QuestionQUESTION: Hi,
I have 3 different '95 Astro vans. One of them is a cargo and the other two are passenger type. All of them have the same broblem.
Type of Noise --- There is mechanical noise (sounds similar to a drill) coming out from under the hood on the driver side. It last for only a second. The amplitude of the nose is the same each time it happens. Each of the vans I have does it, but two of those are noisier then the last one which makes me think that the problem gets to be worse with time (I bought all 3 vans used at the same time not long ago).
When it Happens? --- It happens only when I put the car into drive from a park position and start to accelarate. The noise shows after the car picks some speed (about 5mph). No problem if I accelarate from stop light-only after I start the van. Problem not dependent on engine rpm. I do not believe it to be transmition related since it also happens when I go reverse. Problem sounds the same whether or not I go straight or make a turn, so I do not suspect the drive-tr. Sound seems to be comming from the ABS location, but the brakes seem to be fine...
When it Does Not Happen --- It only happens when the ignition was turned on and I accelarate to about 5-7mph. It does not happen if I am to drive bellow that speed. It does not happen if I am to accelarate from stop at a stop-light. It does not happen if I am to put the van into park (with the ingition on at all time), put it back on drive and accelarate.
Please, if you have any ideas let me know.
Thank you for your time, Ted
ANSWER: This is actually out of my expertise...I'm registered for Driveability & electrical, but I think I can help you.
It's probably the EBCM (electronic brake control module) performing it's self test which is normal. Does it only happen once per ignition cycle? If yes, then I would have to say that is what's making the noise. If it happens every time you accel from a stop...it's something else.
Hope this helps,
Robert
---------- FOLLOW-UP ----------
QUESTION: Hi,
Thank you for the fast response. You have been very helpful.
It does happen once per ignition cycle, so it is probably the EBCM. One last question -- it is getting progressively worse/noisier over the months, so is there a way to service/maintain those or I will have to replace them in the future? Is it save to drive the vans or I have to replace the EBCMs ASAP.
Thank you, Ted
AnswerIf the EBCM fails it will set a code and the ANTI-LOCK brake light will come on. Other than that happening I wouldn't worry about it. Yes I have noticed that some vehicles are a little louder than others...don't know why.
One thing I do on my own vehicles is once a year I will siphon out as much of the old brake fluid from the master cylinder and replace it with fresh new fluid.
