Hi all,

Replaced original engine at 185K (thunk thunk thunk smokestack).
Body/interior Pristine --> Saturn Remanufactured engine installed.
Clutch replaced at same time.

BAD vibe at idle (850 ish) -- pronounced up to 1300, 1400 rpm - then not too noticeable but still present.

1) YES, I changed the TAM.
2) YES, I changed the tranny mount.
3) Cat has been replaced
4) YES, replaced ECTS and connector
4b) YES, I cleaned the EGR and it moves freely.
No, none of these made a damn bit of difference.

5) Drove like crap for a long while before I realized it was running absurdly rich (literally within a tick of failing emissions with brand new cat)

6) Replaced O2 sensor (only pre-cat in 95) -- world of difference -- much less vibe at all rpms. Was choking on gas and shuddering.....
Most of the acceleration is back.

7) Never any codes.

8) ODB I + paperclip + diag mode ---> SES light on and off equal amounts ---> does not indicate overly rich mix while running closed loop.

9) TB cleaned, new plugs/wires/ 2 coil packs with ignition module. (Car does not miss even when intentionally bogged)

10) Compression 205-215 across all cylinders.
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Still vibes at idle way too much for me to rest easy. Almost feels as
if engine is out of balance or as if compression is not even (which it seems to be). I was assured that the harmonic balancing
issues (read: dampening), would have been addressed during rebuild...

I know these engines are not known for their smoothness of operation, but the original purred like a kitten (till it blew).

Any ideas?

Ducky?
Saturntech?

Thanks

Derf




Edited by: derf

 

Have you checked fuel pressure? How many miles on the pump?


205-215 on a remanufactured engine? I have 235 on all four cylinders on my rebuilt engine. Been that way since I built it.

 

Have not checked fuel pressure/fuel pressure regulator either...figured this was a longshot since there was certainly enough gas getting through to run nastily rich....Course I'm out of all the pretty obvious stuff..

I need a fuel pressure gauge (application specific), yes?
Do95's have a shrader valve port under the hood on the fuel line coming from the pump?

Pump is original (205K+ mi). Car starts like a champ (half a crank and it is running).

Trying to tie in how this would have gotten foobarred when the original engine blew (original engine one of the quietest smoothest DOHCs I've come across....

Please advise on fuel system pressure check (95SC2)

Thanks for your reply

Derf

 

Updated info:

Fuel Pressure
after prime (key on): -- 34 psi
at idle: 32
under moderate acceleration: 40
under hard acceleration: 45-47

Removed vac line to fuel pressure regulator: 47

Note: Car bogs under acceleration as soon as fuel pressure exceeds 40....and I hear the pinging/chugging sound come from the exhaust just as I did before swapping out the 02 sensor.....

Will replace fuel pressure regulator.

I suppose it could have been damaged in the fuel system swapover during the engine change - but more likely is just worn out and cannot maintain the proper fuel pressure under hard accel.....

Oh, and my air cleaner was getting nasty (it was not too bad when I began diag many months ago) -- ran much freer with the intake piping disconnected while driving with the pressure gauge attached......

Derf

Edited by: derf