Jeep Strokers

So even though I got my 4.6 stroker running last year and even drove it around town a bit, yesterday was the first time I really got it out on the highway to open it up.

At low rpms and cruising speed, it acts fine. Not as much low-end torque as I'd like, but the real problem comes when I hit the throttle and I get major popping. More like WAAAAP WAPWAPWAPWAP. The engine seems to hesitate and lose power at the same time. If I back out of it and gradually ease into the throttle, then I can accelerate fine without the popping and without loss of power. No tach, so I can't say exactly what rpm this takes place at.

I'm confident in my break-in, so I'm pretty sure it's not the cam. I went over the ignition a billion times and indexed the distributor when I put the engine back together. I have a new fuel pump, new filter and new fuel lines, though I haven't yet checked the fuel pressure. I replaced the throttle position sensor and relocated the crank position sensor using the Advance kit. The temporary exhaust is a Cherry Bomb, no cat, but those pop on decel, not acceleration. I installed an adjustable MAP, but haven't yet tweaked it.

There is some slight ticking from one of the lifters toward the rear of the engine, which goes away after the engine warms up. Oil pressure seems to be good. My gauges aren't entirely accurate, but they're in the ballpark and show about 50psi on startup. Engine vacuum at idle is right around 12-13. And I'm aware that I only have about 50 km on this engine, so things could still be tight.

So I'm at a loss. Does this sound familiar? If so, what's the problem, and how do I fix it?

thanks,
dan

It sounds like a misfire to me, did you index the distributor?

Mine was a tooth off from the factory and would stutter and pop at light throttle cruise. I imagine being a tooth off in the other direction would have the same issues you're describing.

Indexed and re-indexed. I had a no-start right before I first fired it up, so I went through the ignition system at least a dozen times and everything seemed to check out then.

thanks,
dan

Try running 93 octane in it, you may be experiencing pre-ignition issues

already have a full tank of high-test in it. I knew I wasn't going to drive it over the winter, so I put the recommended amount of Sta-Bil into the tank. I wonder if that didn't work as advertised...

thanks,
dan

The high test in your tank now, is that the one that sat over the winter?

yes, it is.

I would burn through that tank, fill with fresh high test then report back.

-Chris

can do.

thx,
dan

I've never had good luck with Sta-Bil. It always does what you explained your engine was doing, sputtering and popping. I was told (not sure if it's true) that Sta-Bil is just the equivalent of 2 stroke oil.

I use this stuff for treatment http://www.starbrite.com/productdetail. ... tron%20Gas

and this stuff for storage http://www.starbrite.com/productdetail. ... Stabilizer

It's actually marketed for marine applications. It's top shelf stuff and it works great. Best product that I have used and you don't need a whole lot to treat with. 1oz treats 5 gallons. It's actually a microbial based product.

Will this stuff work for treating old fuel? I have a couple of jet skis that sat for a year and a half while I was building my house. I tried running them and they wouldn't rev on the water. On the trailer they did ok, but not in the water. Both tanks are full, and if I drain them, I don't know what to do with the old gas.

syphon 5 gallons out and just mix that in with new gas as you go...

Unless its turned to absolute sludge it should run right through without a problem

dwg86 wrote:Will this stuff work for treating old fuel? I have a couple of jet skis that sat for a year and a half while I was building my house. I tried running them and they wouldn't rev on the water. On the trailer they did ok, but not in the water. Both tanks are full, and if I drain them, I don't know what to do with the old gas.

Yes, it will treat old gas, thats actually one of the best features of it.

Here is the product info: http://www.starbrite.com/whatsnew/Startron_Story_V2.pdf

And here are some testimonials: http://www.starbrite.com/whatsnew/Test.pdf

Check out these before and after photos of some crappy fuel



I was having problems with my Motorcycle, wouldn't run right, sputters, wouldn't rev, dumped some of this stuff in and after about 10 mins. it started up and ran tons better until I got some fresh fuel in it. Now it's all I use for treatment. I use it regularly for treatment because for a while we were getting bad fuel around here when they started putting ethanol in the fuel. The problem was the ethanol is a water based alcohol and It would actually soak up more water from the air when it gets humid in the summer. Awesome product...

RAPTORFAN85 wrote:I've never had good luck with Sta-Bil. It always does what you explained your engine was doing, sputtering and popping. I was told (not sure if it's true) that Sta-Bil is just the equivalent of 2 stroke oil.

Interesting. Never heard of any problems with Sta-Bil, but this is the first time I've used it. I haven't gone through the entire tank yet, but it seems the more I drive it, the less it pops and stumbles, so that might just be the case. Wouldn't that be grand if the solution to my problems is just to drive the thing...

And thanks for the recommendations for Starbrite. Is that stuff available at any parts store (West Marine?), or is it just through the Internet?

dan

I buy it at Wal-Mart.