88turbotime

Hey guys,

I know there are about 6 million threads about flooding. I also know the answer is to check the compression. I haven't done that yet, but I will.

Car is an 88 TII. Engine rebuilt and street ported around 30k-ish miles ago by Kevin Landers at Rotary Resurrection. Emissions removed, Racing Beat turbo-back exhaust, K&N cone filter (really more of a cylinder than a cone, but you get the idea... the stock air intake is gone), Walbro 255, 720cc Secondaries, stock primaries, S-AFC II, I think that's about it. I have had the car since about 2003, and the mods have been on it since around 2005 or 2006ish. I don't remember the exact year but it hasn't been messed with in a long time and it has always been really reliable, but admittedly it does sit more than it should.

Anyway I replaced the fuel filter and the sock on the pump trying to fix a hesitation problem (and it had been a while since the filter was replaced anyway, so I figured it wouldn't hurt). The hesitation problem ended up being the TPS, I replaced that and it runs great now. The problem is that ever since I replaced the fuel filters, the thing floods every time I shut it down. I never had flooding problems out of it, but it started happening RIGHT after I replaced the filters. It could just be a coincidence I guess, but the timing was just too perfect in my opinion.

I don't see how replacing the filter would make it start flooding though, even if I somehow messed up. The filter is installed correctly, not backwards or anything. I sent the injectors off to have them tested and have the little seals and parts replaced, but that didn't help. I sent them to Witch Hunter if that matters, but I'm not seeing any difference anyway.

I will test the compression next. I really doubt it is low on compression (I know that's what everybody says when they don't want to bother checking it) because of how good it runs, I mean it runs like a raped ape. But I will check it anyway. When you do that, should I turn the fuel pump off so it isn't pumping fuel into the chambers? I have read the procedure for testing compression, but haven't seen anything mentioned about turning off the fuel pump, so maybe I should leave it on, but it seems like you wouldn't want fuel spraying while you're doing that. The fuel pump does have a switch.

Also after it floods and I start it by turning the pump off, it runs really bad for a while, sometimes for quite a while, before it clears itself out. By running bad I mean it revs really slowly and makes very little power, like its constantly bogged down. I never had it act like that in the past after flooding it the "normal" way (shutting it off too soon before its warm, or something like that).

I will also check the AFM, but I'm not really sure what I'm looking for there. I read recently that there's a flap in there that sometimes gets stuck? Its been a long time since I've had that off, so I don't remember what it looks like in there.


Anybody have any ideas on this? Again, I will check the compression soon, but this issue started the very first time I started it after the new fuel filter. Is there any chance at all that the problem is related to that?

j9fd3s

iTrader: (3)

unlikely, but its possible to bump stuff when you're changing the filter, and so there is that. also if you had the intake off to get the injectors serviced, there are all kinds of places for a vacuum leak

cone_crushr

iTrader: (18)

The best way to diagnose this is to measure your fuel pressure. Replacing a fuel filter should increase the rail pressure due to less filter pressure loss.

88turbotime

Thanks for both of the replies.

Thinking you might be onto something here, I got a gauge to check the fuel pressure, hooked it up right at the regulator like explained in the Haynes manual and it reads basically zero. So either the cheap *** gauge I got from advance auto sucks (entirely possible) or I don't have any fuel pressure. I ordered a new fuel filter in case there is something wrong with the one I put on there (that's when this whole problem started anyway). I had that filter laying around for years (unused and in the box, but pretty old) so maybe it had deteriorated or something? I guess I could hook the gauge up before the fuel filter and see what it says, but I think I'm done messing with it for today.

88turbotime

Well I thought I was done messing with it, but I went and got another pressure gauge and hooked it up right before the fuel filter, and left the other one on the regulator. I have 50psi at the fuel filter at idle, the other gauge still reads zero. I switched the gauges to see if maybe the first one is bad and got the same thing: zero at the regulator and 50 at the filter. So I ordered another fuel filter. If that doesn't help, should I be looking at the pressure regulator?
Oddly, the car starts and idles fine right now, but I haven't driven it today.

doug910

Might be a little late here, but I'm experiencing similar issues. I recently did a rebuild myself in March, and while I was at it, I sent the injectors off to be rebuilt by Witchhunter and replaced the fuel filter as well. After my rebuild, the engine runs just fine, but it definitely has some flooding symptoms after I shut it down. Recently rebuilt engines are prone to flooding in the first place (I only have about 80 miles on the engine since rebuild, have been doing more maintenance since it's still kinda chilly), but I can't help but wonder if my the improved injectors and improved flow of a new filter is causing the flooding. If I have to restart the engine after shutting it down, I have to crank with the accelerator to the floor for the engine to catch, and then I can maintain an idle with my foot until it warms up.

Hopefully my flooding symptoms improve as I put more miles on the engine, but I'll update here if things change.

88turbotime

Yeah I have heard that new engines are prone to flooding until they wear in, Soni wouldn't worry about it yet. Kevin Landers puts a switch for the fuel pump for that very reason, but I never had any flooding issues with mine. I got lucky I guess.

88turbotime

I moved the pressure gauge from before the fuel filter to after the fuel filter, and it reads 50psi after the filter as well, so the filter seems to be flowing fine. I ordered a new fuel pressure regulator and installed that, and it still says 0psi right after the regulator. I can replace the fuel line from the filter to the fuel rail, maybe there is a kink or a blockage in there somewhere, but if that doesn't fix it, I'm at a loss. What could it be?

In summary, I have 50psi coming out of the fuel filter, and 0psi coming out of the fuel pressure regulator, and I have no fuel leaking anywhere. Where in the heck am I losing pressure?

j9fd3s

iTrader: (3)

the pressure regulator, everything before it should be ~40psi (or whatever the spec is) and the return to the tank should be really low

88turbotime

I'm looking at the Haynes manual, and unless I'm reading it wrong, it says after the regulator I should have 28.4 psi with the vacuum hose on the regulator attached, and 35.6 - 37.0 psi with the vacuum hose detached. If I'm wrong and you're right, then I guess I'm good there, I have 50 psi before the fuel rail and very little pressure going back to the tank.


Also, it occured to me today that when I go to start the thing up, it fires right up and idles perfect, and revs good. Then after a couple minutes it starts to bog down and will die if I leave it at idle, I can keep it running if I try to rev it but that's about all it does, barely keeps running. It won't rev hardly at all. Should I be looking at a temperature sensor? Like maybe it's telling the computer that the engine is cold even as it warms up and keeps it running rich?

The emissions stuff is all deleted, so it doesn't do the accelerated warmup thing anymore, but I imagine it still adjusts the mixture based on engine temperature, right? I know there is a temperature sensor right by the oil filter. Is that the one that talks to the computer or does that just go to the temperature gauge?

diabolical1

iTrader: (3)

that's for the gauge. the one that communicates with the ECU is the one at the back of the water pump housing.

88turbotime

Thanks. You think that could be the problem? Like it thinks the engine is always cold so it's fine at start up, then runs crappy as the engine does warm up? Or would that not make a big enough difference to stall the engine out and make it barely run at all?

doug910

I'm 1500 miles later and my flooding issues have not improved nor gotten any worse. Admittedly I also haven't done anything to fix the issue. I've always had a fuel pump cutoff switch installed, so I'm always able to get it to start within a few seconds if it floods.

There's a few things that I've found that I plan to look into:

• Water temp sensor (the sensor that the ECU reads, not for the dash gage). The ECU reads in water temp when starting the engine and adjusts fuel, so it might be worth replacing it.
• Compression test. I rebuilt the engine myself so I almost don't want to know the compression test results, lol.
• TPS adjustment, ECU also reads in TPS when starting the car so I need to double check its adjustment.

Anything else I should check guys?

Boost Lee

iTrader: (3)

You should take the injectors out and have them cleaned. If there is debris in them that is keeping them from closing completely it could explain your situation.

scathcart

[QUOTE=88turbotime;12492710]I'm looking at the Haynes manual, and unless I'm reading it wrong, it says after the regulator I should have 28.4 psi with the vacuum hose on the regulator attached, and 35.6 - 37.0 psi with the vacuum hose detached. If I'm wrong and you're right, then I guess I'm good there, I have 50 psi before the fuel rail and very little pressure going back to the tank.

You should have as close to zero psi coming out of the regulator; that hose simply returns the unused fuel back to the tank.
I don’t think you have a fuelling issues.

- What are your ouside temps these days? Cold
weather affects the battery and can cause you to get a lower cranking rpm, which can cause flooding.
-What condition is your battery in? This can be checked by reading voltage with the key off, and then again while cranking it. A tired battery, again, slows the cranking rpm.
- a tired starter can also cause a lower cranking rpm. If you need to swap starters, the automatic starteror RX-8 is rated higher and can either drop in or be made to fit. I think the later model RX-8 is even faster.
-Lastly, check compression. low Cranking compression makes flooding really easy. Don’t let how it runs fool you; even the most worn out engine can run amazing once it fires.

Flooding is very rarely caused by the fuel system, and since you’ve already got the injectors serviced, you can rule that out.

hope this helps.