Out of Whack Tune root cause of Noticable Engine Vibe??
Just wondering if an out of whack tune could be the cause of a pretty noticable engine vibration. Idle on up it's present, driving or free revving. At about 1800 RPM's it actually begins to wobble the car on the jackstands. You can hear it misfiring a bit at idle due to the oil it's burning off from what got into the turbo's, so I'm leaning this direction but I thought I'd ask the experts.
Engine is a fresh 377 from TSP, clutch is a zero balance OZ700, has a powerbond underdrive pulley that was fine prior. I do have a squeaking pulley up front though, not sure which one at this point.
Absolutely if it's lean and beyond the capability of the PCM to compensate. Log it and see.
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Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
Absolutely if it's lean and beyond the capability of the PCM to compensate. Log it and see.
No capability to log (still living in the LTx era ). Will be possibly seeing my tuner on Saturday, he said if he's in bring it by and he'll take a look at it.
If it was my car, I wouldn't be driving it - unsolicited advice, I know. Ask around and see if someone can come over and throw any sort of OBDII scanner on it to check the fuel trims and timing. You've probably got a lot of time and money in that toy, and it would be foolish to damage something.
__________________
Best regards,
Bill
Calgary, Alberta, Canada
2003 Quicksilver roadster , 1SB, F55, QF5, MN6, Z06 Ti catback, 2 cat H-pipe & air lid, Euro red/amber tails, Vette Net, and HP Tuners s/w - available for free to anyone in Calgary
If it was my car, I wouldn't be driving it - unsolicited advice, I know. Ask around and see if someone can come over and throw any sort of OBDII scanner on it to check the fuel trims and timing. You've probably got a lot of time and money in that toy, and it would be foolish to damage something.
It's already been driven. The motor is actually running quite nice save for this vibration. It's idling around 16 on the wide band, a blip of the throttle will bring it down to around 13.9-15.0. It's just the vibration I'm feeling.
I'm kind of leaning towards it being tune based because it was a 2Bar SD tune that simply had some fuel removed at idle, and had the MAF and O2's turned back on. The maf was deleted for the SD tune obviously, and the O2's turned off for an open loop tune because they were laggy with the turbo's right there. But.......even in open loop starting up I'm getting the vibration.
Good luck, and please post your findings to help the next guy.
Definitely. I'm going to fire it up again tonight and see if some of the oil burnoff is getting any better and take a look at the pulleys to make sure everything is kosher there.
If you have not already, I'd throw a new set of plugs in it, too.
Could just be a misfire due to plug fouling with all that oil in the engine(provided some did get into the cylinders, too)
If you have not already, I'd throw a new set of plugs in it, too.
Could just be a misfire due to plug fouling with all that oil in the engine(provided some did get into the cylinders, too)
It's got a VERY young set of Autolite 605's, but (and before I read this post too) while I was at work at Autozone tonight I picked up another set to swap in so I can get a good read on the ones that are in there. I believe the ones in the car only have maybe 20 minutes of run time on them.
Okay, what did you find that explains the problem you identified?
It just feels absolutely mechanical. It's too sharp and RPM dependent to be a tune issue. The vibration progressed right along with the RPM's all the way up to 4000 RPM today (very easy ride up mind you) increasing in intensity along with RPM increase, and you could feel it through the steering wheel, shifter, chassis, everything. Pop to neutral and it subdues as the RPm's drop, engine braking was slower as the RPM's were dropping slower. Due to the tune the idle likes to drop to 500ish when you suddenly let off the gas, and it was almost imperceptible when it was down that low.
Now, I will say that the car definitely needs tuning and is most certainly running lean as reported back by my wide band. The exhaust waters the eyes in a heartbeat if you're behind it. But I don't think it's possibly that it's tune related given the way it acts.
Man, best of luck finding the issue.
Hopefully you can iron it out, and it turns out to be something simple.
You put a lot of work into that beast, it's never pleasant to have issues.
I know this sounds like a stupid suggestion, but I had a customer come in 3 days ago with a BMW 530i, hellacious vibration from idle up to about 3500 rpm, said it had been at 4 shops, engine/trans mounts replaced, vibration dampener replaced, full tune up w/ coils and plugs, all the usual stuff.
The car had been double filled with oil at a Jiffy Lube and had 14 qts of oil in it, causing the crank to whip in the oil and cause the vibration. It took me a while to find it as I dont normally check the oil level for an engine vibration, but I will from now on.
Good luck with finding it and hopefully it isnt an internal balance issue.
I know this sounds like a stupid suggestion, but I had a customer come in 3 days ago with a BMW 530i, hellacious vibration from idle up to about 3500 rpm, said it had been at 4 shops, engine/trans mounts replaced, vibration dampener replaced, full tune up w/ coils and plugs, all the usual stuff.
The car had been double filled with oil at a Jiffy Lube and had 14 qts of oil in it, causing the crank to whip in the oil and cause the vibration. It took me a while to find it as I dont normally check the oil level for an engine vibration, but I will from now on.
Good luck with finding it and hopefully it isnt an internal balance issue.
That's EXACTLY why I just changed the oil yesterday, put 5.5 quarts of Valvoline VR1 into it (ls2/3 pan conversion). No change.
I am left to try a couple of things tomorrow. I'm going to pull the belts and see if it's perhaps an out of whack accessory given I've got a squeaker. Then when that gets me nowhere I"m going to see if it might be something that can be attached or removed from the flywheel (counterweight). If nothing there........I'm going to look at the motor mounts although with the sharpness of the vibes I doubt it's the cause.
So......I hop out to the car and pull the #2 plug wire. Lo and behold, look what I find:
I think this DEFINITELY could be the root cause of the issues. A not-completely bolted down motor with the block riding on the mount frame. Going to drain and pull the A/C compressor tomorrow and try to fix it.
Could someone do me a favor though and hop out to the garage and see if your mount is sitting flush or not?? Just for verification?
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Out of Whack Tune root cause of Noticable Engine Vibe??
). Will be possibly seeing my tuner on Saturday, he said if he's in bring it by and he'll take a look at it.
