Engine power problem (was balancer..)

Jogi

Registered User
Hello from SC newbie! I have had my -89 SC for about 3 month and starting about 1 month ago idle vacuum has been dropping slowly from 19-20 to 14 and now performance is really poor. Boost comes really quickly but it's pain to get car to go even 60mph :(

Top of engine was build up by last owner and I just changed fresh 255lph fuelpump & filter (they did not make engine any better, so likely it is not fuel problem)

KOEO & KOER test did not give any alarming codes. I also did intake track pressure testing to see if there were any boost/vacuum leaks, only "hissing" came from EGR gasket, and it was too small to create my troubles I think.

Downpipes, cats & rest of the exhaust is quite fresh (2000 miles..) but from what I have read from forum, my cats could be clogged..

Any ideas to check cats or do I just replace them with pipe.. or if you think any other reason my car is behaving like this?

Thanks!
 
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If you are barley getting on the gas and the boost goes to like 10-15lbs I can almost asure you its clogged cats. And it will also take alot of time to get to speed on the highway too. So gut em!
 
my LH cat broke apart in my 94 and plugged up the pipe...i had to limp the car to an exhaust shop....in doing so i had to keep shifting gears to keep the rpms under 1300rpms to keep the car from stalling. in fifth gear my top speed was 28mph before the back pressure would stall the car. even with those low rpms the boost was running a constant 5-10psi. it's a great time for you to open up the exhaust and put true duals on it!
 
I just got cats out and pipes in their place.. cats were just fine :( so problem is still present. Today engine barely started and vacuum was still lower & power even lower.

So what would be next things to check??
 
Well if the cats are fine then some other part of the exhuast is clogged, maybe a bit of the inside of the cats has broken off and got stufft up farther down the system.
 
Problem still present.. vacuum has dropped to 12-13hg-in. I have not even drove the car and now starting is really hard, once started it however idles quite steady.
I doubt that rest of the exhaust could be clogged, quite new flowmaster exhaust.. but I'll check that too if everything else fails..

- Did cylinder balance EEC test today, no problem there, all cylinders drop same amount RPM.
- unpluged MAF also, even harder to start and more sluggish responce to gas pedal
- unpluged cam sensor connector too,.. was harder to start but not much change in anything, except RPM tach naturally did not work anymore.
- checked ignition timing at idle, was about 18-20 degrees (spout not removed..)
- fuel pressure regulator, quick check only -> did not leak through vacuum nibble
- quick EGR test: manually applied vacuum to EGR -> EGR opens and idle went a lot worse

Still to check..
- fuel pressure: have to find suitable pressure meter and fitting..
- remove crank belts and try to see if balancer is bad or cam chain feels stretched etc..

Opinions & help needed... :(
 
Problem still present:

- fuel pressure test done, pressures with- and without vacuum OK
- I reseted the EEC by disconnecting battery for 30min.. no change
- unplucked the crank sensor -> did not start at all, tried starting 10-12 times..

:confused:
 
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Jogi said:
Problem still present:

- fuel pressure test done, pressures with- and without vacuum OK

:confused:

Did you trying dropping the exhaust at the hearders to see if that made any difference?
Mike
 
99GSXR750 said:
Did you trying dropping the exhaust at the hearders to see if that made any difference?
Mike

...coming back from under car... yep, did that just, no difference :(

Next is balancer....

What if my timing chain is jumped 1 or 2 teeths???
 
PearlBird said:
Is it making lots of boost at low rpms when you accelrate?

Well yes.. nothing unusually high but close to my normal, about 9-12psi around 2500-3000. It comes with less pedal effort as vacuun is quite low and drops fast while even little bit acceleration -> vacuum to 0 -> boost..


Stripped belts and I could not feel any "wobbling" or extra movement on balancer. I tried to feel if there is any stretching in the timing/cam chain, but I think I have to get someone to view rockers movement while doing that.
 
What i mean is, are you barley giving the car gas, yet it still makes alot of boost. Like if you where to accelerate to 30mph from a stop, in like 15 seconds, does the car makes boost at this slow accel period?
 
Except for the low vacuum issue and the hard starting issue, it sounds a lot like my car was. With even a small amount of boost, it would sputter and barely accelerate at all. It turned out that replacing the plugs and wires solved the problem. It doesn't sound like an exact match, but maybe that's what is going on?
 
PearlBird said:
What i mean is, are you barley giving the car gas, yet it still makes alot of boost. Like if you where to accelerate to 30mph from a stop, in like 15 seconds, does the car makes boost at this slow accel period?

Yes, lately it went that bad, I could baby it to not go to boost side and get 60mph really slowly but 0-30mph in 15 secs it would make boost, not much but still . Anyway, even a 10psi or something could not get it accelerate much faster.

Do you have some idea what could be going on?

edit: I found similar problem thread.. balancer needs more attention.. http://www.sccoa.com/forums/showthread.php?t=32352&highlight=rotated+balancer
 
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99% sure, balancer broken from where steel sleeve ends... tiny piece of it was already loose and when I rotated the balancer it moved independently compared to the steel sleeve.

Now I have to get balancer and remainings out :( and order that BHJ "all steel balancer" :(
 

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First part of the balancer is out, socond one is harder to get out..
It seems that it was rotated about 15-20 degrees, see image attached.
 

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And second part is out too. Here is image of the selfmade tool to pull that part out.
 

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Just happy update :) I got my BHJ balancer and it went in nicely without honing.
There was little odd thing in the balancer,.. pulley bolt holes were not threated all the way.. anyway, nothing that could be solved by cutting bolts shorter :)

And yes, idle vacuum is back to 20" and all previous HP seems to be back :)
 
I didn't see this thread until now but I remember when Mike was having that balancer problem way back in '02. It's not common that you have a completely sheared balancer being held on only by the bolt, but it's not the first time. It is very difficult to diagnose because if you check timing it will still read ok since the EEC is reading from a false trigger (turned balancer). Usually the bolt will break and the balancer will simply "fall off".

I'm intersested in knowing why the balancer failed. I'm going to guess that the first thing that failed was the elastomer. If you still have the remains, take a pick or screwdriver and stick it into the rubber ring that seperates the hub from the main part. I'm betting that it is hard as rock and probably cracked and falling out too. Is it the fact that the elastomer has failed that causes the vibrations to crack the balancer? I guess it might be hard to say.

I know on my car the elastomer was broken and falling out after 200K miles and you could simply spin the outer ring round and round. It didn't break the balancer though. I'm thinking that some SC engines have better internal balance than others (luck of the draw) and so some will not break the balancers even in the absence of a dampening material whereas others simply won't tolerate it. It's also possible that when a motor breaks a balancer that the crank snout gets bent slightly (remember it's a forged crank) causing subsequent balancer failures. I've noticed that once a car breaks one OE balancer it tends to break more. I've never heard of problems with a BHJ though.

Anyway, sorry for the crappy luck but it's good to see this problem revisited and thanks for the pictures and descriptions. For good posts like this one the SCCOA should be paying YOU for your contribution. :)
 
Garbage truck just picked up trash so I can't poke the balancer anymore but what I can remember when I checked it, rubber/elastomer was in rather good condition.. no cracks, not too hard, just firm rubber.

I think 20-40hp? that a supercharger takes at most starts whole process. And even if a balancer is mainly hold with "press fit", sharp edge and keyway key ending at same point creates more chance to balancer broke in point where it usually brokes.

And thanks, It's my pleasure to write & take pics, I hope it is usefull for SC community. :)
 
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