car breaking up at 5500 and up

[enriquez2000]

car drives fine around town and up to 5500rpm.. but at wot it starts sputtering from 5500 and up. Tried plug gaps from 28 down to 17, afrs stay in line with what they need to be with e85 between 12 and 11.5. Tried fresh plugs and wires are not old at all(few months)

Any other ideas of what to check? I would think if it was the coil starting to go bad Id see it in lower rpms too.

 

[greddy_1700]

Try another set of wires. Also what plugs are you running?

I had awful ignition break up on my car around 5000, turned out to be my Accel 8mm wires. Tried a set of standard wires from NAPA, and the car has been running great since.

 

[enriquez2000]

Plugs are bpr8es.. brand new to tule them out. Wires are a few month old ngk... ill hit napa later i suppose

 

[Mello]

You may want to double check your target AFR's. They change to different values with different types of fuel. I tune AFR's using Lamda because of this. Lamda is a ratio to stoich which is the same independent of fuel.

 

[97 eclenger]

do a boost leak test. and test the knock sensor. a back knock sensor makes performance in the higher rpm poor. can't pull timing as it need to so it lacks performance

 

[enriquez2000]

You may want to double check your target AFR's. They change to different values with different types of fuel. I tune AFR's using Lamda because of this. Lamda is a ratio to stoich which is the same independent of fuel.

Afrs are in check

 

[enriquez2000]

do a boost leak test. and test the knock sensor. a back knock sensor makes performance in the higher rpm poor. can't pull timing as it need to so it lacks performance

Knock sensor bareley blips on e85 anyway so its never pulled timing. A boostleak would cut out from fuel being off o would assume but afrs line up(not saying theres not a leak).

With everything fuel related being on that led me to spark.

 

[miliman13]

Boost leak would remove air, thus increasing richness.
Losing fuel would do the opposite.
Yes coils can work fine low, but break up high.
It can be a number of things. Hard part is you can test your whole car and be in spec, but give out at boost and you'll never know.

People don't like giving members the benefit of doubt, so they will assume your a drunk baby who can't read or do a BLT. I'm a bit of a optimist, so maybe it's your ignition.

Sucks to see thread number 355,790.00 about break up/cutting/buckling............... Because there like 10 unsolved right now.

 

[Mello]

11.5 to 12 AFR are gasoline values, not E85. I think E85 is in the 8-9's range. I think you're may have lean misfires issues.

 

[enriquez2000]

11.5 to 12 AFR are gasoline values, not E85. I think E85 is in the 8-9's range. I think you're may have lean misfires issues.

I use gas afr.. its the same lambda reading. I have another car i do the same with and its 600hp with no issues. No need to debate how we read afrs.. they are in line for sure

 

[enriquez2000]

Boost leak would remove air, thus increasing richness.
Losing fuel would do the opposite.
Yes coils can work fine low, but break up high.
It can be a number of things. Hard part is you can test your whole car and be in spec, but give out at boost and you'll never know.

People don't like giving members the benefit of doubt, so they will assume your a drunk baby who can't read or do a BLT. I'm a bit of a optimist, so maybe it's your ignition.

Sucks to see thread number 355,790.00 about break up/cutting/buckling............... Because there like 10 unsolved right now.

I agree... most people dont follow through if they do fix something. Ill change wires next and see what happens. If that doesnt help ill try a coil. Hate to throw parts without knowing but thats where this is leading

 

[bastarddsm]

The AFR is a little fat for a 16g setup IMHO. I seem to remember misfire issues at 11.0 AFR's and low boost. Lean it out a little and make sure it has plenty of timing. ~15* at 5500 and decent boost. If all that checks out, plugs/wires/coil. I would never spend money on parts store plug wires. Buy Factory OEM NGK. Also throw another set of plugs in it, I've had NGK's bad out of the box. Gap them to about .025" If it needs less gap there is a problem elsewhere.

I used to run Autolite #63's in my stock turbo days. Cheap ($1.19 at oreillys), and durable.

Post a pic of your engine compartment and your plug wires.

 

[bastarddsm]

Last thing, pop your valve cover and make sure you didn't toss a rocker. I did that once with HKS272's and evo 8 springs (not an upgrade at all) Car ran fine driving around, but it would break up really bad under boost.

 

[enriquez2000]

The AFR is a little fat for a 16g setup IMHO. I seem to remember misfire issues at 11.0 AFR's and low boost. Lean it out a little and make sure it has plenty of timing. ~15* at 5500 and decent boost. If all that checks out, plugs/wires/coil. I would never spend money on parts store plug wires. Buy Factory OEM NGK. Also throw another set of plugs in it, I've had NGK's bad out of the box. Gap them to about .025" If it needs less gap there is a problem elsewhere.

I used to run Autolite #63's in my stock turbo days. Cheap ($1.19 at oreillys), and durable.

Post a pic of your engine compartment and your plug wires.

My wires are factory ngk now couple months old but could be bad Have tried 2 sets ngk plugs as well... i flattened timing to 16 from 19 to see if i had too much in it as well. rocker could be issue since we just did cam seals.

 

[bastarddsm]

Yeah that timing looks ok, I've seen break up from really low (single digit) timing.

One more last thing, don't blindly trust the wideband. knock it down to 10.5 then to like 12.5 or 13 and see if it gets better, or worse.

 

[enriquez2000]

It didnt do this until after cam seals so its either coincidence or you might be onto something with the rocker.

 

[bastarddsm]

Sounds like a rocker to me! Get that VC off!

 

[enriquez2000]

Sounds like a rocker to me! Get that VC off!

I hope youre wrong and right at the same time... ugh

 

[Lou98GSX]

If you did cam seals then i would also check your valve timing it might of jumped a tooth .

 

[bastarddsm]

I hope youre wrong and right at the same time... ugh

Pull the lifter out and bleed it down, then there is a tool to push the valve retainer down and you can slide the rocker in. It's not too bad.

http://www.dsmtuners.com/attachments/img_3190-medium-jpg.81861/

 

[enriquez2000]

Pull the lifter out and bleed it down, then there is a tool to push the valve retainer down and you can slide the rocker in. It's not too bad.

http://www.dsmtuners.com/attachments/img_3190-medium-jpg.81861/

So thats definitely it... i dont have that tool.. any way to do it with out it?

 

[miliman13]

That's only if it really fell!!!!


Here it is I have it to.
http://www.amazon.com/Dohc-Hydraulic-Valve-Lifter-Removal/dp/B002YK75CU

 

[miliman13]

So thats definitely it... i dont have that tool.. any way to do it with out it?

Did you confirm?

 

[bastarddsm]

Bleed down the lifter all the way, and use a screwdriver to compress the valve a bit. Make sure the lobe is pointing away from the rocker.

Glad you found the issue. It's an unusual issue that very rarely happens.

 

[enriquez2000]

Confirmed.. i tried bleeding lifter down and then i couldnt get spring to compress without the right tool.. ill try again with something else. All that tool looks like is a metal blade type thing. Ill see if i ca do some creative afro engineering