mikeric

iTrader: (20)

I posted this in the second gen section but have not gotten any useful replies. Maybe they are all too busy drifting. So, repost it here.

I have an S4 TII in an FB. Engine is a recent rebuild and from what I can measure, the compression is good.

Initially, I drove the car home and it started up fine. When I got it home and shut it off, I had a hard time restarting it. I figured that this was due to the engine being new. However, I went to go drive it the other day--for which it started up fine. Once I shut it off it did not want to restart.

I have a fuel pressure regulator that reads 35 psi when the key is first turned and the pump cycles. As soon as the pump finishes cycling the fuel pressure drops to 0. Is that normal? I thought fuel pressure should be consistent and that it should stay under pressure.

Also, when compression testing the L1, I had removed L2 and even though the fuel pump fuse was pulled, I got a smoke and fuel mist coming out of L2. I thought that was rather strange as there should not me any fuel coming out.

Anyway, thoughts? Suggestions? Could I have an internal fuel leak? I had my secondaries leaking and just got new 2,200cc secondaries. Could the primaries be leaking? Anything else I should check?

mikeric

iTrader: (20)

In other words:

Should the pressure stay up after the pump finishes its startup cycle? In piston engines if the pressure drops it means you have an internal leak, I'm just not sure about on rotaries as I never paid that much attention to the gauge on the fuel pressure regulator except when the car was running. I never noticed if the pressure drops with the car on and but the engine off.

82transam

iTrader: (18)

You're correct, it should maintain pressure for at least several minutes after the pump shuts off. I had a problem with this once, turned out to be the small hose connecting the pump to the pump hanger inside the tank. Made enough pressure to run (poorly) but wouldn't maintain enough volume to drive, and hard to start etc.

If it's exhibiting any symptoms of flooding then maybe an injector is leaking into the engine.

mikeric

iTrader: (20)

Interesting. I'm thinking leaky injector or something going on with the fuel pump. It was running well and hard-started once and then we had snow so it sat for a few weeks.

I am a little confuesd about the smoke/fumes coming out of the rear spark plug hole when I was pressure testing the front one (I had removed both leading so that I could swap between them faster as my wife was not happy to be cranking the car in the cold garage. No plugs were hooked up and it should not be getting fuel. Is it just blowing residue out?

82transam

iTrader: (18)

Yeah could be a mist of excess fuel/oil blowing out. When you say pressure tested I'm assuming you mean compression test right? I assume you unplugged the fuel pump or pulled the ECU fuse etc during that right?

Once it's running then it runs fine? If so then my guess would be a leaky injector as well - partially flooding it once you turn the car off. When I had the leak in the tank it wouldn't run worth a damn even once it had started...

wankel=awesome

I know a car that does this on both rotors, and it IS the injectors leaking into the engine. Ofc the car thats doing this has original injectors@160k miles

mikeric

iTrader: (20)

Thanks guys. Yes, fuse was pulled as stated above during the compression test.

Dave had the brilliant idea of pinching the line after the FPR (which has a gauge) and seeing if the problem goes away. If so, it is the injectors. If not, try pinching it before the gauge. If the problem goes away is is somewhere in the tank. If it doesn't go away with either it might be the FPR.

Changing from work and trying that now.

mikeric

iTrader: (20)

So, I removed the intake and pressure tesed the fuel injectors. Infortunately, they are not the issue. May be something in the tank or possibly the FPR.

82transam

iTrader: (18)

What is your setup as far as the pump and fpr etc? Is it in an in tank FC style pump like I'm running?

wankel=awesome

fuel tank vent clogged? Fuel has to be getting from the rail into the engine.... Theres only so many ways that it can...

Drive the car and then unplug r2's injectors after shutdown, and then see if fuel got in there after the 30 mins or so. If you pressure tested them, and they dont leak, maybe something is telling one to open on shutdown or somethign stupid like that. I dont see how the FPR could cause this unless theres something in the FC fuel system i dont recall that lets fuel into the engine.

mikeric

iTrader: (20)

I did not install this one but I believe it is external. I will check on it tonight. I know it is a Bosh 044 that was installed three years ago after the Walboro proved unreliable. It may have gotten gunked up for sitting for so long.

So, the fuel is getting to the engine, that is not the problem. I don't know if it has the correct pressure while cranking and I will check that tonight when i get home. Car will not start which is the nature of the problem so I cannot drive it. I will crank the engine tonight with a jar under the primaries to see how they spray and what they may be doing.

Still, it doesn't explain the sudden loss of fuel pressure the minute the pump shuts off (take about two seconds). I tried pinching the line between the fuel rail and the FPR (which has a gauge) after I shut the pump off and it bleeds slowly and stays about 10psi as my clamps are not folly closing the line.

82transam

iTrader: (18)

I don't have any experience with external FI pumps, but I can't imagine it being much different than my internal pump as far as holding pressure after turning it off.

mikeric

iTrader: (20)

I have to agree.

I have not had a chance to mess with it as I had other obligations last week and this week. I will be traveling to Europe for two weeks this Friday so it will have to happily sit in my garage until I get back.

I just realized that I have been on this forum and a rotarty owner since April 2001 so it has been 13 years. Time has flown by since I fists saw a dusty, uncared for black FC in Clovis, NM with a for sale sign in the window. I believe he wanted $1,300 and I think I paid about $1,100 as I wanted a car for autocrossing and I was a young Airman with not a lot of money. I paid him $550 up front and $550 a month later. Lots of busted knukles and heartbreak with that car but she was my first love.

This was taken at an autocross meet in West Texas.



And later when she was turbocharged and I learned that BMWs make better DD and road trip cars.





Like most exes, I loved and hated her.

Finally, after being hit by a truck and then blowing the transmission, my wife at the time had enough and made me sell her back in 2005.

Sorry, waxing nostalgic today.

82transam

iTrader: (18)

Time flies for sure. Got my first FB back in 2001 as well. Still going strong (many changes later) to this day

notveryhappyjack

iTrader: (4)

you might want to lower the static fuel pressure slightly. From my experience 30-32psi works well. I know I was running into a bunch of hard start issues after I rebuilt my engine. timing was not accurate enough causing hard starts. 5* after top dead center should be accurate enough to start the engine.

mikeric

iTrader: (20)

Thanks not very happy. I'll look into that when I get back from Europe.