geoffriehl
Member
well, not so much a hard start it will die at idle some times
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92 Ranger, int hard start when cold
- Thread starter geoffriehl
- Start date
AgPete139
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- Aug 12, 2007
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- City
- Houston, TX
- Vehicle Year
- 1997
- Engine
- 4.0 V6
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- Manual
- Total Lift
- ~9"
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- 35"x12.50"x17"
When was the last time you did any routine maintenance on it? It actually sounds fuel / air related.
geoffriehl
Member
normal
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Fuel pressure regulator will have a vacuum line attached, pull it off and smell it for gas, or see if gas drips out, if so then diaphragm has a leak, replace it.
Ford uses a fuel prime system, this turns on the fuel pump for 1 or 2 seconds each time the key is turned on.
If you think low fuel pressure is the problem, then turn the key on(count to 2), then off, then on, then off, then on, so 3 times "priming the system" before starting, if engine starts better then low pressure at the rail could be the problem.
I would pull a few spark plugs and see what they tell you, also pull the distributor cap and look at the underside of it and the rotor for signs of corrosion or arcing.
You could have a spark issue.
I think the '92 3.0l used the MAF(mass air flow) sensor, these sense the air flow and adjust the fuel accordingly, they get dirty and tend to cause missing and bogging(power loss).
This is a general guide for cleaning them:
http://www.therangerstation.com/tech_library/CleanMAF.html
The MAF sensor is located either at the intake or air filter end of the air plenum.
There is also an ECT(engine coolant temp) sensor on all fuel injected engines, this is not the same sensor used for the dash board temp gauge.
The ECT tells the computer(PCM) the temp of the engine, this sensor is the "Choke" for a fuel injected engine.
When ECT is cold the PCM runs engine rich with advanced timing, just like a choke did on a carb.
As ECT warms up PCM starts leaning out fuel and returns timing to normal, then the O2 sensors take over.
A failed ECT would usually turn on the CEL, but not always.
The ECT is a resistance sensor so can be tested with an OHM meter, look here: http://oldfuelinjection.com/?p=28
ECT sensors rarely fail, not never, but rarely.
Dash board temp sensor is a 1 wire sender, ECT is a 2 wire sensor, they are usually located next to each other, by the T-stat housing
Ford uses a fuel prime system, this turns on the fuel pump for 1 or 2 seconds each time the key is turned on.
If you think low fuel pressure is the problem, then turn the key on(count to 2), then off, then on, then off, then on, so 3 times "priming the system" before starting, if engine starts better then low pressure at the rail could be the problem.
I would pull a few spark plugs and see what they tell you, also pull the distributor cap and look at the underside of it and the rotor for signs of corrosion or arcing.
You could have a spark issue.
I think the '92 3.0l used the MAF(mass air flow) sensor, these sense the air flow and adjust the fuel accordingly, they get dirty and tend to cause missing and bogging(power loss).
This is a general guide for cleaning them:
http://www.therangerstation.com/tech_library/CleanMAF.html
The MAF sensor is located either at the intake or air filter end of the air plenum.
There is also an ECT(engine coolant temp) sensor on all fuel injected engines, this is not the same sensor used for the dash board temp gauge.
The ECT tells the computer(PCM) the temp of the engine, this sensor is the "Choke" for a fuel injected engine.
When ECT is cold the PCM runs engine rich with advanced timing, just like a choke did on a carb.
As ECT warms up PCM starts leaning out fuel and returns timing to normal, then the O2 sensors take over.
A failed ECT would usually turn on the CEL, but not always.
The ECT is a resistance sensor so can be tested with an OHM meter, look here: http://oldfuelinjection.com/?p=28
ECT sensors rarely fail, not never, but rarely.
Dash board temp sensor is a 1 wire sender, ECT is a 2 wire sensor, they are usually located next to each other, by the T-stat housing
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geoffriehl
Member
All good things to check......
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geoffriehl
Member
hey Ron, thanks for the information!
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What you are describing sounds EXACTLY like a failed fuel pressure regulator. I think Ron already hit the nail on the head. Next time you shut it off, pull the vacuum line off the top. Let it sit for a couple minutes, and I bet gas starts coming out the port on the regulator. If it does, that puppy is shot.
geoffriehl
Member
How long should I let it run for? Take off the vacuum line and if I get fuel coming out of the upper nipple its shot?
geoffriehl
Member
So I went to the truck, cranked it...started right up...pulled the vacuum line off...no fuel and good vacuum pulling on the line...no fuel came out of it....but how long should it run for before I should see fuel?
Inside the FPR(Fuel pressure regulator) is a rubber diaphragm the engine vacuum pulls the diaphragm open sending fuel back to the gas tank when engine is idling and doesn't need as much fuel, at higher RPM vacuum is less so diaphragm closes a bit and keeps more fuel(pressure) in the fuel rail.
If it was leaking you would see it and smell it pretty quick, 30psi of pressure in there.
Think of a car tire with 30psi and a hole in it, your would notice that leak pretty darn quick if you were standing right next to it
When you pulled the vacuum line off the FPR with engine running, idle should have gone up and then come down a bit, the down a bit was the computer closing the IAC(idle air control) which means that is working.
The IAC can get dirty and stick a bit, it is easy to clean, it usually looks like a cylinder bolted to the side of the upper intake, with an electrical connector.
It is, in essence, a controlled vacuum leak, so if it gets dirty the idle can go up and down, but don't think this would cause a no start.
Try turning the key on and off 3 times before starting, count to 3 each time key is on, this triple primes the fuel rail, if it starts every time you do this then you do have a fuel pressure issue.
If you still get the no start now and then, then could be spark or MAF(air flow sensor)
And I would test the ECT sensor just to eliminate it.
Fuel gauge not working sometimes could be an intermittent ground and that could effect the fuel pump, so it may be intermittent as well.
This is a wiring diagram the shows the gauge and fuel pump share the same ground point, Black wire for pump and Orange wire for gauge, I would trace those back from the tank and check that ground.
http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_Enginecontrols4_0_3_0_1of3.JPG
It's a pain, but free.........I would loosen and re-tighten any grounds you see, in the engine bay, under the dash and along the drivers side frame rail.
There is usually a ground strap from the back of the head to the firewall, this is often forgotten during re-assemby, check for it and make sure it's clean and tight on both ends.
The computer uses the grounds to control just about everything, the fuel injectors all have 12v when key is on, the computer grounds them to fire them.
The fuel pump relay has 12v when key is on, the computer grounds the relay to turn on the pump.
The coil has 12v when key is on, ground is used to make it spark.
If it was leaking you would see it and smell it pretty quick, 30psi of pressure in there.
Think of a car tire with 30psi and a hole in it, your would notice that leak pretty darn quick if you were standing right next to it
When you pulled the vacuum line off the FPR with engine running, idle should have gone up and then come down a bit, the down a bit was the computer closing the IAC(idle air control) which means that is working.
The IAC can get dirty and stick a bit, it is easy to clean, it usually looks like a cylinder bolted to the side of the upper intake, with an electrical connector.
It is, in essence, a controlled vacuum leak, so if it gets dirty the idle can go up and down, but don't think this would cause a no start.
Try turning the key on and off 3 times before starting, count to 3 each time key is on, this triple primes the fuel rail, if it starts every time you do this then you do have a fuel pressure issue.
If you still get the no start now and then, then could be spark or MAF(air flow sensor)
And I would test the ECT sensor just to eliminate it.
Fuel gauge not working sometimes could be an intermittent ground and that could effect the fuel pump, so it may be intermittent as well.
This is a wiring diagram the shows the gauge and fuel pump share the same ground point, Black wire for pump and Orange wire for gauge, I would trace those back from the tank and check that ground.
http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_Enginecontrols4_0_3_0_1of3.JPG
It's a pain, but free.........I would loosen and re-tighten any grounds you see, in the engine bay, under the dash and along the drivers side frame rail.
There is usually a ground strap from the back of the head to the firewall, this is often forgotten during re-assemby, check for it and make sure it's clean and tight on both ends.
The computer uses the grounds to control just about everything, the fuel injectors all have 12v when key is on, the computer grounds them to fire them.
The fuel pump relay has 12v when key is on, the computer grounds the relay to turn on the pump.
The coil has 12v when key is on, ground is used to make it spark.
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geoffriehl
Member
ok cool, I think we are getting somewhere,
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I would recommend a new OEM fuel pump replacement, I know it's not my money, lol.
There have been more than a few reports of cheaper pumps failing within a few months, and a wrecking yard pump......well if it's OEM maybe, but weigh that against the time and effort to remove the tank.
Another heads up since the tank will be out, there is a "net/screen" in the tank to prevent debris from getting sucked into the fuel pump, these can get clogged up.
There have been more than a few reports of cheaper pumps failing within a few months, and a wrecking yard pump......well if it's OEM maybe, but weigh that against the time and effort to remove the tank.
Another heads up since the tank will be out, there is a "net/screen" in the tank to prevent debris from getting sucked into the fuel pump, these can get clogged up.
- Joined
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I had an issue with my b-ii running like crap but sometimes OK. It turned out the previous owner replaced the fuel pump but didn't use fuel rated hose to connect the pump to the line in tank. It cracked so I was losing pressure. I doubt that is your problem but is another maybe to check for.
Richard
Richard
geoffriehl
Member
Yea....I know..save a buck and spend 10.....I'm going to take it out and ck it out and report back!
geoffriehl
Member
ok, so...the plot thickens....
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