Smoke after Deceleration (Read for specifics)

magnumP5

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'86 RX-7 Base, '79 RX-7 GS
Well it comes to this - I essentially have a MSP so that's why I'm posting this here:

Well adding about a quart of oil over the past two days (didn't fill it completely the first time I think) I think I may have finally found my culprit. As I was driving down the highway today I let off the gas completely because someone cut me off. After about 5-10 seconds I got back on the throttle to maintain speed (read: not WOT) and as soon as the throttle kicked back in I see a puff of smoke through my rear view mirror. Now me being paranoid I had to replicate the incident by repeating the above steps and sure enough - a puff of smoke every time. I could not however replicate this on the way back (weird).

So what's this appear to be? Symptoms include massive oil consumption and "puffing" smoke when returning on the throttle (read: not constant smoke, only "puff"). There appears to also be a decent amount of oil residue on the hatch (little black spots everywhere). So what does this appear to be: piston ring blown, bad valve seal, bad turbo seal? Any input would be greatly appreciated.
 
check compression on your cylinders easy thing to do if it isnt normal its prob piston rings or valve seals
 
check compression on your cylinders easy thing to do if it isnt normal its prob piston rings or valve seals
Yeah, if I can find someone with a compression checker I will probably do this. Is there any way to tell between the two based upon a compression check?
 
try goin to auto zone they may rent a compression tester out not sure, as for telling the two apart that im not sure about i doubt it but it will kinda give you an idea of whats happening
 
try goin to auto zone they may rent a compression tester out not sure, as for telling the two apart that im not sure about i doubt it but it will kinda give you an idea of whats happening
Yeah because there are also leak down tests but those are crazy expensive. I last had a compression test done back in August and it was 200 psi across all four cylinders.
 
Sounds like its turbo related as opposed to internal or head issues. How often do you have to top off the oil?
 
Sounds like its turbo related as opposed to internal or head issues. How often do you have to top off the oil?
For the past few months, rarely. However, I just recently made a trip to OH (through WV and a lot of mountains so I was in boost a lot) and afterwards I was well over 1 qt short. I check my oil about once a week or so but this sort of consumption is unusual. Hopefully later this week I will be able to pull the first hot pipe to check for oil and get a compression test done.
 
Lol yea when you mentioned your oil consumption the other day and how it smelled through the exhaust I was surprised you weren't smoking. Oh well, good luck finding the culprit.
 
I have had a similar issue with my car. I presume that you are getting that puff when you come off boost. The turbo is most likely sucking oil (seals) and sending it into your intake. It is less noticeable when you are driving normally but under boost the oil intake is more, thus more smoke pufing out. Get your turbo checked.
P.S. I am by no means a mechanic or induction specialist but just sharing based on my own situation and deduction.
 
I had some similar oil consumption over the past 6 months or so. I check my oil every day because of it especially in my new forged motor. I compression tested about 4 times in that period and was around 195 and then with 1/2 tsp of oil I was around 210.

I have read that we have valve guide issues in several threads. Getting worn and not allowing the valves to seat properly. I would get a huge puff of bluish smoke in higher rpms and was going through maybe 1quart a month but I also live 1mile from work so that's alot for me. I'm sure it doesn't help entirely by letting my car warm up for ten minutes probably letting some oil by the rings and then a 3 minute drive and a cool down. So my car is sitting more than it is ever driven.

The black specs on your bumper I think is just from running so rich because I still get that with my new motor and definately no smoke.
 
I've had all the causes of what you can be experiencing. I've had a bad valve seal, turbo seals, and blown piston ring. A valve seal will leak constantly, and slowly. If there's alot of smoke, it's more than likely a piston ring, hate to say it. It's worthwhile to check your oil return line as well, and make sure it's not coked. Also, pull your intake off and check for turbo shaft play.
 
Are you puffing when going into boost or reving high now? Or even at idle?
If its only on decceleration id say valve seals.

Check pcv system.
Compression check.
Check for blowby.
Check turbo for shaft play.
Look for oil residue in ic pipes.
Maybe even possible head gasket damage.

The list can go on.
 
he just had his turbo re done by MPI nick last year around september-october so i wouldnt think it was the turbo.
 
So was your oil issue bad turbo seals or blowby? I have always had black specs on my bumper and I'm definately not going through any oil right now?!
 
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