Nimisys

ok make sure i am understandng this. both the VDI and 6PI systems on S5 cars are controlled by the ECU. the ECU checks both Engine RPM (from trailing coils?) and the load the engine is under (from the voltage ouput off the pressure sensor, along with TPS position?) and applies a 12v signal to the solenoid actuators which routes positive airpressure to the specific actuators. the positive airpressure is grabbed from the air supply tube between the air filter and throttle body and routes under the middle dynamic intake to the spider and splits off to the solenoid actuator banks. if the engine load is not present or the rpm is too low then the solenoids are not fired and neither the 6pi or the vdi activates.

however if the pressure sensor output is too high would the ecu regard it as out of range and disregard its input, and thus never see the load being applied and not activate the systems? or does it default to predefined map and activate them anywyas based upon readings from the TPS or tach signal?

next thing, the ecu takes data from the MAF, the TPS and the o2 along with pre-defined maps to determine proper fuel levels. if the O2 reads too much or too little then it compinsates in the form of the short term fuel trim blocks. however if the long range TPS is shorting from half throttle to WOT, it would still see the correct amont of air still and would still be able to compinsate fuel trim based upon O2 readings, but would tend to run more rich, as the MAF doesn;t react or report as quickly as the TPS would, correct?

sorry for the long questions, just trying to make sure am understanding things correctly as i troubleshoot whats going on with my car.

HAILERS

Don't own a series five, but you seem to have the operation of the auxillary ports right and the VDI. I'm a little uncertain where you think the air pressure comes from. I'm fairly sure you know it comes from the air pump.

If you download the Fuel section for the 89 model at http://www.iluvmyrx7.com and look towards the last few pages you will find a RELATIONSHIP CHART. I think you are looking for something like that.

And I know that you know that the 02 sensor is out of the loop during acceleration and when at idle. Just in case.

Icemark

yep

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the ECU checks both Engine RPM (from trailing coils?)

nope... RPM is sensed off the CAS. only the gauge, power steering, and cruise are off of the trailing coil.

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and the load the engine is under (from the voltage ouput off the pressure sensor, along with TPS position?)

and MAF

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and applies a 12v signal to the solenoid actuators which routes positive airpressure to the specific actuators. the positive airpressure is grabbed from the air supply tube between the air filter and throttle body and routes under the middle dynamic intake to the spider and splits off to the solenoid actuator banks. if the engine load is not present or the rpm is too low then the solenoids are not fired and neither the 6pi or the vdi activates.

or if there is not sufficent air pressure available from the air pump.

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however if the pressure sensor output is too high would the ecu regard it as out of range and disregard its input, and thus never see the load being applied and not activate the systems?

No

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or does it default to predefined map and activate them anywyas based upon readings from the TPS or tach signal?

only tach signal and load

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next thing, the ecu takes data from the MAF, the TPS and the o2 along with pre-defined maps to determine proper fuel levels.

and engine position as I recall- Ted would know for sure

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if the O2 reads too much or too little then it compinsates in the form of the short term fuel trim blocks. however if the long range TPS is shorting from half throttle to WOT, it would still see the correct amont of air still and would still be able to compinsate fuel trim based upon O2 readings, but would tend to run more rich, as the MAF doesn;t react or report as quickly as the TPS would, correct?

In my understanding, yes.

StarionX

After reading all that, I think I'm

Bring back carburetors!!

Nimisys

i have heard it comes from the air pump, but i can not see how the piping works... the outlets fromt he acv seem too small to support the airflow...

Icemark

The S5 VDI and 5th/6th port actuators do get their pressure from the air pump, you only need about 2.5 psi to make them move

Nimisys

ok, how does the ECU respond to a pressure sensor that generates too much voltage then?

also i though a MAF counted incoming air, but a MAP acted as a digital vaccum guage, if this is thew cvse how does the ecu get load information from the MAF?

Nimisys

so the air from the airpump goes tot he ACV, which is dumped out one of the vaccum tubes, routed across the engine to the switching solenoids and then back across again to the actuators?

Icemark

define too much voltage??? it can only put out less than 5 volts and the reading on a NA car it is less than 0 or 0 inches.

MAF measures incoming air mass. The MAP on a NA works more as an ON-OFF switch as I recall (again Ted would probably know for sure), but for better fuel economyit would make sense to also check vac amount (but I don't think the S5 ECU is that sophisticated).

Icemark

no... splits off before the ACV for both the VDI and 5th/6th ports

Nimisys

on the pressure sensor i am getting a steady 4.79volt at 100mmHG and beyond, however its base voltage without vaccum applied is within spec

as fr the air feed from the airpump where does it split then? cause i only got a single 1" (or so) diametee tube running from the air pump to the acv fromt he acv i got one vaccum outlet hose and one that goes to the air funnel (IIRC) but am positive about the sinlge line from the airpump.

HAILERS

http://www.iluvmyrx7.com has a 89manual online for free. And in the Fuel Section, there is a diagram of the auxillary ports and the routing of the air pressure. Also a chart on page F1-77 that will interest you.

I'm going to look at my diagrams. Icemark said the tach signal came from the cas, I remember it coming off the trail coil assy. I must be misunderstanding that.

Nimisys

been studying the fsm for awhile now... it is my best friend at this point, but i am concerned with intermeidates that the manual doesn't illistrate clearly. i got a couple of different problems that i think are related and am trying to understand how they affect each other and the overall situatation. will look closer at the relationship chart and the one on page 77.

Icemark

The Tach in the dash (as well as the engine speed for the PS/Cruise/ and Diagnostic connector, do come off the trailing coils.

But that signal is not referenced by the ECU at all.

HAILERS

Ok. I wasn't paying close enough attention to what you were talking about. I understand now.

RX7_ZRO

This is where poor people like me who only know what about half that stuff was look at it and puzzle for a while, lol.

hugues

that relationship chart at F1-77 is gold.

too bad we, s4 owners, don't have such a thing to ponder on.

hugues -

HAILERS

I think a lot of that chart applies to us as well. I think the series four just wasn't up to speed and there was a demand by the dealer/mechanics for the later models to have more info. You have to discriminate when looking though. I still like the way they did the series four schematics though. The series five seems too crowded and makes you have to go to another page to see the source of power etc. Too labor intensive.

hugues

good point.

but when you have an s4, you have no clue you should be looking at the s5 FSM for additional info.
You assume everything you can get is on the s4 FSM.

It took me a while to finally get the s5 FSM and see what was in there.

Hugues -

NZConvertible

Are you sure about that? I initially thought that too, but have read otherwise here. I think we've been mislead by the FSM schematic. It shows the air pump supply for the 6PI and FSM teeing off before the ACV, and it also shows the same thing for the ACV's relief valve, which also operates from pressure (not vacuum).
But if you look closely at an ACV, you'll see right next to the air pump inlet hose there's a nipple for a vac line, which goes straight into the opening that the air pump hose attaches to. Unbolt the hose attachment and you'll see what I mean. This the pressure feed for the relief valve solenoid. I've only got a Turbo AVC to look at, but I think the NA one will be similar in this respect, and will have a nipple for the 6PI and VDI pressure feed.
I might be totally wrong about this, but it does seem logical.

HAILERS

THIS: *****the same thing for the ACV's relief valve, which also operates from pressure (not vacuum******

It all depends if you have a TurboII or a N/A

TurboII uses pressure.

N/A uses vacuum.

NZ, You need to listen to voice number four!

Ref page FI-61 for the acv and page FI-42 for the aux port actuation. And no, I've never seen a series five in my life, so take it for what it's worth.

Also page FI-63 and the reference to suction for the relief valve on a N/A

Complemented by page FI-6

Icemark

I'll double check later today. I too am going off of the schematic, since my 'vert is 13BT powered now. It might be that the T is at the ACV on its inlet pipe, but not actually part of the ACV other than that.

NZConvertible

Ah, right you are. I never bothered to actually check if they were the same. Assumption is the mother of... Nah, that one always gets me into trouble!

rotary>piston

there is no complexity to the opening of the VDI/6 ports. The vdi opens at ~5500 regardless of load. I've watched it before, I get to the high rpm (i'm not looking at a tach) and the actuator on the VDI moves. As for the 6 ports, I just bypassed the solenoid (it broke) and the actuators happen to open at about 3000.