EVAP/CPC Solenoid Delete?
 

TLDR; Can I delete the EVAP/CPC solenoid and block the hoses or is it going to over pressurize the fuel tank? Yes, I have the CEL disabled.

Full Story below:

A little background about my 86. Greddy T518z turbo, spun a bearing doing 120 MPH in 120 Degree weather (not smart, I know), hole under the block, rod disintegrated, piston damaged, bent valve and camshaft, got a Crawford short block (10.5:1) and upgraded valve springs, new everything that was seemingly damaged, new spark plugs, upgraded injectors, fuel pump, cooling stuff, ACT clutch/flywheel, etc. Rough idle here and there which I thought was due to the lighter flywheel, otherwise ran like a champ for 5000km (always on 98 RON/94 AKI)

Anyway, I had an issue earlier this month after a lot of "high speed" driving. Once I slowed down and drove into town a slight bog/hesitation was happening at about 3k only in 1st and 2nd but not any other gear or neutral. Next morning it drove completely fine until I shut the engine off while parked for about 30 minutes and then the bogging/hesitation/backfiring reoccurred but now it is significantly worse and in all gears even neutral and happens at any hint of boost (high load/demand of fuel)

It was clearly misfiring but with no CELs what so ever. I even disconnected my MAF sensor just to see if it will throw a code (Maybe my tuner turned CELs off?) and it did. Double checked with tuner and confirmed no CELs were disabled.

I went threw the following respectively:

- Disconnected battery
- New Coils
- Cleaned and tested injectors
- Went back to stock fuel pump
- New spark plugs
- Vacuum leak test.
- Clamped EVAP hoses
- Removed catch can
- Reflashed ECU

Non of the above made the slightest difference. Finally decided to pull out the direct injectors. They looked rough so had to swallow it up and buy new ones (number 2s). Once installed, started and idled roughly but the bogging at higher RPM is gone and no more back fires. However it stalled when ever the RPMs dropped after reving.

I read on another thread here how the EVAP/CPC solenoid might cause this idle issue. I'm running my boost controller of the plug that was connected to the solenoid (http://www.frsmod.com/products/plug-...r-frs-brz-fa20) so its only purpose was to block the hoses. I took it out from underneath the intake manifold and plugged the hoses it was connected to (With non other than the used spark "plugs" ;) ). Idled as smooth as if it was bone stock. Took it out for a drive and it spun the tires all the way from 1st to 3rd and I can even say it drove better than before this whole issue even started. Pressure tested the solenoid and it was definetly leaking.

So, can I simply delete the EVAP/CPC solenoid and block the hoses or is it going to over pressurize the fuel tank? Anyone makes a kit? TIA

U ever found a remedy for this ?

Yes, the direct injectors seals were the main cause of the issue. I put down +$700 for all four complete injectors thinking they might have been damaged after the engine blew. However, replacing the seals only might have worked fine and saved me a lot of money. I just wanted the peace of mind.

I have also disconnected and plugged the two hoses going into the EVAP solenoid for the past 4 months or so with no problems.https://uploads.tapatalk-cdn.com/201...0e2615c6a5.jpghttps://uploads.tapatalk-cdn.com/201...f1b4c34779.jpg

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Thanks for the info.

Do people usually just leave all the EVAP solenoid hoses in the stock location after installing the EBCS? Currently building my car and now having mine installed, don't wanna run into this issue... how does the engine compensate for not having the oem solenoid not operational anymore with all the hoses still in place?

Just delete it and block the hoses. With it disconnected it becomes obsolete anyway since its normal operation position is closed. You create the risk of the hose that's not even clamped on from factory to come loose from boost creating a boost/vacuum leak. You can just clamp both hoses on the EVAP solenoid but if for whatever reason the EVAP valve inside malfunctions and leaks somehow, you'll have a bad time.

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Did you just turn off the P0171 code in rom raider or is there another location to disable the evap CEL from happening?

I ended up connecting bypassing the evap solenoid with a single hose; you're suggesting that I cap both sides instead of leaving it open correct? IE cap under the manifold and at the hard line to the right.

I don't think I have P0171 disabled, my tuner would know but he won't turn any code off without telling me first. Looking up P0171 shows that it's most likely a leak in the intake manifold. If you delete the EVAP solenoid, you're gonna have to plug both hoses as the normal position of the solenoid is closed. It only opens momentarily to return any fuel vapor to the fuel tank.

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Thanks, that would explain the issue lol; I had it wide open when I attempted to bypass rather than plug. I'll just leave it powered on for now and once I get my EcuTek tune I'll have them switch it to the boost controller.