1995 F150 "Bucking" uphill: no codes
10-09-2015, 01:34 PM
#41
Good question. Don't know answer. I'm rookie car port mechanic! 
But I failed smog. Guy said my engine was misfiring and all sorts of stuff. Took it to garage cause it was way over my head and they said cat was bad. And they said "hopefully it didn't [forgot what they said here but basically said] burn something towards the engine cause of the heat. But it didn't so they replaced cat and plugs.
Good point. Now you got me thinking "how does one test a cat?"
But I failed smog. Guy said my engine was misfiring and all sorts of stuff. Took it to garage cause it was way over my head and they said cat was bad. And they said "hopefully it didn't [forgot what they said here but basically said] burn something towards the engine cause of the heat. But it didn't so they replaced cat and plugs.
Good point. Now you got me thinking "how does one test a cat?"
I seem to recall the stinky exhaust is a sign of a bad cat.
10-09-2015, 01:47 PM
#42
Great let us know what happens after you cut that sucker off
10-09-2015, 03:35 PM
#43
Checked my vacuum. It's steady around 20-22 at idle, and only drops to about 15 at high rpms. If it really hit the throttle fast, it drops to almost zero for a split second but that seems normal to me. It certainly doesn't explain the uphill battle or the running rough (almost all the time now).
As soon as it cools off a little I'll be putting plugs in. My engine sticker must be gone, but I'm pretty sure they were gapped at 44 so I'm going with that. It does have an MSD ignition system so I could probably go higher but the plugs have always looked great when I've pulled them so... why change.
Will check the battery connections and clean them again because I plan to reset the computer anyway (nothing to lose at this point).
As soon as it cools off a little I'll be putting plugs in. My engine sticker must be gone, but I'm pretty sure they were gapped at 44 so I'm going with that. It does have an MSD ignition system so I could probably go higher but the plugs have always looked great when I've pulled them so... why change.
Will check the battery connections and clean them again because I plan to reset the computer anyway (nothing to lose at this point).
"The technician in this question uses a vacuum gauge to confirm an exhaust restriction. If the needle on the gauge drops steadily from 2500 rpm, check the exhaust for a restriction. This is probably caused by a clogged catalytic converter."
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hoytpr (10-10-2015)
10-10-2015, 12:08 PM
#44
Okay cat is going to be a pain in the butt and has to wait for another day. It is right at the transmission cross member. Not sure the best plan of attack yet. I'm thinking I need to take the crossmember off. I guess I could drop the front of the exhaust but that seems like a problem too.
It might be next weekend until I can try it.
I did notice my negative terminal was loose, I cranked it down and it might be running slightly better, might.
It might be next weekend until I can try it.
I did notice my negative terminal was loose, I cranked it down and it might be running slightly better, might.
10-10-2015, 02:17 PM
#45
Member
Thread Starter
I found this method to check for a bad cat, since you have a vacuum gauge do you want to give it a shot?
"The technician in this question uses a vacuum gauge to confirm an exhaust restriction. If the needle on the gauge drops steadily from 2500 rpm, check the exhaust for a restriction. This is probably caused by a clogged catalytic converter."
"The technician in this question uses a vacuum gauge to confirm an exhaust restriction. If the needle on the gauge drops steadily from 2500 rpm, check the exhaust for a restriction. This is probably caused by a clogged catalytic converter."
PS: There are new vibrations that must be the front U-joint. Probably got damaged from all the bucking.
10-10-2015, 04:06 PM
#47
Member
Thread Starter
Good news! Changed the plug wires and got rid of 90% - 95% of the problem! The fouled plug probably was loose and shorting. There was another plug wire that looked rusty inside like it had gotten wet. Now I'll need to change the U-joint to really feel if the truck is running smooth. I'm not getting my hopes up about the truck running strong uphill, but it's not really "bucking" anymore, though it may still be "missing" slightly. The new fuel filter has to have helped some. I'll go through the KOER tests but plan to take a few hours off today to enjoy a small victory.
Thanks everyone!
Thanks everyone!
10-11-2015, 09:18 AM
#48
Thats great news. Wish I had some.
Mine is running much worse. last night it bucked hard a couple times, definitely is shutting off then on. Then on the way home it stalled at a traffic light, started and stalled again. Then I couldn't get it to start for quite a while, several light cycles.
My problem must be either fuel or spark and seems to be totally random, but getting worse. I switched fuel tanks with no change, making me think it is spark.
I'm not sure what all controls the spark, I have new wires, cap, rotor and fairly new plugs. It idles smooth and seems to run fine other than when it's acting up.
might be ignition coil, it seems fine until it warms up, then is progressively worse.
Also I'm really confused how this new OBD2 system isn't throwing a code and the engine is shuttng off?
Mine is running much worse. last night it bucked hard a couple times, definitely is shutting off then on. Then on the way home it stalled at a traffic light, started and stalled again. Then I couldn't get it to start for quite a while, several light cycles.
My problem must be either fuel or spark and seems to be totally random, but getting worse. I switched fuel tanks with no change, making me think it is spark.
I'm not sure what all controls the spark, I have new wires, cap, rotor and fairly new plugs. It idles smooth and seems to run fine other than when it's acting up.
might be ignition coil, it seems fine until it warms up, then is progressively worse.
Also I'm really confused how this new OBD2 system isn't throwing a code and the engine is shuttng off?
10-11-2015, 11:52 AM
#49
Thats great news. Wish I had some.
Mine is running much worse. last night it bucked hard a couple times, definitely is shutting off then on. Then on the way home it stalled at a traffic light, started and stalled again. Then I couldn't get it to start for quite a while, several light cycles.
My problem must be either fuel or spark and seems to be totally random, but getting worse. I switched fuel tanks with no change, making me think it is spark.
I'm not sure what all controls the spark, I have new wires, cap, rotor and fairly new plugs. It idles smooth and seems to run fine other than when it's acting up.
might be ignition coil, it seems fine until it warms up, then is progressively worse.
Also I'm really confused how this new OBD2 system isn't throwing a code and the engine is shuttng off?
Mine is running much worse. last night it bucked hard a couple times, definitely is shutting off then on. Then on the way home it stalled at a traffic light, started and stalled again. Then I couldn't get it to start for quite a while, several light cycles.
My problem must be either fuel or spark and seems to be totally random, but getting worse. I switched fuel tanks with no change, making me think it is spark.
I'm not sure what all controls the spark, I have new wires, cap, rotor and fairly new plugs. It idles smooth and seems to run fine other than when it's acting up.
might be ignition coil, it seems fine until it warms up, then is progressively worse.
Also I'm really confused how this new OBD2 system isn't throwing a code and the engine is shuttng off?
I've seen the pickup in the distributor act up - work, not work, work again - that's usually before they give up the ghost completely. So maybe something there in the ignition.
Another overlooked thing which is possible is the connections, especially the grounds and most especially the ground where it attaches to the engine. Cleaning up those has solved a lot of mysterious problems, so it's worth a shot - it can't hurt and costs nothing.
10-11-2015, 12:23 PM
#50
Todd; Spark is controlled by the pickup in the distributor, the ICM mounted on the fender below the driver's side hinge and of course the coil. Any one of those 3 things can act up when they get hot.
I've seen the pickup in the distributor act up - work, not work, work again - that's usually before they give up the ghost completely. So maybe something there in the ignition.
Another overlooked thing which is possible is the connections, especially the grounds and most especially the ground where it attaches to the engine. Cleaning up those has solved a lot of mysterious problems, so it's worth a shot - it can't hurt and costs nothing.
I've seen the pickup in the distributor act up - work, not work, work again - that's usually before they give up the ghost completely. So maybe something there in the ignition.
Another overlooked thing which is possible is the connections, especially the grounds and most especially the ground where it attaches to the engine. Cleaning up those has solved a lot of mysterious problems, so it's worth a shot - it can't hurt and costs nothing.
Is there brands to look for with a distributor? I don't see a motorcraft part listed. Was checking rock auto, they have several brands of varying price. One looks to be a factory rebuild? Requires a core return.