1998 F150 rough start, when engine is cold....
11-12-2017, 07:46 AM
#1
1998 F150 rough start, when engine is cold....
Hello,
It's an F150 from 1998 (V6) with about 60K miles, first and only owner. It runs well, don't have much issues with it, except at startup.
The first time starting it up results in a rough idling, similar to having just couple of cylinders working. The other cylinders may catch up and from that point on, the truck runs just fine.
On occasion, the other cylinders don't catch up and the engine stops. Most of the times starting it again, the engine starts up just fine. Other times, the engine still dies, but at third times starting it runs just fine. And again, from that point on the engine runs just fine, idles as it should, no loss of power, does not stall, etc.
It does not seem to matter, if the weather is cold or warm, the symptoms are the same. It is mostly dependent on how frequently the truck has been used. If the frequency is daily, the symptom may only show up in cold weather. If it had not been used for couple of days, the weather does not matter, the symptom shows up.
My guess is that this is related to the engine does not get enough fuel, when it's started. The fuel might just drain out of the fuel line, back to the tank, when the engine is shut off for a longer time period. There's no signs, smell or wet, around the truck indicating a leak. Seemingly, once the fuel pressure builds back up, the engine runs just fine. This may, or may not be the reason, but if it is...
Is there a "check-valve" somewhere in the fuel line that holds the pressure, when the engine is not running? If there's one, I hope that it is not in the fuel-pump...
TIA...
It's an F150 from 1998 (V6) with about 60K miles, first and only owner. It runs well, don't have much issues with it, except at startup.
The first time starting it up results in a rough idling, similar to having just couple of cylinders working. The other cylinders may catch up and from that point on, the truck runs just fine.
On occasion, the other cylinders don't catch up and the engine stops. Most of the times starting it again, the engine starts up just fine. Other times, the engine still dies, but at third times starting it runs just fine. And again, from that point on the engine runs just fine, idles as it should, no loss of power, does not stall, etc.
It does not seem to matter, if the weather is cold or warm, the symptoms are the same. It is mostly dependent on how frequently the truck has been used. If the frequency is daily, the symptom may only show up in cold weather. If it had not been used for couple of days, the weather does not matter, the symptom shows up.
My guess is that this is related to the engine does not get enough fuel, when it's started. The fuel might just drain out of the fuel line, back to the tank, when the engine is shut off for a longer time period. There's no signs, smell or wet, around the truck indicating a leak. Seemingly, once the fuel pressure builds back up, the engine runs just fine. This may, or may not be the reason, but if it is...
Is there a "check-valve" somewhere in the fuel line that holds the pressure, when the engine is not running? If there's one, I hope that it is not in the fuel-pump...
TIA...
11-12-2017, 07:54 AM
#2
'97 F150 V8 4.6L
60k on a '98? Impressive. Sounds fuel related, how's the filter? Plugs fouled? Wires deteriorate over time too, low miles doesn't insure they are up to snuff. You just gotta dig in.
The following users liked this post:
Cr00zng (11-12-2017)
11-12-2017, 08:32 AM
#5
It's hard to tell.... Actually.... On 06/01/11 had a complete tune-up at a repair shop that included the wires, spark-plugs, and fuel-filter. Thanks to my wife's record keeping...
Come to think of it, the reason for the tune-up six years ego was for similar symptom, the truck had hard time starting in the summer. After a dinner at an Italian restaurant, it would not start for about 10 minutes. The place was a fancy/snobbish restaurant and they didn't like my truck keeps cranking there...
I'll start with the wires and spark plugs. It shouldn't be hard to change them, right?
Come to think of it, the reason for the tune-up six years ego was for similar symptom, the truck had hard time starting in the summer. After a dinner at an Italian restaurant, it would not start for about 10 minutes. The place was a fancy/snobbish restaurant and they didn't like my truck keeps cranking there...
I'll start with the wires and spark plugs. It shouldn't be hard to change them, right?
11-12-2017, 08:48 AM
#6
Any recommendation for the wires and spark plugs? The latter ones don't need to have the gap adjusted, correct?
PS: I used to work on cars and my truck, changing stuff like starter, alternator, oil, filters and brake-job for disc and drum brakes. I've just got lazy and haven't done it for ten years or so...
PS: I used to work on cars and my truck, changing stuff like starter, alternator, oil, filters and brake-job for disc and drum brakes. I've just got lazy and haven't done it for ten years or so...
11-12-2017, 08:58 AM
#7
'97 F150 V8 4.6L
I don't know about the v6, on mine the back ones are when the fun kicks in. But doable with a little patience. You always want to check gaps, don't trust nobody. But if that fixed it before it would be a good start.
Trending Topics
11-12-2017, 09:16 AM
#8
With the V6, there's plenty of room for both the spark plugs and wires. AFAIK, it's just a a V8 engine, with two cylinder cut off...
What's the gap requirement for the spark plug?
What's the gap requirement for the spark plug?
12-09-2017, 09:43 AM
#9
It took some time, but got the new parts, spark plugs, wires and ignition coil. All of it ordered from Amazon, but returned the spark plugs. While they looked new, some of them were out of the box and rattled around in the box, just couldn't trust them.
Interestingly, getting the spark plugs from the local Ford dealer was about five bucks more for the set, than at Amazon.
The spark plug gap requirements are between 0.052 - 0.056 and it's stated on the label (emission/vacuum hose routing) over the radiator. All of the spark plugs had to be gapped to these specification, the new ones were around 0.040. Replacing them wasn't as easy as I anticipated, only the end of the plugs are visible. It's pretty much "feel your way around" for installing the new ones. Especially the ones in the back, against the firewall, had been a challenge. I am a tall guys, but had hard time reaching them from the top. The chances are that the spark plugs are easier to change from the bottom, if you have a lifter. At least you can see them...
The ignition coil has been easier. While the 9/32" socket could work, the actual size of the bolt is 7 mm. If the bolts are rusty, the 9/32" socket may round off the head of the bolt, instead of turning, use the 7 mm socket.
The front bolts are easy, plenty of room, but the rear one against the firewall are tricky. There's not much room, the 2" ratchet extension is too long and the 1" extension is too short. Flex socket, flex extension will help in the back. Other than that replacing the ignition coil was easy, just moved over the spark plug wires from the old one to new.
Replacing the spark plug wires one by one had been uneventful, except the ones in the back. They are hard to reach from the top.
The old ignition coil and even the spark plug wires looked just fine, but can't say the same about the spark plugs. While none of them looked fouled, some of them had the electrode melted. Just for the kick of it, measured some of the spark plug gaps. The first couple measured were less than 0.050 and that with about 20K miles on them. I guess the service shop that changed them last time did not change the factory gap of the new spark plugs. Argh...
The verification of having the work done right is starting up the engine, when finished. It fired up with no issues. The truck seems to run quiter at idle and over all, sounds better and more pleasant to drive. Maybe it's just me...
On the other hand, replacing all of the parts did not address the original start up issues in colder weather, especially when the truck parked on a slope overnight, front of the truck being at the higher elevation. It still dies at the first try, fires right up at the second time and runs just fine afterward.
The truck was in for fixing the power window at the Ford dealer and had a chance to discuss the cold start issue with the mechanic. He suspects that the fuel pump in the tank does not hold the pressure in the fuel line, it slowly releases back to the tank and there's air in the fuel line. Since there's no visible fuel leakage under/around the truck, this make sense had been suspected from the beginning. His advice was, "a" don't park on slopes for longer time period, "b" crank the engine twice to start, if you do. Since the fuel pump is still working fine, I'll goo with that...
And while replacing all of the ignition parts did not address the original issue, I am still glad that I've replaced all of the parts...
Interestingly, getting the spark plugs from the local Ford dealer was about five bucks more for the set, than at Amazon.
The spark plug gap requirements are between 0.052 - 0.056 and it's stated on the label (emission/vacuum hose routing) over the radiator. All of the spark plugs had to be gapped to these specification, the new ones were around 0.040. Replacing them wasn't as easy as I anticipated, only the end of the plugs are visible. It's pretty much "feel your way around" for installing the new ones. Especially the ones in the back, against the firewall, had been a challenge. I am a tall guys, but had hard time reaching them from the top. The chances are that the spark plugs are easier to change from the bottom, if you have a lifter. At least you can see them...
The ignition coil has been easier. While the 9/32" socket could work, the actual size of the bolt is 7 mm. If the bolts are rusty, the 9/32" socket may round off the head of the bolt, instead of turning, use the 7 mm socket.
The front bolts are easy, plenty of room, but the rear one against the firewall are tricky. There's not much room, the 2" ratchet extension is too long and the 1" extension is too short. Flex socket, flex extension will help in the back. Other than that replacing the ignition coil was easy, just moved over the spark plug wires from the old one to new.
Replacing the spark plug wires one by one had been uneventful, except the ones in the back. They are hard to reach from the top.
The old ignition coil and even the spark plug wires looked just fine, but can't say the same about the spark plugs. While none of them looked fouled, some of them had the electrode melted. Just for the kick of it, measured some of the spark plug gaps. The first couple measured were less than 0.050 and that with about 20K miles on them. I guess the service shop that changed them last time did not change the factory gap of the new spark plugs. Argh...
The verification of having the work done right is starting up the engine, when finished. It fired up with no issues. The truck seems to run quiter at idle and over all, sounds better and more pleasant to drive. Maybe it's just me...
On the other hand, replacing all of the parts did not address the original start up issues in colder weather, especially when the truck parked on a slope overnight, front of the truck being at the higher elevation. It still dies at the first try, fires right up at the second time and runs just fine afterward.
The truck was in for fixing the power window at the Ford dealer and had a chance to discuss the cold start issue with the mechanic. He suspects that the fuel pump in the tank does not hold the pressure in the fuel line, it slowly releases back to the tank and there's air in the fuel line. Since there's no visible fuel leakage under/around the truck, this make sense had been suspected from the beginning. His advice was, "a" don't park on slopes for longer time period, "b" crank the engine twice to start, if you do. Since the fuel pump is still working fine, I'll goo with that...
And while replacing all of the ignition parts did not address the original issue, I am still glad that I've replaced all of the parts...
