Engine vibration and metal noises

[DMCMW Dave]

Injectors were cleaned and tested professionally less than 2 months ago. Hmmm.... do I need new injectors???

Did you personally test them after they were "cleaned"?

[Ryan S.]

Yes, I performed the spray pattern test before I installed them a couple of months ago. They were working well and had good spray patterns.

Tonight, I tested spray patterns again. I am not entirely happy about #4 and #5 injectors but I decided to put them back in. Restarted the car and it's back to normal. No more vibrations and car runs great. I will probably get a couple of new injectors if this happens again. For now, I am happy that car is working.

[David T]

Yes, I performed the spray pattern test before I installed them a couple of months ago. They were working well and had good spray patterns.

Tonight, I tested spray patterns again. I am not entirely happy about #4 and #5 injectors but I decided to put them back in. Restarted the car and it's back to normal. No more vibrations and car runs great. I will probably get a couple of new injectors if this happens again. For now, I am happy that car is working.

If you got it so it runs try a can of Techron injector cleaner. If the injectors keep getting plugged up it is most often because you have a car that sat for a long time and the fuel system is full of dirt (stale fuel). Cleaning the fuel tank and replacing the filter is necessary but that won't stop any dirt that is already past the filter from breaking loose and getting into the injectors.

[Ryan S.]

Great. I will try techron. Fuel filter is only about 6 months old and fuel tanks was cleaned twice already before the DMCH integrated fuel pump installation. I have been driving this car almost everyday to work before this happened. I have been averaging 250 miles a week. I am guessing that old dirt, already in injector, might be causing this.

[Trstno1]

Did your metal rattle go away when the injectors were cleaned? I have the same sound that is driving me crazy! It sounds like a loose bracket or something rattling when the engine rpm increases. I too checked all fittings and brackets for looseness with nothing to report. I then removed my belts one by one and noticed that the sound went away when i removed the water pump/alternator belt. So now I'm thinking it's a bearing issue in either the alternator or water pump.

At this point I wish I could individually test the alternator and water pump without throwing money at new parts for nothing..... I'm at a bit of a stand still.....

The one thing that I have not attacked is the fuel system. I really have no idea of its condition and am a bit nervous as to what I may find.....

[WelmoedJ]

Did your metal rattle go away when the injectors were cleaned? I have the same sound that is driving me crazy! It sounds like a loose bracket or something rattling when the engine rpm increases. I too checked all fittings and brackets for looseness with nothing to report. I then removed my belts one by one and noticed that the sound went away when i removed the water pump/alternator belt. So now I'm thinking it's a bearing issue in either the alternator or water pump.

At this point I wish I could individually test the alternator and water pump without throwing money at new parts for nothing..... I'm at a bit of a stand still.....

You can test those devices: turn the alternator by hand and feel if there are moments you have resistance, pointing to a bad bearing.
You can apply the same test to the waterpump.
Both test situations of course only without the V-belt in place!

The one thing that I have not attacked is the fuel system. I really have no idea of its condition and am a bit nervous as to what I may find.....

The only moving parts that could rattle in the fuel system are the pump and (a part of) the injectors.
The injectors IMO will not cause rattling.

Does the rattling occur revving at stand still, while driving or in both cases?

[David T]

You can test those devices: turn the alternator by hand and feel if there are moments you have resistance, pointing to a bad bearing.
You can apply the same test to the waterpump.
Both test situations of course only without the V-belt in place!


The only moving parts that could rattle in the fuel system are the pump and (a part of) the injectors.
The injectors IMO will not cause rattling.

Does the rattling occur revving at stand still, while driving or in both cases?

Go underneath and look up at the bottom of the "neck" of the water pump behind the pulley. There is a hole there and if you see any staining or moisture the seal is bad and the bearings are bad. More likely a bad bearing on the alternator and you can't always feel it turning by hand. One way to pinpoint a bad bearing is with a metallic stethoscope. You go till the noise gets it's loudest. You can also take the alternator to a place like Autozone. They will bench test it for free and if the bearing is bad you will know right away.

[Ryan S.]

Mine was related to bad fuel injector(s). Cleaning fixed it but came back. I ended up getting a few new ones and I think that fixed it.