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Old 05-21-2018, 05:47 PM
whitakerjii whitakerjii is offline
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Default Hard to start 1991 4.0L

I have a 91 Ranger with the 4.0L. Completely rebuilt the fuel system. New pump, new filter, new filler neck, new lines, new fuel relay. I have fuel pressure at the rail at all times when the ignition is in the run position. The truck is difficult to start when it has been sitting overnight. It literally takes 15-20 cycles of the key and cranking for 2-3 seconds before it will finally start. Once it starts, it runs great, no hesitation, good power, normal fuel economy. I replaced the original Mass Airflow Sensor and housing hoping that would be the ticket. No dice, I have the same symptoms as before. Any idea where to look from here? I have checked for a vacuum leak from the FPR but didn't find one. I'm stumped.
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Old 05-22-2018, 09:42 AM
crowdpleazer crowdpleazer is offline
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Default Re: Hard to start 1991 4.0L

How are the injectors?
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1998 ranger extended cab, 2wd, 4.0 ohv, 5 speed, sony xploid 52 4 way watt radio, 2 pair of pioneer 240 watt speakers, Cobra 29 LX LCD CB radio pushing 100 watts, k&n air filter, 15 inch exploder wheels, dual exhaust with 4 inch stainless tips, 2 12 inch subs with a 1000 watt amp just for the hell of it!

new project: dirt track modified racing at the local saturday night track.
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Old 05-22-2018, 10:03 PM
whitakerjii whitakerjii is offline
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Default Re: Hard to start 1991 4.0L

Interesting that you mention that. Back story on the truck was that it sat for 7 years after the previous owner passed away. When I purchased the truck the son said it ran about 6 months prior. That was not the truth. I ended up pulling the bed off, completely cleaning the fuel tank which had fuel that was basically varnish. I removed the fuel rail and high pressure cleaned it, replaced the check valve and replaced everything up to that point. The only thing that leads me to think that the injectors aren't the problem, is that once the truck starts, there is no hesitation, no rough idle, and no mpg loss. Any suggestions?
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Old 05-23-2018, 09:19 AM
crowdpleazer crowdpleazer is offline
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Default Re: Hard to start 1991 4.0L

If it takes 15-20 cycles of the key to get it to start, that sounds like a bad relay or lazy/gummed up injectors. That is pretty odd though. I guess start testing relays.
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1998 ranger extended cab, 2wd, 4.0 ohv, 5 speed, sony xploid 52 4 way watt radio, 2 pair of pioneer 240 watt speakers, Cobra 29 LX LCD CB radio pushing 100 watts, k&n air filter, 15 inch exploder wheels, dual exhaust with 4 inch stainless tips, 2 12 inch subs with a 1000 watt amp just for the hell of it!

new project: dirt track modified racing at the local saturday night track.
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Old 05-23-2018, 01:52 PM
roscoe 0202 roscoe 0202 is online now
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Default Re: Hard to start 1991 4.0L

have you looked at the pressure regulator
roscoe
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hi newb here truck 94 b4000 mazda aka ranger
truck is stock just runaround
have project bronco II
i'm 74 and retired
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Old 05-23-2018, 06:39 PM
whitakerjii whitakerjii is offline
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Default Re: Hard to start 1991 4.0L

I've only checked the vacuum lines. But I did test smell the oil dipstick for fuel, didn't detect any, do you think the FPR could still be bad?
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Old 05-26-2018, 10:26 AM
whitakerjii whitakerjii is offline
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Default Re: Hard to start 1991 4.0L

Update! Started smelling strong fuel coming from somewhere. Put key in the run position and found the FPR was leaking from the O ring going into the fuel rail. Decided to err on the side of caution and replaced the whole unit, not just the O ring, and the problem is solved. Truck starts first time, every time. Hopefully this thread will help someone with a similar set of symptoms. Until the next mechanical failure, everyone take care!
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