Borch

I had an issue running 7-8psi, but actually getting a transition. Today, I replaced several hoses and I went out for a test run and she spiked to 20psi.



I have a profec B and spent most of the afternoon changing the dip switches to see if there was a better setting, but to no avail. Still way over 15psi. I ran a hose from the output side of the Profec B to the cockpit with a manual valve and shut it all the way down and opened it all the way, still over 15psi. I turned the Profec B off, it still is over 15psi. I bypassed the Profec B with the same hose and valve. All the way open, all the way closed. Still over 15psi. I even tried installing the old pill, still over 15psi.



Any ideas?:

My mods are
Profec B
Adkins Street Ported engine
J-Spec turbos
Pettit Intake
Upgraded Radiator
Upgrade Fuel Pump
Down Piupe
Mid Pipe
Cat Back

scratchjunkie

am i missing something here? no ecu?

rynberg

Your wastegate is not opening. Look into the other current Profec B thread to make sure the Profec is hooked up correctly. You shouldn't have been able to replace a pill in the wastegate line because that line should be replaced with the Profec loop....

https://www.rx7club.com/forum/showth...hreadid=225230

Borch

No, I am ........



Pettit ECU

Borch

The profec B was running fine for a year before I lost boost. I had the high set at 12-10-12 and the low set at 10-8-10. Exactly where I wanted it.

rynberg

In that case, check to see if the wastegate flapper is still connected to the actuator rod with that little clip. Or make sure your Profec line is still connected. Either way, something is preventing the wastegate from opening.

Borch

The Wastegate actuator rod still has the clip attached. The Actuators are new with the turbos that I had put on last year. I guess it is possible that one went bad.

All the air lines are still conected fine. I haven't gotten a good look at the plug on the wastegate line, but from what I can see there is no leak there.

Snook

iTrader: (12)

i think you have it hooked up wrong
some silly mistake
look over the diagram again and check it out a little bit later when it's fresh.

cruiser

Anyone thought of boost creep ?
Straight-through exhaust and opened intake can cause that, no ?
I installed a restrictor place and its great so far. No issues.

Borch

It has been running fine for a year or so until the boost dropped, so the only thing I could have hooked up wrong is the in / out hoses. I actually labeled one of the hoses (OUT) before I took them off, but I will check again tonight after work.

Thanks!

Borch

I thought about that. There is a little more to the story....

My 1-1/2 year old hi flo cat from Pettit disintegrated, which is why I basically have a mid pipe. I was still running 12-10-12 on hi and 10-8-10 on low after the hi flo fell apart. it was a couple of months after that when the boost started to drop.

I wonder if a kink in the line T'd off of the boost gauge would give the Profec B a false reading that there is very low boost? Something else to check tonight.

cruiser

Maybe you had a boost leak before (a minor) ?
Now that you replaced the hoses you fixed the boost leak and now boost creeps that high ?

Checking ProfecB would only be suitable if you would be getting normal 7-8psi boost when ProfecB is off. Since you get creep even with the unit turned off, you can diss that suspect.

Try putting in a restrictor plate, its not much work and see if it does anything for your boost.

With boost creep either your wastegate isn't opening or it is too small. With 20psi readings I suspect the former.

Borch

Does anyone make/sell them, or do I just need to rig one up?

I guess I really need to get another hi flo cat.

cruiser

I put in a 0.8mm stainless steel plate. Use the stock gasket to copy the layout then just cut it out and make 2" hole into it in the middle. I doubt anyone manufactures it.

Borch

Well, after re-reading how the whole system works, I decided to check all of the hoses that I replaced this past weekend. Lo and Behold, the hose that runs from the rail to the Profec B had a chunk of silicone stuck in the middle of it allowing absolutely no air through it......high pressure on the wastegate, low boost.....low pressure on the wastegate, high boost.

Now I am back to an 8-5-8, but can't seem to get any dipswitch setting on the Profec B to make a difference.....

Snook

iTrader: (12)

Ah hA! I knew it...i was gonna say a hfc isnt gonna help you with 15psi buddy! something with the boost control was wrong.

I know this sounds funny but reset the ecu see if that works

Now again make sure you have all of the pills out of the lines or leave the one for the prespool in...im not sure what you are using to control that. Also make sure the wastegate and prespool solenoid connectors aren't switched if you touched those.

If this doesn't solve it you'll have to explain what you mean by your original problem more because I don't get what the original problem was and what you did to try to solve it "I had an issue running 7-8psi, but actually getting a transition."

Borch

I re-set the ECU this morning, with no change.

I forgot one other issue I have been having that me or may not be relevant. Before any issues started, The car started to have a hesitation that happens anywhere from 3,000 to 3,000 rpm's. This only occurs at medium throttle and at boost in the 3-5psi. It is not present at WOT nor when babying the car. It doesn't happen all the time, but most of the time. Some times it is so violent that it feels like fuel cut and some times it is just a little hiccup. It is more present on warm-up than when the car has been run for a while, but it happened this morning after a 5 minute warm-up and 20 minutes of driving.

I think I am going to bypass the Profec B tonight and put the pills and/or the valves back in to see if it is the culprit.

SleepR1

What was the problem when you were only making 7-8 psi? Was that just on the primary, or primary and secondary after 4500 rpm?

Borch

Both. I am running an 8-5-8 right now, so I am making transition.

SleepR1

Damn, dude, why so low? I thought your boost was too high?

SleepR1

Greg, how long did your high flow cat last? I've had mine since 1998, so five years, and at least, 75,000 miles. Perhaps my low boost pattern of 8-0-4 psi is being caused by an exhaust restriction in the high flow cat (Bonez)?

Borch

Less than 5,000 miles on the Pettit unit.

Borch

Read the post above.....

Snook

iTrader: (12)

sleepr1
i read your post too about your boost problem

doesn't a bad turbo control solenoid the one that is by the air control valve cause low secondary boost?
or maybe your prespool actuator is toasT?

these boost problems are real scary to figure out I'm glad ive never had one myself

SleepR1

Yes a bad TCA solenoid and wastegate/precontrol solenoid can cause low secondary turbo boost. I need to eliminate the possibility of mechanical causes before looking @ electrical causes (bad solenoids), especially since I've recently replaced BOTH of these solenoids.