I seem to get this most often when I leave off then get back in to it or coasting a bit the get into it heavy.I have increase my pumpshot 10% as it was popping just trying to accelarate and that seem to clear that up.could this still be the pumpshot or is there something else that would cause this.mods listed in SIG.thanks

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1991 1LE Z28 355cu 5SPD (ORIGINALLY 305 BEST E.T. 14.186@99.86mph)NO PASSES ON 355 YET.MINI RAM INTAKE,AFR 190 HEADS,10.23:1cr 24# SVO INJECTORS,BBK 52mmTB,AFPR
FULL ROLLER MOTOR,1.6 rockers MSD 6AL
AUTOMETER A/F GAGUE MARCH PULLEYS,HEDDMEN HEADERS 3IN EXH NO CATS FLOWMASTER,POWER TRAX NO-SLIP LOCKER,3:42 GEARS,LAKEWOOD LOWER CONTROL ARMS HOTCHIKS STRUTTOWER BRACE,COMPETTION ENG.SUBFRAME CONNECTORS
MALLORY TACH W/SHIFT LITE
BLACK, TINTED WINDOWS, TAIL LIGHT COVERS BIG BLOCK COWL INDUCTION HOOD,SHAVED DOOR HANDLES

67RS 327cu 92K ORIG MILES.NEWER GM HEADS HEADERS,650 HOLLEY CARB,CAM, 350 TURBO TRANS W/SHIFT KIT&COOLER 12 BOLT POSI 3.73'S MUTLILEAF SPRINGS
NEW VINYLROOF&CARPET, COWL HOOD,HIDE AWAY HEAD LITES,

 

AFRs are they AL?.
Might try disabling the DFCO (decleration fuel cut off). Keeping the chambers hot might cut down on the AE needed for that.
And or taking some timing out in overrun, ie in the 30 K/Pa vs rpm area, at say 1800 and above rpm.

Without DFCO you might have a real crackle in hte exhaust during overun.

 

yes they are Alum.What does that AE stand for.I've have seen many times but have been able to figure what it stands for.I'm sorry I failed to mention that I'm still in the beginning stages of set my lower VE table and I'm currently running very richat low rpm's I've been discussing this in my last post VE vs RPM vs MAP Sorry I didn't add this earlier as it my effect your answer to this post.

 

AE = acceleration enrichment = pump shot

There is a nice list of abbreviations over at the GMECM site. I think its on the FAQ page.

 

Since they're AL I'd go first with disabling the DFCO and see what that gets you, then try taking some timing out during overrun.

 

I think it better it I don't offer opinion on this one.

Does anyone know why?

 

lol @ 89vette. I won't offer an opinion either ...



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TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

That's all very funny but you got a real ideas

 

Can you post the values that you are using in your pumpshot table? Can't offer where to go if I don't know where you are Also, Bruce has some very good suggestions. I would first implement what he has suggested in order to see if that helps the situation.

Tim



------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

pumpshot vs differential TPS

TPS MUTIPLIER
0.0 100.0
3.1 82.2
6.3 54.7
9.4 41.4
12.5 41.4
15.6 41.4
18.8 41.4
21.9 41.4
25.0 27.3
31.3 27.3
34.4 27.3
37.5 27.3
40.6 27.3
43.8 27.3
46.9 27.3
50.0 27.3
I do plan on trying Bruces suggestion as soon I find it I'm using tunercat 8_d ECM where is the DFCO located I don't seem to see anything lable that unless maybe it's labeled different than

 

For an 8D mask;
05E8: FCB 0 ; DEG C FOR DISABLE OF C/O

 

Do you have the lastest verions of the 8D TDF from TunerCat? I had made a LOT of changes to their 8D TDF, but under the previous version of TC, you could only have 50 constants. So I created a special TDF for TunerCat called XXX.TDF that has these DFCO values (well most of them) along with a lot of other things I found useful in tuning the 7730.

Contact TunerCat and ask them for the XXX.TDF from Glenn at www.thirdgen.org IF TunerCat has not added these constants to the "regular" 8D TDF. Due to an "distribution agreement" I have with TunerCat, I cannot distribute any TDFs, including the XXX.TDF directly to people...you MUST get it from TunerCat. If TunerCat cannot find it (the XXX.TDF or forgot where they put it), just tell TunerCat to contact me and I will resubmit it to them so.

You may wish to include a link to this post in your e-mail to TunerCat to "refresh" their memories as it was quite a while ago that I sent TC the XXX.TDF for $8D. Ultimately, most of the constants within XXX.TDF need to be added to the $8D.

 

All kidding aside, the values you listed are 90 Vette 6 speed pumpshot values with a 10% increase. I had to set the first three to 100 values and increase the rest by 35% in order to get the stumble out. Even then, i had the exact same problem you did. If I gave it a little gas while coasting in DFCO, I had a flat spot every time. I had the ability to eliminate DFCO but never did. The MR need so much fuel for quick throttle transitions that I'd get smoke out the tail pipes and the smell of bad emissions. The hesitation after coasting still exsisted. I finially had enough and installed the Super Ram you see in the above picture. Its ported and Extrude Honed and even with the stock 90 Vette upper VE table and a stock pumpshot table, it runs 200% better than the MR ever did on my car.

If you increase the pump shot so the last values are 35 (I think its about a 35% increase) this should help.

Jason

 

I too wound up using 100% for the first three values of the pumpshot table. However, I am in the process of slowly reducing the pumpshot until I get the minimum amount the engine needs to be happy. Again, try what Bruce mentioned. Also, as a quick **test**, just burn a prom with the first 3 pumpshot values at 100% and see if that helps too.

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Also, do you have the AIR Diverter installed on your car or have you removed it? I have been helping a friend with his 383 Miniram car and has removed the AIR Diverter. But this has not been reflected in his eprom (yet).

He too is experienceing a popping with his Miniram and we are going to disable the AIR Diverter in the eprom. I see no good reasons in having the eprom try and enable the AIR when it's not there. Hopefully this fixes it, or at least minimizes it. Possibly with simultaneous changes to the pump shot. I will list all the things we do to finally eliminate the popping.

 

Are you talking about a tip in intake backfire or are you talking about exhaust popping/backires when you leave off the gas?

Jason

 

I'm talking through the intake.now when you guys the the first three set at a 100% you starting at the top of the value table right.Glenn I can't lie to you I don't even know what the air diverter is at least not but that name.So I'm pretty sure I don't have it disabled.I will contact tuner cat in the morning and check on that stuff.Thanks for the help guy your GRRRREAT

 

Yes, starting from the top. Nobody has ever come to a conclusion on this but I think that the TPS values on the left indicate the TPS starting position before you open the blades. If anyone really knows what this is feel free to post

Tim



------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Anyone try this?