What else could make it run rich?
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Le Mans Master
Joined: Feb 2006
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From: Louisiana
What else could make it run rich?
I had a code 33 and got that fixed and thought that this was my rich problem. The exhaust fumes will burn your eyes. I have a 36 psi fuel pressure and just installed 24# injectors before I got it running again (ran just like this before my fuel problems). It cranks and drives but is down on HP end and he whole car shakes while it idles. The car has a chip, but don't know what kind was installed by previous owner. New NGk spark plugs and minor modifications. My service manuel is running late in the mail. Can anyone give me some pointer on the running rich or shake at idle problems. Thanks, early 1986 vette
Race Director
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From: Sharpsburg Georgia
GA Events Coordinator
Originally Posted by RRT vette
No, where could I get one? and what am I scanning for?
I would look to see what your mass air flow or map looked like, look at your o2 counts.
which car are you working on?
Thread Starter
Le Mans Master
Joined: Feb 2006
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From: Louisiana
Originally Posted by Sinister87
You could have an exhuast leak tricking your O2 sensor into thinking your lean or maybe bad tune or fpr.
Thread Starter
Le Mans Master
Joined: Feb 2006
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From: Louisiana
Originally Posted by blown87
Almost any shop will have something like the Snap-On brick scan tool.
I would look to see what your mass air flow or map looked like, look at your o2 counts.
which car are you working on?
I would look to see what your mass air flow or map looked like, look at your o2 counts.
which car are you working on?
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Race Director
Joined: Sep 2005
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From: Sharpsburg Georgia
GA Events Coordinator
Originally Posted by RRT vette
86 vette
do you have a FSM and a digital volt meter?
Sorry, i guess i did not see the 86 in your first post, i looked and saw where you had a vert too so that is where that came from.
Thread Starter
Le Mans Master
Joined: Feb 2006
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From: Louisiana
Originally Posted by blown87
Could be the tune, the injectors, the coolant temp sensor, the mass air flow meter, o2 sensor problems, etc.
do you have a FSM and a digital volt meter?
Sorry, i guess i did not see the 86 in your first post, i looked and saw where you had a vert too so that is where that came from.
do you have a FSM and a digital volt meter?
Sorry, i guess i did not see the 86 in your first post, i looked and saw where you had a vert too so that is where that came from.
Last edited by RRT vette; Mar 18, 2006 at 11:58 AM.
Le Mans Master
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From: San Diego, Ca
A scan may only tell you that the O2 senses a lean condition, so the ECM is adding fuel. The exhaust leak you hear would be the primary suspect. Other causes would be air that gets into the system after the MAF. This includes vacuum leaks or a faulty air pump system. To check the latter out, clamp off the hoses to the headers. If the rich condition is gone, remove the hoses and make sure there is no air flowing to the headers once it's warmed up. If not, one or more of the check valves are probably bad. Remove and make sure air only flows through them in the direction of the headers.
Thread Starter
Le Mans Master
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From: Louisiana
Originally Posted by SunCr
A scan may only tell you that the O2 senses a lean condition, so the ECM is adding fuel. The exhaust leak you hear would be the primary suspect. Other causes would be air that gets into the system after the MAF. This includes vacuum leaks or a faulty air pump system. To check the latter out, clamp off the hoses to the headers. If the rich condition is gone, remove the hoses and make sure there is no air flowing to the headers once it's warmed up. If not, one or more of the check valves are probably bad. Remove and make sure air only flows through them in the direction of the headers.
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Vac leaks will cause it too yes, my bet is that you have that or an O2 problem.
Did all your other codes disappear after the 33 was fixed?
O2 failures also rarely register a code fault.
Did all your other codes disappear after the 33 was fixed?
O2 failures also rarely register a code fault.
Thread Starter
Le Mans Master
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From: Louisiana
Originally Posted by vader86
Vac leaks will cause it too yes, my bet is that you have that or an O2 problem.
Did all your other codes disappear after the 33 was fixed?
O2 failures also rarely register a code fault.
Did all your other codes disappear after the 33 was fixed?
O2 failures also rarely register a code fault.
Team Owner
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From: Athens AL
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Open or shorted or loose knock sensor.
Excessive mechanical noise within engine.
Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM.
Intermittent open in the EST line to the ignition module.
So, both the 43 and this particular problem could be due to an improperly installed chip. If you have the original chip, i'd put that back in.
Excessive mechanical noise within engine.
Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM.
Intermittent open in the EST line to the ignition module.
So, both the 43 and this particular problem could be due to an improperly installed chip. If you have the original chip, i'd put that back in.
Thread Starter
Le Mans Master
Joined: Feb 2006
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From: Louisiana
Originally Posted by vader86
Open or shorted or loose knock sensor.
Excessive mechanical noise within engine.
Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM.
Intermittent open in the EST line to the ignition module.
So, both the 43 and this particular problem could be due to an improperly installed chip. If you have the original chip, i'd put that back in.
Excessive mechanical noise within engine.
Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM.
Intermittent open in the EST line to the ignition module.
So, both the 43 and this particular problem could be due to an improperly installed chip. If you have the original chip, i'd put that back in.
Wish I had the original chip, just to see if there is any difference. This is some good info though. Haven't got around to chcking the code 43 yet. I don't hear any mechanical noise within the engine, but notice the up and down idle (vacuum).
Racer
Joined: May 2004
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From: VA
I'm sure Jesse can add to this but if you have installed 24lb injectors without a tune it is sure to throw off your a/f ratio's, you stock tune thinks it's running stock 22lb injectors so it's keeping the injectors opened the same fl/sec (something like that) although you have the bigger 24's installed, so the engine would be ingesting more fuel, now I don't know if the 2lb's per injector make that big of a difference but I'm sure it's not helping the situation along with your exhaust leak. I believe an intake vacuum leak will cause a lean condition because it unmeasured air.
Race Director
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From: The Top of Utah
Originally Posted by RRT vette
Hey, now that you have mentioned that I have heard a exhaust leak on the passenger side right around the o2 sensor.
Originally Posted by RRT vette
O2 sensor not throwing any codes though.
RACE ON!!!
Thread Starter
Le Mans Master
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From: Louisiana
Originally Posted by CFI-EFI
An O2 sensor on the right side in a 1986???
GIGO. Garbage in, garbage out. The O2 may be performing flawlessly, but based on erroneous input.
RACE ON!!!
GIGO. Garbage in, garbage out. The O2 may be performing flawlessly, but based on erroneous input.
RACE ON!!!
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
The O2 is on the left. You have identified at least two reasons for it delivering more fuel than it needs: an exhaust leak; a vacuum leak. Both put more air into the exhaust stream and neither has been measured by the MAF. The O2 responds to this extra air by adding fuel. If the O2 sensed too much fuel (ie, an injector problem, it would be taking fuel out). If the O2 sensed an extreme amount of air or fuel, it would set a trouble code. The only way to be sure is to scan it. In the interim, and in the absent of any trouble codes, ie, no Service Engine Soon Light and an O2 which is adding fuel based on your sensory perception, everything seems to be working. I'd fix the known problems first. Whether or not you need an injector change can't be known until these problems are fixed. The O2, when working properly, will cause the ECM to shorten or lenghten pulse width to maintain proper fuel delivery. Injector rating, within a couple of lbs, usually doesn't matter, but that can't be determined until it's all working right (and even then, you need to measure Exhaust Gas Temps along with scanning it to get what's best for your engine).