I recently finished up my engine in my truck. It started up right away and ran great while I was breaking in my cam (with the exception of running a little lean, which I figure is normal because it wasnt tuned for the new combo. As I have been tuning, the problem seems to be getting worse. Heres what I changed... I started with a mostly stock '94 K1500 pick up with an EBL Flash ECM with WB O2 and controller, then I put Summit vortec heads, weiand street warrior intake, lunati cam (single pattern with 268 deg of advertised duration, 218 deg @ .050, 110 LSA, .457 inch lift), 1.6 roller rockers, 1800 RPM stall torque converter, vaccume reference fuel pressure regulator set at 40psi at idle (2 injectors, 107 #/hr @ 40psi). It is hard to start when its hot, I have to hold the throttle down about half way and turn the key/ crank the engine over about 2-4 times before it starts. When the engine is cold it starts fairly easily. As I started my VE learns, after shutting the engine off and updating the tune it became harder and harder to start after each flash session. My AFR at idle are between 14.5 and 14.8, while driving my AFR's range from 13.5 to 15.5. Any help is welcome. Thanks

 

Look at the low speed VE table, the 400 RPM row. The high MAP area is used during cranking. Compare that area with the earlier BINs to see if it has changed much. Can also add to the 400 RPM & 100 KPa cell if it is too lean.

There is more info on the DIY_PROM board in this post:

https://www.thirdgen.org/forums/diy-...ml#post5375147

RBob.

 

Ok, I will check it. I am getting terrible fuel economy too. I have been doing VE learns and it seems to be learning, but for some reason it sometimes goes into Launch while its idling. Im also having a problem with the AFRs while driving. I need to do some data logs, but durring moderate to hard exceleration my AFR goes to 10-11.

 

your starter might have a short,my Firebird was doing the same thing last year and after a few months I finally had to get a new starter.

 

With the modified engine most of this is typical which needs to be worked out. Going into launch mode during idle is usually from the MAP fluctuating. Increase this value by say 4 - 5 KPa from it's current setting:

LM - Delta MAP Threshold Enter

With the higher fuel pressure set the two values in this table to zero (0):

INJ - ASync Transition PW - TBI Only

That will prevent async injector firing mode when at short PW's.

With the higher fuel pressure should increase the injector compensation values. Copy these two tables from the EBL_F_3001 BIN file into yours:

INJ - Injector Correction Offset
INJ - Injector Correction Multiplier - TBI Only

Also need to reduce the AE PW tables and the proportional gains tables. See the Intro to Tuning Part 2 on our web site. It covers setting up a starting calibration.

With the Vortec heads also need to use different SA tables. The EBL_F_3000 BIN has the Main & Extended SA tables from a Vortec headed truck engine. Can also try the Main & Extended SA tables from the EBL_F_3001 BIN.

With the way the EBL is set up with 8 calibrations banks, can load each cal into a different bank. No other changes but the SA tables & PromID.

Then go out and try one for a while, then switch to the other and try it.

RBob.

 

Thanks again Bob, you have been very helpful in the past and you still are. I will make the changes and report back. Thanks

 

Bob,

I made all the changes except the proportional gains ones. Im not exactly sure about those because I couldnt fine much info on them. The truck is running WAY better!!! It is a night and day difference in the way it runs. The hunting at idle is gone, my idle is lower, my over all drivability is way better and it is using alot less fuel!!! My only complaint as of now that I need to change is my open loop AFR. I also need to dissable the open loop upon decel as well. my AFR in open loop is 10.0! Overall I am very happy with the changes. I am going to continue making changes to the PE, AE and continue doing VE Learns. The starting is much better as well.

Thanks Bob!!

 

Open loop decel is forced via an option flag:

Option Word 3 - Bit 5 - OpDcl

This is done to prevent surging due to proportional gains and/or very short injector PW's. Once you get the decel AFR in the ball park you will likely find that it will again need to be forced to open loop. And usually requires a bump in the VE.

Don't worry about it showing a bit on the rich side. The density of the mix is very low and requires to be rich in order to light off.

For the proportional gains, reduce this table (all entries):

PRP - Gain vs O2 Error

Do it the same as the AE PW table reduction, by the ratio of the old injector flow divided by the new injector flow.

RBob.

 

Ok, I will make that change and report back. Would you recomend to uncheck OpDcl?

 

Only for VE Learns via BLM mode.

RBob.

 

Ok, so since Im using a WB I should not do this, correct? Also, this morning it was about 50 degrees and the engine did not want to idle. It would start, but would not idle unless I lightly pressed on the accelerator. What tables should I look at to tune this area?

 

Right, when doing VE Learns via the WB the ECM needs to stay in open loop. This is usually done by setting the closed loop CTS threshold high. The three individual flags are to allow the tuner to run closed loop but also force open loop in particular areas.

With the engine warmed up and no additional loads on it, adjust the throttle stop screw so that there is between 5 & 10 IACs step at idle.

See how that is before making additional changes.

RBob.

 

Ok, I will set the idle to have 5-10 IAC steps and report back. Thanks Rbob.

 

Bob,

I got it to idle at 5-10 steps at hot idle, but I cannot get it to idle properly when its warming up in the mornings. The mornings are getting colder and colder here in CT (I used to live in FL). The engine will idle and start all day long in the afternoons and evenings. My hard starting issue is getting better. I have been doing VE learns and then viewing the graph in TunerPro and then manually smothing it out. It has helped tremendously in the gas ussage and overall drivability of the truck. What do you suggest I work on to correct the idle issue in the mornings. I have to hold the RPMs above 1300 until it warms up to operating temp. If I try to put it in gear before then it will stall out. I also went to one heat range hotter for my spark plugs, this seems to have helped as well. I was using one range below stock, and now I am running the stock heat range.

 

There is a AFR multiplier table that is by coolant temperature and a SA compensation table that is by coolant temperature and manifold vacuum. With hotter plugs helping it may be that it is too rich.

Can change the AFR multiplier in the area of CTS on a start up to warm up.

To help figure out if it is rich or too lean, cold start the vehicle and observe the exhaust. Black smoke? then rich.

Can then shut off the engine and pull a spark plug or two. What do they look like?

Can also set up the SA CTS/VAC compensation table with a degree more across the entire table and flash it into bank 0, then another 1 degree more and into bank 1, and so on for all eight banks.

Cold start and flip through the banks to see if any one is better then another.

RBob.

 

Thanks Bob, I will make the changes and see how they work. I know Im not getting too rich of AFR because there is no black smoke durning the cold start up.

 

This morning I watched the WB read out and it was reading 17-18 during the mornings warm up. It takes about 5-7 minutes for the truck to warm up to about 150 degrees. I know it should be around an AFR of 12-13 in the mornings. How should I go about correcting this. My hard starting issue while hot is almost non existant now. I think it was because too much fuel was being injected with not hot enough of a spark plug. I took a significant amount out of the 400 RPM MAP zone on the VE table. Overall, I am very pleased with it. The engine seems to run very well, its resonsive, the power seems to be there, Im getting about 10MPG average with no lean cruise. I dont have any surging any more while driving as well.

 

The lean cruise at highway speeds will likely net a 10% increase in mileage.

Can change the AFR multiplier in the area of CTS on a start up to warm up:

Open Loop - AFR Multiplier vs CTS

A more negative value is richer (lowers the commanded AFR).

RBob.

 

Ok, thanks Bob. That was my biggest question about the Open Loop Multiplier. I will make changes and see how they work. Thanks again Bob. You have taught me a lot recently. I feel much more comfortable and knowledgable about tuning now. Thanks

 

Thanks Bob for all your help. The engine will idle now while warming up in the mornings. I made small changes to the table till it would idle and then I added a couple more which smothed the idle out a bit.

I do have a question though about the WUD. When I view the "trip" info. It says I am getting 18 MPG and I know that is not accurate because from what I have calculated, Im only getting 12 MPH average for city driving. The MPH is right on with what the speedo and GPS say, so I know its correct and the milage is correct. Is there a calibration for this or is there something I need to change in the tune its self? Thanks again bob.

 

This one in the calibration:

INJ - MPG Injector Flow Constant

Set it to the flow rate of one injector. Will likely need to tweak it from there. It is only used by the WUD, so it won't affect the tune.

RBob.

 

I did set it to 107 lbs/hr (the calculation I got from the WUD Utility). I guess I will raise the # till I get it to match. I took a fairly long drive on the expressway yesterday and I noticed the WB was reading very lean on down slopes when my MAP was around 20-30 Kpa (the ECM was also applying Lean Cruise). I checked my Hiway- AFR and the leanest was 16.5, but my WB is reading 18-19. Is there something else I need to check?

 

Was the ECM in DFCO? Otherwise need to be careful of misfire if there is a cat-con on the vehicle.

RBob.

 

Regarding the mileage, in the WUD Preferences Dialog you can check a box so that the WUD accumulates mileage. It is saved at shut down and restored at a restart of the WUD.

This is helpful for getting a better picture of the mileage. Of course you need to connect and run the WUD every time the vehicle is driven in order for this to work.

RBob.

 

I have seen the ECM go into DFCO. It comes and goes, but I would say that it happens during very low MAP areas and while in Lean Cruise. The WUD running everytime isnt an issue, I always have it up while driving. Also, I do not have a cat-con.