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#1 |
Registered User
Join Date: Mar 2003
Location: Wichita, KS
Posts: 137
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What the ....!!!!
I got new dual exhaust put on today...Looks great, Sounds great, but on the way home it's not running right???
![]() Seems like timming, but I can't figure out why it started now. I havn't drove it for several months, but on the way to the shop I didn't notice it running bad. On the way home it was backfiring, missing you name it. I havn't had time to look at it close yet, hopefully It'll be something simple. Any guesses?? By the way I got MagnaFlows with an H pipe, exiting back corners (Hidden Turndowns)...Looks great! Thanks.
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#2 |
go cyclones
Join Date: Jun 2003
Location: Ames, IA
Posts: 1,885
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You now have different back pressure and you are going to have to retime your engine.
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#3 |
Self-proclaimed LED man
Join Date: Nov 2003
Location: Harrisburg, Missouri
Posts: 1,021
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What size exhaust did they put on it? That will definately have an effect on the engine's performance. And it might not run right.
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My LED Website My Photobucket Album of LED's Ask me about hand-made custom L.E.D brake and reverse lights. <- LINK I also do LED: -Third Brake/Cargo -Brake (truck and burb) -Reverse (truck and burb) -67-68 Front Turn Signals -69-70 Front Turn Signals -71-72 Front Turn Signals -GMC Front Turn Signals I can also do custom lights for other vehicles....i did a set for a AMC Gremlin once ![]() Norwood Survivor |
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#4 |
Registered User
Join Date: Mar 2003
Location: Wichita, KS
Posts: 137
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That's what I was thinking but I didn't know it would make that much difference...
First thing I thought of was the cross over... Thanks, for the quick reply.
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#5 |
Registered User
Join Date: Mar 2003
Location: Wichita, KS
Posts: 137
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2.25" pipe
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#6 |
Registered User
Join Date: Mar 2003
Location: Wichita, KS
Posts: 137
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I will get the timming light out tonight and see what I can see..
I tried to time it once before, and finally had to take it in to the shop...The guy told me it was 180 out???? I don't see how this is possible and have it still run at all, but what ever he did made it run better. I guess I'll try again. Thanks.
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#7 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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if it's been sitting for awhile now might be a good time to change air and gas filters and throw a couple cans of drygas in the tank
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#8 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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New pipes would not make it backfire or miss .Did they have your plug wires off for any reason? If so a couple could be crossed.
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#9 |
Young Gun wth Fast Inline
Join Date: Jan 2002
Location: Idaho
Posts: 1,475
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I agree with the wires. New exhaust wont make that much difference in timming. The main thing i would worry about if you have headers too is the fuel mixture will need to be richened. Which is carb. An engine will not run 180 off either so i guess im confused.
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#10 |
Robert Olson Transport
![]() Join Date: Oct 2002
Location: recent transplant to NC USA
Posts: 20,294
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not only off make sure that they didnt make any of the ignition wires or any of the harness touch the manifolds or pipes that will short it out or cause a miss too
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#11 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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I'll asume the headers were new. If so, look for a primary tupe that still has paint on it...that will be the cylinder not fireing.
If they all have paint burned off, then I would go over the fireing order...the 5 & 7 get flip flopped quite easily, and it'll run about like you describe. |
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#12 |
Registered User
Join Date: Feb 2001
Location: Wetumpka, Al, U.S.
Posts: 8,891
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also make sure they didn't put the mufflers on backwards!
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#13 |
Registered User
Join Date: Mar 2003
Location: Wichita, KS
Posts: 137
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I checked the timming, and it was about 14 BDC, I adjusted it from 4 to 16 and all in between. I think it should be at about 8. It runs better at about 14, but the problem is there through out all adjustments.
I swaped the cap with my daily driver, no difference. It has that da....da...da..da.da.dadada sound when you get on the throttle, missing!!! Checked all wires, didn't see anything bad. It has the original rams horn exhaust manifolds, so I can't tell which cylinder is the culprit witht the paint trick. I tried pulling a plug wire off here and there, but it doesn't seem to change it? I put the timing light on all the wires, and all appear to be firing, but I don't think that is a good test. Will try again tomorrow. Thanks, for all the replies. It just realy pisses you off when you fianally spend the money for new exhaust and it won't run to hear and feel it.... ![]() Thanks.
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#14 |
My other Love
Join Date: Aug 2001
Location: Castlegar B.C. Canada
Posts: 4,085
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hmm does it have HEI? hows the distributor cap? firing order right?
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#15 |
Registered User
Join Date: Jan 2003
Location: Central Cal
Posts: 124
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I had a simlar problem after I had exhust done. This might sound weird, but the guy that welded my exhust used a mig welding machine. Well as most of you know welding with a mig uses high current between the neg or ground and the mig tip of the gun. Well come to find out what had happened is that the electic current from the welder shorted out the HEI unit, and that what was causing the mis-fire. So word of caution, always disconect the ground from the battery or disconect the dist from all of your electric system before you have any welding done.
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#16 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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You can spray water onto the manifolds after a few min of running to get the same effect as the paint deal.
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#17 |
Registered User
Join Date: Mar 2003
Location: Wichita, KS
Posts: 137
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That is wild Onelow69, but I have points....thinking about going HEI maybe will befire I get this problem resolved.
I will try the water deal tomorrow. Thanks Longhorn Man
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#18 | |
Registered User
Join Date: Mar 2001
Location: springfield ill
Posts: 836
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Quote:
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