Problem with engine

[keystone]

Hi all,
I have engine related issues with my 95 525i. Engine is shaking as if something is seized. I used Peake to get the codes, which gave me 45 and 46, knock sensors. Stomp test did not give me anything. I changed both knock sensors and while I was doing that I also cleaned the ICV. I changed the spark plugs, oil, and fuel filter. Air filter is relatively new and looks clean. Coolant was changed 6 months ago and looks good and coolant hoses were changed then. The car never overheats, and temp stays at the same spot as it always was. Belts look good, but I am going to take them off and see something is wrong with pulleys, which does not seem likely. All the hoses look fine. Now there is no code on Peake or stop test.
I am not sure it did anything, but I used Seafaom in the engine, 1 and 1/2 oz for each quart of oil as directed on the can, and I put the remaining in the gas tank (everything was okay until the gas was almost gone). Since then I am not sure what is going on, but I am having this issue.
It seems to be worse when the engine gets hot. The water pump is 2 and half years old (it has metal, not plastic).
What do you guys think the problem could be. The engine never shook like that before, when I tried to accelerate, I feel that something is seizing, as if something is prevented to turn in the engine. But after that, it is similar problem while it is idling too. Upper coolant hose is hot and gets hard. Lower coolant hose also hard and I could not squeeze it when I tried a few minutes ago; is the lower hose supposed to be like that?
I appreciate if you could help me solve this problem.

[Tiger]

Change the oil right away... flush out that Seafoam... I don't believe you are meant to drive the car with it in there....

Fill up the fuel tank to dilute the Seafoam.

[keystone]

Change the oil right away... flush out that Seafoam... I don't believe you are meant to drive the car with it in there....

Fill up the fuel tank to dilute the Seafoam.

Thanks, I've changed the oil (the oil with the seamfoam has been drained out). The fuel tank has been filled with fresh gas. But the problem did not go away.

[bsell]

Did you stir something up via running the tank almost empty? Doing so does tend to pick up any trash in the tank and either clog the fuel pump strainer and/or the fuel filter.

The filter is a cheap and easy replacement, especially if you haven't done it in a few years. The pump strainer is more work but may prove equally valuable as you will get to see into the tank and verify it's good to go or not.

When you did the spark plugs, how'd they look? Were the rubber leads from the coil packs good to go?

[Tiger]

I'd probably change the fuel filter first. Then I would suspect fuel pump or CPS.

[keystone]

Did you stir something up via running the tank almost empty? Doing so does tend to pick up any trash in the tank and either clog the fuel pump strainer and/or the fuel filter.

The filter is a cheap and easy replacement, especially if you haven't done it in a few years. The pump strainer is more work but may prove equally valuable as you will get to see into the tank and verify it's good to go or not.

When you did the spark plugs, how'd they look? Were the rubber leads from the coil packs good to go?

Thank you guys. The tank was almost empty when the problem started and I immediately filled it. At a time I thought the problem must be related to fuel since the seafoam was in the tank and the tank was almost empty. Two days ago, I changed the fuel filter. Last summer a new fuel pump was put since the original one died. Do I need to take the fuel pump to get to the strainer?

[bsell]

Yes.

[aston_jag_tech]

Check fuel pressure at the rail-This will ensure fuel pressure is present at the injectors. While in park and engine running rev the engine to 2-4k. Fuel pres. should increase a bit.

Coolant hoses become hard when the system is hot and under pressure(15 psi)

Since you added seafoam to the engine oil and fuel system you should attack those systems...Dont both with cooling system, belts, tires, blinkers. You know what you added, look in those areas.

Do you still have knock sensor codes?? If so you have a misfire most likely. Fuel starvation/Fuel injector leaking/ Spark plug misfire, coil inop, many possibilities. Start eliminating some.

[keystone]

Check fuel pressure at the rail-This will ensure fuel pressure is present at the injectors. While in park and engine running rev the engine to 2-4k. Fuel pres. should increase a bit.

Coolant hoses become hard when the system is hot and under pressure(15 psi)

Since you added seafoam to the engine oil and fuel system you should attack those systems...Dont both with cooling system, belts, tires, blinkers. You know what you added, look in those areas.

Do you still have knock sensor codes?? If so you have a misfire most likely. Fuel starvation/Fuel injector leaking/ Spark plug misfire, coil inop, many possibilities. Start eliminating some.

Thanks. I haven't gotten any knock sensor code since I changed them. Today, I checked the pulleys, which looked okay, but I changed idler pulley, tensioneer pulley, AC pulley and tensioneer, and power steering pulley. I disconnected the battery cables and by connecting them and turning the key to II position, I tried to reboot the car. After starting shaky again, it became smoother and drove about 30 miles, which was good until I was coming home, stopping at lights made the shake come back. Still there is no codes with stomp test and Peake.
Spark plugs looked fine when I took them off, coils were okay, plug boots looked okay. So it must be fuel related. I tried to rev the engine, it seems it accelerates okay, which I assumed the fuel pressure was okay. Do I need a special tool to check the fuel pressure to know the pressure is increasing?

[aston_jag_tech]

The new spark plugs look fine? How do you know coils are ok? Did you do a cyl drop out test?(running engine and disconnecting 1 coil at a time to see if the engine changed in roughness or not), You need a fuel pressure gauge(analog). If you have a test port on the fuel rail youll need an adapter to thread onto the test port. Never assume until you know youre actual specs. :) GL.

[keystone]

The new spark plugs look fine? How do you know coils are ok? Did you do a cyl drop out test?(running engine and disconnecting 1 coil at a time to see if the engine changed in roughness or not), You need a fuel pressure gauge(analog). If you have a test port on the fuel rail youll need an adapter to thread onto the test port. Never assume until you know youre actual specs. :) GL.

Thanks, I really appreciate your help as you can imagine it is really frustrating as I want to fix it. I will do that and see how it is. I will also get fuel pressure gauge.
I found another thing and I appreciate if you could tell me that is also something I need to change. About an hour ago, I started the car again, it was a little shaky for a minute or so, then it was smooth. After the engine was hot, I thought I should turn on AC (the AC was on when this problem started originally). The engine started to shake again. I turned the AC off, but did not make much change. I used a rolled newspaper on the fan, which stopped relatively easy. I read a little about that on the forum and it seems like it might be going bad, if it is not bad already. When the engine is off, I tried to spin, sometimes spins easily, sometimes it is not. Could that cause the engine shake? I am thinking of ordering a new one and noticed that there are two kinds: Behr (which is the same brand as what is on the car currently, Behr with bmw logo), and Fichtel-Sachs. Which one would you recommend if I need to change it? Thanks again.

[aston_jag_tech]

Remove the fan and if the shaking stops- replace the fan assembly, if not, that is not the prob.

purchase a compression tester and check each cylinder. Do the basics.

[keystone]

Remove the fan and if the shaking stops- replace the fan assembly, if not, that is not the prob.

purchase a compression tester and check each cylinder. Do the basics.

Many thanks again. I was afraid of running the engine with the fan off. I did a few minutes ago for fifteen minutes and it did not shake. Tomorrow I will run it again and see if there is any shake again. Hopefully this solves the problem. It is weird that the fan cause the problem of shake.
I will also order the fan assembly online tomorrow. If you have experience with the parts, can you recommend which one I should go with: Behr or Fichtel-Sachs as the online vendor has these two choices.
Thnak you so much again for your help.

[aston_jag_tech]

Sweet! Glad to hear you found the cause!! Regarding parts...Behr or Sachs, I am not picky of manufacturer unless its ignition system or brake system.

After you install your fan assembly let us know how the results are. :)

[keystone]

Sweet! Glad to hear you found the cause!! Regarding parts...Behr or Sachs, I am not picky of manufacturer unless its ignition system or brake system.

After you install your fan assembly let us know how the results are. :)

Many thanks again for your help and time. I will let you know the result.
Thanks.

[aston_jag_tech]

For sure, anytime.