirm there is some fuel pressure. What would be the expected symptom if the fuel pump was not running? Perhaps running for a period of time until the fule in the line is used up and then bogging down? The easiest way is to monitor the fuel pressure PID. Do your HEAR the fuel pump run at initial key on?

Confirm that the PCM is "seeing" the MAF sensor. Again the easiest way to to monitor the MAF PID during cranking. It should change indicating there is at least some communications going on.

Here's some more information that may help.

1996+ Crank with no start check list
 
Last edited:

barandw

New Member
Jan 22, 2020
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Harvest, AL
First here's some information on how to bleed the coolant system on a V6. From the sounds of it the bleed screw was removed while the motor was hot and maybe still under pressure. Remove the bleed screw only when the motor is COLD.

V6 coolant refilling procedure:

IMO it's a mistake to not confirm spark is present. It seems possible to me that most anything could have been accidentally disconnected during the cleaning processes. So assume NOTHING.

Confirm there is some fuel pressure. What would be the expected symptom if the fuel pump was not running? Perhaps running for a period of time until the fule in the line is used up and then bogging down? The easiest way is to monitor the fuel pressure PID. Do your HEAR the fuel pump run at initial key on?

Confirm that the PCM is "seeing" the MAF sensor. Again the easiest way to to monitor the MAF PID during cranking. It should change indicating there is at least some communications going on.

Here's some more information that may help.

1996+ Crank with no start check list
Not used to working on mustangs so I was following similar procedures to subies I normally work on to make sure there is zero air in the system. My mistake lol

I did actually confirm spark after it happened and wouldn’t crank. After that it was late and I left it alone. Last night I confirmed a lost of fuel pressure and my diagnostic table gave me codes P1233, P1093 and P1237 after running a self demand test. So now my question is to myself and you guys is which do you think is more likely just a faulty short somewhere, either a blown fuse or relay, faulty fuel pressure sensor from getting blasted with hot ass coolant or I shorted and fried the fuel pump driver module? Comments or suggestions? This thing is over 2 decades old with over 225k so I’m sure some of this stuff needs to be replaced anyways but if there’s a bad short somewhere I need to fix that first before I replace sensors and drivers to fry them again
 

barandw

New Member
Jan 22, 2020
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Harvest, AL
Also,
Read the data stream for KOEO and the fuel pump monitor circuit was reading high like 400% and the fuel pump duty was tripped at 75% because of the fault. The inertia switch was not tripped I check that. However someone with more stang experience could point me to the first checks i should perform to verify which device is actually faulty or tripped to keep the fuel pump from getting the input to turn on.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,764
493
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Houston Texas
I really don't understand why the thought is to jump to a bad PCM before the "basics" are ruled out.

IMO some of the basics is to confirm there are no blown fuses. Recommend using a test light that will "load" the circuit. Test and confirm on both sides of the fuse. The fuel pump fuse is F1.14.

1999-2004 MY fuse panel schedule:

Previously I mentioned that a FRPS is a no start sensor. Guess what? P0193 indicates a fault to the FRPS. Perhaps there's moisture inside the FRPS connector? Or a short that will make the PCM "think" that the fuel pressure is too high or too low.

An option is to test for initial key on power at the trunk mounted IFS switch. This is more than just checking that the IFS isn't tripped.
 

barandw

New Member
Jan 22, 2020
4
0
1
29
Harvest, AL
I really don't understand why the thought is to jump to a bad PCM before the "basics" are ruled out.

IMO some of the basics is to confirm there are no blown fuses. Recommend using a test light that will "load" the circuit. Test and confirm on both sides of the fuse. The fuel pump fuse is F1.14.

1999-2004 MY fuse panel schedule:

Previously I mentioned that a FRPS is a no start sensor. Guess what? P0193 indicates a fault to the FRPS. Perhaps there's moisture inside the FRPS connector? Or a short that will make the PCM "think" that the fuel pressure is too high or too low.

An option is to test for initial key on power at the trunk mounted IFS switch.
Copy that, I will test for voltage present at the IFS switch. Is there a Key On voltage range that should be present at that connector?

I did check all the fuses within the engine compartment fuse box last night and none we’re blown. I disconnected the FRPS connector and made sure it was dry but that doesn’t mean it didn’t get wet and fault. I do realize that’s a no start condition and plan on getting a replacement but I want to rule out all possible ground faults as well. I have not checked any of the relays yet tho that was on the list as well