1846 backfire? O

all of a sudden i'm backfireing while in gear and decellerateing, and have lost alot of power while driveing, i've got less then half my boost, and all my plugs were charcol black, one even felt rough to the touch like crap had been melted onto it, any idea's guy's? i dont have to drive it for a few day's so i have a little bit to figure it out and if it's safe enough to drive without hurtin anything

Sounds like your running too rich....was that too obvious an answer? Sorry.

i thought about that too but i adjusted the carb and still had the same problem?

Any black smoke out the pipe? or smells?

nope, nothing that i've noticed

Wow, this is almost like I.M., I dunno then, sounds like you need super-tech advice which I am not.

well back to my 10 MPG truck untill it's figured out then

Maybe ck the timming again , distributor loose
Still running points-condensor(new ones)? Get a electric ignition if you dont have one already.

I dont know unless a main jet got loose in a carb but highly dought it

fixed it, dont know what i did to do it tho... oh well, at least it's fixed

guess it's not fixed.. it only seem's to be in the higer rpm's though, could incresed backpressure do that? im also loosing 3/4's of my boost as well

maybe an exhaust leak before the turbo, will cause a loss of boost and a decell backfire , with a carb the fuel mixt can be very rich on decell , air will enter the exhaust through the leak and the mixture in the exhaust ignites causing a backfire.

k, i'll check that tomorrow, thx

Check your coil. sounds like you have a weak one. Under boost the plugs need plenty of voltage to jump the gap especially under boost.

could my turbo going out cause these kind of problem's? i'm getting 1PSI of boost now but i dont seem to have lost any more power then before (im going to replace most of the electrical stuff soon because after i come to a stop, i try to go again and i have to rev it a few time's before the idle straighten's out enough for me to take off, wont be driveing it too much anymore untill i get this figured out)

What kinda carbs are you running? It sounds like you're describing the same type of prob my friend is having with his SU's. When was the last rebuild on your carbs? Dual-sides or single-up?

have no clue the last time it was rebuilt, running a single weber

but i dont think it has anything to do with my carb, my car run's perfectly, i barely get any backfire anymore except at high RPM's, and now im getting spuratic boost pressure, i'll have 1 PSI one minute, then 5 minute's later i romp on it again and i'll have my full 12 PSI

May be the turbo, dude.

that's what im thinking, i just dont want to have to shell out for a new one

anyone know approx how much it cost's to get one rebuilt?

take your chance at a junkyard, find out what kind you've got. t3 probly.

it's an old rayjay out of a VW bug turbo kit, i read on a sight i found that the one out of a 300ZX would fit on nicely

Author	Message
anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Topic: backfire? O_o Posted: 02 September 2004 at 9:22pm
	all of a sudden i'm backfireing while in gear and decellerateing, and have lost alot of power while driveing, i've got less then half my boost, and all my plugs were charcol black, one even felt rough to the touch like crap had been melted onto it, any idea's guy's? i dont have to drive it for a few day's so i have a little bit to figure it out and if it's safe enough to drive without hurtin anything
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defdes Enthusiast Joined: 17 May 2003 Location: United States Posts: 849	Posted: 02 September 2004 at 9:31pm
	Sounds like your running too rich....was that too obvious an answer? Sorry.
	'72 LZ22 510 '71 L16 510 Vintage CS Racer
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 02 September 2004 at 9:31pm
	i thought about that too but i adjusted the carb and still had the same problem?
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defdes Enthusiast Joined: 17 May 2003 Location: United States Posts: 849	Posted: 02 September 2004 at 9:33pm
	Any black smoke out the pipe? or smells?
	'72 LZ22 510 '71 L16 510 Vintage CS Racer
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 02 September 2004 at 9:33pm
	nope, nothing that i've noticed
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defdes Enthusiast Joined: 17 May 2003 Location: United States Posts: 849	Posted: 02 September 2004 at 9:36pm
	Wow, this is almost like I.M., I dunno then, sounds like you need super-tech advice which I am not.
	'72 LZ22 510 '71 L16 510 Vintage CS Racer
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 02 September 2004 at 9:37pm
	well back to my 10 MPG truck untill it's figured out then
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Hainz Guru Joined: 03 December 2002 Posts: 3122	Posted: 03 September 2004 at 12:29am
	Maybe ck the timming again , distributor loose Still running points-condensor(new ones)? Get a electric ignition if you dont have one already. I dont know unless a main jet got loose in a carb but highly dought it
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 03 September 2004 at 6:50pm
	fixed it, dont know what i did to do it tho... oh well, at least it's fixed
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 03 September 2004 at 9:23pm
	guess it's not fixed.. it only seem's to be in the higer rpm's though, could incresed backpressure do that? im also loosing 3/4's of my boost as well
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ZEED Novice Joined: 24 January 2004 Location: United States Posts: 33	Posted: 04 September 2004 at 12:15am
	maybe an exhaust leak before the turbo, will cause a loss of boost and a decell backfire , with a carb the fuel mixt can be very rich on decell , air will enter the exhaust through the leak and the mixture in the exhaust ignites causing a backfire.
	79 620 WITH 83 280Zx TURBO ENGINE,TRANS, INDEPENDENT REAR END,280Z 4-BOLT FRONT HUBS WITH 300ZX ROTORS & 88 TOYOTA 4X4 TRUCK CALIPERS,18INCH WHEELS, DOING BODYWORK NOW.
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 04 September 2004 at 12:26am
	k, i'll check that tomorrow, thx
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74wagon710 Enthusiast Joined: 14 March 2004 Location: United States Posts: 925	Posted: 04 September 2004 at 4:19pm
	Check your coil. sounds like you have a weak one. Under boost the plugs need plenty of voltage to jump the gap especially under boost.
	74 Datsun 710 wagon, all original now, near perfect shape, project vehicle now. 83 Hell Camino. 07 Civic Si Coupe. 07 Yamaha R1
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 05 September 2004 at 4:01am
	could my turbo going out cause these kind of problem's? i'm getting 1PSI of boost now but i dont seem to have lost any more power then before (im going to replace most of the electrical stuff soon because after i come to a stop, i try to go again and i have to rev it a few time's before the idle straighten's out enough for me to take off, wont be driveing it too much anymore untill i get this figured out)
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808DA6 Enthusiast Joined: 12 August 2004 Location: United States Posts: 243	Posted: 06 September 2004 at 8:35am
	What kinda carbs are you running? It sounds like you're describing the same type of prob my friend is having with his SU's. When was the last rebuild on your carbs? Dual-sides or single-up? ~B
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 06 September 2004 at 9:01am
	have no clue the last time it was rebuilt, running a single weber but i dont think it has anything to do with my carb, my car run's perfectly, i barely get any backfire anymore except at high RPM's, and now im getting spuratic boost pressure, i'll have 1 PSI one minute, then 5 minute's later i romp on it again and i'll have my full 12 PSI
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Ryan in Seattle Expert Joined: 08 December 2002 Location: United States Posts: 2701	Posted: 06 September 2004 at 10:19am
	May be the turbo, dude.
	1973 620 "Prerunner" L20B,A87,5spd.Lynx,40dcoe, header,cammed & bored. zx oil pump,starter,headbolts & water pump/pulley.
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 06 September 2004 at 6:30pm
	that's what im thinking, i just dont want to have to shell out for a new one anyone know approx how much it cost's to get one rebuilt?
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Ryan in Seattle Expert Joined: 08 December 2002 Location: United States Posts: 2701	Posted: 06 September 2004 at 8:32pm
	take your chance at a junkyard, find out what kind you've got. t3 probly.
	1973 620 "Prerunner" L20B,A87,5spd.Lynx,40dcoe, header,cammed & bored. zx oil pump,starter,headbolts & water pump/pulley.
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anubis_4_99 Enthusiast Joined: 22 April 2004 Location: United States Posts: 346	Posted: 06 September 2004 at 10:58pm
	it's an old rayjay out of a VW bug turbo kit, i read on a sight i found that the one out of a 300ZX would fit on nicely
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