How To Stop Pre-Detination Rattle?

[etarasoff]

FWIW, attached is a procedure Lexus released for cleaning up carbon from the combusion chamber for GS300s...using GM Upper Engine cleaner of all things! But the procedure would still be basically the same for our engines. Interesting procedure and worth trying?

 

[LFD2037]

FWIW, attached is a procedure Lexus released for cleaning up carbon from the combusion chamber for GS300s...using GM Upper Engine cleaner of all things! But the procedure would still be basically the same for our engines. Interesting procedure and worth trying?

That GM product isn't available anymore & now everybody advises the Mopar Combustion Chamber Cleaner (MCCC) is the best/strongest product out now. It's <$10 @ my local Dodge house. I did the MCCC per instructions Monday but let it sit for 1 hour ,instead of the instructions recommended 5-10 minutes. I got zero smoke after restarting & it did nothing for the pinging. I've read where most people advise to let it soak for 2+ hours. I'll do that next time I change my oil.

 

[etarasoff]

I did the MCCC per instructions Monday but let it sit for 1 hour ,instead of the instructions recommended 5-10 minutes.

Curious. Does its instructions recommend a similar procedure to that of the Lexus PDF? That procedure seemed pretty hard core - basically, pouring the stuff in through the spark plug holes, then turning the motor a little to spread it around in there, and letting it soak...

 

[LFD2037]

No it does not. Get to operating temp., spray foaming aerosol product into throttle body (mine wouldn't run w/intake tube off so I used a PCV hose), just as bottle is empty turn truck off (so it can soak a bit) for 5-10 minutes, restart & drive @ about 4K RPM so it heat up & blow out broke-down carbon.

 

[hammerheadfistpunch]

Just to add to this discussion, here are what my cylinders look like

And my head was decked and rebuilt (new valve seats, re-shimmed, etc) so Im concerned that its NOT the combustion chamber. I have the same issues, they started AFTER the rebuild.

 

[Stevesnj]

That GM product isn't available anymore & now everybody advises the Mopar Combustion Chamber Cleaner (MCCC) is the best/strongest product out now. It's <$10 @ my local Dodge house. I did the MCCC per instructions Monday but let it sit for 1 hour ,instead of the instructions recommended 5-10 minutes. I got zero smoke after restarting & it did nothing for the pinging. I've read where most people advise to let it soak for 2+ hours. I'll do that next time I change my oil.

Here it is, it's still available.

http://autoplicity.com/products/408...1jW2QrGCVcuqm9G-tqU8wigyIwcWYFpv8gaAq628P8HAQ

 

[LFD2037]

Here it is, it's still available.

http://autoplicity.com/products/408...1jW2QrGCVcuqm9G-tqU8wigyIwcWYFpv8gaAq628P8HAQ

Different part. Last number is a 3 instead of the original that was a 2. The one you linked supersedes the 'strong' one. It's now a low VOC product & doesn't have near the strength it originally did. Thanks anyways!

 

[DylanICON]

I've done the poor man water down the intake a few times and it works surprisingly well. I don't think its that dangerous. just don't poor water down a stopped engine or you will bend a rod.

hold the throttle at about 1200-1500 rpm
squirt in water enough to make it stumble but not quite die.
crack throttle as needed to keep it running.
I did about 8oz, a little at a time.

had a neighbor with an old carbureted Montero that wouldn't shut off due to dieseling from carbon build up. did the water thing and it ran great afterward.

on a side note: I ran water injection on my super charged 3.4L Tacoma to control pinging due to boost. this allowed me to run more timing and get more power where typically they would retard timing on boosted engines to stop pinging. also works as an intercooler and has a similar effect to higher octane.
This was a electronically controlled mister system that used the fuel injector duty cycle signal to proportionally meter the water.

 

[Azca]

LFD, any updates on your progress? I did use 100 octane and it did seem to help the knock with a reduction of about 90%, but at $9 a gallon, that is not a solution. Just installed a new rear O2 sensor (had already replaced the front) and.... No change I will be getting colder plugs from Beno in the next few days and will throw them in on Sunday.

 

[LFD2037]

Still the only improvement is from the Shell 93 octane. Like you, it makes it about 90% better. $9/gallon????? It's $3.79 here ($.40 more than 87 octane). I agree, the higher octane isn't a solution. I posted on your other thread, too. It's been cooler here today so I haven't heard it ping @ all today. Saturday should be 90+* so I'm sure I'll hear it again!

 

[Azca]

Still the only improvement is from the Shell 93 octane. Like you, it makes it about 90% better. $9/gallon????? It's $3.79 here ($.40 more than 87 octane). I agree, the higher octane isn't a solution. I posted on your other thread, too. It's been cooler here today so I haven't heard it ping @ all today. Saturday should be 90+* so I'm sure I'll hear it again!

The $9 was for the "Racing" fuel, 100 octane. He also had 110 octane, also $9 but can' t legally dispense that fuel directly into a vehicle as it is for off road us only...

Our premium is 91 octane, don't know where to find 93 around here. Runs about the same price as your premium.

 

[Howard705]

Watch that racing fuel isn't leaded-usually why it's illegal. BAD for cats.

 

[mtullis]

I've had this same problem for about 5 years.

 

[LFD2037]

I've had this same problem for about 5 years.

Pings in summer but not in winter?

 

[mtullis]

Pings in summer but not in winter?

Yes, When I run run 91 octane it's about 90% gone just like yours.

 

[blkprj80]

Too lean could very well be a bad fuel pump relay.

The relay is "open" most times, forcing the current to go through the fuel pump resistor so the pump doesn't run so hard.
Then, when you need it (throttle up), it shorts across said resistor, sending full current to the pump, and giving the injectors the fuel they need.
The ECU doesn't measure the fuel pressure, so it doesn't know how much pressure is above the injectors.
If it isn't the relay, it could also be weak pump, dirty fuel sock, or possibly a dirty fuel filter. But I'd suspect the relay.

One way to check this is to watch the voltage across the fuel pump. Idling should be lower voltage. Startup and high speed runs with throttle, it should kick up to 12V or so. Probably easiest to check at startup, but I don't know how long it holds the relay closed.

My engine pings very briefly if I jump on it from a stop. I'm running 85 octane (Colorado). I don't hear any pinging with acceleration runs. I do have my timing advanced up around 7* I think.

I think there may be a thread saying how to bypass the fuel pump relay somewhere on here. The relay is up behind the fuse box, inside the fender IIRC.

Good Luck with it! Hope this helps.

 

[LFD2037]

I'm going to try to bypass the FPRelay today. I went back to 87 octane and within 45 miles it was pinging just like before. With the 93 octane I had to try to make it ping. So far octane level is the only thing that makes a difference. I'm waiting on a fuel filter and fuel pump filter to be delivered but from what others have said those 2 won't make a difference. I can't justify an extra $35 a month in higher octane fuel, especially since I'm already paying about $240/mo., just for it to not ping. I'll update after I figure out how to bypass FPRelay and what the result was. Doubt it'll make a difference seeing as octane makes such a huge difference.

 

[hammerheadfistpunch]

I'm going to try to bypass the FPRelay today. I went back to 87 octane and within 45 miles it was pinging just like before. With the 93 octane I had to try to make it ping. So far octane level is the only thing that makes a difference. I'm waiting on a fuel filter and fuel pump filter to be delivered but from what others have said those 2 won't make a difference. I can't justify an extra $35 a month in higher octane fuel, especially since I'm already paying about $240/mo., just for it to not ping. I'll update after I figure out how to bypass FPRelay and what the result was. Doubt it'll make a difference seeing as octane makes such a huge difference.

FYI, Im having mine looked at right now in the shop. It didn't ping before the head work and it does now, they are suspecting that the tension on the spring on the intake cam isn't set right. Ill let you know what they find today.

 

[Reelitchy]

Checked your post in the past and it doesn't look like you have changed the fuel pump relay. You have pulled the vacuum line on the FPR and you do have vacuum there and I believe you said the idle raised when you took the vacuum line off so that says that your FPR is lowering FP as needed.
I believe a lean condition is cause by opposite what we would think. High fuel psi would cause a lean condition because the ecu continues to try and lean out a rich condition. If you had low FP your ecu would cause you to run more rich. You can check this w your scan gauge also and I believe you have. Your voltage on your o2 sensor should be jumping back and forth between low and high volts showing that the ecu is switching between lean and rich mixture.
You may have a bad FP relay that is stuck with the contacts causing your pump to stay on full power. Pull the relay and make sure it is sending power to the resistor by putting 12 v on the relay and check for the switch on the terminals

Edit. Easy way to ck it. - disconnect fuel pump resister it should not run

 

[LFD2037]

My UG shows both O2's to be doing what they should be doing. The electrical jargon you used pertaining to the FPRelay is French to me. I'm not electrical savvy. Sorry and thanks.