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-   -   Rough idle / need advice (http://www.mustangevolution.com/forum/f258/t368830/)

curt68 05-30-2015 08:09 PM

Rough idle / need advice
 
My 68' with 289 all of a sudden started running rough, will not idle,miss firing & will not stay running when I put it into gear...put new plugs in, verified fire from every plug wire..Timing looks correct with the light, if it weren't I can't move the distributor anyway. I loosened the bolt and was gonna try to move it just to see if that would improve..Please Help, any advice welcome.
Thanks in Advance

Stang Life....

curt68 05-30-2015 08:29 PM

I forgot to add that I could pull certain plug some of the plug wires off one at a time and it didn't change the idle, but then other ones when pulled off would nearly choke the engine down..

Stang Life....

Tyoung68 05-30-2015 10:45 PM

Check the cap/rotor for corrosion/ points
Coil
Then vacuum.

I have all these problems with stalling and those have all been my problems

ER12883 05-31-2015 12:35 AM

If those all look good, then the carb might be next to check. Could be a sticking float.

curt68 05-31-2015 11:54 AM

Could coil be bad ? Even if getting spark it may not be enough? Does that sound possible? If carb float is sticking would it still allow smooth acceleration while in park but die out under.ooad in gear?

Stang Life....

Tyoung68 05-31-2015 12:03 PM

Rough idle / need advice
 
Quote:

Originally Posted by curt68 (Post 2237264)
Could coil be bad ? Even if getting spark it may not be enough? Does that sound possible? If carb float is sticking would it still allow smooth acceleration while in park but die out under.ooad in gear?

Stang Life....


Could be true about the coil but just check the connection mine the two wires literally corroded away. And if a float is stick I'd imagine you would be running rich so you would be able to smell it. But you could go tap on the carb with a hammer. And I mean tap no hard swings haha to try to knock the float loose

curt68 05-31-2015 12:12 PM

HaHaHa, little frustrated with it right now, probably not good idea for Mr to go near with hammer LOL...the carb is bout 10+ years old and had set up for a while before I bought car..the guy I bought it from took it apart and cleaned but didn't rebuild or anything..what else puzzles is the fact I can pull some plug wires off and kills engine but 6 others don't affect at all when I pull off

Stang Life....

matcox83 06-01-2015 06:23 AM

Individual plug wires causing the idle to change is a big clue. When the idle changes you pulled the wire from a cylinder that is working. When the idle doesn't change, that cylinder was not contributing. If it stays consistent it indicates it is not the coil or carb as they affect all the cylinders. I would check cap and rotor again and maybe replace plug wires. With the engine running, squirt water on the plug wire ends at the cap and at each cylinder. Do it in the dark if you can. If you see electricity arcing, you need new wires due to the boots. If all of that is ok, it's time to check compression and cylinder leak down because you might have a mechanical problem. Before you spend too much money, don't be afraid to take it to a pro.

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Strange Mud 06-01-2015 06:28 AM

+1 if you pull a wire and it does not change there is a problem with that cylinder. Most common would be wires/plugs but a bad cap can cause it. Recheck connections/gap

check firing order...mayhap (don't get offended) you put them on incorrectly

curt68 06-02-2015 08:53 PM

Well I checked and rechecked the firing order, it is correct. The good news is I finally got the distributor broke free so I could move it easily. I readjusted the timing and is idling much better. Still is a bit.hard to start tho, timing may still be a lil off, I'm going by a painted line mark on the balancer that someone else put there, assuming it's correct, no original timing marks to.be found. Got new wires & coil on the way, my other concern is going from park to.drive or reverse causes a huge lurch and of course decreased idle, at least it doesnt choke out when put it in gear now. Any thoughts on why it's such a huge lurch when go from park to reverse or neutral to drive?? Thanks for all the suggestions above. I'd never get offended at advice offered either, hey we're all human & I'm definitely not perfect. Thanks again all.

Stang Life....

Aggiesrok 06-02-2015 09:30 PM

What's your rpm at idle?


Chevy runs deep, don't step in Chevy.

ER12883 06-02-2015 09:34 PM

This is a guess, but could the lurch be from a high idle? At a stop, do you feel like you have to stand on the brake to keep it from creeping forwards?

My experience was my engine was having trouble starting/idling because of poor A/F mixture, no choke and poor timing so the PO compensated by bumping up the idle way too high to keep it from stalling out. But the consequence was a lurch like you described (almost like a miniature neutral drop each time), and having to press hard in the brake at lights to not crawl. Once I fixed the above issues, I was able to bring the idle way down and that fixed things. I found a cheap tool for reading RPMs on anything, and that made setting the idle speed a breeze - I think it was < $10 on Amazon.

curt68 06-02-2015 09:47 PM

No idea on RPM at idle, I have no tach. I would guess 1500-1800. What was the name of the device you found on Amazon to read RPM ? Yea if I idle any lower it chokes down in gear, I've got a rebuild kit for the carb and have ordered plug wires & coil. Hopefully a good tune up will help.


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tym_v6 06-02-2015 09:53 PM

Is there any dieseling?

Aggiesrok 06-02-2015 11:10 PM

Sounds like you might be double the idle you want. But you have to get the other items taken care of first. After the carb rebuild and dist/wire replacement you should be able to get the idle where it needs to be.
PO was compensating for parts that needed to be replaced.


Chevy runs deep, don't step in Chevy.

ER12883 06-03-2015 04:04 AM

Agreed, you're probably going to need to fix the issues before dropping the idle. The one I got wasn't available, but it looked just like this one:

CyberTech Digital Photo Laser Tachometer Non Contact RPM Tach https://www.amazon.com/dp/B00B30FOFM..._p.SBvb13M2K08

I may have been wrong about sub $10, but it was for sure sub $20. You have to apply a piece of the reflective tape to the crank pulley or balancer, point it at it and press the button - pretty straight forward.

curt68 06-05-2015 12:56 PM

Quote:

Originally Posted by tym_v6 (Post 2238979)
Is there any dieseling?

??? What do mean ,dieseling?

Stang Life....

straybullitt 06-05-2015 01:19 PM

Dieseling is when you turn off the key and the engine wants to continue to run.

If those two cylinders, that do not seem to be firing, are right next to one another, i would do a compression test to verify the condition of the cylinders.

curt68 06-05-2015 02:33 PM

Quote:

Originally Posted by straybullitt (Post 2240506)
Dieseling is when you turn off the key and the engine wants to continue to run.



If those two cylinders, that do not seem to be firing, are right next to one another, i would do a compression test to verify the condition of the cylinders.


Naw, it turns right off. I will check the compression . Thanks for advice


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12:55 AM

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