VE Table Too Low?

[Joe BB]

I'm trying to adjust the ve table on a FI conversion on my 85 k3500 pu.All parts are stock from a 2000 mod. year with the exceptions of full lenght headers, 3" daul exaust,&home made air inlet. The problem I'm having is ,the exaust is way too rich. Fault codes banks 1&2 rich set. LTFTs -20 to -25. I've done all the diagnostics I or anyone else I know can think of but no solution. Figured it must be in the tune. Started tuning in Sd mode with wideband. Most of the cells started out around 18-19% rich,adjusted table several times with copy paste special.Now most normal driving cells are around +-1 to2 except for 800 rpm 30 kpa which is hot idle cell. Keeps being around 18% rich . Looks to me that I've already taken out a whole lot of fuel everywhere compared to stock file. Am I missing something or is this normal? All parts are new GM.
Stock program, currnet program, and latest scan attached.
Thankyou for any help.
Joe

[ak95ta]

I believe in SD mode the ecu will resort to the secondary VE Table. I "think" you have to copy the main VE to the seconday. Maybe that will help.

[Joe BB]

Thanks for the reply,but i did copy to the secondary.I think i did it right. This is my first
tune and i'm just not sure if it's normal to whack the VE table as much as i have already.
Thanks again
Joe

[Joe BB]

Still looking for any advise. Reduced VE table even more.... 800 rpm 30 kpa around 350.
blended surrounding cells. When I started engine wideband started reading 13s to low
15s. Shut off engine, restarted several minutes later, afr around 14.3. Quick stab of throttle and afr back to low 12s at idle. Sorry didn,t mention this before... stock 7.4 engine from 2000 k3500 installed in 85 k30. What am i missing ?
Any help greatly appreciated!
Thanks, Joe

[schardbody]

have you checked all the mechanical things like fuel return line, regulator etc.

i mean with VE tables that low and still running rich i'd be looking elsewhere.

[Joe BB]

ckd fuel press,49 idle 58on throttle falls within gm spec.fpr not leaking ,2nd set of injectors, fuel press holds steady after pump shuts off ,less than 3% cylinder leakdown,
cam degreed in straight up, no miss, all sensors new GM,all tune up items new GM,no vacuum leak,Short block has 1500 or so miles on it,heads maybe 700. Truck runs great just too rich. Pcm out of 99 c1500 v6,same service #.reprogrammed for 99 7.4 .Os may be different but all sensors and hard parts the same for 2nd design 99 & 2000 mod yrs. Could pcm be the prob? Thanks for your input
Joe

[schardbody]

im not sure im not that advanced in that area. im sure someone else will chime in though.

[Reucroft]

Can't access your tune at work, but check your injector settings (flow vs RPM) against stock. Sounds like you've inherited upgraded injectors perhaps

[Joe BB]

Thanks for the info. Already compared my program to different stock 2000 vehicle, everything the same. all other tables the same except for a few differences due to auto trans. Joe

[waynehartwig]

I'd really start looking for a vacuum or exhaust leak. I know you say none, but there is something going on.

[Joe BB]

Not trying to argue but ,wouldn't exaust leak show up lean on wideband in sdol ? As for vacuum leak, sprayed intake no change in idle or 02 readings ,removed both upper & lower intakes to check gskt. surfaces. All 8 sealing surfaces less than .001" from flat, could see good gskt. compression around all ports. I know this will end up being something stupid, just out of ideas . Thanks
Joe

[waynehartwig]

Not trying to argue but ,wouldn't exaust leak show up lean on wideband in sdol ? As for vacuum leak, sprayed intake no change in idle or 02 readings ,removed both upper & lower intakes to check gskt. surfaces. All 8 sealing surfaces less than .001" from flat, could see good gskt. compression around all ports. I know this will end up being something stupid, just out of ideas . Thanks
Joe

Yeah, I guess it would. You've gotta have a vacuum leak somewhere...

Start pulling vacuum lines and testing them individually with a vacuum puller. Maybe the leak isn't in the motor. IE Evap system, HVAC controls, power booster, etc.

Also, pull the plugs and verify that it is rich. Maybe you have a bad WB?

[Cantalope Kid]

Upon startup in OL (open loop) your going to get rich idle fueling. This is how the engine warms up quickly and gets the injectors ready for CL (closed loop). Once engine warmed up it enters CL (closed loop) and will then shoot for you commanded afr of 14.7 for example until you give in enough throttle to enter PE mode which has its own commanded afr settings as well. When you blip the throttle it will dump fuel going rich and then lean back out.

[Joe BB]

Wayne, been thinkin bout this all day, vac. leak should show lean on wb also. Plugs look good [only about 200 to 205 miles ],nice brown ring starting to develope.no sings of running rich. when pcm is put back to cl/maf nb 02s read just as rich . while digging thru Gm service man. last night found nominal tps reading to be .47v mine wldnt go below .57, removed tps and set it to .45v started engine & ran for over 1/2 hr. wb read between 14.3 to 15.6v., thouhgt i was done . Replaced tps, new one reads .46 closed throttle. ran engine again wb read about 14.3,.6 for about 10 mins. then went down to around 12.3 &stayed there. Blk smoke from exaust...gave up went to bed. Joe

[Joe BB]

Kid ,thanks for reply, I understand ol &cl operation.Prob. I can't fig out,engine idling fully warmed up [175*-180*] never touch throttle, wb reads 12.3 AFR. exaust definetly rich. Running in open loop/sd. Totally stock engine transplanted into older vehicle. Only mods. full length headers,3" ex. & air intake. Is there any way something from 4.3 program could still be in pcm? 4 plug black box. Thanks again.
Joe