8starion7 Posted September 27, 2010 Report Share Posted September 27, 2010 hello everyone. i am having a problem with my car leaning out completely. it first happened the other day while i was driving, and now that i have had time to try and figure it out i cannot. i am run a gm maf and a maft and a bov. i have check the error codes and nothing is coming up. i can hold the rpms at 2500 in neutral parked in my drive way and it still happens. let me know if you have any ideas. Corey Link to comment Share on other sites More sharing options...
Scotty Dont Posted September 27, 2010 Report Share Posted September 27, 2010 Mine does the same thing, at idle it will be in the mid 13's then jump to 15 or 16 then be back in the 13's for a bit. Cruise is always steady bouncing between 14.5 and 15.1 though. Link to comment Share on other sites More sharing options...
thagremlin Posted September 27, 2010 Report Share Posted September 27, 2010 I get the same thing as Scotty. Sometimes though while taking off from a dead stop the car is fine but out of no where it goes full lean and it feels like the car just falls in it's face then goes back to normal. Link to comment Share on other sites More sharing options...
psu_Crash Posted September 27, 2010 Report Share Posted September 27, 2010 Are you 100% sure it's leaning out and not an ignition issue? If your spark cuts out and the injectors still fire it will show all the way lean when it's actually very rich. I assume you are running a wideband? Link to comment Share on other sites More sharing options...
Metric-man Posted September 27, 2010 Report Share Posted September 27, 2010 (edited) (bov leaking?) Edited September 27, 2010 by starion_cult Link to comment Share on other sites More sharing options...
8starion7 Posted September 27, 2010 Author Report Share Posted September 27, 2010 Scotty and Gremlin: thats how my AFRs have been for a while too. Psu_Crash : yes im running a AEM UEGO wideband. I just figured it was going lean since i watch the gauge go from 14-15 A/F cruising all the way out to 18 then - - -. i will take a look into the ignition more tomorrow. Starion_cult: no it is not leaking. Link to comment Share on other sites More sharing options...
Metric-man Posted September 27, 2010 Report Share Posted September 27, 2010 Try a different known good secondaryand a TPS ? (not at the same time) Would the trouble code for the MAS #3 be shown at all ??, since the translator is simulating the signal to the ECU ? it has been documented that a MAS error #3 can be a false #5 TPS error,also are you using a IAT (Intake Air Temperature) sensor ? where are you taping the vacuum source from, for the MAF? http://img440.imageshack.us/img440/2784/ovcpvacport.jpg Link to comment Share on other sites More sharing options...
8starion7 Posted September 27, 2010 Author Report Share Posted September 27, 2010 Try a different known good secondaryand a TPS ? (not at the same time) Would the trouble code for the MAS #3 be shown at all ??, since the translator is simulating the signal to the ECU ? it has been documented that a MAS error #3 can be a false #5 TPS error,also are you using a IAT (Intake Air Temperature) sensor ? where are you taping the vacuum source from, for the MAF? It is not showing any error codes at all. when i turn the key to the on position to check the codes it only shows the light for about 3 seconds and does not blink after that. not sure on an iat and no vac source that i know of for the maf. Link to comment Share on other sites More sharing options...
Metric-man Posted September 28, 2010 Report Share Posted September 28, 2010 It is not showing any error codes at all. when i turn the key to the on position to check the codes it only shows the light for about 3 seconds and does not blink after that. not sure on an iat and no vac source that i know of for the maf. Are you using the MAFT Pro or and earlier model MAFT (translator) ? Link to comment Share on other sites More sharing options...
dstar88 Posted September 28, 2010 Report Share Posted September 28, 2010 He is most likely using the regular maf-t. Not the pro. Daniel Link to comment Share on other sites More sharing options...
Metric-man Posted September 28, 2010 Report Share Posted September 28, 2010 He is most likely using the regular maf-t. Not the pro. DanielMaybe he just needs more fuel, like 2 secondaries ?If he is not using an aftermarket 3in GM MAS, you have yours set up after the turbo ? any pics ?? Link to comment Share on other sites More sharing options...
8starion7 Posted September 29, 2010 Author Report Share Posted September 29, 2010 i am running just a regular maft. i bought the 3" gm maf and the translator from on green performance. i changed my tune a little and got new spark plugs in and it still did the same thing parked in neutral, but i decided to see how it drives and it is now running fine lol. drove it from tracy to sac and back which is about an hour drive there and had no problems. Link to comment Share on other sites More sharing options...
bha280 Posted September 29, 2010 Report Share Posted September 29, 2010 I am having the same problem too, keep us posted on what you find Link to comment Share on other sites More sharing options...
mistapickles Posted September 30, 2010 Report Share Posted September 30, 2010 it's an amperage problem, check all your grounds and that your alternator is putting out enough amperage, check it after it's warm too. Our alternators are way too small and when they get warm the amperage drops and that affects the computer and the fuel pump hard....my car had all kinds of symptoms; idle up and down, ran lean, bad gas mileage...fortunately the alternator failed and when I replaced it all my problems were solved Link to comment Share on other sites More sharing options...
Indiana Posted October 1, 2010 Report Share Posted October 1, 2010 At idle if the ECU does move the idle motor and the tip switch opens and your 02 is hot enough that will throw you from open to closed loop and that's likely when this changes the air fuel ratio. When it reads the air fuel in closed loop and then it goes back into idle the ECU uses that air fuel and then that effects the idle air fuel until the next time its changes loop and is always doing this. When using a BOV and it is so rich when you lift the pedal then go into idling that effects the idle air fuel ratio. Question is WHEN exactly does the ECU pick which air fuel ratio and decide to use that for adding to the correction for the next time. Your MAFT settings combined with fuel pressure, injector size and your cam profile has your tune different from another cars "tune". You need more fuel in that rpm range and you can tune it or add one psi more base fuel pressure at a time then re-tune. That basic fuel control, you change the parts from stock and you have to tune it out best you can and then still it might suck. BOVs screw with this and you might get a tighter spring so its less likely to open if you rev a few hundred rpms from idle and lift the throttle. The vacuum is good but the spring could be tighter so it won't open as easily. http://www.b2600turbo.com/images/14-14.jpg Link to comment Share on other sites More sharing options...
Metric-man Posted October 1, 2010 Report Share Posted October 1, 2010 At idle if the ECU does move the idle motor and the tip switch opens and your 02 is hot enough that will throw you from open to closed loop and that's likely when this changes the air fuel ratio. When it reads the air fuel in closed loop and then it goes back into idle the ECU uses that air fuel and then that effects the idle air fuel until the next time its changes loop and is always doing this. When using a BOV and it is so rich when you lift the pedal then go into idling that effects the idle air fuel ratio. Question is WHEN exactly does the ECU pick which air fuel ratio and decide to use that for adding to the correction for the next time. Your MAFT settings combined with fuel pressure, injector size and your cam profile has your tune different from another cars "tune". You need more fuel in that rpm range and you can tune it or add one psi more base fuel pressure at a time then re-tune. That basic fuel control, you change the parts from stock and you have to tune it out best you can and then still it might suck. BOVs screw with this and you might get a tighter spring so its less likely to open if you rev a few hundred rpms from idle and lift the throttle. The vacuum is good but the spring could be tighter so it won't open as easily. Good point, I was about to ask what year or if the ISC has two plugs or one because earlier models 86 in particular hunt for idle speed I believe because of the cold start and high altitude option that introduced that year without the extra nose switch function.or maybe just a bad ISC. Unplugging it after the car reaches operating temp and closed loop will tell you if it is the source of your problem. The other possibly I remembered was a oil soaked air filter will coat the MAS wire, if it is mounted right after the air filter.Good to change the spark plugs because those can be tough to diagnose as a contributing factor. Link to comment Share on other sites More sharing options...
Indiana Posted October 2, 2010 Report Share Posted October 2, 2010 They sell MAS cleaner that will clean that heater wire in your GM MAS maybe that would help. -couldn't hurt Link to comment Share on other sites More sharing options...
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