280zx won't run unless return is restricted

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Thanks Stephen,David all great ideas that I will heed to.

Where did I get the notion that the Fuel dampner (snubber) was not required was not needed ?? () a post somewhere like this one.

Yes fellows I'll be putting that back on now I am thinking perhaps of a bit friendlier location just before the fuel filter.Not noticable there either.

What do you think?

*My fuel rail arrived today from Juan on Ebay and I got a nice little 20 buc,0-60 psi marshall gauge for it.

*I will be pinching off the fuel tank line and cleaning the pump inlet screen and installing a nice see through line filter to monitor the tank cleanliness from here on out.I should probably just throw in a new pump and tidy the wiring....hhhmmm 200 bones.

Second thought Ill send that in for rebuild I've seen somewhere that a guy does this and has much expertise and we will see what happens after that.

Can't thank you fellows enough

Dave

[Darrel]

You might also check for any and all vacuum leaks, especially the AFM boots.

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I cleaned the fuel pump strainer and added a clear,inline fram fillter. The system was clean with no debris present.

Unless the return hose is clamped the pressure drops to below 30 psi and car runs really rough, clamp it off and I have up to 60 psi on fuel rail.

I think I will go with another fuel pressure regulator (adjustable) maybe the new one I bought from the old shop on a sunday had been on the shelf forever and no good? but first really check the vacumme from the air intake, I have been over that thing looking for leaks every which way but as you know there are many places to look.

I suppose one way is to place a vacumme gauge at the FPR Valve intake port and measure then compare to that of the FSM? I have not studied this in the manual yet and I am not too familiar with a vacumme system except to know one does not want leaks!!(which I should not have now) after all the lines have been replaced,clamped, tighted,sprayed you name it! Also I already made certain that the fitting was unrestricted with a pipe cleaner and there was not any fuel present.

High Ho High Ho off to fix the problem when my Gfriend is not looking I go!!

pls wipe off your cyrstal balls on this one, does it sound familiar!

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Found somthing interesting on this system and more on the fuel dampner...@ the AustraliaK-Jetronic site plan.

THE FUEL ACCUMULATOR, OR BETTER KNOWN IN AUSTRALIA AS FUEL DAMPER, is located just after the fuel pump. So it's location is between the fuel pump and fuel filter. All K-JETRONIC systems must have this very important component fitted into the fuel supply line. The housing of the fuel accumulator is split into two parts, the same as the fuel distributor. The difference is that the top part houses a very heavy compression spring, and as well, it has a safety fuel bleed outlet or, in other words, atmospheric discharge opening. The joining point to the bottom half is a metal folding lip and houses a heavy duty diaphragm. The bottom part has internally a metal fuel deflection plate, where the inlet fuel line is connected to a metric fitting. The fuel outlet is then taken off from any part of the bottom housing, as well from a 14 mm metric fitting. The exact location of the fuel accumulator is as close as possible to the outlet of the fuel pressure pump, or main pump. This will inhibit any fuel pressure noises from the fuel pump. As we have learned, the relationship between fuel flow and fuel pressure, are constantly changing. The fuel accumulator will now assist in keeping the pressure and flow in the fuel distributor bottom half always the same. The fuel accumulator now has the ability to take into itself the reserve pressure and flow from the fuel pump. Due to the long fuel line to the engine bay, known as fuel pipe flow friction and the system pressure regulator valve in the fuel distributor head, this keeps the diaphragm of the fuel accumulator compressed and therefore stores more fuel while the pump is running. By acceleration, some of the fuel FLOW AND PRESSURE will enter the top half of the fuel distributor, which can only go ONE WAY to be discharged by the injectors. The diaphragm in the fuel accumulator can now compensate for the fuel diversion to the injectors, or fuel diversion via the system pressure relief valve. The fuel accumulator also plays the role of controlling the fuel flow ' back up '. Either to the injectors or via the system pressure valve.

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On mine I found this also EGR valve system worked per FSM manual checks however reveiled that the EGR diaphram had an almost undetectable vacuum leak that caused much grief, it was found with a propane and small hose method by placing tip just under the EGR housing (hat) that covered the diaphram. F_K ME!

My theory is that with the extra air bypassing the metering and management of the AFM/ECU,the fuel pressure then also had to be raised to compensate or for the motor to run smoothly just forget about gas milage!

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I finally found out that it was truly a MAFM (mass air flow meter) problem,

I found a sweet 2+2 thaT had a meter just like it (same model part #) I guess I hesitated buying a rebuild because I had gotten a bad on from a Z shop and the current one on it had passed smog.So musch for that theory.

So I cleaned & WD40'd the thing after a quick paint and hit the ignition....presto! started right up with minimal warmup on a cold morning, The main issue before this change was that I had to raise the return line fuel pressure (installed an inline shut off valve) > to set it HIGH: almost 50 psi! (so much for gas conservation) anyway now I set it to the factory spec of 36 psi, Outstanding!

I also painted the car a (secret) metallic blue and getting ready to reinstall the stock front springs back on> bye bye front coilovers,you suck.

replaced the rear hatch seal it was hard.

Then to the rear I go> replace all the suspension bushings (with the ones I already bought) and renew brakes, new seats, ,there will be !#$%@$^% but compared to building and testing Oil drilling product for 20 years this is therapy, in addition to an occasional Coors light and gettin' jiggy wit it!

Hope this helps - easy now