Update - Question about brake pump

[Johnnystats]

Hey everyone

 

First off, I want to thank everyone for all their help with my questions regarding my TGP.

 

I do have another question about that brake pump runs every so often. I am probably worrying about nothing, but is it normal for it to kick on if you are stepping on your brakes to a complete stop (pressing harder as you get to a complete stop) I want to say it is like 'riding your brakes' but it's not that. Reason I ask is that I have noticed that if I am approaching a stop and pressed the pedal 1x however foot is on the brake for a bit - I hear it kick on. Again, there arent any ABS, Brake lights going on. I just want to make sure I am ok

 

Again, thanks to everyone!

Edited October 17, 2010 by Johnnystats

[mfewtrail]

That's normal. Holding your foot on the brake for any extended amount of time eventually exhausts the pressure in the brake system and it has to recharge by running the motor again.

[White93z34]

Sounds normal to me. Next time I'm out in my car I'll take a listen to see if mine does it.

 

Usually if there is something wrong with PMIII it will heave a abs lamp at you.

[Johnnystats]

I know everyone must be sick of me asking questions about the brake pump . Anyway, today when washing the TGP - I drove it around the development for a few miles. As I was about to put it in the garage - the Antilock and Brake light came on. The Brake light went off and the Antilock remained on. I shut the car off, started it back up to see if it would remain on, but it didnt. I drove it again a little longer than the first time, but the lights didnt come on. Any idea what this could be? Or just a random thing? I have had the car a week and put about 40 miles on it - this was the first time it happened.

 

Thanks everyone!

[White93z34]

Eeeh could be anything... could be something small or major. In my travels its meant "oh shit" but without a scantool its hard to say. Keep an eye on it, take note of how the pump runs and acts when its on.

[Johnnystats]

Thanks Chris - it only did it tonight - so I will see if it happens again. I hope it doesnt have anything to do with the PM3 - before I bought the car they sent that part out to be rebuilt - took them a while but it was finally done. There is a 5 year warranty on that part, but I'd have to send it to Tennessee to be fixed.

[GOT2B GM]

Sounds like the accumulator is still working but just slowly deteriorating, causing the pump to run more.

 

My TGP is at the point where the brakes still work OK. But if I hit the brakes immediately after starting the car, the Antilock and Brake light comes on for a second or two until the pump charges up the weak accumulator then they go out.

 

Check Amazon for accumulators, I've bought two from there.

[Johnnystats]

Update - I decided to take my car to an all GM car show today - about 20 miles from my house. By the time I got there, the Antilock light came on. I parked the car, where it sat for several hours. As I was about to leave, I started the car up - no lights. As I was stepping on the brakes, the Antilock and Brake light came on. No sooner that that happened, I lost all brake power. I shut the car off, started it back up - didnt step on the brakes, and the antilock and brake light came on. I stepped on the brakes a few times, and the pump didnt even kick on.

 

Prior to buying the car - they did some ABS work. I have the work order - here was the problem and resolution---

Check ABS light on all the time. The ABS will run without car being turned on. Fuse needs to be pulled out for it to turn off. Brakes hard to press

Found that customer was removing ABS relay. Ran circuit tests on ABS system and found relay stuck on all the time., ABS pressure is low causing pump to run and pump motor is drawing too many amps which caused relay failure. need to rebuild abs pump assembly.

 

Does the problem I described that happened today seem to be the accumulator?

 

Thanks everyone for all their help!!

[Garrett Powered]

did the fuse blow?

 

I bet your grounds are all stock originals from 1990.

[Johnnystats]

I didnt check that - but will do so. Thanks

[Garrett Powered]

its the red or pink fuse. the slow blow style I think with the window on top.

[Johnnystats]

Thanks - I hope this will be an easy fix

[Garrett Powered]

there is a reason it blows. poor grounds.

[Johnnystats]

If the grounds are bad - would it be more involved than just replacing a fuse? (I'm not familiar with this at all )

[Garrett Powered]

the ground for it is between the block (specifically, the transmission bell housing bolt) and the battery tray. you would have to remove the battery to see it. but you just got to get in there with a wire wheel and clean up the bolt and scrape and sand everything clean.

 

I would replace that one wire with something bigger though. its the weak point on these cars.

[Johnnystats]

Thanks again! Do you think for a 20 year old car with 65K miles - this would tend to be bad at this point?

[Garrett Powered]

I am not sure if GM was trying to make the grounds bad on purpose or what?

 

 

I would weld a stainless nut on there and have better ground strap for a car that uses as much accessory power as the tgp. and maybe not mount it where the battery acid can leak on it?

 

....but I am not GM, I don't paint over where the bolt goes in.

[mfewtrail]

 

Does the problem I described that happened today seem to be the accumulator?

 

 

No. With a weak accumulator, the brakes still function like normal, but the pump motor has to run longer + more often than it should.