Bubbajones_ya

I recently acquired an rhythmic "wobble" or type of vibration at idle with my car. It happens in neutral at idling rpms ( manunal tranmission). It is a consistent wobble/vibration with the engine sound. The RPMS don't appear to be fluctuating at all, the vehicle just wobbles. I can feel it in the seat, it wobbles at like a 1/4 or 1/6 second interval (not sporadically, it's a continuous, same cadence wobble.)


It does not appear to be noticeable when driving at any rpm, just at idle.


Another side thing I noticed is my exhaust sounds different the same time the "wobble" occurred. It sounds kind of as if there is an exhaust leak somewhere, but I checked the exhaust and there is no noticeable leaking (entire brand new system installed headers back to muffler) except for one spot before the muffler that was already there (the pipe was cut over the axle so it's clamped in but isn't a great seal. However, the clamp is in the same spot when I put it there, nothing moved, and I don't see how a leak that far down would suddenly cause the issues I'm having. The headers are all bolted up tight, and the y-pipe seems bolted up tight too.

To me, it almost sounds like the exhaust is sucking air in rhythmically, it's a weird air "putting" type sound, not typical of exhaust leaks. Also, the exhaust "putting" gets louder under load, not necessarily under throttle.




Apart from that, I noticed my shift light is coming on when I'm in neutral at Idle, but as soon as I hit the gas (in gear or neutral), the shift light goes off.
I do have the EBL system installed on my car, and I had the shift light to come on at 4500 rpm in the Bin file, but it is coming on now at idle around 600-700 rpm only.

I was going to get my laptop out to check what the EBL information was going to tell me, but my harddrive failed and the laptop is unusable until I can get a new drive and install an operating system and the EBL program again.


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My questions are:

1.) Does anyone know what may be causing the rythmic "wobble"?

2.) Could the EBL have somehow changed the bin file (causing weird timing/fuel issues) that may have caused this wobble/weird exhaust sound? I wonder this because I know the Bin I uploaded had the shift light disabled until 4500rpm.

3.) Can anyone recommend some other tests to do to narrow down what may be causing my issues?




Like I said, when driving, it feels unchanged and actually pretty good. However, the exhaust (especially under load and throttle) sound different, and it wobbles at idle.

Thank you for your help and hopefully I can get his fixed soon. I'm nervous to drive it much before I can diagnose what it is because I don't want to cause damage.

Bob88GTA

iTrader: (2)

Just a thought, Have you checked your wires? It sounds like 2 are crossed.

Bubbajones_ya

I looked somewhat quickly to see if any were arcing on the headers and it didn't appear that they were, but I haven't checked to see if they are arcing on each other.

I'll go do that now since I have time between work and school. That would be an awesome simple fix to route the wires better.

Bubbajones_ya

Well thank you Bob88GTA for making me go outside and look again... I feel really dumb now.

There ended up being a part of the wire that was arcing under the heads that I didn't see before. I moved the wire out of the way so it's no longer arcing. It was bad enough that I could easily see the arc in daylight....

That probably explains why my gas mileage has gown down a little too. However, the performance didn't seem to be impacted which is weird.



On top of that, the shift light is still coming on at idle, and it didn't used to do that, but once I fix my computer, I'll see if I can figure anything out with the EBL system. I'm uneducated when it comes to tuning anything so I don't really know what to look for, but I'm slowly learning.

Anyways, the exhaust sounds and shaking at idle seemed to have disappeared when I moved that wire out of the way.




Now I have another question,


Does anybody know of a good spark plug wire set I can use with Headers on a 305 TBI engine for these cars? I have hooker 2055 headers if that makes a difference. All the sets available for me to buy at the parts stores didn't seem to have angled plug boots, so I'll probably have to order a good pair.


I ended up having to use some of the older wires that I kept out of my 302 bronco since the plug boots came out at an angle, but I'd rather have a new matching set.

Bob88GTA

iTrader: (2)

Glad you got it worked out and fixed. On the wire sets, I really can't help ya out on that. I use AC Delco, (2 of my TPI'S don't have headers, my 2000 RamAir I used Mallory due to the stock headers) and the TTA has Stock original wires.

Now on my 96 351 Bronco, I use FoMoCo!

TTOP350

iTrader: (8)

I use taylor wires

Bubbajones_ya

Well my wires kept finding ways to touch themselves against the headers, but my new pair of summit wires came in. My car started to idle a bit rough and get the weird putting exhaust sound again.

I finally had a chance to install them and spent a while with looms and stuff so they wouldn't touch the headers.

Despite this, the car seemed to idle rough still, and the exhaust noise was still there. I went over and checked my new wires before driving off and none of them were touching.

After driving for about an hour, I pulled over to check my wires and one of the bastards managed to seat up against my exhaust and burned it pretty good.

I put a wire loom thing over it and made sure it wasn't touching, but the idle is still quite rough, and the exhaust is still making a weird noise. It seems like the new set of wires did not do anything for the rough idle this time.




Could the plugs have fouled from driving on my old bad wires for a couple weeks? I bought new spark plugs but haven't installed them yet, but wanted to know what else I should check. It really seems to me like it would be an ignition problem, but all my new wires are good expect for that one that I managed to "fix up" in the meantime until I replace it. If the new plugs don't fix the issue, then I fear there may be a bigger problem, and I wouldn't know where to look.


------------------------------------EDIT:----------------------------------------------------

I ended up forgetting to plug in a vacuum line when I was rerouting the vacuum lines so they are somewhat more out of sight.... I had a dream last night about doing that which reminded me that I didn't plug a line back in.

The car still has a slightly rough idle, but its pretty much back to it's normal idle now. I still haven't changed the plugs but I'll do that soon. I'm currently working on a friends camaro. We are changing the front end because it got in a small collision. I didn't realize how annoying it is to take that front clip off, but we finally did and got the "new" one back on. His car is now grey, white and red! Pretty soon, when we put the better trunk lid on, it will also be teal! It sure is due for paint soon haha.