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Car sputters while building boost?

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Funfettie

10+ Year Contributor
419
2
Sep 19, 2011
Menomonie, Wisconsin
Hi there,
So im in the process of tuning my car, and Im having an issue where the car runs and drives fine, But when i get on it and try to build boost, it just sputters and wont build more than ~5lbs.

I dont think its a boost leak, but ill be checking again when the engine cools down in an hour or so here. I installed new boots on the COP system cause i thought it was spark leaks, but that didnt do anything.

double checked that the car is at 5* BTDC, FPR is spot on. NGK BPR8es(E85, high boost) are gaped to .024

What else could be causing this?
Thanks!
 
Sounds like a coil bad/going bad. I gap my plugs around .020" if i run more then 20lbs but if its around 5lbs its not your gap. More then likely a coil if your plugs and wires are all fine and its not a fuel thing.
 
I had the same problem for months and could not figure out why.it turned out that i had a small boost leak in my piping.i had a small hair line crack around my bov flange and when ever i would try to boost more than 5 lbs it would cut out and misfire/detonate.
 
I missed that your running COP. Are you running with an msd dis2? Because if not I would bet that is the problem. In my experience the COP without a box actually is weaker and will cause your problem.
 
I am running without a ARC-2 or DIS-2. I dont have any vacuum lines, and and i still need to check for boost leaks, but ill get to it in a few hours here. Is it absolutely necessarily to run a ARC2 or DIS2 with COP? im new to the COP game because i picked one up for cheep from my buddy who was parting out his car.
 
I read that 7es plugs are good to 400 or so HP, and 8es are good from 400-700hp. can anyone verify this? Ill try throwing some 7's in though

The plugs aren't rated in horsepower. They are rated in heat ranges. With pump gas you will need to run colder plugs the more power you make to reduce detonation, but with e85 and race gas you will need a little hotter spark to properly ignite the fuel.
 
Could be running way too rich and its bogging down the motor when boost and fuel pressure go up. Whats your a/f ratio at when this happens?
 
I had the same problem for months and could not figure out why.it turned out that i had a small boost leak in my piping.i had a small hair line crack around my bov flange and when ever i would try to boost more than 5 lbs it would cut out and misfire/detonate.

That's what's is excatly happen to mine, but its going back under the knife having alot of electrical issues so my 99 harnesses are going in. Motor,tail lights and headlight issues motor harness due to cam sensor relocation. Others because wires are cut and throwing everywhere. Will be making a thread on a easy way to do the swaps so be looking for some good advice.

Thanks
dustin
 
The wideband reads 23.1 while daily driving, wayyyy too lean, under full load, it drops to around 9.0. I think its because the wideband sensor is where the rear o2 sensor should be. pretty sure its too far back on the exhaust, so ill be moving it to the downpipe tonight as well

Heres a log i just took a few min ago. I dont really know what to look for, but if theres any guru's that see something wrong, please let me know what you notice! the car runs better and builds a little more boost now, but it starts to backfire and really jerk around at 4500rpm, which is why i let off.
Thanks!
 

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No exhaust leaks, wideband traces the o2 sensor up stream from it, no boost leaks, wideband also reads 23.5 while crusing and drops to 8 or lower while under load. What else could cause this issue. Sparktec ignition system is in and working fine, but It feels the same? Fuel pressure is correct also
 
I'm remote tuning with a guy from the classifieds here. I'm running fic 1550's on e85, and they are dialed in correctly.

Hey Funfettie post on mitsustyle get some help from some MN and WI guys, and where are you tuning at? What injectors are you running, are they scaled properly?

Did this yesterday so far, they can't seem to get over the fact that there are no boost leaks.. I'll be trying to get my hands on a coil pack and wires to see if that. Changes anything
 
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