Quiz of the day - Crazy idle after header and exhaust install
02-16-2009, 07:11 PM
#21
When you did the exhuast install did you reset the ECU?
Are you sure that the light bulb in you dash for check engine is not burnt out?
I try to pull codes anyway, but you may want to reset the ECU and see what happens first. What size tubing did you use?
Are you sure that the light bulb in you dash for check engine is not burnt out?
I try to pull codes anyway, but you may want to reset the ECU and see what happens first. What size tubing did you use?
02-16-2009, 07:17 PM
#24
Contributing Member
Thread Starter
the CEL does come on when the key's turned before the truck starts, so I know the bulb's good
according to Summit (that's the kit I bought, and where I bought it from), it's 2" to the muffler, and 2.25" after the muffler. And the header, once again, according to Summit, 1.5" primaries leading to a 2.5" collector
02-16-2009, 07:21 PM
#27
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Thread Starter
there's a not-so-old gasket on there from when I removed the intake a while back, but I'll be sure to hit around there when I do the ol "spray the starter fluid" test 
yall have got me curious... I'm going to go and unhook it and leave it overnight and see what happens in the morning, lol
yall have got me curious... I'm going to go and unhook it and leave it overnight and see what happens in the morning, lol
Last edited by iamsuperbleeder; 02-16-2009 at 07:22 PM.
02-16-2009, 07:34 PM
#29
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Thread Starter
ok, unhooking the battery(s) took all of a minute 
I'll get out the door a few minutes earlier in the morning and hook er back up and see how that works
as for now, I'm go'n to bed
wish me luck guys
I'll get out the door a few minutes earlier in the morning and hook er back up and see how that works
as for now, I'm go'n to bed
wish me luck guys
02-17-2009, 10:33 AM
#31
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Just throwing things out there...
It's possible that with the reduced backpressure, you have too much valve overlap and it's killing your vacuum, causing you to run lean. Similar to how aggressive cams kill vacuum and either require adjusting the AFM and idle speed or switching out the stock EFI for something more capable. I'd put a vacuum gauge on the manifold and see what sort of vacuum it's pulling and whether it's a constant vacuum or if it surges. If you have the valves set to the tight end, you may try loosening them a thousandth or two and see how it goes.
I'm guessing you have the TPS set properly- but if it's not, the ECU could be looking at the O2 for feedback and since the exhaust is flowing better, the O2 won't be a hot as it should and this could cause the idle to act strange.
It's possible that with the reduced backpressure, you have too much valve overlap and it's killing your vacuum, causing you to run lean. Similar to how aggressive cams kill vacuum and either require adjusting the AFM and idle speed or switching out the stock EFI for something more capable. I'd put a vacuum gauge on the manifold and see what sort of vacuum it's pulling and whether it's a constant vacuum or if it surges. If you have the valves set to the tight end, you may try loosening them a thousandth or two and see how it goes.
I'm guessing you have the TPS set properly- but if it's not, the ECU could be looking at the O2 for feedback and since the exhaust is flowing better, the O2 won't be a hot as it should and this could cause the idle to act strange.
02-17-2009, 05:40 PM
#32
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Thread Starter
weeeeell, the ECU reset didn't do didly squat... I had my hopes up for that too...
had a meeting after work today, so I didn't get the time I wanted to fool around with it, but I did stop by the part's store on the way home and tinker with it a bit.
I started just by grabing some starter fluid and shooting around to find a vaccum leak... no go...
I did find one thing interesting though; I took the air filter off, and with the truck idling, I gave one quick shot into the intake of the AFM, the the idle smoothed out for a couple second! this leads me to believe it's a lack of fuel, since the introduction of fuel smooths it out.
so out of curiosity, I popped the cover off the AFM, marked the OEM spot (yeah, I've learned from that mistake in the past), and loosened the tention up on the spring to open the flap a little. The RPM's came up a little, but it still idled irratically... I went a little further, then things got worse... I bounced back and forth, flicking the throttle a few times with each adjustment, and every try still left me with a crappy idle... so I said screw it, and I put it back to the OEM mark and put the cover back...
so then I played with the timing real quick just for kicks, and that did absolutely nothing...
I really don't know what's going on here... it's driving me absolutely insane...
if I get the time tomorrow, I'll change the plugs, regardless of how they look, just to see what happens... their all of $2 a peice... I might even do the cap and rotor...
but on a good note, I did come home to $1200 worth of computer parts I ordered last week for my new computer build
that's my other hobby... I should have kept the $1200 though and maybe bought a new motor 
had a meeting after work today, so I didn't get the time I wanted to fool around with it, but I did stop by the part's store on the way home and tinker with it a bit.
I started just by grabing some starter fluid and shooting around to find a vaccum leak... no go...
I did find one thing interesting though; I took the air filter off, and with the truck idling, I gave one quick shot into the intake of the AFM, the the idle smoothed out for a couple second! this leads me to believe it's a lack of fuel, since the introduction of fuel smooths it out.
so out of curiosity, I popped the cover off the AFM, marked the OEM spot (yeah, I've learned from that mistake in the past
), and loosened the tention up on the spring to open the flap a little. The RPM's came up a little, but it still idled irratically... I went a little further, then things got worse... I bounced back and forth, flicking the throttle a few times with each adjustment, and every try still left me with a crappy idle... so I said screw it, and I put it back to the OEM mark and put the cover back...so then I played with the timing real quick just for kicks, and that did absolutely nothing...
I really don't know what's going on here... it's driving me absolutely insane...
if I get the time tomorrow, I'll change the plugs, regardless of how they look, just to see what happens... their all of $2 a peice... I might even do the cap and rotor...
but on a good note, I did come home to $1200 worth of computer parts I ordered last week for my new computer build
that's my other hobby... I should have kept the $1200 though and maybe bought a new motor
Last edited by iamsuperbleeder; 02-17-2009 at 06:05 PM.
02-17-2009, 07:43 PM
#34
Registered User
You're not one of those hacker people are you?
Back to the problem you seem to have with the yota. I noticed you said that it ran smoother after a shot of fluid, thus leading you to think it might be a fuel delivery issue. Have you checked the "O" rings on the injectors and the injectors themselves? I know if the little ring goes out or has a rip it will make the idle odd and I also know that a funky injector will cause off idle. This idle problem may not have anything to do with the new exhaust it may have just cropped up at an odd time. Just a thought.
02-17-2009, 08:08 PM
#35
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I am going to keep my eye on this post. If you find the problem please post what the solution is. I am having a very similar problem, my truck seems to be doing the same exact thing. I have a lc header, engnbldr street rv head, 268 cam, jardine cat back. I have a very similar idle, (it sounds just like my truck). I have checked the vacuum hoses, new injectors, new tps, new o2 sensor, cleaned the intake, etc. I am also beating my head against the wall trying to figure out why it idles like that. I have searched through posts but every one seems to not find a solution, or they don't post it. I think I may take abecedrian advice and try a little looser valve clearance, I have mine on the tight side. I have heard the saying, a tappy engine is a happy engine.
02-18-2009, 03:26 AM
#37
Contributing Member
Thread Starter
on what? 
Ok, $1,000... my $200 case will show up today
about the injector o-rings, I sprayed all around there with the starting fluid though; I figured if that's what it was, it would have sucked some fluis through there...
1200$????? What on earth are you building? I just built a new system for half that from Newegg.
You're not one of those hacker people are you?
Back to the problem you seem to have with the yota. I noticed you said that it ran smoother after a shot of fluid, thus leading you to think it might be a fuel delivery issue. Have you checked the "O" rings on the injectors and the injectors themselves? I know if the little ring goes out or has a rip it will make the idle odd and I also know that a funky injector will cause off idle. This idle problem may not have anything to do with the new exhaust it may have just cropped up at an odd time. Just a thought.
You're not one of those hacker people are you?
Back to the problem you seem to have with the yota. I noticed you said that it ran smoother after a shot of fluid, thus leading you to think it might be a fuel delivery issue. Have you checked the "O" rings on the injectors and the injectors themselves? I know if the little ring goes out or has a rip it will make the idle odd and I also know that a funky injector will cause off idle. This idle problem may not have anything to do with the new exhaust it may have just cropped up at an odd time. Just a thought.
about the injector o-rings, I sprayed all around there with the starting fluid though; I figured if that's what it was, it would have sucked some fluis through there...
02-18-2009, 02:28 PM
#39
Contributing Member
Thread Starter
