That gauge may be wrong and out of calibration.
At idle spec is 30-32PSI and the gauge shows 37PSI

Pump on engine off should be 36-38PSI but you show 40PSI

I suggest you get another gauge and verify. Because if you really are running higher pressure than spec you will run rich.

The plugs are wrong type and should not be used in the 3.2 engine. I suggest you use these plugs instead:

NGK 6637 BPR6EIX Single Iridium Spark Plug, but these are 5K Ohm resistance and best used with non resistance wires.
SKU: #BPR6EIX
ITEM: # NGK6637
BRAND: NGK

Stock plug gap is 0.7-0.8mm

The plug type you currently have can not be properly gap-ed.
But I can already tell that you likely have injector over fueling issues in 5 and 6 cyls.
And those plugs are to cold, I can see this on the color of the ground strap.

as Sal said those plugs are for 930 not for you...In Europa we use wr4CC plugs for non CAT ..Or i could recommend this Euro company in Czech, Brisk..they are world wide known manufacturer and they have an excellent reputation among racing peeps.I just got myself a set, to be installed..
here
https://www.brisk.cz/katalogy/zapalovaci-svicky/filter/auto/12567,12568,12569

they make the best quality with silver tips-pricey but perfect

Just an idea...
Ivan

I really like these plugs in the 3.2L

NGK 6637 BPR6EIX Single Iridium Spark Plug, but these are 5K Ohm resistance and best used with non resistance wires.
SKU: #BPR6EIX
ITEM: # NGK6637
BRAND: NGK

Stock plug gap is 0.7-0.8mm

spark
 

i hear you...honestly i use WR4CC for several years here in Europe and no issue what so ever..But i`ll give it try to this NGK 6637 BPR6EIX..after i do the silver Briks..
Then again i have no problems with what i have,100 octane fuel plus toluene-ABOUT 2q per tank.. 420 miles trip (last weekend) plus 1/4 of a tank of fuel left in it;-) oh ya i did drove the hell out of it too;-)

Thank you Sal and Ivan for the input.

Fuel pressure reading being high... will look back to pressures when Radium gauge was newly installed. I recall pressures being very close to spec back then. Post those pics when I find them.

On the menu:

Arduino wide band system is making progress. Will bench single side set up before buying into parts for second side (for SSIs.) Benching should happen within a few days.
Will test fuel pressure at rail, swap injectors side-to-side (and later pull plugs for another look,) and compression test cylinders. Looking to accomplish this within a week.
.

Karl ..just do not use those plugs...that should help you a lot

Ivan

Am all over it Ivan -- TY. One step at a time and this puzzle is being solved. I just copied into my reference file the factory fuel pressure page you posted 4 years ago.
.

The WR4CC plugs are also a good choice.

Comparing fuel pressure from 2020 to now, 2024. Gauge = Radium, fixed into system after fuel filter and before Y hub leading to rails. Pressures displayed nearly spot on in 2020. Since then... gain of about 6 lbs from something...

Gauge?
New fuel pump?
Pressure regulator?
Combo?

http://forums.pelicanparts.com/uploa...1721387671.jpg

http://forums.pelicanparts.com/uploa...1721387671.jpg

http://forums.pelicanparts.com/uploa...1721388567.jpg
Factory ref courtesy Ivan.


Testing pressure at rail tomorrow.
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The gauge could have gone out of calibration from sitting in the hot engine bay with tons of vibration? I'd get a 2nd test gauge and install it on the fuel rail test port and compare the 2 gauge readings to verify the existing gauge.

At idle the FP should be 30-32PSI if not the regulator needs to be replaced.

One more fuel test that should be done is fuel delivery rate. As follows:

- Remove the test port 22mm Nut on the driver's side fuel rail
- Get a clean clear plastic 1 gallon milk container
- Put a length of hose over the test port with a clamp securing it
- Put other end of hose in milk jug
- Jumper 12vdc to the fuel pump fuse to run the pump for exactly 1 min
- You must get at least 1/2 gallon of fuel in the jug in 1 min

A healthy 3.2L fuel system typically delivers 3/4 to 1 gallon of fuel in 1 min but the minimum allowable amount is 1/2 gallon.

This test should also be done after you test fuel pressure.

Given the amount of diagnostic required to fix your current problem, maybe simplicity? :D

Good luck with it though!

Or is it power and performance? A somewhat richer mixture would give a few extra hp at higher rpm when compared to a mixture that is optimized for mpg with the O2 sensor and closed loop mode.

I have a Euro engine with no cat no O2 no nothing and car runs pretty well, but my mpg has never been excellent. Reason why I am following this thread and thinking about investing in this AEM wide band gauge. I may run on the too rich side, at least at part throttle.

Yup John..;-) i`d start with the correct spark plugs....but Karl knows by now..also little turn on AFM (to make it leaner)would help too;-)

Wazz..same here, euro no cat no oxy and mileage is perfect.i by-passed the oxy circuit in my comp..with a switch, when i used to go for smog i just flipped it back....

Ivan

Ivan, thanks for the response. Can I mail you pics of my plugs (WR4CC) so you tell me what you think.
Don't want to hijack this thread.

you got my mail ,right?

Attending that today Sal.


On menu.


Thanks Jonny. Wideband O2 program is in the making. Arduino-based. (Nothing simple about this MPG sort out but puzzle will be figured out.)


Good idea with the mixture screw Ivan. Do that later today. Plugs are ordered. Am going with Iridium given the discussion I had with Sal before seeing your post.


Had discussion with Charles of CJ Motorsports concerning fuel pressure gauge. Unit I have is 1 1/2" barrel, 1 3/4" face. He and I discussed the manufacturer of these units---they're made in China with the ability to custom design/brand the face given a minimum order of 100 or so. Main topics... durability and the lens. Lens is made of acrylic. I told him I was wanting glass. He's going to look into it. Concerning durability, he said many buyers of these gauges use them temporarily in conjunction with his adjustable pressure regulator. For those that mount them permanently, it's a given that heat will eventually take them down. Perhaps we're seeing that here.
.

Pressures measured at stock rail port:

http://forums.pelicanparts.com/uploa...1721585251.JPG

Pump ON, engine OFF. Air is bled. Calling this 38.5 psi. Spec = 36.26 psi +/- 2.9 psi Within spec. "Spec book" am referring to here is page provided by Ivan --- TY.


http://forums.pelicanparts.com/uploa...1721585251.JPG

Engine now at idle. See this as 34 psi. Spec = 29 psi. Over spec by 5 psi.

Assuming test gauge just used at rail is correct, installed Radium gauge in fuel line is off (high) 3 psi.


http://forums.pelicanparts.com/uploa...1721585251.JPG

http://forums.pelicanparts.com/uploa...1721585251.JPG

Flow test. Hose is connected to rail port. Pump ON for 60 seconds. From spec book, 60 second flow is 1,700 cc / 1.79 quarts. Being at at 3.5+ quarts, flow is measurably over spec.

I have original Bosch injectors that were removed from engine in 2020. Given uneven look of plugs and down pipe temps, am leaning towards Lucas injectors being questionable. Monday, am sending Bosch injectors to Mr. Bill to test & refurb. Provided they come back in good form, idea is to have them on hand to eventually test them against Lucas (from FiveO) that are currently installed and now suspect (without proven guilty as it stands. I know better that to think one thing is wrong here. Could be a combo and so testing this & that to rule things in or out.) Sal suggested swapping injectors side-to-side... running engine... then having a look at plugs again.

Still have to sort out opening mixture screw as Ivan suggested. 3mm Allen has temporarily escaped me.
.

If you look at the manual it actually specifies to disconnect the return hose hose and to connect the hose to you r catch bucket on the return side. this will test the flow rate at the 36psi load not at open rail (0psi). your pump will likely still pas sthe test as you are seeing higher than specified pressures when running, so it doesn't seem like it is a pump supply issue.

http://forums.pelicanparts.com/uploa...1721590752.jpg

Interesting. Thank you 76. In this case, measured flow is what makes it past regulator.

Am looking at Porsche Technical Specifications booklet. Page you show is not in there. Is that the large format service manual you have? Is there a volume indicated for the 30 second flow?
.

Yes, this is from the Porsche Work Shop Manual. This page (20-2) covers the setup for the test. Page 24-3 shows the required specifications.http://forums.pelicanparts.com/uploa...1721597008.jpg

Do you not have a copy of the WSM? what is your email address?

Karl: you can also get all the info from Porsche specs booklet..
link in your message

Ivan

Thank you 76. Do not have that. Only have the small spec booklet. PM'd you my email.


Just saw your PM. Thanks Ivan.
.

What this test is measuring here is the pump max flow, and it appears that the pump is good. No regulator is involved, since engine is not running. Pressure regulator and damper work only with vacuum produced by running engine.
Also, injectors are not involved in this test. Again, because engine is not running, injectors are bypassed and not actuated. They are closed and fuel running inside the rails is skipping the injectors.

I can send you a copy of the spec book pdf if you want. I have it OCRed, which allows for text searches. PM me your email if you want it.

Yes!


You mean just cleaned. They can't be "refurb", a misconception by many.

This is not entirely correct. the test is actually testing the fuel flow at engine off rail pressure which is ~36 psi. the fuel flow created in this scenario is the amount of fuel the pump can push at that rated pressure. This specification is drastically different than than asking for fuel flow at 0psi.

For instance if you have a fuel pump for a carded engine (~5psi) and you test it as described earlier in this post with the fuel rail open you may get a result around 2 g/m, however if you use this same pump and test it on the outlet side of the regulator which requires 36psi to open, you will have 0 fuel flow since the 5 psi generated by the carburetor pump is insufficient to force the fuel through the regulator.

the idea of this test is to test the minimum flow produced by the pump at the maximum fuel pressure (no vacuum at the regulator).

This statement is wrong. the vacuum supplied by the engine to the regulator specifically lowers the fuel pressure. The highest fuel pressure is when there is no vacuum supplied to the regulator Either engine off, vacuum source disconnected or effectively at WOT.

Yes, sorry for the misconception and wrong information. I overlooked the test setup and thought the fuel flow was measured right at the feed line.
Thanks!

http://forums.pelicanparts.com/uploa...1721687081.JPG

...Sensor gets very hot very quick.

http://forums.pelicanparts.com/uploa...1721687081.JPG

First bench of 4.9 wideband. Put a lit match at tip of sensor and data dropped. Still needs much attention but given things are ON and data is moving in the right direction... is one step closer to sorting this MPG puzzle out.

Power supply here = Arduino 5v / connected to laptop. Lambda shield 12v / connected to car's battery.
Display = 0.96" OLED. Plan is to mount this where Fasten Seatbelt plaque currently is. (TY Joe.) Bezel designs in Onshape then 3D prints.
Data = Lambda on top line. AFR on bottom line. (Screen is focused. iPhone pic blurred it.)
.

First in-exhaust test of 4.9 - engine at standing idle / 800 rpm

Plugs: W6DPO - cleaned since prior photo
Injectors: Lucas low impedance 24lb. from FiveO
Mixture screw: 3 ¾ turns out now - was just recently adjusted from being 2 ¼ turns out.
Wideband: ArduinoUNO w/Bylund Shield & sketch + u8g2lib.h + SPI.h —- no mods yet
Sensor: Bosch Lambda 4.9
Power: Arduino via laptop. Shield via car battery

OLED Display = AFR top line / Lambda bottom
Data = 1-2-3 side (SSIs)


Only the Bosch sensor is installed here. All else is sitting on the ground next to the car. Is a progressive bench test to see what numbers are displayed, how the display is working, see if any glitches exist to be sorted out. If there are glitches, what scale are they? What I’m after here is to decide if the system is worth duplicating for 4-5-6 side of engine. Or, does it go in the bin? If it works well and I can sort problems out, I’ll pull all the cables and do all the in-car wiring once.

(Why bother? All this is for the purpose of displaying data on a 0.96” display. ZADA TECH offers a miniature display system using 4.9 but one has to choose between seeing Lambda or AFR data. The USA rep for ZADA is a Porsche guy, Joe, aka “Joesmallwood” on Pelican. Excellent to deal with IMHO. Would certainly be simpler to go the ZADA route. I fancy torturing myself and so the design/build route.)


Start engine… then display is shot at noted minutes from engine start. While these are static images of the display, in real time the numbers are in constant motion. I did not stay by the display to study the range as the setup was too near the exhaust. Only got near when the timer went off to shoot the display.

http://forums.pelicanparts.com/uploa...1721840091.JPG
2 min.

http://forums.pelicanparts.com/uploa...1721840091.JPG
5 min.

http://forums.pelicanparts.com/uploa...1721840091.JPG
10 min.

http://forums.pelicanparts.com/uploa...1721840641.JPG
15 min.

http://forums.pelicanparts.com/uploa...1721840554.jpg
Temp at 15 min.


Not saying AFR/Lambda figures are correct here. Rather, they are what they are for the time being, notably at a standing idle only.

Plan now is to swap out installed plugs for Iridiums, and installed Lucas injectors for original Bosch injectors---provided Bosch injectors test & clean well by Mr. Injector. Then repeat this interval test with no adjustment made to mixture or idle screw, or anything else other than as noted. When replacing plugs, will do compression test to rule out plugs---as seen in last photo---suffering from any excess oil in cylinders. Will be a few days before I hear on the Bosch injector status from Mr. Bill in Idaho. Iridiunms arrived all gapped to 0.8mm.

Going through this testing, replacements, testing, then adjusting whatever is to be adjusted according to the numbers seen be the numbers right or wrong... THEN checking the city mpg... those mpg results will be revealing.

As I finish these notes, realize it would be possible to test AFR/Lambda with the engine under load provided a 4.9 extension cable long enough to reach from the wheel well into the cabin. Simple enough to Blue Tape cables to car's exterior. Would be interesting to see "loaded" figures with current plugs & injectors... Other fish to fry so will pass on this.
.

Update...

5 of the 6 Bosch 0280 150 158 injectors I sent to Mr. Bill tested good. 1 failed. Found another and sent that to Mr. Bill to see if that works.

Arduino based wideband system is in progress. Diagram completed. Waiting on various electronic parts to arrive.
.

http://forums.pelicanparts.com/uploa...1723566054.jpg

http://forums.pelicanparts.com/uploa...1723566054.jpg

Wideband controller for both exhaust sides is done. 4-5-6 side in SSI needs a hole put in and bung installed. Wanted to position 4-5-6 sensor exactly the same as on the 1-2-3 side but is questionable whether it's possible to drill a hole on the top side of the exhaust tube with the SSI installed on the engine. Nothing appealing about removing that exhaust section. Need a low profile 90 degree drill bit fixture. Also on menu is finding a stainless welder willing to get in under the car. And all the cabling needs to be run.


http://forums.pelicanparts.com/uploa...1723566054.jpg

My original Bosch 0280 150 158 injectors serviced by Bill. As always, Bill is a pleasure to deal with.
.

I've been flogging a dead horse for the past weeks. Doing so, I've found Bylund Automotive's shield and other products of his being useless. The Bylund forum is an empty shell. All Bylund YouTube vid's have comments shut down---a sure tell that I missed because I wanted this gear to work. And all of what was invested was because I wanted wideband data displayed in a tiny 0.96" OLED that fit into the Fasten Seatbelt plaque space. I'd flog myself but "win some, loose some" comes to mind and that is more appealing space.

Have been holding off on swapping plugs and injectors wanting to see what the O2 status was under various engine loads with the existing W6DPO plugs and Lucas injectors. A baselining of sorts. I figured to be past that stage by now but the wideband build... I don't give up easily, sometimes to a fault.

What the course is now depends on a response from Zada. I will finish this project.

Am continuing this project in new thread. Dual Innovate wideband is now installed...

https://forums.pelicanparts.com/porsche-911-technical-forum/1170007-wideband-data-3-2-getting-10-mpg-city-what-do-you-think.html
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