kedvesh

Greetings!

Problem: My Accusump doesn't seem to pressurize its normal indicated operating pressure when the engine is running.

Discussion:

I have a C5 that's been mod'd with a built LS3. It is supported by a 3-qt Accusump mounted inside the left front fender. I have a remote switch to activate the sump (as well as a switch for the tranny/diff coolers) mounted in my former ash tray.

Recently, my fuel pump failed, leaving me stranded on the side of the road for a few hours. After towing and having the pump/senders replaced, I found that both switches in the ash tray seemed inoperative and/or the sump and diff/tranny coolers did not want to activate/operate.

I pulled the fuses for the diff/tranny coolers, but they were good and I put them back in. Subsequently, the diff/tranny coolers started working again for whatever reason when I next flipped their switch. Both have continued to activate/operate with no further issues.

As for the Accusump, whether the engine is running or not, the only pressure the gauge coming off the unit reads is the amount of air pressure I've put in the sump's bladder. Thinking the gauge is at fault, I turned the key on with the engine still off and activated the sump, which should have momentarily spiked the DIC oil pressure numbers, but the indicated oil pressure only went up to about 2 PSI and then quickly dropped back to zero.

I had my current mechanics check the electrical connections, especially at the switches, and they seem fine. I'm told they heard the sump come on when the switch is thrown, but I myself haven't heard any of the usual sounds.

I also had them check to see if any lines appear damaged from the tow I needed, but they didn't notice any issues from underneath the 'Vette.

Their current opinion is that a faulty main valve assembly or stuck open relief valve may be at fault. (The relief valve has a hose on it to route any upchucked oil back to the engine, so I wouldn't notice any expelled oil on the ground.) But, I'd like to try and avoid having the fender removed to access the sump for any fix if I can help it. (It's a pain to do!)

I want to check any related fuse (inline or otherwise), but I don't know where that may be. As a last resort, I'm thinking of doing as I essentially did with the diff/tranny cooler fuses, but this time pull all the fuses and the relays to see if any are bad or not and if it will "reset" my Accusump's electrical system (if that is possible or is the problem).

Final notes. I've driven the 'Vette out on my local roads up to about 55 mph, but have yet to take it out on the local expressways to see if that has any effect on things. Also, I don't know if the outside temperature is an issue as it's been quite cold (sub-freezing) over the last bunch of weeks. The car has not been driven in the last week+ due to snow.

So, does anyone in the CF community have a suggestion on what my indicated sump pressure problem may be?

Thanks in advance for the advice!

waddisme

Have you reset the accusump itself, ie charging to ~60 lbs and then bleeding down to 7lbs? Seems like it can get "hydro locked(?) iirc from my install directions. Also, make sure there is enough oil in system to fill accusump. The pressure switch on mine went bad and I had to repl but all is good now. HTH.

kedvesh

Didn't know or think of trying that. (I don't have any installation directions as I personally didn't put it on the car.) I'll update the thread if your reset suggestion helps or solves things. Thanks!

waddisme

Just went to their website and they have pdf install directions there, including how to do pre-charge. Good Luck with it.

kedvesh

Looks like your suggested fix worked! All indicated pressures back to normal.

Thanks for the advice...have fun and be safe out there this season!

SouthernSon

Have had two problems with my Accusump; first was the valve started leaking at the pressure drop sensor. I eliminated it and all was well (for a while). Then the pressure started doing funny things while trying to build pressure with engine running - switch on, or running switch off or pressure would build with switch off, or wouldn't push oil into the crankcase with engine off and switch on,etc.... seemed to be no rhyme or reason. It just didn't behave as expected in any scenario.

Problems solved: I simply went to a manual cable to open the valve. All is well once again. I believe the Accusump site now suggests the manual valve for track use.

waddisme

My EPC valve switch went bad, but Canton sent me a new one for free and spent some time dealing with issues in my thread. If this switch goes south, I am going to manual valve. I use mine mainly for pre-oiling on start up in the mornings. At the track, with oil temps at 260*, oil pressure stays around 35lbs anyway. I have an OBDII BT reader, just waiting on software that can log my oil pressure during a session.

redhot400

I have an 05 Z51 LS2with 470 RWHP and am just beginning to get on the track via NASA HDPE program. Am concerned about oil starvation and have read everything I can on Corvette Forum about the Accusump system, its problems etc. and am wondering what is the best approach and whether its worth the money and if so the best application for my usage. The car is both a track and street car but only driven maybe 100 to 200 miles a month on the street otherwise it sits in the garage waiting for the next track event. Any suggestions or ideas?

kedvesh

Congrats on deciding to learn more about your car's capabilities in a safe environment--on a supervised race track, NOT on the street--and in the process, also becoming a more knowledgeable driver!

As the OP, one who's an enthusiastic HPDE participant (since 2003...when my wallet allows it) and who's not a trained mechanic or in the racing industry, your question deserves a thread of its own to be better answered by more knowledgeable people than I.

Recommend you create such a thread, also in the Autocrossing & Roadracing section.

However…

To make a long story short, yes; it's worth the money to have a supplemental oil pressure system in your 'Vette, especially if you track it on road courses. It's cheaper than experiencing the rotten luck of having an engine oil starvation situation and later finding you've grenaded your engine.

Because you have a C6, maybe it would be easier to retrofit in a stock or similar dry sump system. That would be one of my choices if I had your model. (It was a very expensive option for me and my C5. Thus, the reason why I chose the Canton Accusump.)

The other would be to consider selling your modified C6 and buying a used C6Z06 or even a new C7. The decision might sting a bit (no pun intended), especially if you have a "history" with the car or have already opened your wallet too much over its mods. But both, as I’m sure you know, already have additional oil support systems (and more) designed and built into them from the factory. It could save you a lot of potential heartache, etc. in retrofitting your C6.

If you would like to discuss things further with me, please send a PM.

Good luck, be safe and have fun!