Questions

[Oren09]

Do Festivas have a computer controlled rev limiter?
I've always been afraid to take mine over 6,000. What is the max red line?

Engine braking. I do it sometimes, but these engines don't really have enough compression to slow you down fast or completely. My question is how it affects fuel economy. It saves brake wear but what about gas mileage?
Since the throttle plate is closed and probably no more air flow than idle, does that mean it is only using as much fuel as idle speed? If i turn off ignition while slowing in gear, the engine sounds pretty much the same. And if I turn the ignition back on, there is no change- as long as my foot is off the gas pedal.

And- timing. I have not yet been able to time my car. Its been bugging me for over a year. I've removed and reinstalled my timing belt at least three times. I'm positive it's lined up. But I can never get the crank marks in the right place. So I time by driving it and adjusting the distributor.
I had the dizzy set where everything felt ok and I've been running midgrade gas- about 89 octane here. I've had a noise- like ratting, odd sort of noise- mostly when under large load like hill climbing in 4th or 5th gear. If I put in regular octane (87) on accident the noise seems louder and more common and I also notice a decrease in fuel economy.
Last week I filled up with premium (91 octane) and the rattly noise is gone. Period. I haven't noticed a gain in mileage, but with the disappearance of the noise and higher octane, I can assume my timing is not correct.
Also, since I've gone to premium, I've noticed a slight hesitation when accelerating hard in the higher gears.
Before anyone says it. I last did a tune up just over a year ago. The plug wires, cap, and rotor have less than 30,000 miles on them. I replaced the spark plugs with NGK V powers in January this year.

[blkfordsedan]

Yes, I believe they do have a rev limiter. I don't know what it's set at, but I'm sure someone on here does and also knows how to unhook it. IMO, I don't see much advantage to winding these things up over 6000.....The stock engine really doesn't make any power much over 5500 anyway.

The timing belt effects cam (i.e. valve) timing, which is completely different than ignition (spark) timing. Cam timing is not adjustable and has nothing to do with any of the timing marks you see on the crank pulley. No reason to ever mess with the timing belt, except to replace it. It does, however, need to be properly set or engine performance will suffer.

The sounds you describe aere spark knock, caused by the ignition timing being too far advanced. Driving it with spark knock can destroy an engine in short order....you need to get it properly adjusted ASAP and then leave it alone.

[Safety Guy]

I've read here that FI cars are electronically governed (rev limiter), but carbed cars aren't.

Karl

[blkfordsedan]

I've read here that FI cars are electronically governed (rev limiter), but carbed cars aren't.

Karl

Yeah, I'm pretty sure I recall someone telling me there was a way to disable the rev limiter as well. I don't think I've ever actually hit the rev limiter on the Festy. Even the B6 I'm building with a FMS cam should only make peak power around 5500 RPM.

LOL, I have, however, bounced off the rev limiter (6250 RPM I believe) on my Mustang several times :p....

[link5186]

My B6 swap with B61k ECM tears clear up to 6800 RPMs for the limit. I've bounced the aspire off the rev limit when the auto trans decided to hang between shifts. I'd imagine they're somewhere close just by ear.

On the ignition timing issue, I had trouble getting my b3 just right for a long time as well. Part of the problem in my case was bad cam timing because I set the belt tension without the tensioner spring (it broke). I could get it close but it threw the cam off enough to make accurate timing at the dizzy impossible. I wound up setting it with a dwell meter at 10* and that was the only way I could get it to stop the spark knock rattle. Any little bit one way or the other and it would rattle.

[kellen302]

I've bounced mine off the rev limiter, in 1st and 2nd. 25mph on stock 12" rims in 1st, and 50-55mph in 2nd. I think I read somewhere it was at 6500. If you redline 1st you can chirp 2nd if you flat shift it... I've only done it once or twice

[Oren09]

I don't want to remove the rev limiter. I was just wondering where it was because the engine sounds bad at 6,000RPM and has a noticeable loss of power. Shifting from 2nd gear at 6,000 to 3rd puts 3rd right in the power band at 4,000 and jerks the car.

I've redone the timing belt to make sure that the cam timing is correct. It does have an effect on ignition timing. Since the noise has gone away with premium, I will adjust timing a little more to get rid of hesitation and go down an octane level at next fill up to see how its doing.

[blkfordsedan]

If you have the cam timed properly then you don't have to worry about messing with it again. You can now concentrate on getting the ignition timing set. If it "pings" on 87 or 89 octane, but not on 91 octane, then it's either A) too far advanced or B) you have another issue like carbon build up in the cylinders, too lean of fuel mixture, vacuum leak, etc. If everything is 100% then it should be able to run at the factory timing advance or even a slight added advance and not "ping" on 87 Unleaded.

[Oren09]

Good info.
I run Seafoam through a vacuum port every once in awhile and I get a cloud of smoke, but never anything major.
I'm not sure about vacuum leak or lean fuel though. The O2 sensor was replaced along with the other tune up items with a Denso unit.

[newcomb]

in my white 93 it bounced off limiter at 6800 then side step clutch

[Oren09]

6800. Wow. My engine has a slight noise/knock so I've always been afraid to rev it high and I didn't know if the computer had a "NO!, don't do that" feature.