I have been pulling a CEL code P0033 and have zero boost while driving. The codes says its the bypass solenoid so I swapped it with a new one and still nothing. While running with the bypass mod boost returns, but only to 5-6psi during WOT. The codes says the circuit is open. Do any of you guys know how to go about pin checking this, or have another ideas?

 

check the bypass actuator it could be stuck open

 

While the car is idling I move the lever by hand and it always returns to its original position. I had a friend rev it up a few times with me watching and it had some movement. I will try lubing it up tonight when I head into work and see if that helps.

 

No dice with just lubing up the actuator rod and little lever it moves. Got anything else? Being only able to vacuum sucks........ Crickets....... Pun intended......

 

the solenoid is powerd closed(allows boost) depowered open(no boost) engine manifold vacuum opens the bypass actuator (idle and cruise conditions) at wot there is no manifold vacuum so the bypass actuator closes allows the blower to create boost if the iat2 or boost goes to high then the pcm will depower the boost bypass solenoid allowing positive manifold pressure to open the actuator dumping boost

I would check the bypass actuator for an air leak or a weak spring

 

I will check for leaks. If for some reason the PCM decided to cut off power to the solenoid how would I go about getting it to change its mind? I have clear the CEL several times but after a day or two it always comes back. Would disconnecting the battery to 'reset' the computer do it, or would that cause a whole other set of issues?

 

Do u have a scan gauge or hp tuners so you can see whats going on...

The PCM will pull timing and boost pressure if IAT's reach a certain threshold.

 

I do have a scanner that gives live stats. I have never worked with a boosted car before or have never done any sort of tuning so I have no idea what I'm looking at/for.

 

if you disconect the line from the bypass solenoid to the blower bypass acuator it should go to full boost if it dosent then the problem is with the actuator

the code you are throwing may be due to a bad wire or wires from the pcm to the bypass solenoid

 

If those thresholds were broken for whatever reason and the pcm is adjusting to limit the engine would it stay like that or after a while would it go back to normal. I have been without boost for probably like a month now and are debating on disconnecting the battery so it has a relearn everything. Would that help?

 

disconecting the battery wont help check the bypass canister and use a meter on the wires going to the solenoid to check for voltage

 

on a stock pcm, boost only drops 10%, and pulls 3-8 degrees on timing at 212 degrees iat2 throughout the powerband. would definitely be noticeable though

 

I just checked the wires from the solenoid to the PCM 2 connector pin 29. (The grey one) I don't know where the other wire for the solenoid runs to. The grey one checks fine though 0.1 ohms and it wasn't grounding out. I disconnected the vacuum line from the actuator that runs to the solenoid and plugged it with a screw. When I get out of work I have like a 10 mile drive I'll watch it and drive different styles to see how the boost goes and post what happens.

 

Highway cruising with that line plugged everything was the same as it's been. I pulled on it hard twice (once from a stop and once merging onto the highway) and both times it boosted to 6-7psi. I plugged the scanner up to it when I got home and no codes were there. Even for the half boost it was nice having it decently pulling again. :-)

 

So since with the line disconnected between the actuator and solenoid, and boost not returning to full status again you think it's the actuator? The rod moves when you unplug it with the car running, so maybe it just has a leak?

I have found a few places selling them online for like $150 so if theres any other tests I could do to be sure before dropping a decent amount of cash that would be great.

 

Pull the blower and check the valve, with the bypass done it should build full mechanical boost, as suggested before maybe the blade is sticking and not fully closing, any leak, even a small one, will reduce boost pressure greatly.