North American Turbocoupe Organization



On the road, but a harmonic viberation question emerges.
Tedybear315 Offline
Junior Member
#1
Finally got the car on the road.  No thanks to the local DMV being shut down and supposedly "We will mail locally your plates same day we get the paperwork and fee's".  Took them almost a full week to drop the stuff in the mail..

Okay, enough about that.

Car goes down the road decent.  Most we get out of boost is only 5-6lbs, but we're not going to whine much.  The car hasn't had plates or on the road for almost 6 years or something..

Anywho.  Issue that presented.   It has a harmonic type vibration out of the engine.

Also the exhaust almost sounds like it's got a leak.  But I replaced it from the cat-back.  Not too concerned about loud exhaust.

But the harmonic vibration is pretty noticeable.  Once going down the road it seems to mellow out.

I can really feel what's best described as an exhaust "vibration/noise" under my feet on the passenger side-  Really presents itself at idle.  It's there while driving at 60 as well, but smoother.  That combined with that harmonic vibration at idle has me concerned.


Out of caution I will re-torque the crank pulley tomorrow.  I do not believe that will be it.  But just to eliminate that from the list.

Engine seems to be running okay otherwise.  I did note a very tiny fluctuation when I did a vacuum gauge test.  It hovers about 18-19", but has a noticeable tiny twitch.   I think it's not a related issue.  It's not much, but worth a mention.

Ideas?  Always welcome.  It's got a full tank of fresh gas (finally).  New plugs, cap/rotor/etc...  Fuel filter is also new..  Idles a touch on the high side while warmed up.  But that might just be me getting used to things.

Thanks in advance for ideas!!  At least it's on the road!

S-
Reply

Mikey97D Offline
Member
#2
What brand plugs, cap and rotor? What did you gap the plugs at?
Might be worth checking if there are any codes. If you look in the technical faqs here they have good instructions on how to get them.
1988 TC, 5 spd, Stinger 3" Exhaust, Schneider Roller Cam, -4° Cam Pulley, Cone Filter, Gilles Boost Control Valve set at 17 psi, CHE Rear Lower and Upper Control Arms, Braided Brake Lines, Hawk HPS 5.0 Front and HPS (F) Rear, CRES Inserts in front calipers, and '93 Cobra Wheels with General 235/50R17 Tires.   
Reply

Tedybear315 Offline
Junior Member
#3
The only codes stored as of yet would be for the EGR not working.  The solenoid is shot and not allowing the EGR valve to work.  Its stuck in the closed position thankfully.  Can't seem to find any replacement for that solenoid either.  The parts catalog's drop off at 1987, and the key notch isn't in the right position for the wiring.

Tune up parts all new, and as close to OEM as I could make it.   The engine doesn't seem to be misfiring at all.  In fact it's pretty solid.  Just has a very odd harmonic vibration we're trying to figure out.

Cap and Rotor:  United Auto Parts OEM type. 
Spark Plugs:  MOTORCRAFT SP447A   Gap set according to the sticker under the hood.  I'm not at the car, but they are gaped as per the emissions sticker.

Plug wires didn't get changed out.  The PO had new Motorcraft plug wires in outstanding condition.  So we reused them.  Probably will swap them out as $$ allows just so it's all done at about the same time.  I'm a bit of a fanboy of the NGK products.  Might swap over to all NGK at some point.  

Also we did the timing belt and tension pulley.  Timing is set as per the sticker.  10BTDC with the spout removed.  IAC replaced with good spare, as well the TPS replaced with a good spare.  (Tested using meter.  Smooth as silk and not jumpy like the one we removed.)

I can't detect any miss-firing as mentioned.  Just a really odd harmonic vibration.  Seems to be really noticeable at the firewall/under my feet in the passenger area.  Concerned about the turbo unit.  However the turbo spooling up/down seems to have no effect on it.    I will double check the torque on the crank pulley to be safe.  Pretty sure it's right-  But it's an easy thing to check.

I've got plenty of time, as I'm laid off.  But all ideas are welcome!  I'm more of a 302/351w engine nut.  This 2.3 "Lima" is a bit new to me.  Not bad to work on, just has it's own quirks.

S-
Reply

Jeff K Offline
Administrator
#4
It isnt the crank pulley unless if is bent / damaged. 2.3 is internally balanced so the crank pulley is just a pulley, not a harmonic balancer like the V8s use.

Look for damaged / collapsed motor / tranny mounts, exhaust hitting the frame, etc.

Check the 4 bolts that mount the K member to the body to be sure they are tight.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

Tedybear315 Offline
Junior Member
#5
(04-23-2020, 03:28 PM)Jeff K Wrote: It isnt the crank pulley unless if is bent / damaged. 2.3 is internally balanced so the crank pulley is just a pulley, not a harmonic balancer like the V8s use.

Look for damaged / collapsed motor / tranny mounts, exhaust hitting the frame, etc.

Check the 4 bolts that mount the K member to the body to be sure they are tight.
Crank pulley was in fact slightly loose.  I re-torqued it down about another 1/4 turn until it 'clicked' in where it belongs.  Not enough to cause issues.

Today was a bit of a cluster.  Took the 'Bird to the Dodge shop for a part for a different SUV.  (Parking brake cable for a 2010 Dodge Journey.  Latest one on the 'fleet' I can't afford)

On the way back I give it some boost to spread it's wings (pardon the pun)  I happened to glance down and the oil pressure gauge was barely into the normal range.  But acceptable, so I took it up north where I work on stuff.  I get up there, and now the needle is in the red.  So I call the wife  (Yeah, I'm writing a short story here...)  And we pull the oil pressure sender and hook up a MAC TOOLS pressure gauge made for engine/transmission pressures.  

Engine cool (not cold)  about 40 lbs @ 1500.  Engine HOT (to the point the fans where getting ready to fire up)  About 28.  (probably 20 if in gear. That 28 was just sitting at idle...)  When I was driving at about 2200RPM the gauge wasn't going above the top of the 'red'.  We installed a new NAPA oil pressure sender.  Gauge is sluggish just like all of 'em, but functional.  

On to the vibrations!....   IMO?  Turbo or related area.  I placed my hand onto the valve cover,  Not bad...  I put my hand onto the intercooler-  Loud and Clear.  You can feel it very strong.   Boost works okay,   Doesn't change rhythm or 'pitch' for that harmonics for different RPM ranges.  

Mounts appear to be okay.  I will double check the K-Member bolts, but I suspect they will be okay.  Just feels like it's resonating to the point you can feel it crystal clear when hand placed on the intercooler.

S-
Reply

Jeff K Offline
Administrator
#6
Possible that the intercooler is hitting on something and vibrating? Years ago, I had an annoying vibration under certain RPM and load conditions I traced to the IC (stock IC). It was apparently hitting something, but I never figured out the exact problem. I discovered, by trial and error, that if I loosened the nut holding the IC to the stud on the exhaust manifold and pulled the IC up (toward the hood) about 1/4 inch, held it there and tightened the nut, the vibration went away. To be able to move the IC up the 1/4" I took the stock bracket and cut the hole in the mounting bracket into a slot with an air powered cutoff wheel. Vibration hasnt returned in 15+ years.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

Tedybear315 Offline
Junior Member
#7
Interesting.  I'll give that a shot by repositioning it.  It almost sounds like an exhaust leak out of the turbo to be honest.    Sense it's not really changing the 'harmonic frequency' with engine RPM that's what has me really puzzled.

If it's a rotational issue with the turbo:  I would expect it to get 'higher' or change in pitch with the spinning.    Same would go with exhaust leak(s).  Faster the RPM the exhaust leak would get to the point it'd be a different pitch.

Something I did notice that has me greatly concerned.  The coolant level has steadily dropped.  At first I figured some air pockets in the engine might have worked themselves out.  But the wife pulled it out of the 'barn' after we replaced the oil sending unit.  I noted a bit of white smoke that normally I would consider condensation burn off.  So she pulls down the hill and after about 10 minutes she restarts to drive home.  Pretty fair amount of white smoke...and it vanished after about 1/2 a mile (normal 'clear' exhaust). 

Think we'll put the front end up in the air and drop the front exhaust from the turbo.  I've got a pressure tester and can put about 18lbs on the radiator and see if we have coolant leaking out of the installed turbo-  That is one possible cause of the white exhaust for only a few moments.

Trying to work bugs out of this.  (Sun roof fixed itself!   Okay, 1/4 can of Fluid Film as well..but it's fully functional now)  Fun when you put a car on the road after it's been sitting for about 6-7 years due to unknown issues.

I told the wife I would prep the spare turbo unit just in case.  It needs the bolts holding the wastegate replaced.  The gate is 100% seized up and of course the bolts snapped off.  So I will drill and tap for replacement over the weekend or next week...  I'm still furloughed from my job-  So I've got plenty of time to screw with this thing.

Fairly sure the coolant bit isn't the head gasket or head.  I can do a combustion test to be sure.  I've had the white problem happen also due to coolant seeping into a cylinder via that intake manifold.  (that would suck.)

I'm thinking out-loud on this one.  But I'll chase a few things down.  #1 is that intercooler remount and check 

S-
Reply

anasazi4st Offline
Senior Member
#8
(04-24-2020, 02:23 PM)Tedybear315 Wrote: Interesting.  I'll give that a shot by repositioning it.  It almost sounds like an exhaust leak out of the turbo to be honest.    Sense it's not really changing the 'harmonic frequency' with engine RPM that's what has me really puzzled.

If it's a rotational issue with the turbo:  I would expect it to get 'higher' or change in pitch with the spinning.    Same would go with exhaust leak(s).  Faster the RPM the exhaust leak would get to the point it'd be a different pitch.

Something I did notice that has me greatly concerned.  The coolant level has steadily dropped.  At first I figured some air pockets in the engine might have worked themselves out.  But the wife pulled it out of the 'barn' after we replaced the oil sending unit.  I noted a bit of white smoke that normally I would consider condensation burn off.  So she pulls down the hill and after about 10 minutes she restarts to drive home.  Pretty fair amount of white smoke...and it vanished after about 1/2 a mile (normal 'clear' exhaust). 

Think we'll put the front end up in the air and drop the front exhaust from the turbo.  I've got a pressure tester and can put about 18lbs on the radiator and see if we have coolant leaking out of the installed turbo-  That is one possible cause of the white exhaust for only a few moments.

Trying to work bugs out of this.  (Sun roof fixed itself!   Okay, 1/4 can of Fluid Film as well..but it's fully functional now)  Fun when you put a car on the road after it's been sitting for about 6-7 years due to unknown issues.

I told the wife I would prep the spare turbo unit just in case.  It needs the bolts holding the wastegate replaced.  The gate is 100% seized up and of course the bolts snapped off.  So I will drill and tap for replacement over the weekend or next week...  I'm still furloughed from my job-  So I've got plenty of time to screw with this thing.

Fairly sure the coolant bit isn't the head gasket or head.  I can do a combustion test to be sure.  I've had the white problem happen also due to coolant seeping into a cylinder via that intake manifold.  (that would suck.)

I'm thinking out-loud on this one.  But I'll chase a few things down.  #1 is that intercooler remount and check 

S-

The advice I’ve always heard is, “Don’t check the cylinders for compression unless you want to be disappointed or are prepared for bad news.” Too many times younger, often enthusiastic car owners do that just to see what’s going on—and, many times are upset with the results.

But, I think in this case you should test all the cylinders for compression. It’s one less thing that could be wrong.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
Reply

Tedybear315 Offline
Junior Member
#9
Well for those playing at home:

Compression Test:  (Dry)

#1:   140-150
#2:   140-150
#3:   115-120
#4:   140-150

Numbers vary sense my compression test bleed down valve decided to start leaking.  I wet tested #3 and it shot up to about 210. 

Engine is tired.  However it is running pretty smooth.  I let the wife know that we should probably look into an engine swap in the future.  Or perhaps rebuilding the other engine block, and going with a reman head.  

Onto the coolant leak:

Pressure tested.  The damn thing still had some pressure in the system from sitting overnight.  Nice surprise for yours truly!  Pumped it up to 18lbs and the coolant line to the turbo started dripping again.  It's double clamped on both ends.  I snugged it down and that leak stopped.  That one makes sense, as it 'fixed' itself at lower pressures.  Going to higher pressure/operating pressure is when it started dripping.  So no marks on the ground.

Harmonic Vibration:

Thankfully I wet tested #3.  I asked the wife to crank it over with the intercooler removed.  Of course it won't run for more then a second-  But that was all I needed to see a smoke show out of the connection from the turbo to the rear pipe with the O2 sensor.  Nice puffs of blue smoke in a rather rhythmic fashion!.

Needless to say I'm not thrilled, as I hate repairing exhaust.   So I'm putting the next project  (Rust abatement on a 2010 Dodge Journey...Before it goes on the road we're going to de-scale and rust treat the undercarriage.  For 10 years old?  It's pretty bad).

We're taking it in for inspection, and then parking it back in the 'barn' so I can get that gasket and mating surface prepped and repaired. 

Anyone happen to have a part number for that gasket?  LOL!  Looks like I'll need to attempt to source one out!

There's the updates!

S-
Reply

Tedybear315 Offline
Junior Member
#10
Searched and found the Remflex gasket. One of the eBay sellers is about 4 blocks away LOL! Pity he's a reseller using a supply house in PA. However if there's a quality control issue, I've not far to go.

S-
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB