sluggish at higher rpms

[Bikercmbc]

so ive been trying to put miles on my second car recently. was driving it around sat and got on the throttle and the car is not as "peppy" on take off as my other car. but on higher rpms above 3000 it just is struggling, and if im in a higher gear 4/5 and climing a hill and done down shift it starts bogging down unless i down shift. im thinking fuel mix is off, does this sound right- too lean? does anyone have the write up on how to properly set the air/fuel mix that davemw wrote a few years back using the dwell meter?

[jawn101]

so ive been trying to put miles on my second car recently. was driving it around sat and got on the throttle and the car is not as "peppy" on take off as my other car. but on higher rpms above 3000 it just is struggling, and if im in a higher gear 4/5 and climing a hill and done down shift it starts bogging down unless i down shift. im thinking fuel mix is off, does this sound right- too lean? does anyone have the write up on how to properly set the air/fuel mix that davemw wrote a few years back using the dwell meter?

Wouldn't go straight to the mixture. Does it idle well? Smell bad?

I'd look for vacuum leaks at the WUR first.

[Bikercmbc]

nope idles good, starts immediately. has all new vacuum hoses and looked them over last night, everything looks good and connected. reason went back to fuel mix was cause I had it running rich and leaned it out some and now it seems sluggish. it had been about a month since I drove it and might not have gotten on the throttle or just dont remember it being that much slower than my other car, but it is significatly slower.

[jawn101]

Interesting. Since it has all new vacuum hoses it wouldn't be impossible that a new one is loose or torn during installation.

Never hurts to check the mixture of course - but changes should be well thought out first :)

Basic procedure is to hook the + lead of your dwell meter to the orange wire leading to the diagnostic connector. Ground the other lead to the block. You want to see ~40 on the 4 cyl scale with the motor running cold. The FV should be buzzing. Press the WOT microswitch and the dwell should jump to ~50. This confirms the meter is hooked up right and the system is accepting input. Now let the engine warm up. Once the O2 sensor comes online the dwell should be swinging, around 30-50ish centered on 40ish.

If it's not, you can adjust - but in very, very small increments. 1/16th of a turn is a world of difference in this system.

[Bikercmbc]

thanks, exactly the info I was looking for, Im sure it is off some cause I was running real rich before and just did it by smell and idle. Ill adjust it this weekend and hopefully will get better throttle in the higher rpms. if not ill be looking deeper into the problems that it could be.

[David T]

thanks, exactly the info I was looking for, Im sure it is off some cause I was running real rich before and just did it by smell and idle. Ill adjust it this weekend and hopefully will get better throttle in the higher rpms. if not ill be looking deeper into the problems that it could be.

My guess is ignition break-down. Check:
Spark plugs
Ignition wires
Distributor cap and rotor
Ignition coil
David Teitelbaum

[Bikercmbc]

everything is brand new less that 500 miles on the car since I bought it and did all the work to it. only thing that isnt new is the ignition coil. I could have a weak spark.

[opethmike]

New doesn't definitely mean good. Test everything in the ignition system regardless of new or not.

[Ron]

Actually the dwell should be a steady 50 to 60 Cold (<60F) and fluctuating between 35 and 45 when warmed up.
There are several other dwell tests you should perform listed in the WS manual, D:04:15

[Bitsyncmaster]

Check that the vacuum advance is working. No advance would give you poor power. Best way to check is with a timing light.

[jawn101]

Actually the dwell should be a steady 50 to 60 Cold (<60F) and fluctuating between 35 and 45 when warmed up.
There are several other dwell tests you should perform listed in the WS manual, D:04:15

Thanks for the correction Ron!

[Bikercmbc]

Thanks Ron. I was going to use the timing light to check the timing adv but my light wasn't working so ill get another one this weekend. Timing adv and mixture were the first things that came to my head when I felt this problem.

[Ron]

NP!

Just remember to set the CO absolutely last if you have to adjust it....

[DMC Fanatic]

Are you supposed to turn the mixture screw when the engine is cold? My cold dwell reading is at around 45 instead of 50 and when I turn the adjustment screw, the needle on the dwell meter doesn't seem to change at all. I'm also having a cold start problem and I think the mixture is causing it. What's happening is it starts for a half a second and dies, then takes several cranks to start and I get a puff of blue smoke from the exhaust which eventually clears up when the car is running. I've never had this problem before and this started when I reinstalled my intake. I don't mean to hijack this thread but any advice would be great!

[DMCMW Dave]

Are you supposed to turn the mixture screw when the engine is cold? My cold dwell reading is at around 45 instead of 50 and when I turn the adjustment screw, the needle on the dwell meter doesn't seem to change at all. I'm also having a cold start problem and I think the mixture is causing it. What's happening is it starts for a half a second and dies, then takes several cranks to start and I get a puff of blue smoke from the exhaust which eventually clears up when the car is running. I've never had this problem before and this started when I reinstalled my intake. I don't mean to hijack this thread but any advice would be great!

No, because cold the O2 sensor isn't working. so the dwell meter will not change.


Puff of blue smoke on starting = valve seals are leaky. How do the spark plugs look?

[DMC Fanatic]

Just did a full tuneup with new spark plugs, wires, cap and rotor. I also forgot to mention that the blue/yellow starter wire is unplugged because the electrical connector broke off, but I'm assuming this wouldn't be causing this?

[Bitsyncmaster]

Just did a full tuneup with new spark plugs, wires, cap and rotor. I also forgot to mention that the blue/yellow starter wire is unplugged because the electrical connector broke off, but I'm assuming this wouldn't be causing this?

That wire is just to boost your spark when starting the engine.

[DMC Fanatic]

If I reconnect it, do you think it'll help turn the engine over faster and possibly solve my issue? Or is it not worth it?

[Bitsyncmaster]

If I reconnect it, do you think it'll help turn the engine over faster and possibly solve my issue? Or is it not worth it?

It won't crank faster but may start quicker because of higher spark power. If you have the Eagle starter, just connect it to the white/red wire.

[DMC Fanatic]

Yea I figured it's worth a shot to reconnect the wire and see if it makes a difference. Thanks for your advice

[David T]

If you *just* replaced all of those parts (spark plugs, cap, rotor, and wires), it is very possible something is either defective or you damaged it during install. Especially if you did not have this problem before you replaced these parts. Having said that, it is also possible you knocked a hose loose and now do not have vacuum advance and/or your mechanical advance is not working. That wire you referred to is only active during starting so it can have no part in this problem.
David Teitelbaum

[DMC Fanatic]

The weird thing is the car runs fine after I get it started after the several cranks it takes. The idle is almost perfect and the car revs fine with the exception that when you come to a stop the idle dips to about 500 rpm and then settles to 750 rpm. I confirmed that all the vacuum lines are hooked up correctly. I also forgot to mention that the car starts up good when hot, so this is a pretty weird issue. Any other ideas or suggestions are greatly appreciated

[DMC Fanatic]

I'm wondering if the engine needs that stronger spark coming from that starter wire for those cold starts...

[David T]

I'm wondering if the engine needs that stronger spark coming from that starter wire for those cold starts...
It can't hurt. The symptoms about the high revs is not weird. It sounds like ignition voltage break-down. It will worsen and become noticeable at lower and lower revs. Could be as simple as not snapping a spark plug wire on correctly to a spark plug.
David Teitelbaum