breaking up/stputtering

BoostedSUV

BoostedSUV

Active member
Let me try to explain this the best I can.... At low RPM or at constant driving speed under 2500rpm my Ty gets a stumble almost like it loads up or runs out of fuel. Under hard accleration it seems to be fine and driving above 2500rpm's its fine.

I can pull it into low gear and accelerated slow and feel it stumbling, as it does this the Air/fuel gauge is off showing no reading, but then it will come up to two bars rich instantly and the motor will smooth out and come up 500rpm's with out moving throttle position. While driving the as long ad A/F gauge is reading properly it will run fine, then the gauge will act erratic for a second and "go off" showing no indicator and the truck will stumble as if the ignition was turned off and back on quickly.

I have tried adjusting fuel pressure with out any luck. The ECM showed a CODE 42 in the history but the check engine light doesn't come on at this point. I just intsalled a new engine, 50# injectors, 3 bar map, and Ultimate chip. The gauges were already in place. possibly bad ground? bad chip?? any help is needed ASAP, this truck is my daily driver! Thanks
 
QUICK STORM

QUICK STORM

B.A.M.F. BMW Tech
Re: breaking up/stputtering

maybe your o2 sensor has a hiccup, you might need to replace it. check your basics, and it probably could be a bad ground, ecm, etc...
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

I just re-did all the egine grounds and had no luck. while driving it around its almost like the truck runs out of fuel from ~1500-2500 at light acceleration then clears up. Under heavier acceleration it wont do it. Maybe ignition module in dist.?? The ultimate chip disables the 02 sensor and basically only used for a wideband or Air/Fuel gauge. The A/F gauge works perfect and when it dives to the lean side the truck stumbles, it comes back to normal and the truck clears right out... At a steady cruising speed within ~1500-2500 the A/F reads nothing and the truck stumbles as well.
 
QUICK STORM

QUICK STORM

B.A.M.F. BMW Tech
Re: breaking up/stputtering

check vacuum leaks, i.e. bike tube test or smoke the intake.

could be a bad fuel pressure regulator
 
QUICK STORM

QUICK STORM

B.A.M.F. BMW Tech
Re: breaking up/stputtering

checked your other thread, i would definately try an ign.module,maybe install an MSD blaster coil while your at it too
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

vacuum lines are all good, I have a vacuum tester. I already installed a blaster coil, new cap and rotor. I was reading through the books and i think the code 42 is in the memory from when i disconected the bypass to set the timing.... that just dawned on me. that still doesn't explain my sputtering issue in my other post.
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

could it be the 02 sensor reading too rich and overcompensating by leaning out the motor? I think the Ultimate Chip makes the 02 a closed loop system and it can be removed all together. It may just be a flaw in the chip?? I have to get a data logger and see exactly what it's doing. More $$$$ on this truck I intended to keep stock!! Already spent about $7000 on motor, chip, injectors, turbo kit, reg, converter etc all because I broke a rod. What's another couple hundred?? haha
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

QUICK STORM said:
did you change to an adjustable fuel pressure regulator?
Click to expand...
Yeah it has a brand new Adjustable fuel reg. I have set it from 40psi all the way to 50psi to try and see if it helps. made no difference, pinged bad at 40psi.... that's about it
 
QUICK STORM

QUICK STORM

B.A.M.F. BMW Tech
Re: breaking up/stputtering

well then i would try a new ecm and/or make sure your ultimate is seated properly, sounds to me like the ecm has a glitch
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

I would point more towards the Ultimate... its really the only thing i changed. ECM worked fine with this motor and 10n1 chip. I spun a bearing and had the motor re-done and changed to 50#ers and ultimate and re-installed the motor. I have had this problem since I first drove the truck on sunday. i triple checked my chips to be sure they are seated right... I personally upgraded my 10n1 to an ultimate with Eproms that Todd from Sy/Ty chips sent me....... frustrating enough that the motor has been out 3 times since it was built new (3 months ago) and when I think I finally have everything right I end up with a different problem....
 
QUICK STORM

QUICK STORM

B.A.M.F. BMW Tech
Re: breaking up/stputtering

i would definately check the ultimate. maybe you should contact phil long about a custom chip.
 
Don W.

Don W.

Stab it and steer it
Re: breaking up/stputtering

Some thoughts from the manual: Bad TPS, (TPS is linear from idle to WOT. If it's bad in the 2500 RPM range it will throw thing off.) Make sure it moves free. Erratic system voltage will cause the IAC to change position. They also mention the MAP sensor.

The TPS is an easy fix. (Don't know the cost but I can't imagine it's a lot.) Might be worth it just to be sure.
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

QUICK STORM said:
i would definately check the ultimate. maybe you should contact phil long about a custom chip.
Click to expand...
I connected phil long before I ordered the Ultimate. He didn't have any programs for my combo.

Don W. said:
Some thoughts from the manual: Bad TPS, (TPS is linear from idle to WOT. If it's bad in the 2500 RPM range it will throw thing off.) Make sure it moves free. Erratic system voltage will cause the IAC to change position. They also mention the MAP sensor.

The TPS is an easy fix. (Don't know the cost but I can't imagine it's a lot.) Might be worth it just to be sure.
Click to expand...

I will check that out, don't see why it would have gone bad, it did work before, buts it easy enough to look into.
 
QUICK STORM

QUICK STORM

B.A.M.F. BMW Tech
Re: breaking up/stputtering

thanks for the help don, i totally forgot about this. thats the great thing about the BB is there is always somebody out there that can help. we will get your truck running right
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

Plugs read rich, and so does the Air/Fuel. I changed the ignition module, and O2 sensor and it didn't help. i think there is a glitch in the Chip that I put in when I installed the new motor. I am waiting to hear back from Todd from SyTyChips.com who burnt me the Ultimate.
 
M

MikeRenz

not stock
Re: breaking up/stputtering

if the plugs were rich for a bit i bet they fouled. slap some new plugs in and i bet it'll be good for a little until you foul them again by being too rich :)
 
BoostedSUV

BoostedSUV

Active member
Re: breaking up/stputtering

the problem is the plugs were brand new when I put the motor in on sunday.... the truck was having this issue in the first 5 miles I was driving. I have the plugs that are recomended for a stock setup, maybe I should go w/ NGK's or something instead?? I still think its and ECM/Chip issue
 
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