lilroach

well i got my turbos rebuilt and did the vacuum lines at the same time. i think, but not sure my problem is with the wastegate solenoids (electrical connections) are swaped. as in this previous thread https://www.rx7club.com/3rd-generation-specific-1993-2002-16/10-8-5-boost-fixed-357815/

also today i hooked up my commander (PFC) for the first time and the boost is reading -438 at idle. would this also be a symptom?

jeffrored92

If you've just done a vac hose replacement, you might want to double check the vac hoses from your wg/pc actuators to the solenoids, because they might be swapped as well.

Once you've checked them, then check the electrical connections. Strictly speaking, it shouldnt matter if the vac lines to the solenoids are switched: you could just swap the electrical connectors to match and everything *should* work.

To check the electrical connections, you could just swap them and go for a test drive, and see what happens. OR you could:

1. Disconnect the battery, then the ECU (or PFC)
2. Solder a long wire to a needle and insert the needle into the ECU harness plug, into the pin that controls either the wg/pc solenoid.
3. Reconnect battery (leave ECU/PFC out)
4. Turn key to on (don't start the car)
5. ground the long wire in the engine bay and listen for the clicking.

This should help you identify which connector is which, and also rule out an electrical discontinuity between the ECU and solenoid connector. If it doesn't click, make sure you test the solenoid itself before assuming an electrical problem.

PS. If you do this test, and your connectors aren't marked with a white dot, it would be wise to mark one of them somehow so you can remember which connector belongs to which solenoid.

lilroach

thanks... thinking i'm going with the first of the two because it will take about 15min instead of an hour. but also when doing a ten second boost chart (PFC commander) it also fades consitantly lower as rpm levels increase

jeffrored92

Tell us more about your overall boost pattern @ WOT. What happens to your boost @4500rpm around the transition.

lilroach

not quite sure because i was the only one in the car plus i was using my commander. the boost pressure is not in lbs its in mmHg. but like i said before it idles at -438mmHg and boost into the low positives. never did see number at full boost

jeffrored92

438mmHg is around 17.25inHg which is good, within the healthy range for a stock motor. With a healthy stock turbo system you should be seeing up to 10psi (~520mmHg) maximum. Your boost pattern should be 10-8-10 (psi) or 520-420-520 (mmhg) obviously allowing for slight deviations depending on any mods you have.

Just in case you dont know what the boost pattern means - at WOT you should get 10psi (520mmHg) by 3000rpm dropping to 8psi (420mmHg) around 4500rpm and a quick recovery to 10psi (520mmHg) just after.

Do you have a boost gauge or do you rely solely on the commander?

It would be a lot easier to offer suggestions if you could give us an indication of your maximum boost and boost pattern through the RPM range. If you rely on the commander and have difficulty reading it while going WOT, take someone with you. Or if you can get some sort of graph out of it, do that. I don't know anything about how the PFC commander works.

lilroach

no boost gauge just the commander. but the fact that it is negative 438mmHg has me worried.

jeffrored92

Don't be worried about that - that's good! Don't get stressed because it's negative - the negative just means vacuum. A reading of -438mmH is within the healthy range for a stock motor.

If you're having trouble with converting pressure units, go to http://www.convert-me.com/en/convert/pressure

When the engine is idling, the engine is sucking in air, and with the throttle valve closed there will be a vacuum in the intake manifold. My boost gauge is connected to a nipple on the upper intake manifold (UIM) so when I idle I see 17inHg vacuum. That corresponds to 432mmHg, meaning that if I had a PFC it would read -432mmHg (remember, the negative just means vacuum, as opposed to pressure)

At idle you SHOULD be seeing 16-18inHg (407-457mmHg) of vacuum in the intake manifold, for a healthy stock motor. So any reading between -407mmHg
and -457mmHg is good in your case.

lilroach

Thanks Jeff you been a big help. While installing a new battery i decided to chech out the solenoids. The connections were right and the white markings were correct. So while i was at it i looked under the UIM. I found two of my vition hoses were crimp shut (directly behide the solenoids. I ran the car after the tight squeeze fix.... and it ran great.

lilroach

It may have cause only the primary turbo to be boosting. because only after the fix did i see the transition point on the 10sec boost chart.

jeffrored92

No worries mate

Hey which two hoses were affected, and did fixing it increase your primary boost? What numbers are you seeing now on the PFC?

I'm interested because I'm troubleshooting low primary boost, and I've checked the solenoids, electrical connections, and vac hoses to do with wastegate and precontrol, haven't found any problems.

I'm banging my head against the wall - it feels like everyone else is sorting out their boostage problems but me!!!! (But I'm happy for you though )

lilroach

the vacuum hoses effected are marked in red

jeffrored92

Awesome, cheers for that.

I'll have a squiz at them this weekend.