Well changed Valve Springs, and still same problem

[qws2000]

Ok, as most of you guys on here know my car was coughing, breaking up and sputtering. Well just about everyone told me I needed new valve springs. So I took out the Beehive, and went with Comp 941. The car would just fall down at 5000rpms, now I put the 941 in and it starts to breakup at 5,000 but goes to 5600 still cracking up... I have changed everything I know and whatever any suggests. Lost

 

[buickGN3:16]

i would look at the fuel or spark area or voltage drop under heavy throttle causing the pump to poop out or something possible there.


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[MikeL.]

Check out post by Alaskabuick. Similar issues, turned out to be crank sensor.

Mine started out as a light flutter as if it needed more fuel. Eventually it progressed to a loud 'POP' around 5k rpm.

Started the motor, got.it up to temp, unplugged cam sensor and it pulled clean. If you do this do not shut off the motor with cam sensor unplugged, plug it back in before killing the ignition.

Sent my cam sensor to scott @ gns and got it rebuilt. Problem solved.

 

[qws2000]

wait.... I unplugged the cam sensor and car would not start.... the car should be running then unplug???

 

[qws2000]

the fuel is 112, and the pressure is over 40.. and 3 months ago I changed plugs, coil, MAF and wires

 

[TurboTdr3.8]

wait.... I unplugged the cam sensor and car would not start.... the car should be running then unplug???

yes running first

 

[bison]

Throw in new plugs. Id get a weekend out of plugs with leaded race fuel in the past. After that it was a crap shoot. Verify misfire isn't lean out. Use ignition tester and let it go for several minutes. Module has to get hot for accurate diagnosis.


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[qws2000]

Brian, What plugs and Gap? if its not Im shutting it down, and putting the stroker in early

 

[Lil Truck]

I have been chasing the same problem you have described. I changed springs and got the extended rpm range but did not solve the problem. Was thinking my flat tappet cam with only 3k miles might be going flat, but I see you have a roller with the similar symptoms. I went with autolite 23s gapped at .030, I also tried .025 gap with no change. I run 91 & meth and the 6.1 TT chip with the WB on all the time. I made 1 run on the Dyno with out alky, 110 and low 20 lb boost, same result.

My engine has a 300 rpm drop at 4700, then milder rpm drops to 5700.

On the street I found it is not as noticeable.
Found it ran smoother after disconnecting the 2 step, but I have not been back to the Dyno to confirm.

I was considering the cam sensor or crank sensor?

Don't give up!

 

[lost2a6]

What is your AF ratio? Mine has a flutter with the AF at 10.8 however I can lean it out to a 11.2 and it pulls clean. This is with alcohol.

 

[Lil Truck]

My WBO2 shows 11.0 AFR the Dyno shows 11.2. After I put new springs on there was good improvement and rpm range was extended past 5700. The dip in rpm is always at 4700 to 5000 range?

 

[mtocrs1]

I had same issue until I tightened up the plug gap.

 

[Lil Truck]

I had same issue until I tightened up the plug gap.

I went from .030 to .025 with Autolite 23 with no major change. How tight did you go?

 

[mtocrs1]

I will have to check I can't remember. Might get to it later tonight

 

[mtocrs1]

Gap is .020
I know seems crazy but has been fine set this way for as long as I can remember. Before doing this I changed plugs, installed high output coil pack, wires. This is the only this that worked. Give it a try just to see what happens.
My plugs are Delco R44TS

 

[Lil Truck]

Hey I will give it a try!

It is the cheapest fix on these cars!

Thanks

 

[mtocrs1]

Any updates on this?

 

[Lil Truck]

There will be, currently working 14 hr days continuous. I should have a day off in a few weeks! A trip to the dyno will be the true test.

 

[vacuum 6]

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[qws2000]

update from my end... I changed the plugs Gap at o.30, then the cam sensor cap took a dump on me. A Huge Thanks to Dave Husek who did build and design the motor, he is awesome and figured it out in less than an hour.. Dave is a great guy. The car is running much better with new springs RPMs going to 5700 and pulling very hard Thru.. I also did put the new 6466 turbo on early... Also want to note thanks to Brian (Bison) all the calls and Texts. Thanks.. I am running the power logger tonight with logs to follow