Pizza

20 nm.

bd0nalds0n

Sorry to dribble out the questions--how did you arrive at 3/32", and do you or anyone have thoughts about what are the potential consequences of using thinner or thicker?

Ralph Newman

I will probably pull my SC off in the next month or so to paint. I will let you know how the gaskets look. Also, I am only boosting about 5.5 psi which might make a difference.
Best to all.

Pizza

DR told me that was the original thickness of the material Andy used with our kits.

oz928s4

This thread has been extremely helpful for my install thank you all that have contributed but now i have installed and run up on dyno I have a major question.
I am running the 30lb injectors (cleaned and flowed) as advised and running the 2 1/2 bar (30-35lb) FPR off the 85 s2 as advised and am still leaning out.
Clamp the fuel return line to achieve 50psi and it is better but still lean on cruise and doesnt want to come under around 14.8 to 1
Didnt get to WOT.. does this sound right.
Compared the TE reading to dyno AFR and comparitively close...so it is definetely lean.
I have no vac leaks according to the smoke tester and it idles like a dream with the FP down at 35lbs idling at 14.5 to 1 ..manifold vacum at -18 to -19 on idle
Do I need to add the rising rate reg or go to an adjustable FPR...idle becomes difficult running so rich with the big fuel pressures as I dont thnik I can trim enough out of it.
Any one have a suggestion(s)

John Speake

You are running open loop ?

And you are only getting to 14.7 on cruise even with map values set to +127 ?

Are you sure your crimped fuel line isn't causing a reduction in fuel flow capability at higher rpm/load values ? Better to use the S4 regulator.

You don't need a RRFPR. Try setting the injector size in "Custom" to something less than 30#. This will fool the LH to open the injectors longer. This should provide more fuel as long as your system can provide the volume.

oz928s4

Yes thats it John, even with +127 in it it is still leaning out at cruise

I dont think the crimped return line is slowing fuel flow down as it fattens the mixture up.

Open loop..not sure about that one ...want to enlarge...

I did think about fooling it and selecting a smaller nozzle size in the set up
but was going to check my duty cycle and ensure I didnt have a MAF or sensor narrowing the duty cycle..I am starting to suspect a MAF as the culprit.
By the way can you supply me the 12 pin cable for diagnostic port to ST

John Speake

Something very wrong there....

Open loop running would be selected by the coding plug if the car was originally supplied as a non cat car, with no O2 sensor. Closed loop if supplied with cats/O2 sensor. If closed loop then it will always try to keep A/F to 14.7 at idle and cruise.

Sounds like your car is non-cat with no narrow band O2 input to the LH ECU ? The O2 sensor plug small circular three pin conenctor on floor in front of fuse/relay panel, also will have an idle mixture pot fitted above the fuse/relay board or on the LH/EZK bracket, depending on MY.

Have sent PM about 12way lead.

oz928s4

John
you are close I think.
I have cats definetely as I was there this morning putting in the TE and wide band sensor...but the old O2 sensor that came out did not have a loom attached it was just cut off at the top.
Further to this i have a mixture pot above the fuse relay board but I definetely have cats..maybe later exhaust thrown on the car.
So what is the story I have cats but no narrow band O2 input to the LH ECU as I have the mixture pots as you say.
So does this mean I could be running in closed loop and if so how do I get into open.
I sent you PM

John Speake

Only the mixture pot above the fuse/relay panel is used (not the one on the MAF).

You need to check the wiring on your coding plug which is the 8 way plug/socket that should be clipped to the plate that holds the LH/EZK boxes.

Check the wiring against the diagrams on page 24-221 in Vol 1A of the WSM. It should be set for the non-cat option that relates to your car.

oz928s4

Thinking about it what I thought were cats might have actually been silencers
I have mulled it over since I boldly posted I had cats...I will check the 8 plug configurement. I have the download of WSM looking at ROW build with out cats and AT pins 1,2,4,6 should be used. If they check out does it mean it can switch from open to closed or closed to open

John Speake

That pin configuraion is correct. The SharkTuner would tell you what the coding plug is set to - on non-cat maps you will get the blue operating point marker. If you tried to select the cat maps there would be a warning message "This map is not being used !" and there would be no blue oeprating point marker.

Also, check on the System monitor screen and you should be able to vary the idle CO pot and observe those changes in terms of pot resistance and pot %. If you can't get sensible A/F ratios with the pot set to 380 ohms, then your MAF is suspect. (assuming fuel pressure is OK)

oz928s4

Thanx for that John I will give it a go thru the week.
BTW I did get the "blue operating marker"

oz928s4

Post 1978...is that the year they started selling the 928

oz928s4

I think i know what is leaning the car out.
i have the 88s4 TPS on the Throttle Body that i drilled the back out of and turned it around 180 degrees. This was due to the TB having a different throw.
Well i feel silly but i didnt swap the wiring to suit the change of direction for the switch.
In essence what is happening is that when the car is at idle the WOT wire is getting power and when at WOT the idle cut off wire is getting power.
i cant believe I havent picked up on this.
it just jumped out at me this afternoon.
i read in the "twin screw" thread that you swap the TPS across after drilling the hole out and reversing it but they didnt say "SWAP THE WIRES"..I should have known
Ringing a bell for anyone...!!!!