Sputtering.. Backfiring
10-28-2009, 07:32 AM
#1
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Sputtering.. Backfiring
my 94 4runner 3.0 didnt make it to work today cause the sputtering and backfiring got worse this morning. ran seafoam through it, changed out the plugs, dist. and rotor, regapped the injectors, head gaskets all new, fuel pump and filter changed, timing set correctly... used a piece of paper to see if the exhaust would suck it in thinking valves were sticking, thank god it didnt. sat it running warm in neutral and brought the rpms to the redzone and thats when the sputtering/backfiring/popping sound came to play. opened up the vafm and pressed on the flapper and it boggled out so im guessing its okay, just guessing.. would my o2 sensor cause any of these symptoms?.. how hard is it to adjust the tps or should i just replace it. and if i replace it, is it just a screw-in kind of job or do i have to adjust other components like the timing. went to autozone to see if they could run me some trouble codes but they said they couldnt diagnose from 94's.. only 95 and newer. i tried to jump t1 and e1 with a paperclip but its not working. im getting no flashes whatsoever. been driving with this problem for a couple weeks now and my CEL hasnt came on once yet. please help!!!
10-28-2009, 07:51 AM
#2
Registered User
Check for vacuum leaks? Timing set correctly (as in you jumped the terminals when setting it)?
TPS isn't just a bolt on, would need to adjust it to spec.
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
I have read that if the TPS is bad and you unplug it and the vehicle runs better then it could be the TPS.
TPS isn't just a bolt on, would need to adjust it to spec.
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
I have read that if the TPS is bad and you unplug it and the vehicle runs better then it could be the TPS.
Last edited by BoostinChick; 10-28-2009 at 07:53 AM.
10-28-2009, 08:15 AM
#3
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
fixed the vacuum leak. ended up being my intake hose cracked on the bottom, replaced it with a new one. still sputtering/backfiring. i had my timing reset by the my mechanic just recently. are u saying i can run it with the tps unplugged. i'll give it a try. also i noticed that my dashpot lost its cap, therefore its missing its seperator, and filter for it. i had it running like that since i got the vehicle couple years ago and it didnt give me problems then.
10-28-2009, 08:28 AM
#4
Registered User
Join Date: Mar 2008
Location: Temecula Valley, CA
Posts: 12,723
Likes: 0
Received 4 Likes
on
4 Posts
Afterfiring (out the tail pipe) and backfiring (up through the intake) are usually caused by one (or more) of: a spark plug firing when an intake valve (backfire) or exhaust valve (afterfire) is open; hot spots in a cylinder causing spontaneous combustion when a valve is open; unburned fuel spontaneously combusting when it hits a hot section of the exhaust; overly lean or rich fuel mixture; significant vaccum leak.
That it is happening at higher RPM's makes me think it's an inconsitancy in the ignition system, possibly the igniter module, but I can't rule out an injector that is not operating properly resulting in a lean condition at higher flow / RPM conditions.
I've mentioned it elsewhere, that my 88 4Runner behaved similarly when its igniter started going south, getting progressively worse over a few months. It only triggered a CEL condition when it was at its worse. What was happening was the igniter was creating multiple spark events when it shouldn't, and was causing backfiring, afterfiring and such.
That it is happening at higher RPM's makes me think it's an inconsitancy in the ignition system, possibly the igniter module, but I can't rule out an injector that is not operating properly resulting in a lean condition at higher flow / RPM conditions.
I've mentioned it elsewhere, that my 88 4Runner behaved similarly when its igniter started going south, getting progressively worse over a few months. It only triggered a CEL condition when it was at its worse. What was happening was the igniter was creating multiple spark events when it shouldn't, and was causing backfiring, afterfiring and such.
10-28-2009, 09:32 AM
#6
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
okay so i went back under the hood and jumpered t1 and e1 again. i counted the flashes and they were consistent as followed... 1111..1..1..11..1111..1..1..11..1111..1..1..11 and so on... gonna do a search on what these mean.
Trending Topics
10-28-2009, 09:55 AM
#9
Registered User
Join Date: Mar 2008
Location: Temecula Valley, CA
Posts: 12,723
Likes: 0
Received 4 Likes
on
4 Posts
got to ask... there should be a short pause between digits of the same code and a long pause between individual codes.
so it was like 4-1---1-2---4-1---1-2, right?
so it was like 4-1---1-2---4-1---1-2, right?
10-28-2009, 09:59 AM
#10
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
alright i just jumpered it one more time to make sure that i was getting the same codes as my first time.... still going.... it actually started with a one-flash.... ,it went , 1 pause 2 pause 4 pause 1, and then it repeats itself... abecedarian i appreciate your help very much. are those the only codes u mentioned related to the flashes that i'm having? tps signal and igniter
10-28-2009, 10:53 AM
#12
Registered User
All your pauses are confusing me.
It should flicker, then short pause, then flicker. If you have more than one code that's where the long pause comes in. Count how many times the CEL flickers that is the first digit, it will do a short pause, then count how many times it flickers again.
http://www.4crawler.com/4x4/CheapTri...CheckConnector
http://www.off-road.com/toyota/tech/codes/index.html
It should flicker, then short pause, then flicker. If you have more than one code that's where the long pause comes in. Count how many times the CEL flickers that is the first digit, it will do a short pause, then count how many times it flickers again.
http://www.4crawler.com/4x4/CheapTri...CheckConnector
http://www.off-road.com/toyota/tech/codes/index.html
Last edited by BoostinChick; 10-28-2009 at 11:04 AM.
10-28-2009, 11:05 AM
#13
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
okay let me try this again...it went.... flash, pause, flashx2, pause, flashx4,pause, flash, long pause and then it started all over again. im thinking abe got it right,... code 12 and 41... high rpms.. and tps
10-28-2009, 04:43 PM
#14
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
so i spent the day trying to figure out the problem with my tps... i unplugged it with the engine on and the idle changed a bit. assuming my tps is still working. i adjusted it a little by loosening the screws. didnt have a guage feeler like the directions say so i just left it at that. being that its very cold and windy out here in vegas, i managed to take it for a spin. didnt feel any sputtering/backfiring. im still however flooring the gas and riding 3rd gear to keep up wit traffic. soon as i got home i jumpered t1 and e1 so see if any change... all it did was flash constantly with no pauses. weird i thought.. so i unplugged the efi fuse and disconnected the battery terminals and replugged it all again, then jumpered it once again.... same constant flashing. hmmm.. guess i'll find out tomorrow morning if that light comes on and also the sputtering.
10-28-2009, 05:05 PM
#15
May i ask why your reving your engine in the red zone? Red means no no... so um yea i'd not do that.... possible egr problem as well with your tps. Unplug egr vac line and see results....
10-28-2009, 05:11 PM
#16
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
sorry i had my foot too heavy on the gas while i was watching all the smoke empty out after i ran some seafoam through it. oops my bad.. i disconnected the vacuum hoses from the egr with the engine running and didnt notice anything, idle stayed the same. my first time checking it, can u tell me what i should be looking.
10-30-2009, 07:37 PM
#19
Registered User
Thread Starter
Join Date: Jan 2007
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
removed the egr and blocked everything off, just temporarily. took it for a drive and no sputtering occured at all. guessing the egr was going downhill afterall. i wouldve replaced the egr but right now im outta cash right now and really need to get my car back up and running. thanks for everyones help. i'll replace the egr when i can afford it. just a question, i live in vegas and we require to get smogged every year prior to renewing registration, has anyone passed emissions without the egr hook up?
Thread
Thread Starter
Forum
Replies
Last Post
