wont start when warm
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New User
Joined: Dec 2007
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hmmm, update on my problem. gotta test it some more tho. i tried for about 10-15 minutes to start it with no luck. maybe its coincidence, but i popped the hood and opened up the air intake and it started right up. the filter looks nice and clean. seems like it wasnt getting good air flow. i push down the gas pedal and it would try to start at least. maybe it was trying to start because it was opening up the throttle plate for a little more air flow? i see the mass air goes into the bottom of the intake tube. whats the other set of wires for? some kind of temp sensor? seems when its hot it wont start. maybe thats my problem. i have no idea. next time it wont start im gonna try and pull the intake apart again.
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Personally I don't believe in coincidence. If it'll start with the air box open, it may be the MAF sensor may be causing something funky in the PCM thus stopping it from starting until it cools. But that doesn't explain the other codes or the lack of them from the MAF. But then again the other codes may not have anything to do with it. Try cleaning the MAF and report back with the results.
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From: Denmark,WI
Freshman User
Joined: Sep 2010
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new here but have worked on cars my whole life, how about the iac valve? you 304 code could be a loose plug wire or improperly gapped plug. i know i know the guy at the parts counter guy/gal says "there pre-gapped" BS...they get shipped dropped and everything else, always double check em. i would look more to your iat sensor, with it messuring the outside air coming and it malfunctioning it can be confusing the crap out of your computer, thirdly how about a fuel filter?
Senior User
Joined: Oct 2008
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From: Denmark,WI
new here but have worked on cars my whole life, how about the iac valve? you 304 code could be a loose plug wire or improperly gapped plug. i know i know the guy at the parts counter guy/gal says "there pre-gapped" BS...they get shipped dropped and everything else, always double check em. i would look more to your iat sensor, with it messuring the outside air coming and it malfunctioning it can be confusing the crap out of your computer, thirdly how about a fuel filter?
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Buy another 1 and install it, umm check the repair manual it should give you tips on how to with and ohm meter
Fleet Mechanic
Joined: Feb 2007
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From: Boston, MA
ok so you don't have any codes right? you have a new iacv, you have a new fuel filter. you need to cycle the key a few times to get it going.....right? I doubt very much it is the iat sensor. a dirty air filter can cause this issue. I also would clean the maf . then remove the neg bat term for a while to reboot the ecu.....a funky ect sensor can cause this issue also..You also might want to plan on doing a fuel pressure test.
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Senior User
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From: Denmark,WI
ok so you don't have any codes right? you have a new iacv, you have a new fuel filter. you need to cycle the key a few times to get it going.....right? I doubt very much it is the iat sensor. a dirty air filter can cause this issue. I also would clean the maf . then remove the neg bat term for a while to reboot the ecu.....a funky ect sensor can cause this issue also..You also might want to plan on doing a fuel pressure test.
Fleet Mechanic
Joined: Feb 2007
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From: Boston, MA
egr valves don't fail very often. they do get dirty though. if that was my truck I would finsh the tuneup including cleaning MAF, TB, PCV, EGR, I would then do a fuel pressure test , and add a large bottle of Techron to the tank......also if you have a scanner of any kind I would try and catch a pending code
Senior User
Joined: Oct 2008
Posts: 276
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From: Denmark,WI
egr valves don't fail very often. they do get dirty though. if that was my truck I would finsh the tuneup including cleaning MAF, TB, PCV, EGR, I would then do a fuel pressure test , and add a large bottle of Techron to the tank......also if you have a scanner of any kind I would try and catch a pending code
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Joined: Dec 2016
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Fixed my problem
Mine would start cold, but not when warm. It was the Air Filter!!!!
Here's how I figured it out:
It had to be either the Fuel Pump, throttle body, mass air flow sensor, timing belt, O2 sensor, cam phaser, fuel injectors, spark plugs, fuel filter, or battery/cables.
I checked the battery with a multimeter and it dipped below 10 volts while cranking. So I bought a new battery.
Still hard cranking
So, i unplugged the MAF sensor next to the Air Filter box and tried to crank it. Still hard to crank. I plugged it back in and took off the air intake hose going to the air filter and it started working a lot better but the engine would die and i would get a wrench symbol on the dash with a error code of P1719. I put everything back together, hard started, drove straight to autozone and bought and air filter am BAM!@#$ CRANKED RIGHT UP EVER SINCE.
I was going to buy a MAF sensor next while at AutoZone, then next have them test the fuel pressure while turned off. But no need. $20 FIX
Hope this helps someone. GL
Here's how I figured it out:
It had to be either the Fuel Pump, throttle body, mass air flow sensor, timing belt, O2 sensor, cam phaser, fuel injectors, spark plugs, fuel filter, or battery/cables.
I checked the battery with a multimeter and it dipped below 10 volts while cranking. So I bought a new battery.
Still hard cranking
So, i unplugged the MAF sensor next to the Air Filter box and tried to crank it. Still hard to crank. I plugged it back in and took off the air intake hose going to the air filter and it started working a lot better but the engine would die and i would get a wrench symbol on the dash with a error code of P1719. I put everything back together, hard started, drove straight to autozone and bought and air filter am BAM!@#$ CRANKED RIGHT UP EVER SINCE.
I was going to buy a MAF sensor next while at AutoZone, then next have them test the fuel pressure while turned off. But no need. $20 FIX
Hope this helps someone. GL
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Joined: Apr 2020
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my 97 f-150 starts up every time.........the first time. after i drive for awhile and shut it off it gives me a hard time starting. it just cranks over but wont start. if i give it gas it catches and tries to start but dies out right away after i let go of the key. sometimes after up to 10 tries and 20 minutes later it starts up again, so far! any ideas? also there is a gas smell, but im thinking thats because of putting the gas pedal to the floor. could it be plugs? i bought it with 180,000 miles on it. i pulled a plug and it does look pretty rough so i am going to change em tomorrow.
the parts store calls out iridium plugs. the guy told me any plugs will work. said the only difference is the mileage you get out of em.
50,000 on regular plugs
100,000 on platinum
150,000 on iridium
not sure thats the case but i bought platinums. i had my 20.00 credit @ autozone so they only cost me 6 bucks
i changed the plugs and wires and it runs great now. stopped for gas yesterday and still had to put the pedal to the floor for it to start. only one try and it started tho...... what next?<!-- / message -->
the parts store calls out iridium plugs. the guy told me any plugs will work. said the only difference is the mileage you get out of em.
50,000 on regular plugs
100,000 on platinum
150,000 on iridium
not sure thats the case but i bought platinums. i had my 20.00 credit @ autozone so they only cost me 6 bucks
i changed the plugs and wires and it runs great now. stopped for gas yesterday and still had to put the pedal to the floor for it to start. only one try and it started tho...... what next?<!-- / message -->
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The_Drew
1987 - 1996 F150 & Larger F-Series Trucks
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Jul 3, 2017 09:29 AM
