1996 F-150 cold start problem
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1996 F-150 cold start problem
I noticed ,this spring, my 96 F-150,auto,302 was starting a bit harder than normal.Then last week I changed my fuel tank and everyday it seems to be getting worse.From what I can tell the truck is losing its prime.
When the tank was first changed it was a cold start problem and after that the truck started fine for the rest of the day but as a few days have pasted I notice now that after a few hours of sitting the truck is hard to start.Would this be a fuel pump or maybe injectors?
I am the only owner of this truck,this is the 2nd time I have had to change tanks and I can't remember replacing the fuel pump.Strange thing is on the highway it works fine.
Next week I am scheduled for a pressure test to try and further diagnose what is happening but I thought I would post to see what you guys think is wrong.
A few other notes:
Last night night I parked the truck on a down hill slope and this morning it actually started alot easier.
If I apply a little throttle when starting the truck starts easy.
When the tank was first changed it was a cold start problem and after that the truck started fine for the rest of the day but as a few days have pasted I notice now that after a few hours of sitting the truck is hard to start.Would this be a fuel pump or maybe injectors?
I am the only owner of this truck,this is the 2nd time I have had to change tanks and I can't remember replacing the fuel pump.Strange thing is on the highway it works fine.
Next week I am scheduled for a pressure test to try and further diagnose what is happening but I thought I would post to see what you guys think is wrong.
A few other notes:
Last night night I parked the truck on a down hill slope and this morning it actually started alot easier.
If I apply a little throttle when starting the truck starts easy.
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cold start
I have an 87 5.0 efi and have had the idle air bypass valve to stick and cause cold start. Cleaning the valve would help a while but finally i just got so I change it at the first sign of slow starting on a cool morning or cool day about 65 F. I just bought one today and will install it in the morning. It fails gradually. on a cool morning it will be hard/slow to start but as the day warms up it will start fine. Sometimes holding down the gas pedal will help. you may notice rough idle or surging idle or engine dies when you let off the gas. It seems like I have to replace mine about every 2 to 3 years. the original lasted about 5, so i have replaced several over the past 22+ years ive had the truck
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From: Easton,Ks
Sounds like you have a bad check valve inside one of the Fuel Delivery Module inside the fuel tank.
If you have two tanks then it would be in the tank that fills while running on the other tank.
With the truck headed down hill the fuel is not running back into the tanks at night.
This would eliminate the Fuel Injectors and why it started right up.
If you turn your key on and off about three or four times before you try to start it it should start right up after it has been setting. This would confirm the bad check valve.
If you have two tanks then it would be in the tank that fills while running on the other tank.
With the truck headed down hill the fuel is not running back into the tanks at night.
This would eliminate the Fuel Injectors and why it started right up.
If you turn your key on and off about three or four times before you try to start it it should start right up after it has been setting. This would confirm the bad check valve.
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1996 f-150 cold start
SubFord and Greedy up until today changing the idle air bypass valve worked for me. So your suggestion about the in tank fuel pump assembly check valve might just be the ticket for Greedy. A new IAV didnt do it for me today. It starts ok it just seems to surge and almost die when I let off the gas or it idles a little erratic. Fuel pressure was 34 psi and with the engine off would hold pressure for several minutes but would eventually drop to zero after an hour or so. I thought you might be a little off with the uphill downhill thing. But when I looked at the level of the tank and the level of the injectors and the distance beween them, if the hill is steep enough it would keep the line between the tank and engine primed. Just eye balling and depending on one tank or two short or long wheel base a drop of 1 foot for 8 to 12 feet would keep the line primed.
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Sounds like you have a bad check valve inside one of the Fuel Delivery Module inside the fuel tank.
If you have two tanks then it would be in the tank that fills while running on the other tank.
With the truck headed down hill the fuel is not running back into the tanks at night.
This would eliminate the Fuel Injectors and why it started right up.
If you turn your key on and off about three or four times before you try to start it it should start right up after it has been setting. This would confirm the bad check valve.
If you have two tanks then it would be in the tank that fills while running on the other tank.
With the truck headed down hill the fuel is not running back into the tanks at night.
This would eliminate the Fuel Injectors and why it started right up.
If you turn your key on and off about three or four times before you try to start it it should start right up after it has been setting. This would confirm the bad check valve.
Does that check valve come on a new pump or is that something else that needs to be ordered?
Fuel pressure check tomorrow afternoon.
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Fleet Owner
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From: Easton,Ks
Mine is a single tank,short wheel base.Tank aft rear end.This morning when I started up ,after sitting 2 days,it was not pretty,several attempts made(I didn't do anything to help it out) but again when it starts it idles and runs fine.
Does that check valve come on a new pump or is that something else that needs to be ordered?
Fuel pressure check tomorrow afternoon.
Does that check valve come on a new pump or is that something else that needs to be ordered?
Fuel pressure check tomorrow afternoon.
Did you try turning the key on and off about four times before you tried to start it?
The FDM (Fuel Delivery Module):
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1996 f150 cold start
Subford you stated "Sounds like you have a bad check valve inside one of the Fuel Delivery Module inside the fuel tank. If you have two tanks then it would be in the tank that fills while running on the other tank."
On a 2 tank model I thought the tank that was selected got the return flow. or am i misunderstanding what you are saying. I thought the tank selector valve blocked flow or drain back to the other tank. wouldnt the not selected tank over flow if both were full?
On a 2 tank model I thought the tank that was selected got the return flow. or am i misunderstanding what you are saying. I thought the tank selector valve blocked flow or drain back to the other tank. wouldnt the not selected tank over flow if both were full?
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Subford you stated "Sounds like you have a bad check valve inside one of the Fuel Delivery Module inside the fuel tank. If you have two tanks then it would be in the tank that fills while running on the other tank."
On a 2 tank model I thought the tank that was selected got the return flow.
On a 2 tank model I thought the tank that was selected got the return flow.
You are filling the tank that is not selected by the pressure line and into it by way of the bad check valve.
Yes it would if it can get passed the check valve in the fuel cap.
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From: Easton,Ks
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[quote=subford;7908675]It comes with the new pump that is inside the FDM (Fuel Delivery Module).
Did you try turning the key on and off about four times before you tried to start it?
Not 4 or 5 times,the most I tried it is twice but after sitting overnight tonight I'll try it but I'm betting the check valve is the trouble.
A friend told me I better put a new fuel pump in when I change the tank as he has had that happen to him before.Live and learn.
Did you try turning the key on and off about four times before you tried to start it?
Not 4 or 5 times,the most I tried it is twice but after sitting overnight tonight I'll try it but I'm betting the check valve is the trouble.
A friend told me I better put a new fuel pump in when I change the tank as he has had that happen to him before.Live and learn.
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Fuel pressure check showed 32 psi on idle,36 on throttle and after 20 minutes of sitting it went to 26psi and within the same amount of time to 16 psi so i ordered the new fuel pump.Not gonna frig with after market pumps,I'm going with the motorcraft pump.
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I thought I would post to close out this thread, after much cranking this month the starter seized(original) and after changing the fuel pump the ole 96 F-150 is starting like a new truck.I also swapped out my original rims(rusty) for factory Ford rims in almost mint condition and the truck rides like it is new again(no vibiration).
I want to thank all the people who participated in this thread as the advice you guys gave made it easy to diagnose and get the problem fixed.
I want to thank all the people who participated in this thread as the advice you guys gave made it easy to diagnose and get the problem fixed.