TBI adaptations

[xCaliK5x]

I searched but couldn't find a specific. I disconnected the battery to clear my codes, how long does it take the computer to relearn the parameters properly for mixture, timing, etc? All of the equipment on the truck is stock and fully functional. I am unfamiliar with domestic stuff, most of the cars I work on, later model BMW's will set in about 20 miles. I put it on the smog machine tonight after I reset it and had driven around the block. My emissions were great at idle, way worse then it was before I fixed my exhaust leak and changed the 02 when tested under load at 15 and 25 MPH. That is why I was wondering about the adaptation/learning curve of the TBI ECU. Thanks in advance.

 

[Mountain_man]

i really hope someone has this answer too cause after I change my timing it seems to take a few days to adjust itself. or disconnect battery as you say.

 

[4X4HIGH]

It only takes a few seconds to clear the codes and i've never noticed any drivability issues after having disconnected the ECM/battery to clear codes. You might have other issues as well. Have you rechecked for codes after you disconnected the battery? The only code you should always get is a 12 which basically means the system is working properly.

 

[Thunder]

I have found it takes about 20 miles of all around driving to get the BLM setteled down and things runnin right after changes have been made.
Also you should fully warm up the vehicle before doing the smog test. A short trip around the block wont do it. You will still be in open loop without the 02 sensor controlling the fuel mixture. The Cat convertor will not be fully heated up to clean the exhaust.

 

[xCaliK5x]

I drove it around the block, and left a pedal prop on it at 2K RPM for about 10 minuets until fully warm before I put it on the rollers. I got no codes back. I will go drive it today to put some load on it. Runs like a champ.

Funny thing is, after all the work I've done, it runs smoother, has more power, doesn't smell nearly as bad, but somehow is dirtier then before! LOL. The state of Kalifornia really wants these things off the road. Cash for clunkers didn't get it, but CARB tightening their standards every year on these things may catch up to it eventually. I mean every thing is there, and functioning as it was when it was new. How can you ask the thing to run CLEANER then when it was new? We need to push for the reinstating of the 25 year roll off of cars like this. It may see 100 miles of use a month, its not a threat to Bambi, and nature, er, at least smog wise!

 

[4X4HIGH]

Might help if you post up what your smog numbers are and maybe someone can help you eaiser to figure out what/where you need to focus on.

 

[xCaliK5x]

I dont have all the numbers on me, but What I do know is EVERYTHING is good. Except Hydrocarbons, which are norm 120PPM, max was 230PPM and I was at 560 BEFORE all this work, no I'm at like 750PPM. This truck has been nothing but a PIA for me, not to mention trying to break my ankle. I think its time to cut it loose. Its been forsale in the classifieds, I just lowered to to $3K as it sits. I'm throwing in the towel. I don't have the time or money to keep this up.

 

[4X4HIGH]

Hydrocarbons are unburned fuel, make sure that all of your plug wires are connected tight and in the correct firing order. Also make sure there are no burned spark plug boots as that could be enough for the spark to jump to ground and cause a high HC reading since that cylinder wouldn't be firing.

 

[xCaliK5x]

yup, got all that. All those parts are good and new. I'm at a loss. I have checked the carbon canister and pinched off the line, no change. Disconnected the PCV valve, no change. Doesn't smoke, nothing.

 

[Jason4x4]

what about tb base gasket? or bumping up the idle? what octane you running? dump some rubbing acohol in it.

 

[xCaliK5x]

I checked for vacuum/intake leaks with carb cleaner, I couldn't find any. I haven't pulled the TB off though. I'm running 89. My issue isn't idle, its HC under load at 15 and 25 MPH. Since Octane is resistance to ignition, maybe 87 would fare better, more of a better burn?

 

[MIKESMONZA]

I have A Question,
For you and All of Us as a Group!
as I also Have A Simular Testing Whoa's,,
Have You replaced The 208 Speedometer Drive; 2-Gear's,,
to match the Tire Height and Axle Ratio,,???

I went from a 4:10 Rear Gear to a 3:42 and have Basicaly Stock 15''Tires 31"height .X10.25 wide,
But have Not Swaped the SpeedOdometer And It is Off By a Lot

I was Wondering if the ,,,(VSS),, Vehicle Speed Sensor,,
Compensates for Any Timing and Fuel Adjustment's,,

AS They were using my Speedometer to run the Test or were they using
the Dyno's Rolers to Measure the Road Speed???

I have Not Made a Correction,,
as My future Tire Diameter Height May Change To a Taller Tire,,,
Mike

 

[xCaliK5x]

the machine calculates the speed so the vehicles speedo is irrelevant UNLESS the ECU needs a VSS for something.

 

[dyeager535]

VSS missing/not in use will PROBABLY hurt emissions at times that they let off the throttle, etc., but I don't *think* it has any bearing on the parameters at cruise (for TBI) except EGR and probably AIR/EVAP.

But I'm not sure if the dyno machines are reading when they let off the throttle as well.

WOT would help little, if any, for the ECM "learn" function, as WOT has nothing to do with mixture learn. WOT is "fixed" in the PROM, so cruise/around town is where all your learning happens.

 

[MIKESMONZA]

Dorian ; Thanks For the Opinon,,
I Appreciate the Help,,
As Some of you all have Some simular experiances,,,

XCali5X Keep us Informed,,

On other Thing's I have Tried,,,
At the Sugestion of the Tester Technician;
Was Retarding Base Timing,,a Few Degree From Zero,,First Test Failure
Replaced EGR, Intake Temp Sender,,

And Advancing Base Timing from Zero 6 degrees
(With the Control Wire Disconected Of Course!!! 2nd test
Filters Oil Gas,Air ,CHanged Plugs N' Wire's and Hose,,
Air Filter was Really Suspect and was Not Clean at all

Then Last Test Failure in June09;3rd Test,,
he Told Me To bring it Back to Zero (Factory Stock)
as It had Improved And Almost passed;
EEEOW!!!
>>>After
Intake Manifold Temp Sensor
New Wire's, Plug's And Oil N' Filter Change,,Fuel Filter,,
Air Cleaner Cartridge,,,, Replace A Suspect Vacumn Hose,,
Air Snorkle Door, Pre Heat Hose,,
And Still not Getting a Code Light,,lol,
Mike

 

[xCaliK5x]

I drove it about 20 miles Saturday, and now it has Death Wobble! I put 1 turn in on the toe (about 1/8") on friday, It drove fine on surface streets for 15 miles of 0-40 stop and go, then at about 30MPH I **** my pants and thought a wheel was going to come off! Eekk. it didn't stop until I got down to about 10 MPH. I tried to get it to do it again, but just barely got it to make a little squirm. I will take that one turn BACK OUT tomorrow!

Now that I have some driving cycle mileage on it, I will put it back on the rollers. Failing that I will check the TB gasket (and intake bolts if they are as tight as the rest of the truck) carb cleaner netted me NO idle change.

My snorkel flap is shut when its warm. It moves freely but will not open. I left it this way since my NOx was way low I could afford the heat to help with HC's.

 

[dyeager535]

You may be starving the engine of air, thus rich. The THERMAC doesn't look to me like it flows anywhere near what the snorkle does.

 

[xCaliK5x]

Good call, I didn't even think of that. That would make huge sense. It was fine at idle where the pre heat tube would be sufficient, but under load, at a higher RPM, thats where my issue is and the pre heat tube would be a huge restriction. I will flip the air cleaner lid over and try it again tomorrow. Thanks!

 

[BGKYK5]

Also, IIRC, TBI does not have a inlet air temp sensor. If you are getting much warmer (less dense) air, that will also make you run rich.

 

[xCaliK5x]

Well, Its not the THERMAC flap, I flipped the air cleaner over and the numbers are the same. HC's are around 740PPM under load. At idle they are fine. My NOX is really low (probably due to the rich condition).

I pinched off the air injection line to the manifold, I am getting a slight air leak past the valve it seems when the truck is hot. IIRC I'm not supposed to have ANY air coming into the exhaust when warm. This would cause it to go rich, then it would adapt, lean out then start to richen up again and I would end up back at square one.

The NEW EGR valve has a fitting on it that was loose causing a vacuum leak, fixed that.

Double checked the timing. 17 degrees warm WITH the wire hooked up at idle, 1 degree with it unhooked.

I'm going to test the new O2 Sensor with a propane enrichment and capture the voltage swine on an Oscilloscope. Since it is running RICHER after I replaced it AND sealed the exhaust manifold, I think I may have an issue there.

Which brings me to the tires. I have 36" Swampers with 4:10's, I'm wondering If I can get a close to OE tire size this will help with not only RPM but load since its speed dependent.