Car running rich, why?
#1
Member
Thread Starter
Join Date: Apr 2000
Location: Tx
Posts: 107
Likes: 0
Received 0 Likes
on
0 Posts
Car running rich, why?
I cant pass emissions because of to much unburned fuel. I really dont know what todo. Help!
------------------
92 Firebird
305TBI, Edl.Tbi Perf.Manifold, Full exhaust, air intake, 16" wheels, Tbi spacer
------------------
92 Firebird
305TBI, Edl.Tbi Perf.Manifold, Full exhaust, air intake, 16" wheels, Tbi spacer
#2
Junior Member
Join Date: Mar 2001
Location: Lewisville, TX. USA
Posts: 38
Likes: 0
Received 0 Likes
on
0 Posts
I would suggest checking the vacuum line to the MAP sensor. If it is broken or missing that allows less vacuum to be on the MAP sensor which causes the ECM to think the car is @ WOT all the time (dumping quite a bit of fuel into the engine). This would definitly cause the unburned fuel problem.
Also I'm sure you checked spark @ all 8 cyl.
Also I'm sure you checked spark @ all 8 cyl.
![](https://www.thirdgen.org/messgboard/wink.gif)
#3
Senior Member
![](https://www.thirdgen.org/forums/images/ranks/tgo10.gif)
Join Date: Oct 1999
Posts: 6,621
Likes: 0
Received 1 Like
on
1 Post
Car: 91 Red Sled
Axle/Gears: 10bolt Richmond 3.73 Torsen
Ditto on the spark plug check. Then watch the injectors at idle, they shouldn't be firing too crazy and just have a friend give it a little gas, watch the rate increase. Do you have an aftermaket chip? Do you have any codes pop up?
Change the wires and the cap/points. Sometimes the easiest stuff gets overlooked.
Another option could be to get a MSD 6a box but that would be after you figure out the rich condition.
------------------
, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost
Change the wires and the cap/points. Sometimes the easiest stuff gets overlooked.
Another option could be to get a MSD 6a box but that would be after you figure out the rich condition.
------------------
, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost
- Holley 670 TB unit w/ 1/2" spacer/adapter
- Edelbrock RPM vortec intake
- 350ho 330hp vortec crate motor
- 8" harm. balancer
- Stewart stage 2 water pump w/160 thermo
- SLP tri-y headers to full 3"
- Rebuilt trans w/ SLP shift kit
- Centerline 16x8's all around
- 36/24 mm sway bars
- Full poly bushings, even motor mounts
- SLP LCA and panhard
- Alston SFCs
- Edelbrock 3 point STB
- Global west steering brace aka wonderbar
- Eibach pro kit springs
- Bilstien high perf. struts and shocks
- All this and I still have AC
#5
Member
Thread Starter
Join Date: Apr 2000
Location: Tx
Posts: 107
Likes: 0
Received 0 Likes
on
0 Posts
Well I put new plugs(NGK) and wires on. The plugs are a little hotter and I gaped them more than 3.5. Never knew those things could make such a diff. Runs great now! As far as the running rich, I think it was the vacume line dealing with the egr. Still a little more checking todo though.
#6
Senior Member
![](https://www.thirdgen.org/forums/images/ranks/tgo10.gif)
Join Date: Oct 1999
Posts: 6,621
Likes: 0
Received 1 Like
on
1 Post
Car: 91 Red Sled
Axle/Gears: 10bolt Richmond 3.73 Torsen
Good to hear it was the little stuff
. I had that same problem when I did my engine swap. The old wires were crap and there was major arcing, I changed them and the car runs without stalling and doesn't miss.
------------------
, Jon (350 TBI! it's trenuous and efficacious while getting 23mpg highway with off the shelf eprom)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost
![](https://www.thirdgen.org/messgboard/smile.gif)
------------------
, Jon (350 TBI! it's trenuous and efficacious while getting 23mpg highway with off the shelf eprom)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost
- Holley 670 TB unit w/ 1/2" spacer/adapter
- Edelbrock RPM vortec intake
- 350ho 330hp vortec crate motor
- 8" harm. balancer
- Stewart stage 2 water pump w/160 thermo
- SLP tri-y headers to full 3"
- Rebuilt trans w/ SLP shift kit
- Centerline 16x8's all around
- 36/24 mm sway bars
- Full poly bushings, even motor mounts
- SLP LCA and panhard
- Alston SFCs
- Edelbrock 3 point STB
- Global west steering brace aka wonderbar
- Eibach pro kit springs
- Bilstien high perf. struts and shocks
- All this and I still have AC
#7
Member
![](https://www.thirdgen.org/forums/images/ranks/tgo10.gif)
Join Date: Jan 2000
Location: New Boston, MI
Posts: 285
Likes: 0
Received 0 Likes
on
0 Posts
Car: 92 RS
Engine: 406 SBC
Transmission: 4R70W
Axle/Gears: Moser/Strange 9" 3.73, spool
You should also check the water temperature sensor on the intake manifold (at the front). If it's not working right, it will cause it to run rich and sometimes stall at idle. I know this because it's exactly what my car did before I changed it. Runs 100 times better now. Your air intake temperature sensor could do the same thing too (the one in the air cleaner).
------------------
1992 RS
305 TBI, Edelbrock Performer TBI, TPI heads, Open K&N filter, SLP 1 5/8" headers, !cat, custom 3" exhaust, Flowmaster 80 series, MSD 6-AL, MSD Blaster GM coil, Accel Cap and Rotor, Accell 8.8 MM wires, World Class T-5, B&M Ripper Shifter, Nitto 275/50/15 Drag Radials, Radial T/A's up front, LakeWood LCA's, Edelbrock panhard rod, Aluminum driveshaft, LakeWood Drag shocks, IROC rear springs, custom interior, etc.
------------------
1992 RS
305 TBI, Edelbrock Performer TBI, TPI heads, Open K&N filter, SLP 1 5/8" headers, !cat, custom 3" exhaust, Flowmaster 80 series, MSD 6-AL, MSD Blaster GM coil, Accel Cap and Rotor, Accell 8.8 MM wires, World Class T-5, B&M Ripper Shifter, Nitto 275/50/15 Drag Radials, Radial T/A's up front, LakeWood LCA's, Edelbrock panhard rod, Aluminum driveshaft, LakeWood Drag shocks, IROC rear springs, custom interior, etc.
Trending Topics
#8
Member
![](https://www.thirdgen.org/forums/images/ranks/tgo10.gif)
iTrader: (1)
Join Date: Dec 1999
Location: Chicago, IL
Posts: 138
Likes: 0
Received 1 Like
on
1 Post
Car: 1989 Trans AM GTA
Engine: 5.7 TPI - Stock
Transmission: 700R4
Your cat could be the culprit. If you still have the original catalytic convertor I would have it replaced. I failed emission test due to being to rich and passed when the new cat was incorporated.
#9
Member
Thread Starter
Join Date: Apr 2000
Location: Tx
Posts: 107
Likes: 0
Received 0 Likes
on
0 Posts
Well I finally passed! I changed my sparkplugs to a hotter plug and that seemed to work. H\c was at 22 instead of 448. I might have to look into replacing the water temp. sencor, its loose. Maybe the air sencor too, Its looking worn if you know what I mean. Thanks for all the help guys!
Thread
Thread Starter
Forum
Replies
Last Post