LS vtec Stumbles on acceleration until VTEC engages

DroolinBuddie

New Member
Hey, I have a 94 acura integra...
recently dropped out the motor and got a donor car...had a LS vtec in it. pistons were blown...and car had no title...so i stripped it for parts. I rebuilt the entire thing inside and out, rehoned the cylinder walls, ordered new pistons and new rods...etc...when i first started it, it was idling rough...fixed it...had a crapload of CEL's...But also fixed them all

Now i'm having an issue...Sometimes the car would Idle normally...Sometimes it would idle VERY low...
it randomly happens...driving low RPMs is normal and fine...sometimes when i hit 2,500xrpm...It surges straight to 4-5,000xrpm and goes back and forth...

The problem:
when i accelerate hard it just straight Stumbles...the car will bog down like crazy and sound like it's havin a seisure...but once it hits vtec...it runs normal and runs very strong...
I had a chipped ecu in it, chipped by dinan(P28) but i figured it was a bad ecu...so i swapped it with a spare ecu i have...a p28 also.Still has same problem...

What i've done to try to fix it:
checked the fuel systems, replaced injectors...
checked ignition coils, replaced it
checked spark plugs/wires...all replaced
distributor is new
valve clearance all checks out good.

I'm not sure what it is anymore...Really thinkin hard about just going back to regular LS...But i Know i don't want to...Help would be appreciated...

stuff in the motor...just incase anyone has an idea...

skunk2 stage 1 street camshafts
pr3 pistons
p72 rods
gsr crankshaft
skunk2 Intake manifold( Yes i checked all vaccum lines and harnesses they are all correct)
stock fuel rails and injectors
stock distributor w/ msd dizzy
10mm sparkplug wires
ACT Clutch (Forgot what type but it's the whole kit)
p28 ecu
 

Integraguy04

CORNER CARVER
usually that happens if the tune isnt that good...like it falls on its face till vtec engages and then it hits and its strong..

i know thats what happened to my brothers until he got it tuned
 

DroolinBuddie

New Member
I see... what should i do?...like.. normal tune ups?...I've done a lot already Im not sure what else to do...lol sorry im still learning...and if tune do you mean ECU tune? i switched back to the regular p28, it got a little better...but still fails...and yes it does fall flat on it's face until vtec engages and yes it is VERY strong i like it...but hate the fact that it...studders until vtec...
 


DroolinBuddie

New Member
Oh i see...do you know a good website that has one? as long as it runs normal...nothing too pricey...The chipped ecu i haave works fine in my hatchback sohc vtec...that's weird that it doesn't work well in my ls/v build...lol im still new to the tuning part...Is it possible to tune it myself?...like hooking it up to a laptop etc...taking it out on the road to "Dyno run" it?...stuff like that?
 

Samurai_Blue

Yolo Whippin'
yes you can with a Hondata s300,
other programs require other stuff.
Your single V ecu will not work for the ls v as its a different set up each motor is different and needs its own basemap etc. You can get a chipped ecu from pharable dot net but it wont be 100% as its basemapped
 


DroolinBuddie

New Member
Ohhhh...no wonder...okay im understanding now, Thanks a lot Samurai_Blue!...very helpful... quick question...I got a Dinin ecu that was chipped for a type r motor... can i reprogram this ecu ?...if yes, can i do so with any company? or just from Dinin?...the ecu just has the Dinin decal on it...and a chip inside that says "Dinin"...i searched on google and bmw's came up...lol im confused...
 

DroolinBuddie

New Member
@_@...I don't have any dyno's around here....crap...Can't i just send in my ECU to phearble and get it tuned like that?...I just want my car to run normal...not trying to be ultra fast or anything...I like how the car kicks now...Just hating the seizure attacks...@ 3,000 -4,500...
 

SexySSBP

Kwicherbichen
phearable.net can get fairly accurate basemaps, but the more you've done, the harder it gets. It will be better than what you have now... Go to their website and you'll learn a lot about what they can do. I have my third one coming tomorrow :)
 
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DroolinBuddie

New Member
phearable.net can get fairly accurate basemaps, but the more you've done, the harder it gets. It will be better than what you have now... Go to their website and you'll learn a lot about what they can do. I have my third one coming tomorrow :)
O_O...Have you ever ran any of ur cars without tune? like...to test drive around not racing ...does it stumble really bad like as i described mine?...

What if i just went back to stock camshafts in my LS Vtec...will my car be running normal?...
 

SexySSBP

Kwicherbichen
O_O...Have you ever ran any of ur cars without tune? like...to test drive around not racing ...does it stumble really bad like as i described mine?...

What if i just went back to stock camshafts in my LS Vtec...will my car be running normal?...
No, I haven't...my car is obd2 converted to obd1, so I just got a socketed, chipped ecu from them in the first place. I don't even have a stock basemap for this ecu.

I have no idea if putting stock camshafts would help, I know very little about ls/vtec builds and would assume there could be many other things. My only point is that phearable makes decent basemaps.
 

DroolinBuddie

New Member
I see, Thank you...

On a side note...I have a JDM GSR laying around... but the block is...erhm...Destroyed...previous owner had JDM and USDM pistons mixed in...plus Turbo, and the idiot driver ran the car with NO OIL....WTF???...epic fail...but i got the motor at a good price...

anyways the head cylinder is perfect still, stock cams and valve train...I'm going all motor, using the GSR head is obviously better correct?...besides the PR3 head i have on now...I have a hunch that my PR3 head cylinder could be bad...because the previous owner of it said it had head cylinder problems, but he couldn't figure it out either...could it be valve float?...sorry i elaborate so much, Just very interested in fixing things...and curious.
 

DroolinBuddie

New Member
Oh, also i just got an email from phearable.net they told me my best bet would to check if my dinin ecu chip is socketed, if so i can purchase a basemap from phearable for $35...what do you guys think?...I just want my car running normal Not going to add any more aftermarket parts when im done with this...going on to my hatchback next...(i dont want to open 1 million threads so im asking in this one)
 
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