Bob_The_Normal

ROTFL.

I was reading this entire thread going "WTH... when is someone going to say it's an intake leak?"

It might not be but damn man before you went through all this, look for a leak inbetween your air flow meter and the engine.... obviously that's a lot of ground to cover, but it has to be a BIG leak to turn off the car, like the intake is wide open..

Also like someone mentioned, make sure your AFM is working correctly.

Doesn't sound like a fuel problem.

--Gary

WonkoTheSane

iTrader: (2)

I'll go double check for vacuum leaks.. I have done all of the emmissions removal, and every unnessicary vacuum connection has been sealed with RTV and then capped off with a vacuum cap, so it won't be too hard to double check all of them..

ALthough I should know what TID stands for, right now I just can't think of it.. I know I've heard it tons of times, and I've probably even used it once or twice...

I think I have enough energy to go out and play again for a few minutes, so I'll go look

eage8

iTrader: (9)

lol, sorry, you probably haven't used it

it's stands for turbo intake duct. it's just the intake pipe going to the turbo... and since your an NA you don't have one.... but check the pipe going to your TB and all your Intake manifold gaskets as such.

-Myk

WonkoTheSane

iTrader: (2)

Ah, gotcha.. You know I still knew the acronym.. damn cold clogging up my head. I'll go double check all the lines and make sure my intake duct doesn't have any cracks and such again..

Thanks.

Wyznewski

Did you ever try the AFM? My car did the same thing when I put the new motor in it and forgot to plug in the AFM (Oops).

HAILERS

The fuel pressure should be approx 28psi at idle.

With the key to ON, and the fuel check connector jumpered, you should see b/t 34-39.8 psi. The fsm does something similar. It runs the engine at idle and has you energize the fpr solenoid to get those results.

Actually, your 32psi does sound low. If I remember right I usually always see 37-39psi when at idle and the vac line is off the fpr OR engine off/key on and the fuel pump check connector jumpered (37-39psi).

Another way would be to idle the engine and just pull the vacuum line off the fpr to get the 34.1 to 39.8psi results.

With the fuel pump blocked off from the return line, you should see approx 71 to 92psi.

Get rid of the Haynes and download the fsm.

Your car shows no signs of needing a fuel pump rewire. To determine that, put a meter on the input wire of the fuel pump.......turn all the lights on and the heater fan at full blast, and drive the car up a steep hill at wide open throttle in third and forth gear. See if the voltage stays above 12volts. I just made that test up, but it is a good clue as to whether your electrical system is up to the job.

WAYNE88N/A

Lol, we have the Haynes checks, the FSM checks, and now the "Hailers tests"

A bunch of guys were confused on the previous page on the fuel pump continuously running with the check connector jumpered. As long as at least one of the two coils in the circuit opening relay is provided with a ground (as is the case with the connector jumpered), the pump will continuously run and push fuel. This is because of the return system on the car...

Now here's the "Wayne test" to see how your fuel pump voltage is doing- check the voltage, to ground, at the connector on the left strut tower, with the car idling. You don't have to disconnect the connector, just backprobe the blue wire on the HARNESS side with the positive lead (negative lead to a nearby bare metal spot). Record this number (mine's around 13 to 13.5v, so I would guess that's normal).

With the car still running, now record the voltage at the battery posts. This is your "source voltage" to compare the pump's circuit voltage to. If the voltages are within ABOUT 1 volt or less of each other, your pump wiring is good...

WonkoTheSane

iTrader: (2)

I didn't make it out to doublecheck the system tonight, as soon as I got out there, it started raining, and I'm too sick to deal with cold rain right now...

I've had the same problem with the fuel pump jumpered, so the AFM is out of the question, fortunately

If I could drive it up a hill or check the pressure at idle, I wouldn't be concerned about it I know that my lights and such dim when everything is on, but I have a new 3rd gen alternator ready to drop in to compliment my new battery.

As for the pressure, all I can test is with the system turned on. I know i'm getting reasonable voltage at the fuel pump connector, I checked it with the battery charger hooked up, and it was pulling a nice stable 13-14v when on, and then 10-11v while cranking.

I do have the FSM, however the haynes manual is easier to have while i'm out working on the car, as it's about 10 volumes less to have spread out in the engine bay It's not that bad, really.

Again, if I could have the car running, I wouldn't be as concerned about my fuel pressure





I think the most frustrating thing is that occasionally (once every, say, 25 cranks?), is that it will fire up for 5 seconds or so.. there's absolutely no change or adjustment when this happens, it'll die like normal the first time, start and run for 5 seconds, then die, then i'll get excited and try to start it again 5 or 6 times, and it'll die like normal every one..

very frustrating.

Thanks for the ideas guys, keep em coming if you think of anything additional.

WAYNE88N/A

Just for s#its and grins, put a meter on the AFM input at the ECU (pin 2E on the S4's). Key on should be about 4v, and voltage should fall as the throttle is opened. If you're not getting this, go back to looking at the AFM as the culprit...

HAILERS

An RX7 should idle just fine with only 28psi and I'd wager a n/a could run pretty decently at speed with just 28psi. It ain't the fuel pump itself.

Maybe the afm switch. But then again, if you have a hacked in fuel pressure gauge and it never drops below 28psi, then it isn't the afm's fuel switch either. In fact I've no idea what it is. Flooded maybe?????????????????????? Pull the fuel pumps plug off and try starting the car. Sorry, I'm not a big fan of pulling EGI COMP or EGI INJECT fuses.

WonkoTheSane

iTrader: (2)

The AFM shouldn't have any affect on the system if the fuel pump jumper is shorted, though, right?

I'm pretty sure it's not flooded, as it will randomly start, and it died when I was driving it (in the same manner that it dies every crank now). .That and it will occasionally start for a bit, before dying in the same fashion. It also turns over every time I crank it, just rarely runs for more than 1/2 of a second.

I do have a fuel pump cut-off switch, though, and I occasionally flick that off and spin it a bit just to make sure..

rather wierd, eh?

WAYNE88N/A

You gotta remember, the AFM door switch isn't the only thing that goes wrong with our AFM's...The switch could be fine, but if the ECU isn't receiving good variable inputs from the door potentiometer (a totally seperate circuit), she'll shut you down too.

Think about what happens when the fuel circuit is jumpered, but the AFM plug is off- you'll still get the fuel pump to come on, but it's obvious she won't run without an AFM input...

Bob_The_Normal

Exactly Wayne... except what I'm thinking of is you're running way off on your A/F because the ECU either ISN'T getting a signal from the AFM... or it's getting a signal for X amount of air and you have a leak that's letting in TWICE as much... obviously it's not going to run.

I think if anything you've done so many tests to your fuel system that at least you know in the future it's in great condition! lol

I'm curious to see what solves this.

--Gary

WonkoTheSane

iTrader: (2)

Right on guys, when I get home from work, i'll tear off the AFM and do a thorough diagnosis. When I put it back in, I'll go through the entire intake ductwork and make sure there is nothing letting air into the system.

This sounds promising I didn't realize that the AFM could still shut the system down if the fuel pump was jumpered, I learn something new every day.

WAYNE88N/A

Actually, I'm not sure if it will, the ECU might have a funky fail-safe circuit to fall back on if it totally loses the AFM's signal, but the best case scenario would be that she would run like crap (or shut down, maybe, lol)...

WonkoTheSane

iTrader: (2)

Well, I tested the AFM... The bad or good news is that the AFM is responding within spec. I haven't tried to start the car without it as it's bloody cold, and all I wanted to do is get the AFM off and bring it inside to diagnose. I'll see what it does tomorrow without the AFM.

The only thing that I haven't specifically tested is the FPR, but it seems that if I'm pulling a constant pressure across the fuel system, it probably isn't that...

Just to recap - Things I have checked/replaced:

Fuel system -
Checked voltage to the pump: OK
Checked fuel system pressure: Ok
Sent Fuel Injectors out for cleaning: Ok

Air Intake -
Checked air system for Leaks: OK
Checked for Cracks in ducting: OK
Checked AFM for proper Function: OK
Checked for dead animals/debris in airflow path: OK

Spark -
Replaced all 4 plugs +wires: OK
Checked CAS and Coils: OK
Replaced ECU: OK

So, I thought you only needed Fuel, Air and Spark for an engine to run?

WAYNE88N/A

Don't forget about the compression required to ignite the fuel mixture, lol...

Are the plugs wet at all after the starting attempts?

You could try reading all of the important sensors out at the ECU with the key on, just to see if any of them are messing with you...

WonkoTheSane

iTrader: (2)

I'm sure I have enough compression, as I can definatly hear it turn over EVERY time i crank it.. if you want I can record a sound clip/video clip of it..

The plugs are wet though, not sopping wet or anything, but wet enough that it will cause it to backfire a little bit sometimes on starting.

Any ideas which sensors I should start with? If you can give me a list, i'll start checking the FSM and going through them tomorrow

Thanks

WonkoTheSane

iTrader: (2)

Anyone have any good ideas on what sensors to check/adjust?

Start with the TPS, and go from there is what I'm thinking now.

It would be rather handy to have a nice list of critical sensors to check, if any of you get bored

Bob_The_Normal

TPS isn't required for the car to start though...

And if a sensor wasn't working the car would most likely throw a code for it too...

I'll let you know if I can think of anything that this could be.

--Gary

WAYNE88N/A

Heck, at this point I'd have read them all out. The ones that have an active input with just the key on, anyway. Once you get to the ECU, you're right there for all of them. Have the FSM page in front of you, and just go right down the list. I hardly ever find something bad at the ECU when troubleshooting my car, but the important thing is that I'll know what's NOT bad after doing this.

What kind of shape are your injectors in? If the plugs are wet, then the entire fuel injection system is probably working. You just need to figure out why she's not lighting off and sustaining herself...

WonkoTheSane

iTrader: (2)

According to Cruizin' Performance, they're pretty good, they weren't even that bad before I sent them in (3 weeks ago). It's definatly firing, it's definatly starting, it's just the sustaining that's the problem

Good call at checking them at the ECU.. I'll do it all.

WonkoTheSane

iTrader: (2)

Okay, I was out metering some of the connections at my ECu, and out of frustration I started metering every fuse connection I could.. I found something interesting: I have no power @ my 80AMP main fuse in the engine bay, the big black one. I checked both sides, and there's nothing there. I would think that the MAIN power for the car should have 12v running through it. Anyone have any good ideas where I should check for where my 12V went on that?

RotaryEvolution

iTrader: (30)

that fuse is supplied by the smaller guage wire that runs directly off of the battery positive terminal, follow the wire from under that fuse back to the battery. maybe clean the terminal and post and recheck it. if you have a clamp down aftermarket terminal i would alse pull the wires out, cut some fresh ones and scrape them with a razor blade to get a good connection and clamp it back down tight. do the same with the negative terminal also.

WonkoTheSane

iTrader: (2)

Cool, I didn't know if I could run power direcly from the battery.. I'll check the existing wiring, and then If I get annoyed, I'll run it directly..


I'm about [ ] this close to taking out all factory wiring, building a MegaSquirt and going with fresh wiring for everything....

Thanks.