1994 Ford Mustang Car won't crank. Oil pressure pegged

Tiny
SCOVOL
  • MEMBER
  • 1994 FORD MUSTANG
  • V8
  • 2WD
  • MANUAL
  • 95,000 MILES
My oil pressure gauge reading was creeping upward over several days. Then, suddenly, the car was dead with absolutely no cranking of the engine. I assumed it was the battery and so I pop-started it going downhill and drove it about 10 miles home - as I was driving the oil pressure gauge was almost pegged. I parked the car and shut it down and didn't notice anything abnormal other than the high oil pressure. Later, while the car was sitting the oil pressure totally pegged HIGH-HIGH-HIGH and doesn't move regardless of the battery or ignition - yet the other gauges on the dash are functional. And it doesn't crank but the Key On Engine Off diagnostic passes. Meanwhile, I've replaced the battery (and something drained it to 3V so I’ve disconnected it while not testing) and I pulled the starter and had it tested - the starter PASSed diagnostics at the local auto parts store. I also checked the engine to see if the crankshaft would turn with a ratchet and it does. I have checked the fuses and they are all OK but I don’t know anything about the three relays. But it still won't crank.
Tuesday, October 20th, 2009 AT 9:57 PM

7 Replies

Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok lets take one problem at a time. First using the pic below, I would like you to check the S term on the back of the starter solenoid for power when the key is in the start position. So what you do is simply hook up either a digital multi meter or test light to the S term on the starter and the other end to a good ground and then turn the key to the crank position do you get power? If not then we will check the clutch switch. The clutch switch is also a neutral safety switch so it is bad there will be now power there. Get back to me with what you find. If there is no power to the S term on the starter then I would like you to make a fused jumper wire and check the clutch switch. Unplug it and jump between term 30 and 46 (see pic below), make sure that the wire colors are as such too, red wire with light blue strip to white wire with pink stripe. Make sure it is in neutral and see if it starts. If it does then the clutch switch is bad.
Here is pic for starter test.


https://www.2carpros.com/forum/automotive_pictures/249564_Graphic1_17.jpg


Here is pic for clutch switch.


https://www.2carpros.com/forum/automotive_pictures/249564_Graphic_145.jpg

Was this
answer
helpful?
Yes
No
Wednesday, October 21st, 2009 AT 10:49 AM
Tiny
SCOVOL
  • MEMBER
  • 7 POSTS
I was not able to light the test light from the S terminal + ground. Not only does the starter click but it seems to be moving the car (but not the flywheel) a bit when it is cranked. And there is a mechanical sound like the starter trying to turn a flywheel that won't move. I am bewildered now unless.(I may learn something here). In test #2 how many amp fused jumper are you talking about? I'm ready for test #2 if that is where we are going.
Was this
answer
helpful?
Yes
No
Wednesday, October 21st, 2009 AT 3:12 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok if you didn't get a light at the S term then the starter can't be engaging as there is no power there to start. With the fuse 15 or 20 amp just to protect the circuit. If it still won't start then I would like you to check the starter relay (see pic below). The relay has 4 contacts and you may only be using 3 of them or all 4. Either way you have battery cable to one large contact, the other large contact goes to the starter and the S term goes to engage the starter. So what you do is check for power at the S term with key in start position if power is there then check to see if there is power at the larger term with the cable that goes to the starter with key in start position. If no power there then replace starter solenoid switch. This solenoid switch is on the inner fender near the battery. Let me know what you find.


https://www.2carpros.com/forum/automotive_pictures/249564_51047_2.jpg

Was this
answer
helpful?
Yes
No
Thursday, October 22nd, 2009 AT 10:03 AM
Tiny
SCOVOL
  • MEMBER
  • 7 POSTS
It appears that the relay you refer to last was for when you don't have a starter-mounted solenoid as I do (if I'm not correct then it appears to have been removed from the firewall). According to the Ford manual, there should be continuity between the M&S terminals on the starter solenoid. I don't seem to have that - it is difficult to get hooked up in there but I'm not seeing continuity there. Perhaps I should take the starter out again if it can be bench-tested and see if the solenoid is functional?
Was this
answer
helpful?
Yes
No
Thursday, October 22nd, 2009 AT 6:31 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok I seems that you don't have the firewall mounted solenoid. I checked my Fords and My 95 F-150 has the firewall mounted and the starter mounted solenoid. Now my 98 Mustang does not have the firewall mounted. So next thing to look at is the starter relay in the relay box that is under the hood on the left (drivers) side near the strut tower. Now what needs to be checked is that the yellow wire to the relay has constant battery power. Then check the white wire with the pink strip make sure it is getting power when you try to start it. If it don't then I need you to check the clutch switch as I have previously instructed. You will have to use your owners manual to tell you which relay is which. Let me know what you find.
Was this
answer
helpful?
Yes
No
Friday, October 23rd, 2009 AT 10:27 AM
Tiny
SCOVOL
  • MEMBER
  • 7 POSTS
Your support has been absolutely stellar! Despite favorable starter testing results at the auto parts store, the starter solenoid was not functioning properly which was causing a substantial voltage drop and drain on the battery and took down the oil pressure gauge too. I put a new starter in and it fired right up. This is an awesome service. Can you tell me where 155 psig compression test results fit for the motor in this car - approximately? I can't seem to find a straight answer anywhere. It is pretty even +/- 5 psi for all eight.
Was this
answer
helpful?
Yes
No
Wednesday, October 28th, 2009 AT 11:46 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok with 155 psi you are good. Having 160-155 would be normal and within 5 psi difference is fine that is less then 10% so no worries there either. The engine is stock 9.0:1 just so you know. As for the starter great glad to hear it is fixed. If you need anymore help just ask. Thanks again and have a great day.
Was this
answer
helpful?
Yes
No
+1
Thursday, October 29th, 2009 AT 10:20 AM

Please login or register to post a reply.

Related Engine Not Cranking Over Content

Car Not Cranking? Try This | EASY
VIDEO
Car Not Cranking? Try This | EASY
Instructional repair video
Starter Not Working
GUIDE
Starter Not Working
This guide is designed to help you identify whether the issue with your non-working starter motor is due to an electrical problem or a fault within the starter motor itself...
VIEW MORE