High RPM Cutout

[DFG 5OH]

Just curious what my prob. could be, maybe i could get some answers. When i was on the dyno sat. up around 4-5k rpms in 4th gear the car would try to "cut out" i guess it the best way to describe it. It also happened that night when i did a big burnout, and held it at 5k in 1st. It kinda "misses" i dunno. Maybe its not getting enough fuel at the higher RPM's. I need to check my pressure, thats on my list of things to do.

 

[CManT1914]

Could be a number of things. I instantly though of something ignition related. When my coil was going out, it would climb to 3500 or so, and then just not rev any higher. It was like I hit a brick wall. Might try pulling the codes of course.

 

[DFG 5OH]

i already pulled the codes twice, i do it like everyday since i got the codes. It COULD be ignition, it'll rev up, just REALLY slow...what could cause that? plugs, wires, cap and rotor are all pretty new.

 

[CManT1914]

No codes huh? No good.......

Is it lacking power? Have you tried cleaning your maf? I'd check the maf too. When mine went out, it did similar things, revved real slow, lacked power and stuff. It also never threw a code for a long time. Is this an intermittent problem, or a constant thing? My coil was an intermittent problem, whereas the maf thing was constant.

 

[DFG 5OH]

its all the time, in the high RPM's...it does lack power...and i've cleaned the maf twice, no luck...could a bad maf cause this...i'd be willing to get a new one...

 

[CManT1914]

Hmm..... I'm not gonna say go get a new maf to try, because I don't want you to waste money on something that you don't know for sure will fix the problem. As you might or might not know, I don't believe in throwing money at problems hoping new parts fixes something. I believe in knowing exactly what's wrong before throwing money at it.

That being said................ if it doesn't fix it, take it back and say you got the wrong part, lol.

 

[DFG 5OH]

haha, is there a way to test the one i've got to see if its bad?

 

[CManT1914]

Yep, check your Hayne's manual. You'll need a digital multimeter. I don't have my Hayne's manual on me, but I can get you the numbers you're looking for tomorrow.

 

[DFG 5OH]

good thing i keep a haynes on my comp, and in the garage i'll be doing that tomrrow too

 

[95CobraMike]

im having the same problem....let me know what you find out, all of my ign stuff is pretty much new (new msd btm, new plugs and wires)
havent however cleaned my maf (considering it is way down in the fender)

 

[wytstang]

I would lean toward bad wires. From what you've said while the engine is under a load it beakes up/miss. I would suspect the wires failing while under a load.

 

[DFG 5OH]

I would lean toward bad wires. From what you've said while the engine is under a load it beakes up/miss. I would suspect the wires failing while under a load.

i thought about that too, but the tires are FMS 9mm's and are less than a year old, with maybe 8-10,000 miles on them.

 

[BlownFiveLiter]

Maybe valve float? The dyno chart you posted a few days ago was pretty choppy looking, have you done any compression tests or anything since? Did this start since after you ran on the dyno?

 

[CManT1914]

Maybe valve float? The dyno chart you posted a few days ago was pretty choppy looking, have you done any compression tests or anything since? Did this start since after you ran on the dyno?

I don't think it is valve float. I don't think valve float usually causes the engine to cut out, but rather to gradually lose power higher up. And while the factory springs suck, I really don't think he is spinning his stock engine high enough for valve float to be an issue. Just me though.

 

[a50sn95]

If you were boosted I would say you are blowing out the spark (hint for 95CobraMike)
I have my gap down to .030, and run a Blaster coil with my stock ignition and 8 lb's of boost. When it was at .035, it would do what you described.....
Dennis

 

[DFG 5OH]

Tonight i'll be doing a compression test, and testing the volts my MAF is putting out, i think its more of a fuel/air problem than anything, my car is stock, and i know the dyno was choppy, that could mean i'm not running on all 8 cylinders, if thats true i'l just live with it until i can build up a new engine.

I'll post up what happens tonight with the compression test, and the MAF check. It COULD be the wires i dontkow, hopefully i can figure it out, and gte4 my car running right. it sucks having it running like crap and being so slow.

 

[95CobraMike]

If you were boosted I would say you are blowing out the spark (hint for 95CobraMike)
I have my gap down to .030, and run a Blaster coil with my stock ignition and 8 lb's of boost. When it was at .035, it would do what you described.....
Dennis

i'll have to check that.... i know my plugs are platnium and shouldnt be, but i dont know what the gap is

 

[a50sn95]

i'll have to check that.... i know my plugs are platnium and shouldnt be, but i dont know what the gap is

If they are the out of the box plugs for our cars, then they are .045 or .050, which will be too much on a boosted car. Definitly my guess for your car.
Also the platinum plugs are not recommended for boosted vehicles. I looked up why once, but forget. Something about not being able to take the extra heat and actually melting off the plug and the bits could damage other parts...

 

[95CobraMike]

ouch.... i'll get some diffrent ones gapped at .030

 

[95WhiteVenom]

Mine used to do that and it was the coil causing the problem. Got a blaster 2 coil and it fixed it real fast like.