BUILD THREAD 87 Cutlass EFI build: 9/13/23..NEW STUFF!

[Injectedcutty]

Shitfire, proof of life post i guess. Alot has transpired since being on here last. Really haven't driven the car much because adulting, but have some issues to be rectified. Last month I lost a rear brake caliper bracket bolt on the way to street rod nationals, proceeded to scrape a path on the inside of my rear right wheel lol. Got that issue fixed, but still dealing with a horrible vibration at 60+mph!!!!!! Went to LS fest last weekend, got to meet Streetbu and his awesome Malibu along with GroceryGetter83 and that fast *ss crewcab of his!
Anyways, the vibration is load related, meaning it only does it when drivetrain is under load. I can coast at 80 and its smooth. I have some things to check as its getting annoying. Also had a fuel pump relay die leaving ls fest. Managed to get car running and get home, what a way to celebrate my 40th birthday. Here are a few pics of stuff.
If anybody has any ideas to look for on vibration let me know. I'm off on weds and thurs so gonna put the cutlass in the air and see if anything sticks out to me.

 

[Injectedcutty]

Forgot to mention, I had the privilege of parking at the BP Automotive booth for LS fest. I have their efi harness on my car, and the owner Bill is a super cool dude. They're local in KY, and everything is USA made with ridiculous QC standards. It was cool to see the attention the cutlass got by actual car people instead of the normal boomers who think our cars are dumb. Gained some traction with some companies for hopeful future endeavors, and also going to start preparing for Bluegrass World of Wheels in January. I entered, just have to hurry and wait for a response. That's all for now, I think.

 

[Texas82GP]

Shitfire, proof of life post i guess. Alot has transpired since being on here last. Really haven't driven the car much because adulting, but have some issues to be rectified. Last month I lost a rear brake caliper bracket bolt on the way to street rod nationals, proceeded to scrape a path on the inside of my rear right wheel lol. Got that issue fixed, but still dealing with a horrible vibration at 60+mph!!!!!! Went to LS fest last weekend, got to meet Streetbu and his awesome Malibu along with GroceryGetter83 and that fast *ss crewcab of his!
Anyways, the vibration is load related, meaning it only does it when drivetrain is under load. I can coast at 80 and its smooth. I have some things to check as its getting annoying. Also had a fuel pump relay die leaving ls fest. Managed to get car running and get home, what a way to celebrate my 40th birthday. Here are a few pics of stuff.
If anybody has any ideas to look for on vibration let me know. I'm off on weds and thurs so gonna put the cutlass in the air and see if anything sticks out to me. View attachment 227886 View attachment 227887 View attachment 227888 View attachment 227889 View attachment 227890

Nice to see you back. I wish I was still 40. Vibration under load, my gut says driveshaft/U-joints. Have you checked your driveline angles? Misfire could also be the culprit. Have you checked the PCM for misfire while you feel the Vibration? Just spit-balling from 1000 miles away.

 

[Injectedcutty]

Nice to see you back. I wish I was still 40. Vibration under load, my gut says driveshaft/U-joints. Have you checked your driveline angles? Misfire could also be the culprit. Have you checked the PCM for misfire while you feel the Vibration? Just spit-balling from 1000 miles away.

Thanks my friend. Driveshaft/u joints are new, only 2k miles on them which doesn't necessarily throw it out, but issue has been around since the swap. I'm leaning towards pinion angle being off. I've talked to several people, and it should be pointing down, but measures almost 2 degrees up at ride height. Car is lowered so it could be throwing it off. Shawn gifted me some adjustable uppers over the weekend, so prepping to swap them out and get the pinion down.
Also, no codes present. Engine runs great, pulls like a train.

 

[Texas82GP]

Thanks my friend. Driveshaft/u joints are new, only 2k miles on them which doesn't necessarily throw it out, but issue has been around since the swap. I'm leaning towards pinion angle being off. I've talked to several people, and it should be pointing down, but measures almost 2 degrees up at ride height. Car is lowered so it could be throwing it off. Shawn gifted me some adjustable uppers over the weekend, so prepping to swap them out and get the pinion down.
Also, no codes present. Engine runs great, pulls like a train.

I think you're on the right track. Good luck with it. Post back with how it turns out.

 

[scoti]

I'm w/Texas82GP on the vibration issue.

For the record, when they say the engine/trans angle should be pointing slightly down & the pinion angle should be pointing slightly up, this would be in a stock set-up that has not been altered. For most stock set-ups, there is a significant difference between the component heights. Lower the suspension/ride height & things become more critical. Your pinion might need to be level vs. pointing slightly up. You want the angles to cancel each other w/o being @ zero so the needle bearings in the joints still get slight movement/rotation.

 

[Tony1968]

Nice to see you back. I wish I was still 40. Vibration under load, my gut says driveshaft/U-joints. Have you checked your driveline angles? Misfire could also be the culprit. Have you checked the PCM for misfire while you feel the Vibration? Just spit-balling from 1000 miles away.

I agree with the u joint being the likely suspect. Before you go adjusting pinion you should get under there and grab the driveshaft and with all your strength try to turn it and see if there is any movement at the joints especially the rear.

 

[Injectedcutty]

So, crawled under and checked the driveshaft. Both u joints are solid with zero play. However, it does move a bit...not sure if its a trans tailshaft issue or what. I'll upload a video in a bit.

 

[Injectedcutty]

 

[scoti]

Doesn't seem excessive to me based on my prior experiences/vehicles I've owned. Someone doing driveline work for a living would have a lot more exposure for the answer.