98 Ram 1500 318 backfires when engine is cold

rnered · 08-19-2009, 12:42 PM

Hello,

Hope you can help. I have a 98 Ram with 94K miles. I cannot find what is causing it to backfire wen cold. I've changed the plugs, wires, coil, #1 fuel injector (would get a 301 error occationally but didn't seem to get the code when the truck was sputtering), and now I just change the TPS. I've read through the forum and cannot get any other info. Any suggestions would be greatly appreciated.
Regards,
Rick

BernieB · 08-19-2009, 01:09 PM

Backfiring is caused when unburned fuel ignites in the exhaust, or as the exhaust valve opens. Since it only happens cold I suspect you're running too rich, or the timing is being retarded too much. Check the timing and make sure it's to spec and check your airflow for restrictions.

rnered · 10-08-2009, 05:37 PM

well after four machanics, it sounds like it "may" be carbon build up on the number one cylinder valve. The last mechanic isolated the issue to the #1 cylinder by performing a leak test. It showed 65% leakage. He said that may be caused by the cam being worn down , the piston ring, or a burnt valve. These repairs would cost anywhere from 2000 to 3500. the blue book on the truck is 2000. I ended up pouring some seafoam down the air intake. This seemed to help the issue. I will perform this one more time to see if it will resolve the issue entirely. Hope that helps.

BernieB · 10-08-2009, 09:17 PM

A worn cam can't possibly cause leakage through the valves. The cam would have to actually "grow", rather than wear down, for it to keep the valve open like that.

leolkfrm · 10-09-2009, 04:58 AM

was anyone adjusting on the valves lately? maybe to quiet a noisy one?

6.9CLUNKER · 10-12-2009, 11:05 PM

Check your throttle body for carbon buildup as well, Dodge trucks are known for getting carbon buildup on them - clean with brake cleaner or throttle body cleaner if dirty(remove throttle body from truck if possible - but you will need new gaskets).
Carbon buildup wreaks havoc with TPS sensor and IAC motor.

08-19-2009, 01:09 PM	#2
BernieB Senior Member Join Date: Jul 2009 Location: Fredericksburg, VA Posts: 1,906	Backfiring is caused when unburned fuel ignites in the exhaust, or as the exhaust valve opens. Since it only happens cold I suspect you're running too rich, or the timing is being retarded too much. Check the timing and make sure it's to spec and check your airflow for restrictions. __________________ If the guys who design 'em had to take one home, use it every day for 2 years, and do all the maint and repairs themselves, cars would have a button on the dash to change the oil, filters & plugs.

10-08-2009, 05:37 PM	#3
rnered Junior Member Join Date: Aug 2009 Posts: 2	98 Ram backfiring well after four machanics, it sounds like it "may" be carbon build up on the number one cylinder valve. The last mechanic isolated the issue to the #1 cylinder by performing a leak test. It showed 65% leakage. He said that may be caused by the cam being worn down , the piston ring, or a burnt valve. These repairs would cost anywhere from 2000 to 3500. the blue book on the truck is 2000. I ended up pouring some seafoam down the air intake. This seemed to help the issue. I will perform this one more time to see if it will resolve the issue entirely. Hope that helps.

10-08-2009, 09:17 PM	#4
BernieB Senior Member Join Date: Jul 2009 Location: Fredericksburg, VA Posts: 1,906	A worn cam can't possibly cause leakage through the valves. The cam would have to actually "grow", rather than wear down, for it to keep the valve open like that. __________________ If the guys who design 'em had to take one home, use it every day for 2 years, and do all the maint and repairs themselves, cars would have a button on the dash to change the oil, filters & plugs.

10-09-2009, 04:58 AM	#5
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	was anyone adjusting on the valves lately? maybe to quiet a noisy one? __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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08-19-2009, 12:42 PM	#1
rnered Junior Member Join Date: Aug 2009 Posts: 2	98 Ram 1500 318 backfires when engine is cold Hello, Hope you can help. I have a 98 Ram with 94K miles. I cannot find what is causing it to backfire wen cold. I've changed the plugs, wires, coil, #1 fuel injector (would get a 301 error occationally but didn't seem to get the code when the truck was sputtering), and now I just change the TPS. I've read through the forum and cannot get any other info. Any suggestions would be greatly appreciated. Regards, Rick

10-12-2009, 11:05 PM	#6
6.9CLUNKER Full Member Join Date: Oct 2009 Location: SAN PERLITA TEXAS Posts: 11	Check your throttle body for carbon buildup as well, Dodge trucks are known for getting carbon buildup on them - clean with brake cleaner or throttle body cleaner if dirty(remove throttle body from truck if possible - but you will need new gaskets). Carbon buildup wreaks havoc with TPS sensor and IAC motor.

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