Engine knocking then quit running altogether

[gmyoyo]

95 blazer 4.3 CPI ODBI

Concerning the sea foam post and fouling or otherwise foam the plugs as BlazerLT put it. I beleive that's where I'm at right now. Any suggestions on what to do. Pull all the plugs and clean?

Here's the history.

Replaced EGR, cleaned EGR several times since. Still getting carbon pellets. Replaced spark plugs, wires, oil, filter. Then did a sea foam application. Some in the PCV valve for chamber cleansing, some in the crankcase and a can to the gas tank. I changed the oil since the add.

I was getting a knocking sound in the engine. To me it seemed to be the number six cylinder, could have been any on that side of the engine for sure though. Noise was loudest there. The engine screeched to a halt yesterday when I was listening for possible fuel pressure issue while looking into why my vehicle is running so rough. Please tell me there are ways to check to see if I didn't sieze the engine.

Blazer LT, I've read a lot of your post around this subject already, and plan to start looking to things you mention that I haven't done.

I plan to pull the spark plugs and after inspecting a cleaning, yet while they are out I will try and turn the engine manually? I know to disconnect battery as I read your warning on that as well.

Right now the only thing I didn't do was cap and rotor.

Fuel pressure was 60 psi and holding, until I did a can of sea foam in the gas tank, now it drops to around 30 if I don't start the car. If I do (or did) start it ran rough, and made the knocking noise. I'm thinking it's possible inside the intake plenum that I need to take a look at as you did in your other post replacing the CPI or whatever the thread called.

Could this be an oil pump or something related issure. It had oil, although it had been run low in the past, and I know that isn't a good sign, but did run fine until now, but all I did was replace the EGR valve.

All, any suggestions would be appreciated...

[BlazerLT]

Your engine is knocking because your oil is probably full of fuel from a leaking CPI injector.

Do a search for

CPI injector

[Rick Norwood]

Originally Posted by BlazerLT

Your engine is knocking because your oil is probably full of fuel from a leaking CPI injector.

Do a search for

CPI injector

It could be a thrown rod. I did the same thing on an 1982 Olds. I added an oil cleaner additive and threw a rod the next day.

[gmyoyo]

Oooh, don't like the sound of that (thrown rod).

I'll be peeking under the vortex plate and upper plenum over the next day or so...I'll be sure and let everyone know what I find.

How would I know if a rod is thrown, not able to manually turn motor?

Anything else I should be aware of or on the lookout for?

By the way, I'm a "wanna be mechanic". Patience, I have, a lot of mechanical background I do not... Lack of money drives me to want to do these fixes myself whenever possible...

[Rick Norwood]

Originally Posted by gmyoyo

Oooh, don't like the sound of that (thrown rod).

I'll be peeking under the vortex plate and upper plenum over the next day or so...I'll be sure and let everyone know what I find.

How would I know if a rod is thrown, not able to manually turn motor?

Anything else I should be aware of or on the lookout for?

By the way, I'm a "wanna be mechanic". Patience, I have, a lot of mechanical background I do not... Lack of money drives me to want to do these fixes myself whenever possible...

The first thing is to check your dipstick like BlazerLT said.

If there is no presence of Gasoline in your oil and the oil level is normal, the next thing I'd do is try turning the engine over manually.

Disconnect the battery and use the appropriate socket and ratchet.

If the engine seems to turn over o.k. manually, you might try removing ALL of the spark plugs and cranking the starter (after you reconnect the battery) this might help you to pin point the knocking noise.

[BlazerLT]

Checking for gas in the oil pan is just the start.

Do the real CPI check by removing the IMTV valve in the top of the plenum and look in and look for washing like the other cpi injector threads have talked about.

[gmyoyo]

Originally Posted by BlazerLT

Checking for gas in the oil pan is just the start.

Do the real CPI check by removing the IMTV valve in the top of the plenum and look in and look for washing like the other cpi injector threads have talked about.

I looked, it's washed. I'm going in deeper and planning on just replacing the parts as you have recommended.

CPI Unit
Nut Kit
Gasket

BlazerLT,
I am wondering, should I get a CPI unit from the dealer, or the GP-Sorenson part on Autozone? Or is it the same thing? Obviously the AZ is cheaper or I wouldn't even ask. It saves about 50 bucks (always good), but I don't want to by cheap stuff. Is it a viable replacement? I've already got the nut kit from the dealer.

[Rick Norwood]

Originally Posted by gmyoyo

I looked, it's washed. I'm going in deeper and planning on just replacing the parts as you have recommended.

CPI Unit
Nut Kit
Gasket

BlazerLT,
I am wondering, should I get a CPI unit from the dealer, or the GM-Sorenson part on Autozone? Or is it the same thing? Obviously the AZ is cheaper or I wouldn't even ask. It saves about 50 bucks (always good), but I don't want to by cheap stuff. Is it a viable replacement? I've already got the nut kit from the dealer.

Did you have a lot of gas in the oil?

[gmyoyo]

Originally Posted by Rick Norwood

Did you have a lot of gas in the oil?

It did smell like gas...It is a fresh change also, I didn't/haven't drained it again

According to all these threads, that plus the washing on the passenger side, that I could see through the IMTV valve indicated I need to get inside there. Didn't have time lst night, but will be at it again this afternoon.

I'm waiting now to dig into the plenum.

[BlazerLT]

Originally Posted by gmyoyo

It did smell like gas...It is a fresh change also, I didn't/haven't drained it again

According to all these threads, that plus the washing on the passenger side, that I could see through the IMTV valve indicated I need to get inside there. Didn't have time lst night, but will be at it again this afternoon.

I'm waiting now to dig into the plenum.

Go get a service manual before you do it to help you do it properly.

The GP injector is completely fine.

Also, clean your EGR gas hole in the upper plenum cover while you have it off.

More info can be found here:

http://www.s10forum.com/forum/showth...pi+replacement

[Rick Norwood]

Originally Posted by gmyoyo

It did smell like gas...It is a fresh change also, I didn't/haven't drained it again

According to all these threads, that plus the washing on the passenger side, that I could see through the IMTV valve indicated I need to get inside there. Didn't have time lst night, but will be at it again this afternoon.

I'm waiting now to dig into the plenum.

Look at your dipstick, is there "OIL" above the FULL mark? If so, how much? 1 inch, 2 inches?

[gmyoyo]

Originally Posted by BlazerLT

Go get a service manual before you do it to help you do it properly.

The GP injector is completely fine.

Also, clean your EGR gas hole in the upper plenum cover while you have it off.

More info can be found here:

http://www.s10forum.com/forum/showth...pi+replacement

I've printed your work already for additional reference...

Right, I will tackle the EGR as well. Thanks for reply.

I take it when you say service manual, you are talking about like a Haynes guide. I already have that...

By the way, BlazerLT and RickN, thanks for the all the help here...

[gmyoyo]

Originally Posted by Rick Norwood

Look at your dipstick, is there "OIL" above the FULL mark? If so, how much? 1 inch, 2 inches?

I noticed the smell, maybe a there was and excess, because I didn't put but 4 quarts and it was reading full. should have been 4.5 with filter change.

So maybe it had gas in there. I really haven't looked back at it since it stopped running, I know it was fresh oil, still clean, did smell like gas, and I did wonder why the level was higher than I expected.

I haven't tried to crank since, and I haven't pulled the plugs and tried to crank either, I also have not tried to manually turn the engine...

But like I say, now I'm kind of follwing the motions of looking for a problem up stream from the oil with gas smell, specifically an injector leak, because the gas pressure goes to 60 then bleads down to 25-30 after two second pressurizing, so I'm assuming it leaked it into the oil and it caused the knocking sound as well as the engine screeching to a halt.

Already having verified that washing is occuring, I'm following those fixes.

[BlazerLT]

Drop the oil ASAP and don't fill it back up until you have fixed it.

You have a major leak.

[Rick Norwood]

Originally Posted by BlazerLT

Drop the oil ASAP and don't fill it back up until you have fixed it.

You have a major leak.

I repeat, Look at your dipstick and see how high the oil is above the full mark, and then do like BlazerLT says, drain the oil. My suspicion is that if the crankcase was full of gas/oil mixture, you may have done some major internal damage to the engine bearings and pistons. Before you spend a lot of time and money replacing parts, make sure the engine is not siezed and will at least turn over manually. If you cannot get the engine to turn over using a socket wrench and a socket, you could be wasting your time by replacing the Nut Kit etc.