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Hi Site Been a while….not sure, but whatever adds .080 inches….if they are .040 inches, 2 would do. Don’t hesitate to call Eiji….tell him you’re my cousin and if wants to keep eating steak at our house, he needs to be nice! 🤪 He’ll sell you the right stuff.

O.P., you should probably pull a spark plug or six and see if (how much) they are sooted up. The Fuel Pressure Regulator (FPR) on an EFI engine is "vacuum referenced" or Manifold Absolute Pressure (MAP) referenced. Meaning it has a hose connection to the intake manifold. The FPR is supposed to maintain a fairly constant fuel pressure differential with the manifold pressure. Nissan uses 2.5 BAR or 36.3 PSI as the required differential. That means WITH the engine NOT RUNNING and fuel pump RUNNING the pressure to the fuel rail and injectors should ~36.3 PSI. When the engine IS running, the FPR will SUBTRACT the manifold pressure while under VACUUM or ADD the manifold pressure if under boost (positive manifold pressure). You don't need to consider boost. But, say you have 10 PSI of VACUUM while the engine is running at idle, your pressure at the fuel rail and injectors should be ~26.3 PSI (36.3 - 10 PSI). First: The ECU DOES NOT get the "tach signal" - that circuit if for the GAUGE ONLY. It is pointless to look for it. The Electronic Ignition Module figures out when to send a signal for the coil to fire - it gets the information from the distributor electronics (pretty sure - I haven't handled the original Bosch L-Jetronic for a blue moon...) Second: Have you tried operating the engine WITHOUT the cold start valve? Disconnected from wiring and/or fuel? (IS your engine only running on the cold start fuel??)

Thanks - another (perhaps market specific ?) - the U98. Do you know which year (s) please ?

Ok thanks but would you know the casting number on the OEM exhaust manifold please ?

Yes, he did and on the same day you apologised - thankyou. The beauty of forums such as this compared to the social media is that information remains visible, unswamped by daily 'chaff' to refer to by new members. But that is a double-edged sword and without having the courtesy and rerspect to edit or delete your unfounded comments, they remain there in perpetuity and rare is it that anyone will scroll further down once having seen your post ! "If you haven't got money in deal I'd seriously think about MSA ceramic coated headers. I've got 6to1s on both my cars and very pleased after 10 years of running them with MSAs 2.5" aluminum, I think, to the back bumper. They have other configurations but I like the sound and backpressure of the the 6to1. It's loud but only if you chose. Stay out of it until you get away from neighbors and then who gives a flip. If the guy won't talk to you, it's not going to have a wonderful ending no matter what you pay him. Get out while you can." You suggested the cheapest mild-steel headers available on the market and have you really inspected the welding quality and the flange in particular ? A 6-1 header is not even conceived for the street but track and drag runs in order to dump as much exhaust gas as quickly as posisble.....even then Nissans' own race headers were always 2-1 and their S20 exhaust line a full twin-pipe system to the rear to improve torque for the 'little' 2.0ltr. And MSA's exhaust line in not made of aluminum lol but the same mild steel and heaven knows why they haven't proposed a resonator (not just for the noise and it IS loud) but for the engines' performance (google exhaust scavenging). You 'like' the backpressure ! Your exhaust system is totally de-restricted meaning you have an absolute minimum of restrictions to the exhaust gases with a paradoxal low exhaust-gas velocity, especially during street driving. This is losing you power, most likely between 10 and 20% - call it 15. On a stock L24 making 130 hp DIN max, adding your exhaust is in fact reducing your net power down to perhaps 110hp....it sound loud, it sounds fast but stick it on a dyno and weep ! You'd be much better off fitting MSAs 6-2 (Pacesetter), same exhaust line but having your exhaust shop fit a resonator just behind the transmission....costs a bit more but the benefits are real. That's where MSAs' technology stops and I was fitting them and also the twice-pipes kit back in the early '90s because it was all I could find...back in the day of catalogues and sending faxs to order ! :-) I chose to produce more expensive, I'll admit, but still more affordable than the parts available in Japan and still the only single stainless-steel pipe system that doesn't have an over-sized diameter (3" for a n/a engine - get outa here ! ) which are efficient for road and track use for different size engines and also with different characteristics (compression ratios, camshafts etc.....) and also different driving styles 'cos I don't believe one size fits all. https://www.roadandtrack.com/new-cars/car-technology/a14530205/what-is-exhaust-backpressure-and-why-is-it-bad-for-horsepower/ I'm not sure that you're best placed to advise anyone on exhaust choice. You told texasz to get out while you can cos it's not going to end well whatever he pays ! Perhaps you should ask him how it ended...........

I believe he mentioned 10 plus years.

So what do you recommend? Keeping the 1.5 ohms pertronix and 1.5 ballast resistor i the circuit?

I've been stuck on this album for a couple of weeks now. I'll put on something else and after that finishes I'll say to myself... Let's give John Hiatt - Walk On another play.

I do, I ordered another from Nissan to replace mine. When I get back in town from Boston, I’ll post the p/n. Can’t remember if it was superseded.

I live in arizona... i bought it and it just arived in less than 24 hrs. fastest turn around for a relay i thought i would have to wait 1-2 months for.

Im in good company!!

Thanks Matthew for a great write-up =) Here is my tiny contribution to it: You were wondering about the Thermal switch 22110-E8000 and stating that it's probably for the automatic model only. I found information which connects it also with the manual model, with the emission control device (EGR) to be more precise. It can also be found from the -73 wiring diagrams (both manual/auto). Please see pictures below: Keep up the good work!

They look better wet.😁 Mine has water allergies though. Now for some windshield time.

It's a EX-mouse.. 🤣

Thanks for the mention! I just updated the thread as I’m diving head first into the AFM rabbit hole. Some tips I picked up on my journey: - Clean all the electrical connectors to the sensors (also the bullet connectors in the harness). - Measure the resistance to the AFM air temperature sensor and the coolant temperature sensor to make sure there within spec (coolant sensor is one of the most important sensors in the EFI system!). - Buy or borrow a timing gun and make sure the timing is set correctly. - Verify you are getting enough spark (right type and gap spark plugs, distributer contacts in good condition, ignition coil resistance within spec (0,8 to 1 Ohm)). - Install a wideband O2 sensor with gauge (cheap Chinese one is good enough for now) or if you don’t have a bung in you exhaust buy an exhaust sniffer so you can measure you AFR (Air Fuel Ratio). Idle should be around 14,7 and wide open throttle 12,5 I believe. - Try and see (while monitoring the AFR) if only you idle or the entire rpm range is out of spec. If it’s only idle maybe try and play with the idle air screw on the AFM to get the idle AFR back into spec. And If nothing work only then take the AFM off the car and start testing the resistance values. The number 7 pin is hard to measure the resistance so you must hook it up to a battery (9 or 12V) to test the output voltage on the number 7 pin. If you determine that that is your issue then welcome to my world! As you are based in the US maybe an AFM rebuilt offered by jdm-car-parts or Z-store is an option for you. Unfortunately I am not so it would cost an fortune to do so for me in postage and import tariffs.

Little update as I don’t have much time to work on the car. After connecting the AFM to a spare battery and testing the voltage on pin 7 I noticed very inconsistent voltage readings and a lot of gaps in the carbon track even though it doesn’t look damaged. And yes I know the AFM has a logarithmic scale with a range of 0 – 9 Volt, Its basically just a voltage divider and a potentiometer in one. Here is a picture I found together with the link and some other useful links (last one is for a Range Rover but it’s the same concept and same Bosch style AFM). https://www.atlanticz.ca/zclub/techtips/afm/sizeupgrade/index.html https://www.atlanticz.ca/zclub/techtips/afm/index.html https://www.gomog.com/allmorgan/AFMadjust.html After a bunch of searching I did fine more reference pictures of the Datsun 7 pin AFM’s and other Bosch AFM modules of the same type, that bend is 100% not supposed to be there. I did notice that if I press the copper part of the wiper hard against the carbon track I do get some sort of reading but so maybe somebody tried to “fix” the AFM by bending the wiper. Unfortunately the track has failed in its entirely and I can’t find anybody that can fix the circuit board. Enlarging the bolt slots and moving the wiper to a fresher part of the track also didn’t work. This lead me deep into the Bosch AFM rabbit hole that is the world of Datsun / BMW / Porsche forums. I found an Australian forum post that mentions a slightly larger 90’s Toyota AFM being plug and play for his L28E 280Z(X?) with the part number F201 13 210 (197100-3420). This is also a 7 pin style AFM With the same internal (and pin) layout as the Datsun 7 pin AFM’s. When looking if I could find this AFM in Europe I actually found one at a local junkyard from a 1988-1992 2.2i GT Turbo 12V Ford (USA) Probe for €25,- so I ordered it immediately to try and test this theory (same AFM was also used on the Mazda 626 and 929, also found a part number from Standerd "MF9107"). The original post did mention you need to loosen the tension on the flap by 3 teeth as the flap is bigger than the Datsun AFM’s. https://www.viczcar.com/forums/topic/6951-larger-afm-for-a-280zx If this doesn’t work I will continue to look for an replacement Datsun AFM that doesn’t break the bank (I know, that’s a tough one). I might also look into making a custom plug and play MAF swap. I found a US based company called Split Second that makes MAF to AFM conversion modules and MAF conversion kits for BMW’s. They also have a 0-9 Volt module (PSC1-009) that might work with the stock Datsun ECU in theory. https://splitsec.com/product/psc1-009-programmable-signal-calibrator-afm-to-maf-hv-output https://splitsec.com/wp-content/uploads/technotes/TN2_AFM_to_MAF_Conversion.pdf And yes I will post all my findings online as there isn’t much information to be found about AFM sensors and there alternatives. Also no I don’t want to carb swap my car, I want to stay EFI but don’t want to spend thousands yet to upgrade the entire EFI system. If anybody has a 0-5 Volt (or 5-0 Volt) AFM module that needs a rebuild / modernization I found an interesting company in Switzerland called SyncroSweets that swaps the wiper potentiometer for a modern programable potentiometer that’s plug and play. https://www.syncrosweets.ch/en/luftmengenmesser