Long start 1991 Ranger 3.0
Grandson 1991 Ranger 3.0 v6 69,000 miles We have a long start issue after it has sat for 30 mins. plus. If you open the throttle part way while cranking it will start fairly easily. Fuel pressure comes up instantly when you turn on the key. It runs at 39 psi pull the vac line off regulator it jumps to 49 psi. Fuel pressure does drop to about 30 psi after setting an hour. It kinda acts like it is flooded when it starts. so far we have done a complete tune up plugs wires cap and rotor. The ignition module has been replaced twice last one a real Motorcraft. New fuel pump and filter. Cleaned the fuel injectors with Ford cleaning system . Kinda running out of ideas. I will replace the coil next and maybe clean the iac. Any ideas would be appreciated.
Boy you've been busy on this one. With all of the things you've done, checking the usual suspects, it kinda sounds like a fuel injector with a runny nose, as you've noticed it acts like an over rich fuel condition on a restart & the psi leaks down in an hour. When you replaced the plugs, did you do a cyl plug read as you removed them???? Do you remember Any particular cyl spark plug looking more carbon fouled than the others???? If so, maybe pull that cyl fuel injector for inspection & or bench testing.
Any trouble codes set, or pending???? Did the problem come about suddenly after some event, or slowly over time????
More thoughts for consideration, let us know what you find.
Well i did a leak down test on the fuel rail only. Nothing jump out there held 90 psi for an hour. So i replaced the Fuel pump with a a new Bosh (man they are quite) thought I had fixed it. No such luck. Only codes are an 11 and 10 which means all is well checked the timing it is right on the money test the IAC it seems ro be working fine. My old sun analyzer says all the plugs are firing normally and it idles like a top. and will start right up if it doesn't set more than 30 mins. anything after that and you need to open the throttle to get it to start. No fuel in he FPR vacuum line. There is no egr on this truck. But what is the sensor on the intake just behind the egr block off plate.
OK, well lets think about this some more. It takes air, fuel, spark & compression to make em run, so what's going missing when it won't start after an hours hot shut down heat soak?????
Seeing as it'll start if you open the throttle a little, it sure sounds like its a fuel delivery problem of some sort.
SO, is the fuel old, such that it might be winter adjusted for a lower vapor pressure???? If so, it could be vapor locking after a hot shut down heat soak.
I've also heard of coilpacks & icm's offering up trouble with a wimpy spark after a heat soak.
Is the battery voltage up to snuff after a hot engine shut down heat soak???? Monitor it while your helper cranks the engine.
I have the code 10 as cyl 1 low on cyl balance test. So does cyl 1 have a compression problem????
Did the problem come about suddenly, after some event, or slowly over time????
Fuel is new. Havent owned truck very long. When i bought it it had an occasional miss that was a bad wire. Did complete tune up. then fuel pump quit replaced with one I had here at the house also installed new filter. Then Ignition module quit replaced that. Never have caught it with out spark using a spark tester. Replaced fuel pump with new Bosh unit it honestly acts lack it is losing fuel prime. Fuel rail pressure test didn't showed negligible pressure loss over an hour. I should have checked the pick up tube for a crack will do that next.
If you think its a fuel pressure bleeding off, next time it doesn't want to hot start, cycle the ignition switch from off to run 3-4 times, remaining each time at "on", long enough for the fuel pump to run for a couple of seconds & time out, Then go to start to crank the engine & see if it makes a difference in how it starts.
Are you certain the TPS resistance is within range when its hot & the throttle is closed???
Here is an update i installed new fuel injectors and put on a new motorcraft TPS. And I still have the problem. It runs good has good power cruises nice down the road. Starts fine cold. Starts fine after setting ten mins. Long hard start after 30 mins have to open throttle to get it to start. Here is the list of what has been done.
New Bosch fuel pump and filter.
New cap, rotor, wires and plugs. Timing is spot on.
New set fuel injectors
checked wiring harness connectors for corrosion
checked for vacuum leaks
Fuel pressure normal and doesn't leak off over a period of an hour.
plenty of fire from coil. When it does the long start it acts flooded
P.S. No codes
Anybody got any ideas. Only thing I can think of now is the distributor
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