Start Knock help!

[gn87turbo]

Hey guys, my car has about 87k miles and runs great, no problems. The last few months I've noticed some start knock when the car has been sitting a while when I start it. It usually never sits more than a week or two without being driven. It will last about 3 or 4 seconds and goes away but I can't stand it and it cant be good for the car. What is causing this and how can I fix it? Also, I'm running mobil 1 10w-30 with ac delco filter.
Thanks in advance

 

[vacuum 6]

No one is seeing this issue?????

Hey guys, my car has about 87k miles and runs great, no problems. The last few months I've noticed some start knock when the car has been sitting a while when I start it. It usually never sits more than a week or two without being driven. It will last about 3 or 4 seconds and goes away but I can't stand it and it cant be good for the car. What is causing this and how can I fix it? Also, I'm running mobil 1 10w-30 with ac delco filter.
Thanks in advance

Mmmmm odd no one is seeing this issue.

My stock and mod engine does this after sitting for ~ a week.

 

[quadzila]

Start knock

I have the exact same problem on my 58,000 mile gn and oil filter was changed to a wix's and took out the synthetic oil went back to conventional oil and still after a week i get bottom noise for 2 seconds.

it was suggested to me to unplug the fuel pump harness at the gas tank then crank the car 5 seconds or so to build up oil pressure then plug it in and start. i would love to see if there's an easy fix or maybe an ESP pre lube kit will solve the problem.

i cant be good for the motor at all so im planning on a building a stroker because of it. i hope it lasts till November.

 

[gn87turbo]

I was told a couple of years ago you can unplug the computer at the battery and crank it for 10 to 12 seconds and then plug it up and it cranks fine. I've done this and it does work. I just don't want to unplug the computer everytime I crank the car when it has sit for a week or so. Was hoping someone esle was having the same problem and had a fix. Could it be the filter anti drain back valve?

 

[earlbrown]

What you are hearing is the lifters that have bled down and take a second to re-pressurize.
The Delco filters have been oursourced overseas and they are in the crap pile with Frams now.

 

[quadzila]

Start knock

when my oil filter was changed to the wix's it was empty, when this happens is it possible that the bottom end can lose its prime as well?

 

[gn87turbo]

When I bought the car the previous owner used NAPA filters with no problem, I've always used the delco but sounds like I'll being trying a switch to see if that fixes the issue.

 

[vacuum 6]

Ok so what filter(s) should be used? I’ve always used the Delco.

I'm not convinced it’s the lifters that bleed down.

 

[quadzila]

start up noise -- any bad motors from it???

I want to believe that its the lifters, and hope it is. I haven't herd from anybody yet that they had same noise and confirmed it was in fact the bottom end getting worse to needing to be rebuilt. Please let us know.

 

[vacuum 6]

I started the car Saturday and ~24 hours later started it again. It had a little start up knock not bad. Assuming its the lifters, mine bleed down less than 24 hours.

 

[gn87turbo]

Mine only does it when it has been sitting for several days like a week or so. I started it up this weekend several times and no start knock. I'm hoping its the filter, bought a Purolator Pure1 yesterday so I'll try that and see if it helps and ditch the Delco thats on it.

 

[vacuum 6]

Mine only does it when it has been sitting for several days like a week or so. I started it up this weekend several times and no start knock. I'm hoping its the filter, bought a Purolator Pure1 yesterday so I'll try that and see if it helps and ditch the Delco thats on it.

Currently I have a Delco.

Let me know what you find.

 

[gn87turbo]

With the new Pure1 filter, I let the car sit for 4 or 5 days and started it today and no start knock. I'll keep you posted, I think the true test will be when it hasn't been started for a week or more which is hard to do this time of year :biggrin:

 

[Dino1]

Knock

If it's a tapping sound it is proberbly the lifters. But if it is a knocking sound, much deeper sound, the rod bearing are toast. They need a little more cushion to quiet them down.

 

[vacuum 6]

If it's a tapping sound it is proberbly the lifters. But if it is a knocking sound, much deeper sound, the rod bearing are toast. They need a little more cushion to quiet them down.

Rod bearing are toast? Need more cushion?

I'm seeing knock until oil psi comes up. Seems to me its a start-up oil psi issue.

 

[gn87turbo]

Just wanted to give an update. Since I've switched to the Pure1 filter and ditched the ac delco, my problem seems to be gone. I have let the car sit for around a week and at start up, no start knock so I'm assuming it was the delco filter.

 

[TrAb]

Im using a wix and was using a mobile 1 before that and mine did it with both...

 

[Quik Six]

My knock sensor sometimes goes off when I start the car but it is a very irregular event. Don't like it but haven't been concerned as car settles down and is extremely quiet. Guess I can flip the kill switch and turn it over for a few moments and then flip the switch back to start it.

 

[vacuum 6]

Just wanted to give an update. Since I've switched to the Pure1 filter and ditched the ac delco, my problem seems to be gone. I have let the car sit for around a week and at start up, no start knock so I'm assuming it was the delco filter.

Got the Pure1 part number?

 

[WIKEDV6]

Hey guys, my car has about 87k miles and runs great, no problems. The last few months I've noticed some start knock when the car has been sitting a while when I start it. It usually never sits more than a week or two without being driven. It will last about 3 or 4 seconds and goes away but I can't stand it and it cant be good for the car. What is causing this and how can I fix it? Also, I'm running mobil 1 10w-30 with ac delco filter.
Thanks in advance

Back in the early 90's my car used to make the same noise, I am sure they were the lifters. I ran a can of Dura lube or T plus additive. I think they were the Teflon additives that were popular back in the days and the problem went away. That stuff really worked. They said that it puts a protective coating on all the hard parts that help with startup lubing.
HTH
Prasad