jeffrored92

OK guys

Here is a link to my last thread about my boost problem
https://www.rx7club.com/showthread.p...ng+information

My car is stock, with a downpipe. Boost pattern is something like 7.5 - 5 - 5. Builds up to 7.5psi very very quickly and the drop to 5 at 4500rpm is very sharp.

I've checked and rechecked intake piping and cannot find any leaks.

I checked the vac lines from the primary compressor to the pre-control / wastegate actuators, and they have the pills in there, the slightly larger pill in the wastegate line.

I tried switching electrical connectors on the solenoids, no difference.

I disconnected the vac lines to the wastegate/precontrol actuator (dangerous yes I know) and capped the two nipples on the turbo side so as not to vent any boost. Went for a spin and voila - boost! Could build 10psi without even going WOT. Being very careful I spiked once at 12psi and not once did I hear anything sounding like a boost leak.

Wicked I thought, I've narrowed down my problem.

I now have the two solenoids out and have tested them, they seem to work perfectly. Closed with no electrical connection, open with 12V applied. They don't seem to leak or anything. My oven is still heating up so I'll let you know how the "hot test" goes.

I have connected some extra hose to both precontrol / wastegate actuators and I can blow air through them up to the pipes behind the pressure tank so there are no blockages in either of those lines.

I connected a bike pump (no Mityvac and still trying to locate a similar product in Aus) to the actuators and was able to watch the rods move in and out quite freely, using my finger on the pipes behind the pressure tank to hold pressure in the actuator.

It is looking more and more likely that it is a shonky electrical connection to the solenoids, or a dud ECU (I read some dude had an ECU which was playing up with respect to the duty control of these solenoids). What is the best way to go about testing the electrical connections between the ECU and these solenoids? I imagine there is a pin on the ECU that grounds the solenoid, that would be my guess.


I'm starting to lean towards a manual boost controller setup........

jeffrored92

Ok tested the solenoids pre-heated to 100C and they still seem to work fine.

Max13BREW

Exact same problem on mine, however mine is in a workshop. Has been in there 4 days now, and they still havent found the problem (But are suspecting the ECU)

God knows how much 4 days at $80 an hour, plus multiple dyno runs are going to cost me...It had best fix the problem though, I have to hit the track in a few days!


I will post what they find hopefully tomorow.

jeffrored92

Haha well I put everything back together, after changing some of the vac hoses on those solenoids, and still have the exact same boost pattern.

So I'm down to either the electrical connections or the ECU.

Hopefully it's just a dodgy electrical connection, which can be easily fixed with a manual boost controller.

Although if there is an open circuit somewhere (which the ECU would regard as there being no solenoid) then I would expect the engine warning light and one of those silly code things which I know nothing about yet.......I might go unplug the solenoids and see if anything happens. Tomorrow. It's too late now and I've spent the best part of today on the car!

dgeesaman

iTrader: (7)

Keep at it man. There isnt a whole lot to suggest but it sounds like youre on a good track. Make sure to report the final cause (when) you find it.

Dave

spooledUP7

Which two solenoids did you test (heat)? Just the precontrol and wastegate? The one solenoid which gave me troubles was the turbo control (vacuum side) solenoid mounted to the ACV. I swaped out the coil from the purge control solenoid with the turbocontrol coil and it worked perfectly. The better solution would be to replace the solenoid all together.

jeffrored92

Yeah I only tested the wastegate and precontrol solenoids.

I'm leaning towards those two (or their electrical connections) being the problem because when I disconnect the vac lines from the primary turbo compressor to both wastegate and precontrol actuators, thereby keeping them both shut, I can build boost quite happily. And there is no sound of a boost leak.

On a quick note, I probably should start another thread, but where is this check engine light (CEL) I read about? I've searched and can't seem to find where it is located in the car. I've read that only US versions have them but my car (Australian) has this weird light like an LED next to the ashtray. I for some reason thought it was an exhaust gas temperature warning light, but not sure where I got that idea from.

CANRX7GX

iTrader: (1)

Could it be that the pills are the wrong size and are restricting boost too much???
Just a thought. I also had massive boost problems with my car. I ended up finding vaccuum lines with splits in them. Barely visible, but all the way through none the less.

jeffrored92

Hmmm those are both good thoughts.

My argument against the wrong sized boost pills kind of supports your cracked hose theory.

My car was stock when I got it, and judging by the look and feel of some of these vac lines, they aint never been touched! So I doubt the pills have been changed.

I had to replace the 4 hoses on the wastegate/precontrol solenoid assembly, because they were baked on. Trying to get them off with needle nose pliers just shattered the vac hose it was that brittle! The hoses with the pills seemed to be in pretty good condition, I stuck them back on because the 6mm ID vac hose I have is smaller external diameter than the stock hose, and I wanted to re-use the spring clamps. I might have to swap them out with some new tubing and use cable ties instead.

Max13BREW

Just in case it helps , my car was exhibiting 11/4/6 boostage,
turned out that i had a number of vacuum hoses stuffed. Replaced all of them and still had a very similar boost pattern (A bit higher..but not significant!)
The remaining fault was the actuator arm on the wastegate (From what I can remember) had a rust problem. Due to the car boosting so low for such a long time, rust had formed on the part of the arm that was not retracting fully. When the vacuum was fixed , and the actuator tried to move the arm fully it stuck on the rust..

Thankfully Reliance automotive in Canberra only charged a bit over $500 to fix it! It took them 4 days to find it (using the try this..dyno it..wait for it to cool, try next thing method!) As $200 of that was in Dyno fees I think it was pretty fair pricing.

Now I have gone from 146.7rwkw (196rwhp), to 161rwkw(215rwhp). Still 100% stock standard (Except the 18" heavy rims!)

Good luck with finding your prob

jeffrored92

Rusting of actuator rods, now there is a problem I haven't heard of before!

Glad to hear you sorted your issues out.

I've tested my wastegate and precontrol actuators with a bike pump of all things and they seemed to operate smoothly. I'm going to double check them for rust just in case.

Sickass7

let us know when you figure it out!

LAracer

Sounds like you're having fun . I wish I could be more helpful, but the best I can do is show you my own problem and hope it inspires a solution for you...

http://www.geocities.com/laracers_vr..._problems.html

http://www.geocities.com/laracers_vr_r1/boost_plots

Good luck, and let us know when you finally find the problem

jeffrored92

Yeah I'd say I'm having fun, I'm loving learning about the car. I just wish I didn't have to work so I could keep playing with my toy.

Still haven't tested the electrical connection to those solenoids, will do that asap.

Plenty of fun yet to be had!

CANRX7GX

iTrader: (1)

Yikes well, hope you figure it out soon. I know how much of a PITA that problem is

DCrosby

Couldn't you manually ground the actuators, the same way you're testing them now !? Just apply 12 V !?
If that works, you've got a bad ecu, or wire, start testing continuety with a multimeter... and run a spare wire for teh bad one...

jeffrored92

You mean manually ground the solenoids right? Yeah that's not a bad idea, the only problem is I'd rather not take off the UIM just yet. I WAS thinking of rigging up my own duty controller to the solenoid though, that woud be kind of cool. Bit too much effort though, I'd need to know the duty period, and the power rating of the solenoids.

I guess if you've got the UIM off you might as well just take out the solenoid rack to test them.

If I end up narrowing it down to a dud wire I may look at running a spare, but would more than likely go to dual manual boost controllers to avoid problems in the future. Don't want to get the boost controllers to band aid a problem I haven't found though, so will find the problem first.

jeffrored92

Well tonight I pulled my ECU, got a needle, soldered a wire to it and started grounding my solenoids at the ECU harness.

After trying to figure out why my wastegate wire was connected to the fuel pump relay (and realising that I was an idiot) I came to the conclusion that the electrical connections between the ECU and wastegate/precontrol solenoids are both good. I could switch them both, and guess what the right plugs were connected to the right solenoids.

I doubt that the issue is with switched vacuum hoses because when I switched the plugs over the other day, it didn't fix the problem.

Now while I was in there I used my needle to test each solenoid to do with the turbo control system. The CCA works nicely, there was still vac in the tank so I could even watch it move (had a long wire attached to the needle).

The CCR solenoid clicked nicely (but I still need to verify that the valve is actually delivering vacuum through to the CCR, I don't think it did just quietly)

When I was testing the TCA solenoids (have to do both together because they are electrically connected) I could only hear one operating. I did it over and over, and It still only sounded like one solenoid. And I think I did this test before I depleted the vacuum tank so I probably should have heard some movement from the TCA, but I didnt. I'm thinking one of my solenoids for the TCA has gone.

My biggest frustration is, nothing seems to point to my low boost.

OK so if the CCA seems to be working, then the primary is isolated from the secondary. So we can rule out the CCR solenoid from having any effect.

And if one of the TCA solenoids has gone kaput, then my TCA might not be operating properly, which could be the cause of my low boost in the top end (7.5 - 5 - 5) pattern. But that DOESN"T explain my low primary boost!!!!


WANTED
10PSI BOOST
$1'000'000 REWARD

dgeesaman

iTrader: (7)

I think fixing the bad TCA solenoid is the next step.

Also, double-check the pc and wg lines - they work at different times exclusively - so that while the lines will send the air to the right place, the ECU won't actuate them at the same times.

As I think here, a switched line between the pc and wg in combination with a bad tc solenoid could explain everything.

If TCA solenoid doesn't fix the secondary, I would then check to see that the TCA is holding the door properly closed at all times. Look for that half-pin width of pretension on the actuator arm.

Dave

SexyRX

I'm glad you posted this thread, my MB is doing the same thing. My first thought was vacuum lines, and my mechanic is thinking IC piping, but we haven't had a chance yet to get in there and check it out...now I'll check the solenoids and keep checking this thread- keep us posted! And, of course, good luck...

jeffrored92

You've lost me here mate. I've checked that the electrics are plugged into the correct solenoids (wg on right, pc on left), using the wiring diagram and testing from the ECU pins. The return on both solenoids go to the same place (intake just before primary compressor) so we can ignore that bit. I figured that IF my problem was switched vac lines (wg actuator to pc solenoid and vice versa) then swapping the electrical connectors would fix that side of the problem, because it would essentially *swap* the solenoids over.....or at least that was my train of thought. I'll double check this all again soon.

OK well I restarted the car to charge up the vacuum/pressure tanks. Then I took out the ECU again and went back to testing solenoids.

As a starting point, I re-tested the CCA solenoid. The CCA actuator pulled the rod in. Good.

Then I put my mouth to the air box end of the CRV pipe, and blew through the valve, no worries. Tested the CRV solenoid and could no longer blow through the valve. That must have looked funny, me giving head to a pipe. Good ( the valve, not me giving head, fools)

Then I tested the TC solenoids, being very careful to listen to any actuator noise. I could hear it, but it sounded like it was taking it's time. When I disconnected the solenoid, I could hear a small *whoosh* of air. I bled the pressure tank, tested the valve again, and same deal, same whoosh of air. So it looks like the TC pressure solenoid might be a bit suspect. Repeated tests depleted the vacuum tank. I could still only make out one click. Can anyone verify that a *double click* is obvious when testing these two solenoids in this fashion?

Put the car back together, went for a test drive, and same deal, 7.5 - 5 - 5. BUT I made a point of doing a test in first gear and got something like 5 - 2 - 5 where the drop to 2psi and rise back to 5psi was VERY quick, around 4500rpm. Weird.

Given that if I disconnect the vac lines to my wg/pc actuators, I can boost up to 10+psi easy. Thus I hypothesize that my TCA problem, IF it exists, doesn't contribute to my low primary boost. Unless the door isn't closed properly allowing some exhaust through to the secondary when it shouldnt.......I'll check that.

I agree with you, the next step is to chase down what I do know is wrong, so I'll have to get the car up on jackstands tomorrow, and get in and have a look at the TCA, WG and PC actuators. I can feel my first UIM removal coming on, in the not so distant future.

I also should probably take CANRX7GX's advice and double check the size of the pills to make sure they are right. Unlikely they have been changed since new, but best to rule it out nonetheless.

My apologies to anyone reading these long posts, and cheers to everyone for helping so far.

jeffrored92

No worries champ

I *think* I isolated my primary boost problem to the wg/pc by disconnecting them and being able to boost to 10+psi. The only problem with that theory is that I've tested everything but the ECU and it all seems so far to be working fine!!!!!!!

I think I need to find a friend with an ECU I can swap in there. Oooooooh I think I might know one I can get. That would definately rock. Oh yes Oh yes.

dgeesaman

iTrader: (7)

I realized later I wasnt too clear. I just meant that this test must be done by switching both the electrical connectors as well as one side of the vacuum hoses. Knowing now that you correctly identified the pc and wg connectors, then focus on the vacuum lines compared to the vacuum line diagram.

I found it very helpful to follow some troubleshooting by teeing a pressure gauge into the pc and wg lines and do a wot run. Below 4500, the pc should make the needle jiggle like a jackhammer, and stop at 4500. The wg line will do the opposite.

Then tee into the tc lines and do wot runs - again, you should see both full pressure and vacuum immediately upon hitting 4500rpm. A slow solenoid should appear in this way. I finally did this with the vacuum and pressure tanks, ensuring that there was a full 10psi loaded in pressure and 20inHg in vacuum whenever I intended to do a wot run.

This tee testing business I got from scuderiacirianiäs turbo troubleshooting page - it's about midway down the page. Basically, youre testing the inputs to each actuator, and if you find any unusual results, it points you to test the components upstream that contribute to that particular actuator.

Dave

jeffrored92

Ok that's what I thought you meant, so yeah I'll double check those vac lines. Shouldn't take long.

That teeing the boost gauge into vac lines approach, I've been meaning to get onto that for some time but haven't as yet got a t fitting. I'll see if I can pick one up from a hardware store tonight.

Wasn't aware that you'd see jiggling of the gauge when teed into the wg/pc lines, so that would seem to be a good way to confirm that my ECU is actually duty controlling the solenoids.

jeffrored92

Didn't spend a lot of time on the car tonight, had a bit of a break.

I did tee into the vac line between the wastegate actuator and the wastegate solenoid, closest to the solenoid.

Now during primary boost I would expect to see little to no pressure, as the wastegate duty cycle is 95%, meaning that the solenoid is ON (bleeding pressure) for 95% of the time. This I got, pretty much 0psi climbing to between 1 and 2 psi as I approach transition.

At the transition I would expect to see a spike in pressure here as the wastegate solenoid becomes the sole contoller of boost (precontrol should now be fully open). The stock wastegate opens at a spring pressure of 7psi so I would on a perfectly functioning stock system, I would expect to see 7 psi or slightly above. I was also expecting to see the needle jump about a bit based on what dgeesaman said. Does that all sound about right? What I DID see was a quick spike to 5psi @ 4500rpm, and this held through to redline. I did a couple of WOT runs in both 2nd and 3rd gears, same result every time. No bouncing of the needle!

Any thoughts? Keep in mind my total boost after 4500rpm is also 5psi, so I'm seeing full boost when teed into the vac line between the wastegate actuator and wastegate solenoid. That seems to suggest that the wastegate solenoid is fully closed, which agrees with the fact that there was no bouncing of the needle. Perhaps my solenoid, whilst appearing good, is no longer capable of switching at such high speeds?

Tomorrow I will try and tee into the pre-control vac line between actuator and solenoid, in a similar fashion, before I drive to work.

I wish there were more FD's around, so I could just ring a buddy and borrow some of his solenoids/ecu/brains!!!