Foxbody engine shakes at idle only

zlightlystoopid · Jan 29, 2020

Whats up guys i have 90 Foxbody mustang 5 speed, stock bottom end i did a gt40 heads/gt40 upper and lower intake and a tfs1 cam swap, 70mm TB, 76mm MAF with stock 19 injectors, bbk shorty headers, underdrive pulleys. The car starts fine and drives fine but just at idle the engine shakes pretty bad if rev it up the shake goes away. I already put new plugs and wires, new o2 sensors, fixed some vaccum leaks but still shakes, any thoughts? Thanks!

Potomus Pete · Jan 29, 2020

Just did my harmonic balancer. Same problem went away . I got under it a little , and touched the side of the balancer with my finger while it was idling . Was off pretty bad.

zlightlystoopid · Jan 29, 2020

Potomus Pete said:
Just did my harmonic balancer. Same problem went away . I got under it a little , and touched the side of the balancer with my finger while it was idling . Was off pretty bad.

I was thinking about the balancer too but i dont see it wobble or anything so i just assumed that wasnt the problem, is it possible for it to be bad and not wobble?

Potomus Pete · Jan 29, 2020

Try to do the touch test. I didnt think mine was bad. I was surprised at the wobble.

zlightlystoopid · Jan 29, 2020

Potomus Pete said:
Try to do the touch test. I didnt think mine was bad. I was surprised at the wobble.

Sounds good then ill try it out thanks man

Rdub6 · Jan 29, 2020

Check the fan clutch too. I had the bearings blow out of mine, and caused a pretty bad vibration. Easier fix than the balancer, so worth a look.

zlightlystoopid · Jan 29, 2020

Rdub6 said:
Check the fan clutch too. I had the bearings blow out of mine, and caused a pretty bad vibration. Easier fix than the balancer, so worth a look.

Oh never thought of that ill check it out for sure, thanks!

General karthief · Jan 29, 2020

Go back over your work. Sounds silly but simple things often are the problem.
Check timing, firing order, it could be a miss, pull the plug wires one by one while at an idle, you can feel/hear it drop a cylinder. Be careful, the wires will shock you if your not careful.
Compression test, I know you just installed the top end but strange things happen.
Harmonic balancer and fan clutch could be an issue too as mentioned above.

wicked93gs · Jan 29, 2020

Could always be failing motor mounts too, but balancer is the most likely.

zlightlystoopid · Feb 3, 2020

Whats up guys finally had time to check over those things, i tried that touch test on the harmonic balancer and didnt really feel a wobble like maybe a bit but couldnt really tell, i also checked the fan clutch and mounts seem fine checked over my work everything looks fine, seems to be running a bit rich too i can smell fuel when its idling, here's a link to a video i took let me know what u guys think https://gofile.io/?c=EzbRzg

General karthief · Feb 3, 2020

Part of the problem could be the air filter being so close to the maf

Foxbody engine shakes at idle only

zlightlystoopid

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Potomus Pete

I'm still waiting for the fully nude shots

zlightlystoopid

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Potomus Pete

I'm still waiting for the fully nude shots

zlightlystoopid

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Rdub6

So while I wait to figure out my rear end issues

zlightlystoopid

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General karthief

wonder how much it would cost to ship you a pair

wicked93gs

zlightlystoopid

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General karthief

wonder how much it would cost to ship you a pair

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Foxbody engine shakes at idle only

Member

I'm still waiting for the fully nude shots

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I'm still waiting for the fully nude shots

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So while I wait to figure out my rear end issues

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wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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