fragmare

I've noticed this happening recently after installing a new distributor. When the engine is cold, the car starts up immediately and idles beautifully. If I drive the car on a long trip (30 minutes or more) and shut the car off, then start it back up, it generally starts right up with no problems. If I make a couple of short trips (5-10 minutes) and shut the car off, when i try to restart it, I notice the engine acts like it's flooded. It will sometimes sputter and then die, or sometimes just crank. If i wait a few minutes and open the throttle wide, it'll usually start up, idle rough for a few seconds, billow a cloud of white smoke from the exhaust, and then resume idling nicely. I also notice that after one of these "flooding" episodes it will act like it wants to bog down when shifting to Reverse or any drive gear (it's automatic). I've got some ideas as to what could be the culprit, and heard people mention at least as many more. Fuel pressure regulator, fuel pump, leaky injector, main relay, etc. The fuel filter is also brand new. Where should I start troubleshooting? Any ideas?

jbpnoman

Leaky injectors are easy to figure out. Do a fuel pressure test, and see how long it holds pressure. It should hold it for a few hours. With a leaky injector, it won't.

fragmare

Yea, I need to get to the autoparts store to borrow their fuel pressure test kit tomorrow and check my results against the tolerances in the service manual. So you're saying to test for leaky injectors you simply leave the gauge hooked up for a few hours and see if the needle drops? Is there a way to isolate which of the four injectors is the problem?

jbpnoman

Any easy way? Short of removing the injectors and feeling which one is wet, not really.

You could also pull your plugs and inspect them for fouling.

fragmare

Alright, if I find the gauge dropping slowly tomorrow during the fuel pressure test, i'll pull the injectors and see if i can find the leaky one. Seems easy enough, it's all right there on top of the engine. I've already pulled the plugs and checked them out, but they're all basically brand new (less than two weeks old), so they haven't really had any time to become fouled. Thank you, sir.

jbpnoman

Not a problem.

I would still pull the plugs and see if one looks visibly different than the other. Brand new plugs actually make a possible plug diagnosis a lot easier. At least we know any fouling on any of the plugs isn't old.

Former User

This^ sounds like a blown head gasket. If your cylinders were flooded with fuel, the smoke would be black.

Compression test the cylinders.

fragmare

I know it's not that. The head gasket, as well as the intake and exhaust manifold gasket, are all brand new. I replaced them about a month ago. I also replaced the cam pulley gasket, distributor o-ring, cam holder gaskets, spark plug seals and valve cover gasket/seals. I ran the fuel pressure test and these are my results:

w/o fuel pressure regulator hose attached: 44 PSI (right where it should be)
with fuel pressure regulator hose attached: 35 PSI (also, perfect)
After reconnecting the pressure regulator hose the pressure rose back to 44 PSI (which is what it should do)

However, when I shut the car off and let the fuel pressure gauge sit for a while, I noticed the pressure decline at the following rate:

Immediately after shut off: 35 PSI
+15 minutes: 28 PSI
+30 minutes: 25 PSI
+45 minutes: 23 PSI
+60 minutes: 21 PSI
+75 minutes: 20 PSI
+90 minutes: 19 PSI

This leads me to think (from jbpnoman's replies) that there's some sort of injector leak on at least one cylinder. Not sure if it's an o-ring or an injector itself. I checked the vacuum hose that leads from the bottom-right of the intake manifold to the engine block and it seems okay. I still have a full set of injector o-rings leftover from the head gasket set, so I might try putting those in and see if that does the trick before i spend ~80 bucks in a new injector. If anybody has any other ideas, I'd love to hear them.

jbpnoman

I would send your injectors off to a professional cleaner before I looked at replacing them. A lot of the time, they can be refurbished for a lot cheaper. Injector RX and Witch Hunter both do good work, from what I've heard.

Are you talking about the o rings between the injector and the fuel rail, or the gaskets between the injector and the intake manifold? The gasket wouldn't cause your pressure to drop, but the o ring would, especially if you accidentally clipped it while doing your head gasket.

fragmare

Yea, I'll definitely look into that. The injectors could probably use a good cleaning anyway. When I did the head gasket, I noticed there was a ton of gunk caked inside the intake manifold around the injectors. I got most of it off with some brake cleaner, an old toothbrush and a rag, but some might have gotten up into the injector nozzle(s) while I was cleaning it. I'll Google those and see what I can find. I've also seen some stuff called Sledge Hammer that hooks up to your injectors like an IV bag you hang off your hood. I might research that too, to see if that's even cost effective (or effective at all). Have you, or anybody else, heard anything about that stuff?

The o-rings I'm talking about are the ones between the fuel rail and injector. I've got a set of four (plus one for the pressure regulator too, i think) just sitting in my garage left over from the head gasket set. I might install those just to see if they do any good. If not... well then, hey, at least my injectors have fresh o-rings. :D

fragmare

Well, I replaced the injector and pressure regulator o-rings and and that didn't do the trick. I ended up getting stuck at the gas station and had to wait like 10 minutes before the car started again. The dealership said a bad fuel pump seal could be causing it to lose fuel pressure after shut-down. Could that also cause the intermittent engine flooding? The pump certainly primes just fine and supplies good pressure when it's running.