Help with idle and start up Fast 102
Thread Starter
Teching In
Joined: Dec 2009
Posts: 9
Likes: 0
From: San Francisco
Help with idle and start up Fast 102 Had my tuck dyno tuned at a well known shop in Fremont Ca. pulled 367hp 382tq. Tuner tried everything to get it to idle off idle and start without giving it throttle.
2003 5.3L, 243 heads milled .030, comp cams 228 230 114lsa, comp 918s, Fast 102 LSXRT w/ Fast 92mm tb, stock truck injectors, LTs, 2.5" H-pipe w/ bullets, TH400 3200 stall, 12bolt 4.10s
Truck ran fine with a TBSS intake manifold and Fast 92 tb. Can anybody help me?
2003 5.3L, 243 heads milled .030, comp cams 228 230 114lsa, comp 918s, Fast 102 LSXRT w/ Fast 92mm tb, stock truck injectors, LTs, 2.5" H-pipe w/ bullets, TH400 3200 stall, 12bolt 4.10s
Truck ran fine with a TBSS intake manifold and Fast 92 tb. Can anybody help me?
When did you buy this FAST? I assume it is the truck FAST correct? Some of the really early truck ones had a few issues that no amount of tuning could correct.
With the heads milled that much, I would be concerned with looking at the intake gaskets to make sure they match up and were not cut or damaged. And honestly those truck injectors will not help out. You need at least some LS2s in that to keep up. I am very surprised your tuner did not tell you.
Can you send a log at wot? just like a 3rd gear wot pull with no downshift to simulate a dyno pull or if you have logs of the dyno pull. I would be very interested in looking at the injector duty cycle.
Also I am assuming you have a cable TB?
With the heads milled that much, I would be concerned with looking at the intake gaskets to make sure they match up and were not cut or damaged. And honestly those truck injectors will not help out. You need at least some LS2s in that to keep up. I am very surprised your tuner did not tell you.
Can you send a log at wot? just like a 3rd gear wot pull with no downshift to simulate a dyno pull or if you have logs of the dyno pull. I would be very interested in looking at the injector duty cycle.
Also I am assuming you have a cable TB?
Thread Starter
Teching In
Joined: Dec 2009
Posts: 9
Likes: 0
From: San Francisco
Bought the Fast LSXRT and cable Fast 92mm tb around Feb 2011 and there is no problems with it sealing. I do have ls2 or 8.1L non marine injectors ready to install. Injector duty was around 100+.
Got the truck to start without throttle by adding 16* advance in spark cranking table, but it will sometimes die if i do not tap throttle when shifting into gear.
Got the truck to start without throttle by adding 16* advance in spark cranking table, but it will sometimes die if i do not tap throttle when shifting into gear.
Ok. Sounds good. I kinda knew they would be toast lol. For the LS2 injector do you have the adapter harnesses for them?
Are you looking at a walbro/racetronix fuel pump now? If so, I would recommend the drop in kit that WS6 Store has. It works like a champ in most 03 and earlier trucks. Just have to vin verify.
Are you looking at a walbro/racetronix fuel pump now? If so, I would recommend the drop in kit that WS6 Store has. It works like a champ in most 03 and earlier trucks. Just have to vin verify.
-You have 0.00 dialed in to your default injector pulsewidth from 3500rpm on up, that looks off.
-You running a MAF?
-You have an ETC Scalar value of 0.0255 entered. If your running a cable TB, this should be zero.
-You running a MAF?
-You have an ETC Scalar value of 0.0255 entered. If your running a cable TB, this should be zero.
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Verdad Gallardo At the very beginning, there are 2 blips on the TPS, 4% and 5% is that you? And the very end, what are those slight blips of the throttle....you or not you doing that? It goes to like 2% then back then 2% then back.
Thread Starter
Teching In
Joined: Dec 2009
Posts: 9
Likes: 0
From: San Francisco
I have to tap the throttle to start and when shifting into gear or it just stalls. Once in gear it will idle if you sit there but when you drive and let off fast it stalls. When stay in second and the revs comes down slow it will idle.
As for open loop that is how the tuner set it up. Almost $550 and 45mins on dyno this is what I get.
As for open loop that is how the tuner set it up. Almost $550 and 45mins on dyno this is what I get.
On The Tree
Joined: Apr 2011
Posts: 181
Likes: 1
@ 4,500 rpm you're over the recommended 80% injector duty cycle (current wimpy injector can't keep up!) Get these swapped out and the replacement injector values updated in your tune.
You also need have tuner run an idle tuning session...
http://www.hptuners.com/forum/showthread.php?t=36318
Enjoy!
Why leave final tune in open loop? Might as well just eliminate the MAF and go speed density too! Lol
Did they not nail the fueling adjustments enough so that STFT/LTFT are < 4%-5% error when o2 sensors active in closed loop?
You also need have tuner run an idle tuning session...
http://www.hptuners.com/forum/showthread.php?t=36318
Enjoy!
Why leave final tune in open loop? Might as well just eliminate the MAF and go speed density too! Lol
Did they not nail the fueling adjustments enough so that STFT/LTFT are < 4%-5% error when o2 sensors active in closed loop?
Last edited by 2TR; Nov 14, 2011 at 11:35 PM.
