‘93 Ranger 2.3 crank no start

[Mbtech]

I have a 93 ranger 2.3l that cranks but will not start. When you turn ignition on fuel pump comes on but will not shut off. When you crank it will keep cranking and fuel pump stays on. After so many times it will start. I have replaced ecm, ecm relay, diode, fuel pump relay. I cannot find reliable test to figure out why fuel pump will not shut off vehicle will start. Any help would be awesome. Thanks

 

[RonD]

Welcome to TRS


First do 50/50 test to see if fuel is the reason it won't start
Spray gasoline or Ether(quick start) into the engine, try to start it
If it starts up and then dies you do have a fuel issue
If it doesn't start then its a Spark issue
50/50 instant results

Have you had this 1993 Ranger for awhile or is it new to you and you are troubleshooting?
Because previous owner may have grounded fuel pump relay as a "fix"

The computer Grounds the Fuel pump relay as it boots up(key on) then unGrounds it after about 2 seconds, this is for safety reasons
Doesn't hurt that it stays on but yes that would mean there could be a computer problem
And a computer problem can cause no start or rough running

1993 Ranger will have an EEC-IV type of computer
Picture here: http://www.auto-diagnostics.info/ford_eec_iv

You can see the 3 BLUE capacitors on the circuit board...................these can leak after 20+ years and cause different issues, one being no fuel pump relay or always on fuel pump relay
But when that happens there are other issues

Computer is in engine bay driver side between firewall and inner fender
You may want to pull it out and take top off to see what circuit board looks like

 

[Mbtech]

Thanks for your response. A little more information, the truck will not start usually in mornings with heavy dew/moisture. By the afternoon starts, runs, and drives great.
When it will not start fuel pump keeps running with key on engine off. When fuel pump shuts off truck will start.
I know I’m getting spark on exhaust side, fuel pressure is 40psi at rail.
I have already relaxed pcm/ecm, both fuel pump relay and ecm relay, ignition module, both coils, air mass, tps, iac valve.
I know original owner, has never done anything for this issue. Sold to me because didn’t want to deal with it.
Will have to try ether tomorrow if it doesn’t start again.

 

[RonD]

Yes, do the 50/50 and see what that tells you, spark or fuel issue

testing spark and fuel pressure is all well and good but doesn't tell you much with a No Start

50/50 test tells you if there is spark and if its at the RIGHT time
Also tells you if fuel is making it into the engine or just at the injectors

 

[black_demon69]

Thanks for your response. A little more information, the truck will not start usually in mornings with heavy dew/moisture. By the afternoon starts, runs, and drives great.

Take a closer look at the coil pack for cracks or separation between plastic housing and epoxy sealant or any place water could get into the coil......

 

[wbrockstar]

I would also check the LB/O wire,between the fuel pump relay & ecu (pin 22) and the ecu (pin 22) & diagnostic port (where a scanner gets plugged in to extract codes) for a short to ground.The ecu controls the fuel pump relay by cycling its ground on/off.If the LB/O ground wire is shorted to the chassis somewhere between the points I listed above,the fuel pump relay will be on anytime the key is on instead of only when the ecu turns the relay ground on.The harness has to be disconnected from the ecu & the fuel pump relay in order to test this wire for ohms with a meter.It should read 5.0 ohms or less between the two pair of locations I mentioned above.If its higher than 5.0 ohms,the wire is shorted.

 

[Mbtech]

Welcome to TRS


First do 50/50 test to see if fuel is the reason it won't start
Spray gasoline or Ether(quick start) into the engine, try to start it
If it starts up and then dies you do have a fuel issue
If it doesn't start then its a Spark issue
50/50 instant results

Have you had this 1993 Ranger for awhile or is it new to you and you are troubleshooting?
Because previous owner may have grounded fuel pump relay as a "fix"

The computer Grounds the Fuel pump relay as it boots up(key on) then unGrounds it after about 2 seconds, this is for safety reasons
Doesn't hurt that it stays on but yes that would mean there could be a computer problem
And a computer problem can cause no start or rough running

1993 Ranger will have an EEC-IV type of computer
Picture here: http://www.auto-diagnostics.info/ford_eec_iv

You can see the 3 BLUE capacitors on the circuit board...................these can leak after 20+ years and cause different issues, one being no fuel pump relay or always on fuel pump relay
But when that happens there are other issues

Computer is in engine bay driver side between firewall and inner fender
You may want to pull it out and take top off to see what circuit board looks like

After 2 weeks the fault reoccurred. Truck cranks- no start. Fuel pump keeps running in key position 2, tried to start with ether. Started up and keeps running. Even after shutting off truck keeps starting with no issue.

 

[RonD]

Was it a warmer day when the fault reoccurred?

And how much time passed from when you shut it off and then got the Crank but No Start?

The ignition module would do that, get heat sensitive, so caused a no start when they would get heat soaked just after shut down on warmer days, they would cool off and work fine
When you shut off an engine the engine bay gets very hot very fast with no fan cooling it, engine block and head also heats up with no coolant circulation, so parts can get heat soaked
Ignition module on the 1993 is cooled direct by the fan

Maybe spark was just weak, ether has a lower ignition point than gasoline


And may its a computer fault, fuel pump running at 0 RPMs is not right, but I wouldn't expect a restart and continued running with ether added if computer had injectors off

It is a puzzler