Surging and jerking 50 to 60 mph
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From: Live Oak, TX
Surging and jerking 50 to 60 mph
Posted this in the drivetrain because I first thought it was a transmission issue. I don't think it is now!
My 1998 with 2.5 and auto just started to jerk and surge at about 50 to 60 mph. About the time it goes into OD but it will do it in drive as well. Never in 1st or 2nd. It will do it nearly every time. Sometimes it does it several times and then others it will do it 2 or 3 times as it it speeding up. Above 60 and below 50 it is perfectly normal. No loss of power, no CEL, and still gets 20-22 mpg.The surging and jerking is very quick. It appears to drop the RPM but it happens fast so hard to tell by how much. Yesterday driving home it did it A LOT! But today driving into work it did not do it at all. It ran perfect. I have gotten the P0301 cylinder 1 misfire code but ONLY when warming up after first start. NEVER gotten the code when the issue is happening. It does feel like an engine issue. This started out of the blue about 2 weeks ago now. Before the issue started I had replaced a 4 injectors, TPS, IAC, fuel filter, one coil pack, cleaned the MAF and EGR. Plugs look good and wires are fairly new. (Replaced before I bought the truck) The truck has been running very good for several weeks.
My 1998 with 2.5 and auto just started to jerk and surge at about 50 to 60 mph. About the time it goes into OD but it will do it in drive as well. Never in 1st or 2nd. It will do it nearly every time. Sometimes it does it several times and then others it will do it 2 or 3 times as it it speeding up. Above 60 and below 50 it is perfectly normal. No loss of power, no CEL, and still gets 20-22 mpg.The surging and jerking is very quick. It appears to drop the RPM but it happens fast so hard to tell by how much. Yesterday driving home it did it A LOT! But today driving into work it did not do it at all. It ran perfect. I have gotten the P0301 cylinder 1 misfire code but ONLY when warming up after first start. NEVER gotten the code when the issue is happening. It does feel like an engine issue. This started out of the blue about 2 weeks ago now. Before the issue started I had replaced a 4 injectors, TPS, IAC, fuel filter, one coil pack, cleaned the MAF and EGR. Plugs look good and wires are fairly new. (Replaced before I bought the truck) The truck has been running very good for several weeks.
Unplug the TPS and see if it does it, there will be a hesitation when accelerating with no TPS and CEL will come on, you are testing if TPS has a dead spot
Anything thats "new" is suspect, new means NEVER TESTED
Or you can swap back the old "tested" TPS
Clean MAF again
Anything thats "new" is suspect, new means NEVER TESTED
Or you can swap back the old "tested" TPS
Clean MAF again
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From: Live Oak, TX
OK I'll try that today on the way home. And I can clean the MAF again today.
I've read about recessed valves but not sure if this would be that. Some days like this morning it ran great with no issues at all. I think a recessed valve would be all the time. At least I hope that is not my issue!!
I've read about recessed valves but not sure if this would be that. Some days like this morning it ran great with no issues at all. I think a recessed valve would be all the time. At least I hope that is not my issue!!
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From: Live Oak, TX
I did a compression test today
Dry Test Wet Test
1 130 / 180
2 145 / 205
3 155 / 200
4 155 / 210
I didn't expect the wet test number to go up that much (more than 10%) but I may have put more than a tea spoon amount of oil. It was hard to get it in there! LOL
After I finished and started it back up it obviously smoked for a while but it also started to make a loud tapping noise. At idle it was hard to hear but as I increased the RPM it got louder. After a while it finally quieted down but it is still there. It never had this noise before. Not sure what that could be.
Dry Test Wet Test
1 130 / 180
2 145 / 205
3 155 / 200
4 155 / 210
I didn't expect the wet test number to go up that much (more than 10%) but I may have put more than a tea spoon amount of oil. It was hard to get it in there! LOL
After I finished and started it back up it obviously smoked for a while but it also started to make a loud tapping noise. At idle it was hard to hear but as I increased the RPM it got louder. After a while it finally quieted down but it is still there. It never had this noise before. Not sure what that could be.
You can use a Straw to add oil to spark plug hole, dip it in a bottle of oil and put your finger over the end, lift it out and put it in spark hole, remove finger
Just an FYI
Not sure what the tapping might be, valve train most likely, but if you put too much oil in you can hydro-lock a piston but hard to do when just using starter motor
The 130 dry is low
The 2.5l Lima runs 9.1:1 compression ratio, I use the multiplier of 18, so 18 x 9.1 = 163.8psi would be expected on a NEW 2.5l engine
So your 155s are fine even the 145 is OK but marginal, and it did come up to 200 like the other 2
I think the 130 is most likely a valve issue not rings since it didn't come up to 200
Just an FYI
Not sure what the tapping might be, valve train most likely, but if you put too much oil in you can hydro-lock a piston but hard to do when just using starter motor
The 130 dry is low
The 2.5l Lima runs 9.1:1 compression ratio, I use the multiplier of 18, so 18 x 9.1 = 163.8psi would be expected on a NEW 2.5l engine
So your 155s are fine even the 145 is OK but marginal, and it did come up to 200 like the other 2
I think the 130 is most likely a valve issue not rings since it didn't come up to 200
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From: Live Oak, TX
You can use a Straw to add oil to spark plug hole, dip it in a bottle of oil and put your finger over the end, lift it out and put it in spark hole, remove finger
Just an FYI
Not sure what the tapping might be, valve train most likely, but if you put too much oil in you can hydro-lock a piston but hard to do when just using starter motor
The 130 dry is low
The 2.5l Lima runs 9.1:1 compression ratio, I use the multiplier of 18, so 18 x 9.1 = 163.8psi would be expected on a NEW 2.5l engine
So your 155s are fine even the 145 is OK but marginal, and it did come up to 200 like the other 2
I think the 130 is most likely a valve issue not rings since it didn't come up to 200
Just an FYI
Not sure what the tapping might be, valve train most likely, but if you put too much oil in you can hydro-lock a piston but hard to do when just using starter motor
The 130 dry is low
The 2.5l Lima runs 9.1:1 compression ratio, I use the multiplier of 18, so 18 x 9.1 = 163.8psi would be expected on a NEW 2.5l engine
So your 155s are fine even the 145 is OK but marginal, and it did come up to 200 like the other 2
I think the 130 is most likely a valve issue not rings since it didn't come up to 200
I'm pretty sure the valves in 1 are my issue. I have had the P0301 code also and this mostly confirms why I sometimes get it.
I was doing some research on replacement heads. I would rather just swap out a new or already rebuilt head with new cam. One thing I noticed is some places ask if it has the 6mm or 8mm t-stat bolts. Is there any way to know without removing one? I'm pretty sure they are 8mm but need to make sure.
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Well after more testing and a camera in plug hole #1 you can see coolant getting in! So I would rather just buy a new or re manufactured head so I can just do a swap for the least amount of down time.
My question is, several places specify 8mm or 6mm thermostat bolts. Without taking them out is there a way to know which I have? Or where can I find the Casting number?
My question is, several places specify 8mm or 6mm thermostat bolts. Without taking them out is there a way to know which I have? Or where can I find the Casting number?
Last edited by Rock304; Feb 26, 2020 at 05:40 AM.
In a 1998 2.5l, no, after 22 years there is no way to tell because thermostat has most likely been changed before so either size could be there now
Ford says 8mm socket but have read quite a few posts that say they needed 10mm socket
Head bolts are TTY, so can't be reused
Ford says 8mm socket but have read quite a few posts that say they needed 10mm socket
Head bolts are TTY, so can't be reused
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From: Live Oak, TX
I will definitely buy new head bolts! I'm also going to do new timing belt and water pump since it's all coming off anyways.
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FINAL UPDATE:
I replaced the head. The gasket was bad in one very small area but it was enough to cause the issues I was seeing. I have put about 125 miles on it and it runs great! Starts fast and easy and no other issues.
I also replaced the timing belt which was definitely needed! and the waterpump, t-stat housing, plug wires (and plugs of course) so hopefully this is the last thing I need to do!
I replaced the head. The gasket was bad in one very small area but it was enough to cause the issues I was seeing. I have put about 125 miles on it and it runs great! Starts fast and easy and no other issues.
I also replaced the timing belt which was definitely needed! and the waterpump, t-stat housing, plug wires (and plugs of course) so hopefully this is the last thing I need to do!
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