OOC-07Rubi

So it has been cold here in the Bay Area and I noticed that when i first start the jeep, it has the threaded knock that everyone talk about. Its only for few seconds and then goes away. I heard here on the Forum that some people step on the gas pedal all the way down and start the jeep just to give enough time for the mechanical pump to get oil up on the head. I have tried this for a couple days now and it seems to eliminate my dry start-up knock.

This is what i actually do for couple mornings now: i step on the gas pedal and turn on, the jeep just keep cranking and doesn't stop. I have to actually turn the key to off to stop the crank after 3-4 seconds. I then let go of the gas pedal then turn on the jeep. It starts right up without any knock.

Now my question is...Is this good for the engine? I think that by doing this, I'm fooling the engine that its flooding but is it really flooding? Any professional engineers here or knowledgeable people here that can advise me whether this is good or not.

Thank you in advance.

Woodturner

When you step on the gas pedal and crank it, the computer actually cuts off the fuel injectors. They do this so you can clear a flooded engine. This shouldn't damage the engine in any way.
Just be sure you don't over crank it, if you do you could cause damage to your starter motor from over-heating it.

OOC-07Rubi

Cool thanks...make sense now. it actually cuts fuel so that's why it doesn't start.
So i guess my 3-4 seconds crank time is not too bad. Thanks again. It totally eliminated my dry start knock.

ronjenx

Thanks for that. I wasn't thinking of it from a "clearing" point of view. My thought was limited to preventing a start with a wide open throttle, which may be part of it, too.

I remember it working to clear a flooded engine back in the carburetor days.

kik

Shouldn't he just replace the oil filter. I thought the dry start knock was caused by a faulty blow back valve in the filter.

ronjenx

Changing oil filters brings varying results.
I use a MOPAR filter and get no start-up tick/knock. Other people tried it and got start-up tick/knock until they switched to another brand. What works for one, may not work for another.

Red Belly

All I do is turn the key to ON/RUN, wait until the beeping stop. Then START.

Runewolf1973

I actually just tried this after I read your post. And guess what... It's -50 with the wind chill and my Jeep has been parked all night. NO start up knock when I did this. I had the Jeep plugged in overnight, but at this temperature it would normally get the knock regardless off whether it was plugged in or not...it's just that damn cold. Your suggestion worked and I thank you!!

OOC-07Rubi

Is that true for mechanical pump tho? i thought the engine has to turn for a mechanical pump to work. It makes sense for an electrical oil pump but mechanical...

I have tried doing the key on thing and still has it. I might have to try different oil filter.

ronjenx

You are thinking in the right direction. Sitting with the key on does absolutely nothing toward getting oil into the places it needs to be.