clokker

iTrader: (2)

Sigfrid sent me a few pics yesterday, notable not for anything new on the car but for her new location...in the driveway.
Given her new "running" status and attempting to curry favor with the wife unit, Sigfrid cleared out the garage (for the first time in the five years I've known him) and her Honda can now park inside.


Since I'll be dealing with the fuel system, the driveway is probably where I'd have ended up working anyway but I'll be that much more dependent on semi-decent weather.

I was somewhat nonplussed by this shot:


...but it turns out that Sigfrid slightly redid the wiper linkage to eliminate a barely perceivable clunk at full swing and he's declared the wipers now "perfect". That's nice, I spent an absurd amount of time gathering up the various parts so it's good to know it worked out.

I think the next few weeks will really determine what happens to the Z.
If she becomes reliably driveable before S. returns for Christmas, he says he'll register/tag/insure her which means she can come live at my place and work can continue.

So I am highly motivated.

Weather is supposed to warm up again midweek (we went from 70° on Saturday to 35° on Sunday...damn Canadians!) and I'll get on it then.

Should all this come to pass and I have the car, the first major job will be retrofitting a FC fuel tank. It's been done before and solves several issues.
The spare tire well in the floor must be removed (our wheels won't fit anyway, so who cares?) but after that, it's almost a drop in affair (supposedly).
This would give us a filtered in-tank pump, eliminate the bulky standalone vent system and the FC sending unit will work with the Miata gauge cluster.

First though I'll be checking the lines/fittings we have now, see if I can't definitively narrow the problem down to the FPR.
For the first time, the engine is responding to the different adjustments and sensors and we've checked all the ECU inputs...it all checks out. To get her running we had to trick the ECU into thinking the car was hot (unplug the thermosensor), crank the clockspring on the AFM flapper to full tight and adjust the FPR to full bypass.
In other words, lean the **** out of it.

Best case scenario is I find a blockage in the return from the FPR. If the return is restricted, maybe the FPR is physically unable to bypass enough and the resulting high pressure would flood us out.
Maybe.

The deep dark fear is that we have the wrong injectors, maybe from a later model turbo.
Rock Auto only shows one part number for our car (all the NA Z's use the same injector) and we confirmed we ordered the right number but I don't recall ever checking the new parts themselves...I just whomped 'em in.
As one does.

Anyway, if she can be leaned out, she runs great...so there's that.

TonyD89

iTrader: (10)

I just have to say....




I think I really like the wheels that are on there now. You keep bitchin' about them.


I know the offset sucks but how thick is the lug nut hub of the wheel? A guy could maybe skinny some off the mounting face, if he thought he could, and pick up a few millimeters, maybe...

clokker

iTrader: (2)

I don't hate them, especially since we got her to sit on the wheels better (STANCE!) but still don't feel they are the correct style.
Also, the spokes stick out beyond the rubber...if dropped on the outer side, the spokes get all scratched up. I know this from experience.
Thank god for Sharpies.

That said, I thought she looked great as I watched Sigfrid motor up and down the street.
Wheel gap is perfect for a street car and and the front three quarter view, with the driving lamps and gaping maw, looks proper menacing.

TonyD89

iTrader: (10)

OK my bad. I thought you were complaining of off-set earlier. Personally, I think she looks bitchin'.

clokker

iTrader: (2)

Thanks.

Checked the fuel lines today.
Found out the "pre-filter" installed between the tank and pump was very restrictive, flow is now greatly improved with it removed and the system even holds residual pressure (a first).
All the fuel was clean and nothing blew out of the hardlines, so I'm thinking we're good.

Even with the suction side restriction removed, the pump is still a noisy SOB and more fuel was not exactly what we were looking for, but there you go. I'm now confident the fuel loop is good, so that pretty much leaves the injectors.
There are some markings cast into the injector body but google doesn't know anything 'bout em.

She still runs/starts well with fuel pressure dialed down to 10psi and the thermosensor unplugged.

Not sure what to do/think about the super rich condition but I do have some thoughts about mitigating pump whine. I need some more fuel hose to experiment with, see what lowering the pump does. It's only sited about 7-8" above the tank but maybe decreasing the height it has to suck from will shut it up.
If it just turns out to be a naturally noisy pump, I'll be pissed.

pfsantos

iTrader: (1)

Weren't you talking about switching to an in-tank pump? And is the noise really that bothersome? I'm too damn OCD, but there is a point at which the pain in the *** of doing something isn't worth the trouble.

Oh, and a video of the car running and driving by is in order!

edit: so you checked all the sensors to make sure they were within spec. in terms of resistance vs. temp. and/or aiflow, etc.?

driftxsequence

iTrader: (8)

Why bother if you are planning on doing a FC fuel tank?

clokker

iTrader: (2)

I'd like to install a FC tank which not only provides the internal pump but would also eliminate the Z's external vent system.
The noise is horrific, I don't think I'm being overly picky.
Granted, the bare, all metal interior ain't helping, but even so...

I'll get right on that, Rose.

Yes, multiple times.

Having verified fuel system function (yeah, it was stupid to have waited so long), I'm treating the fuel pump noise as a NVH issue instead of a performance problem and ignoring it for now. It's pumping sufficient gas and that's all that matters to the engine.

Since yesterday I've only come up with two ideas to try, one is cheap and relatively simple, the other, less so.
Obviously, it would be nice to throw another set of injectors in but that's a lot of money to spend on a hunch.

I vaguely recall reading about a "California/High altitude" switch or setting on the ECU. IIRC, this reduces fuel by @6% across the board...maybe that would help.
Need to research that and see if it can be activated on our ECU(s).

j9fd3s

iTrader: (3)

we just dealt with a noisy fuel pump thing all weekend, and if you're getting fuel, maybe the pump is just loud.

our problem was that our pump was sucking itself to the bottom of the fuel cell, and then we'd get no fuel, our problem was bad in a race car, i would have gladly traded it took us about 12 hours out of the 25 hour race to fix it...

i would try the high altitude switch.

i'm surprised you don't have the old injectors? i'd toss those in, if i had em

clokker

iTrader: (2)

We have an external pump, so noise is somewhat expected but this unit just sounds wrong.
The altitude correction (switch) is #1 on my list, fuel pump next.
Sigfrid is looking for a set of used stock injectors in CA; lots more CL options out there apparently.
Our originals were real garbage and S. probably tossed 'em (they can't be found at any rate)...but I must admit that if they were around, I'd probably try them out anyway.

I'm housesitting over there again this weekend, so rather than commute this week I'll just wait till Saturday and do it all at once.

j9fd3s

iTrader: (3)

actually i should add we could tell when the pump was restricted because it would get loud, you could hear it clearly even though it was in tank, and on a race track. when it was working it was quiet

pfsantos

iTrader: (1)

clokker - you sure there's no rag or anything blocking air going into the engine? Or maybe a kinked hose or supply and return lines switched. Just thought of this and it may be stupid but I figured it's worth throwing in here.

clokker

iTrader: (2)

Given the silly mistakes/assumptions I've made, nothing is "stupid" but yes, all that stuff has been checked.

At this point I'm treating the pump noise and the over-rich running as two separate issues. I can't reconcile the symptoms into one single cause>effect equation.

See, normally a loud pump would be the result of restriction or insufficient flow (on the suction side) and both/either of those conditions would result in reduced fuel flow at the engine. I've already deleted the filter between the tank and the pump (which is much favored by Z guys but is not stock) and the pump is currently hanging only by the rubber hoses, so it's not hard mounted to any sheetmetal.
I disconnected the return line at the tank, put it in a jerry can and turned on the pump- flow was strong, clean and steady. I pumped about two gallons through although I didn't time it.

The pump whine varies as the FPR is cranked up and down but never sits at a reasonable level...it goes from ridiculous>unbearable.

When next I work, the last thing I can think of is to connect direct from the tank>pump>back to tank and just bypass the entire fuel system, see what it sounds like then.

But as I said before, we're getting too much fuel not too little, so the pump and its noise issue doesn't seem connected to the engine problem.
(This could be the genesis of another terrible assumption)

I'm hopeful the altitude switch correction will help.

j9fd3s

iTrader: (3)

oh you might try a page out of Mazda's playbook, and put a resistor in the fuel pump circuit, running it at 9v will slow it down

clokker

iTrader: (2)

Hmmm, hadn't thought of that.

DeaconBlue

iTrader: (31)

Could be that the fuel pump is way over sized for the job?

I love it when someone puts a Walbro 255 HP L/hr pump in an application that only requires a 110 or 150 L/hr pump at most. The pump ends up killing itself (it make a dreadful noise) because the line restriction over works the pump - too much head pressure and not enough flow. Also you will see the fuel pressure creep higher at idle due to the restriction of the return line when +95% of the output of the pump has to flow back to the tank.

I understand what you are doing and why you removed the pre-filter, but that will end up killing the pump in short order, especially in a project car that has sat for a while. The pump sucks up any garbage that happened to find it way into the tank during the build process and that kills the pump. For an EFI application running below 5 BAR, it is best to use a 100 micron pre-filter to protect the pump and a 10 micron filter after the pump to protect the injectors.

A properly thought out and executed fuel delivery system is a thing of beauty. Hope you get to the root of the problem soon.

clokker

iTrader: (2)

Sigfrid called the Z Store (think: Mazdatrix) and bought the pump they recommend for a stock NA motor. It's not like we wanted an upgraded pump, just one we could rely on.

Thanks.

I'd like to have a pre-filter but the one all the forum guys like is too restrictive, IMO.
Datsun never installed one and our tank was hot tanked/sealed and is in good nick.
All the fuel I've flowed through the various parts of the system has come out clean and debris-free, so at least for now I'm comfortable without the extra filter.

The proper way forward is to replace the tank/pump assembly, so I'm not willing to spend much time/effort on this till she's closer to street ready and Sigfrid decides what's going to happen.

clokker

iTrader: (2)

I managed to eke out six hours of work Saturday before the snow set in, here's what I got done...

-The pump is noisy no matter the config/position. Maybe running on 9v would help but as long as it's fed 12v, it whines. A lot.
Flow is still strong though, so I'll continue to treat this as a NVH issue and assume it's not affecting performance.

-Need to get her up on a lift to rehang the exhaust, laying on your back under jackstands doesn't give enough leverage and grip to budge it. This slip-fit POS is useless.

-The altitude switch actually does make a difference. Not a whole lot, but definitely a difference.
With the "switch" activated (basically just sending +12v to ECU pin #12), the thermosensor can be plugged in and she starts and runs without smoking. This is progress- for the first time she runs with all the sensors/switches connected/functional.

-Fuel pressure must still be dialed way down (the minimum I can see is 10psi with the FPR set on full bypass) to run normally. Ramping up pressure to the spec of 36 psi gives rough running with billows of smoke...not good. The AFM is still adjusted to full lean as well...again, not particularly good.

I don't know what to make of this.

-I upgraded the valve cover vent yet again. It's a meaningless detail that continues to demand my attention...the engine might run poorly but she looks great doing so.

-And one final bit of cheery news...
The test for engine vacuum integrity is to remove the oil fill cap on the valve cover with the engine running; it should stumble and hesitate until the cap is replaced. Ours now does, so at least we have no leaks.
That's something, I guess.

Sigfrid remains relentlessly positive and we'll see what he wants to do next week when he returns for xmas vacay.

HRnico

iTrader: (7)

Its like your down to injector size. A bit to big?
Sounds like my RTEK 2.1 tuning I'm currently working on . After ever tuning run, I pull more fuel. Its still pig rich.
Rtek on 550/550 setting using 4 @ 680cc and 40psi static

TonyD89

iTrader: (10)

A stupid question (not reading back through the whole thread), are you confident your fuel pressure gauge is correct?

clokker

iTrader: (2)

Very possible.

Not at all.


Because of the car's uncertain future I've been trying all the "cheap" fixes, unwilling to spend much (of Sigfrid's) money on hopes/hunches.
Were we more committed to this engine, new injectors, Megasquirt and a better exhaust
would be no-brainer purchases and I bet we'd be done.

I'll get a better grip when I see S. over the holidays.

toplessFC3Sman

iTrader: (1)

This suggestion isn't going to help very much, but I've seen a case (on my megasquirt) where a piece of the flyback circuit burnt up and caused a similar issue - the car would run incredibly rich, but still respond to the gas and engine speed. The commanded pulsewidth was still changing with load, but the injectors were sticking open for longer because the flyback circuit wasn't able to take care of the reverse-current generated by the injector's internal solenoid coils, which was preventing them from closing as quickly as they should. This had the biggest effect at idle, and reduced as load and thus pulsewidth went up.

I know you don't really have a way of checking the pulsewidth without an oscilloscope on the stock ECU, but maybe a multimeter on AC mode may be able to give you an idea of the duty cycle (% duty cycle = 100 X measured voltage/running battery voltage), which you may be able to compare with factory specs.

Could it be possible that the resistor pack being used to make the low-impedance injectors act like high-impedance ones isn't a high enough resistance? This could allow the injectors to open more quickly and deliver more fuel than intended, and possibly have damaged the flyback circuit above? Maybe get some 60W capable 1-ohm resistors, and just try wiring one of them in line with each injector to see if it runs a bit better?

clokker

iTrader: (2)

Oh no, that's potentially very helpful but you're right...no good way to test.
We do have a spare ECU and the car runs about the same using either, so maybe both are damaged in the same way?
Possible.

This whole "moving to California/not sure what's happening" has severely warped the path of the project.
Until S. makes some hard decisions about where the car will end up and what use it will have, it's impossible to figure out the smart way forward.

Had that disruption not occurred and the car was staying here, the next logical step- counterintuitive as it might seem- would be to ditch the FI setup completely and slam a carb(s) on her.
We can get used carb setups for @$200-300, which is way cheaper than any of the future FI purchases and it would be infinitely easier to get running.

And that's the primary goal now if the project is to continue.

We need to get her to an alignment shop and an exhaust shop.
The interior needs building/install and we need to evaluate the basic engine itself, see if we even want to continue with the L28 platform.

The car doesn't have to be perfect, just driveable enough to be easily/reliably moved around. Once she gets to a more complete state, we could reevaluate the engine and decide where to go from there.

But that "disruption" did occur, so I'm floundering till Sigfrid gives more specific instructions.

DeaconBlue

iTrader: (31)

Wow - something is dead wrong here!

At 10 PSI, those injector would not really be able to atomize the fuel very much if not at all - it would be just squirts and dribbles at best. That is also something close to a 50% reduction in flow rate from what they would be doing at 36 PSI. If there is not an issue of an over-sized pump or restriction in the regulator return port or in the return fuel line itself and if the gauge is anywhere close to being accurate, then you have the wrong sized injectors or the wrong impedance. What is the resistance of the injector measured across the two connector contact terminals? It is in the 12-16 Ohms range or something a whole lot less? It that what the manual says they should be? If these are low impedance unit, is there a resistor pack used with these somewhere? If so, have you tested it?

You may want to remove the injectors and send them to someone like WitchHunter to have them cleaned and flow tested. At least you would know what you have and if they are working correctly.

WitchHunter Performance - Injector Cleaning & Flow Testing Services

archaphil

iTrader: (1)

late to the party, 255 wally screamed like a ***** in my old red NA/7. They are just noisy bitches.

I have nothing else to add to the party, that is all. *shuts door behind him*