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Backtobirdy

Registered User
Hi everyone, thanks for the help and assistance with the previous issues, cars been running really good! But I've developed some sort of vacuum and boost issue. Along with a pinging issue? Well it seems like pinging to me that is....
Ok, so the vac and boost. I've re-sealed the IC tubes. Top hat etc. I've also checked as many vac lines I can get to, and put zip ties on the ones I can reach. Car has been idling at 15 in-hg in park or neutral. In gear it's dropping to 12"ish". On WOT boost, I'm getting around 8-9# and it feels like it's not all there, I know what full boost feels like in these cars. Car off, needle sits dead at"zero". With the zip ties (excluding the IC tubes) it dropped from 15, to around 12 in-hg at idle and 9"ish" in gear and now I'm getting only like 6-7# of boost. No change after IC tubes were pulled and re-sealed. While pulling ic tubes, (bottom one left in the car due to not knowing if I had to pull p.s. pump to remove it) I swapped out plugs due to a pinging and not really hard start, but more of a drawn out crank to start. After inspection of the old plugs, there was no electrode on any single plug! How the hell was this thing running!? :eek: new plugs installed, and same pinging exists. Bit confused now.
K, so I have a slight, and I mean SLIGHT exhaust leak either at the downpipe, or exhaust manifold, wanna say drivers side. Still trying to pinpoint it. Will that cause a low vac/boost pinging issue? So lost, maybe I pinched a vac line wrong with a zip tie? Could the pvc valve on the passenger sides grommet be so old that I'm losing vac there? Thanks in advance for any input or advice.
 
Propane

Also, forgot to mention I tried the propane method. No help or signs of leaks? Also forgot the car is a 90 sc, 35th anny. 135k automatic.
 
Also, forgot to mention I tried the propane method.


Problem with that is the computer has a good chance of smoothing the idle faster than you can try to tip it.

Chronic low vacuum when no leaks outside the engine is frequently worn rings/cylinders, so you may need to do a compression test, but that's a pain on our cars, so...

But low boost, vacuum and pinging could be might also be a shifted/busted balancer trigger and/or plugged cats...

How many miles on the engine?

Have you run the codes?

Did you confirm the firing order? Some manuals have it wrong.
 
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Problem with that is the computer has a good chance of smoothing the idle faster than you can try to tip it.

Chronic low vacuum when no leaks outside the engine is frequently worn rings/cylinders, so you may need to do a compression test, but that's a pain on our cars, so...

But low boost, vacuum and pinging could be might also be a shifted/busted balancer trigger and/or plugged cats...

How many miles on the engine?

Have you run the codes?

Did you confirm the firing order? Some manuals have it wrong.

Yes a compression test would suck on these cars!
Car has 135k, thought I mentioned that above, maybe not.
I agree, computer and car acts so fast in response to propane etc but I didn't notice anything change at all. Maybe a good vac tester? But what does that do for boost? Has anyone tried a can of air? Like for computers keyboards etc? Or oxygen in a can? To pressurize the system and listen for a leak? Keeping someone in the car watching the Guage and not going over 15# of boost on the gauge might be ideal? (Don't have an air compressor)
I thought about gutting the cats, I hate cats, will that effect emissions or the way the car behaves? Will it lose any more boost with gutted cats? I'm not talking completely hollowed, but just more like, idk bored out some?
Busted balancer trigger? Is that the crank sensor?
I'll run codes again tomorrow, or friday. Last time only codes thrown at me koeo was for the fuel pump circuit and maf.
I doubt the firing order is wrong, it runs really well, idles good, no noticeable misses, it doesn't stumble, and power is there without a miss, it just don't feel like it's ALL there.
I'll report back as soon as I get the codes pulled and I'll double check firing order.

Thanks!
 
Sorry I missed the 135k note - might be near having low compression...

Based on suggestions here for one method on checking for vac leaks, I plumbed up compressed air to pressurize the intake tract.

No opinion on gutting cats. I run hi-flos. You might want to check the cats to see if one is hotter than the other...a temp gun will tell.

The balancer uses a magnet to trigger the crank sensor. The balancer is at least two major pieces...one inside the other via a rubber ring. If the rubber falls apart, the outer ring can shift from it's original position where the inner hub is keyed to the nose of the crank. Misaligned timing can happen w/a badly shot balancer, and can be a pain to diagnose if not suspected.

See:
- http://www.sccoa.com/forums/showthread.php?t=111166&highlight=balancer+picture

Can you do a fuel pressure check?
 
Sorry I missed the 135k note - might be near having low compression...

Based on suggestions here for one method on checking for vac leaks, I plumbed up compressed air to pressurize the intake tract.

No opinion on gutting cats. I run hi-flos. You might want to check the cats to see if one is hotter than the other...a temp gun will tell.

The balancer uses a magnet to trigger the crank sensor. The balancer is at least two major pieces...one inside the other via a rubber ring. If the rubber falls apart, the outer ring can shift from it's original position where the inner hub is keyed to the nose of the crank. Misaligned timing can happen w/a badly shot balancer, and can be a pain to diagnose if not suspected.

See:
- http://www.sccoa.com/forums/showthread.php?t=111166&highlight=balancer+picture

Can you do a fuel pressure check?

Original issues were a shot fuel pump, new pump is installed, with great results on pressure. 40psi koeo, # for # climb with acceleration in boost. Balancer has been replaced by me with a good one. I guess I'll try to smoke the system and look for leaks. Really not wanting to do a compression test haha... sucked bad enough doing plugs! Off to bed, I'll report back when I have more tests done. Need to search how to pull KOER codes.

Thanks!
 
a leak at the manifold can sometimes makes it sound like an engine is pinging/ticking..
try and run out the gas you currently have in it with some injector cleaner or seafoam mixed in ( i personally always used atf fluid) and when you go to fill up put in like 3 gallons of premium ( obviously ) and add a bottle of octane boost..reason i say 3 gallons is the less gas the better the octane boost works. with the higher octane rating and somewhat cleaner fuel system and intake it may help with pinging.Also suck hlaf a can through ur brakebooster to help clean out the intake system..i was reading on here that with all our cars oil blow by the fuel/air mixture gets thrown off because of the oil/sht coating the inside of our intake systems...
for boost/vacuum leak, idk? if you were making 15 vacuum that sounds correct to me and then maby ur having a supercharger issue..whats the condition of that? i put in an oil additive into my sc and ran just that for a mile and then sucked it all out and put in royal purple (forgot what weight oil to use, yes even delearships now use oil in the eatons rather than the motorcraft or gm specific oil) when i did that i got back 2lbs of boost and so if swelled some seal somewhere and stopped my minor boost leak i had...
 
for boost/vacuum leak, idk? if you were making 15 vacuum that sounds correct to me and then maby ur having a supercharger issue..whats the condition of that? i put in an oil additive into my sc and ran just that for a mile and then sucked it all out and put in royal purple (forgot what weight oil to use, yes even delearships now use oil in the eatons rather than the motorcraft or gm specific oil) when i did that i got back 2lbs of boost and so if swelled some seal somewhere and stopped my minor boost leak i had...

With no issues? I'm curious as to which weight and additive yiu run.
 
Update!

Ok, went and replaced 90% of the vacuum lines, installed a CAI, 3" aluminum tubing, 6" cone filter etc. Anyways, as for vacuum and boost, I've gotten back to 15 in hg, and I hit 11psi of boost. So I've gained a cpl pounds :) more responsive, bit more torque it feels like, and over all feels better.

My exhaust is leaking off the manifolds, will that cause a low boost reading since it's not holding back ALL the back pressure? I'm good with 11 psi, might overdrive it a bit, 5 or 7% but no more than that. Gonna hollow out the cats, (I hate cats!) And install new exhaust manifold gaskets. Should be better after that. Thanks for all the input fellas!
 
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