Car Staalling after disconecting batery

[nero6]

Car Stalling after disconnecting battery

I have an 87 Mustang GT, just purchased a few weeks ago. It had a big autometer tachometer I was not a fan of so I decided to take it out. I disconected the battery and due to the way it was wired I had to take the gauge cluster out. While I had it apart I decied to clean it up a bit so I took off the plastic cover of the intrument panel and cleaned all of the gauge cluster which was a mess, in the process I did hit the oil pressue needle by accident, but it dropped back down to where it was before I hit it. I took out the wiring for the autometer tachometer, and re-connected the stock wiring where it was spliced for the autometer tachometer (one wire was spliced into a crane cam ignition coil).

I put everything back together and took it out for a drive. Drove for about 10 min and everything was fine. On my way back home coming to a stop, the oil pressure gauge drops down to almost 0, the amp light comes on, the low coolant light comes on, and check engine light comes on, then the car stalls. Start it back up and the oil pressure is reading very low. Same thing happens coming to the next stop sign except I kept it from stalling. Get it back home in the garage and shut it down. I check things out, disconnectd the oil pressure sending unit and connect it again and start the car up again. The idle is all over the place, surging up and down almost stalling each time. The oil pressure reads in the middle but also drops up and down with the idle.

I know the car has to 're-learn' after the battery is disconected but I had disconnected it before to install a stereo and had no issues after starting it up again. What are your toughts on the oild pressure, is it just to gauge or could I have an oil pressure issue? Is there anything else that would need to be done to re-set the idle after disconecting the battery? I do have underdrive pullies. My biggest fear is the oil pressure, any easy way to accurately check this? The engine was just rebuilt 5000km ago.

 

[jrichker]

Put a tee fitting on the oil pressure sender plumbing and use a mechanical gauge under the hood to check things out. The oil pressure sender is located down by the oil filter. You can get a cheap mechanical gauge from Home Depot or Lowes along with most of the fittings you will need to do the job.

Don't forget the gauge line restrictor anytime you install a mechanical gauge. It will save your engine if the tubing springs a leak like mine did...

See the "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[nero6]

looks like my idle issue corrected itself. Disconnected the battery again, re-connected it and let the car idle for 20min and it worked itself out. Oil pressure reads low but then again the gauge is all over the place, is there step by step instructions on how to install mechanical gauge?

 

[jrichker]

looks like my idle issue corrected itself. Disconnected the battery again, re-connected it and let the car idle for 20min and it worked itself out. Oil pressure reads low but then again the gauge is all over the place, is there step by step instructions on how to install mechanical gauge?

Mechanical oil pressure gauge installation.​

1.) Remove old pressure sender. It is located down by the oil filter and has 1 wire on a push on screw connector.
2.) Install ¼” pipe tee fitting with a short ¼” nipple on the place where you removed the oil pressure sender.
3.) Install the original oil pressure sender back in one of the tee ports.
4.) Install the gauge line restrictor in the remaining port of the tee.
5.) Connect the flex tubing or hydraulic hose to the gauge restrictor. Be sure to route the tubing or hose away from the exhaust manifolds. Be sure to either use hydraulic hose or oil and heat resistant flex tubing for the pressure line. Do not use copper tubing for the connection to the gauge restrictor or engine. Over a period of time, the vibration will work harden the tubing and cause it to crack and fail.
6.) If the gauge is going to mount under the hood, connect it to the end of the hose or flex tubing. Use some Tie-wraps to secure the gauge and its plumbing to the wiring harness on the driver’s side inner fender.
7.) If the gauge is going to mount in the passenger compartment you get to find a place to run the tubing through the firewall. I suggest that you pick your spot from the inside since that is the area with the most difficult access. Do not run the tubing through the exact same hole as the steering shaft. It will tangle up with the steering shaft and cause major problems.
8.) Install the gauge inside the car in the location of your choosing. Connect the pressure line to the gauge and secure it out of the way of moving parts with Tie-wraps.
9.) Be sure to ground the gauge lighting wire to clean, shiny bare metal. Connect the other wire from the gauge lighting to a light brown/red wire on the radio wiring harness. There are 2 connectors in the radio wiring harness, but only one of them has the light brown/red wire you need for gauge illumination. Solder the gauge lighting wire to the light brown/red wire on the radio harness and cover the soldered joint with heat shrink tubing.

How to solder like a pro - Ford Fuel Injection How To Solder Like a Pro a must read for any automotive wiring job.

 

[nero6]

Perfect. Thanks.