2.5 liter oil fowling out plugs and gas in the oil (Page 1/1) Briar sharp MAR 21, 05:54 PM I've got an 87 fiero that is getting oil in the gas and gas in the oil I don't think it's a vacuum leak because if I clean the plugs off and put them back in it runs great I mean like a top for about 3 miles or so them the plugs fowl out again and It spits sputters and dies but it also has gas in the oil at first I thought it was just getting flooded and gas is getting in the oil that way but I changed the oil three times now and it still has gas in it every time I check it I can smell the gas in the oil Patrick MAR 21, 06:25 PM I'd be curious to see a picture of the four spark plug electrodes to see what they're being fouled with. With the air filter top removed, can you see the injector spraying normally? The gas isn't pouring out of it? I'm not sure about the 2.5, but the diaphragm of the fuel pressure regulator on the 2.8 can rupture and leak fuel into the intake. Briar sharp MAR 21, 06:35 PM When you turn the key and try and start it it does seem to me to be putting a lot of gas into the carburetor and I will post a picture of the plugs in just a minute thanks Patrick MAR 21, 06:41 PM quote Originally posted by Briar sharp: ...it does seem to me to be putting a lot of gas into the carburetor Is your Fiero an '87 or a '67? The fuel injector is located within a throttle body. There's no carburetor. Briar sharp MAR 21, 07:43 PM Haha my bad that's what I meant it just looks like a carburator with an injector on top of it to me but anyway so it will flood out really easy too so I don't know I just got this car but i do know that it does run really good if I clean the spark plugs out really good for a couple miles then they fowl out again and when I pull them out again they are black as hell with black **** caked up around them Patrick MAR 21, 07:51 PM Any stored trouble codes? theogre MAR 22, 11:23 AM See my Cave, 700 TBI ⚠️ 700 TBI regulator is know to fail and leak. Mostly when true, leaks, flows on air cleaner mount area then suck into the engine. If that leaks, get a Rebuild Kit Not just a Regulator part. Kit has same piece and likely need other gaskets. TBI gets hit when dog bone is bad or hardware gets loose and bottom, middle or both gaskets won't seal. If Fuel lines are damage, Anything block return line will cause problem. High system pressure or even destroy the PF because FP needs constant fuel flow to stay cool and lubed. Iffy O2 sensor, Leaking reg or High Pressure can make engine Running Rich and maybe set Codes. Before replacing O2, check/fix ground bolted to engine. Tan "ground" is actually a return wire for "1 wire" O2. You can't tell just by looking are TBI. Only may tell if is leaking a O-ring etc because will have fuel dripping/spraying when ECM turn on FP to prime the system w/o actually starting the engine. If ECM is "bad" often won't turn on the injector. But driver "chip" or wiring can fail and keep injector on. Or Injector is sticking and allowing more flow. Both can allow flow after shutdown. May not flow until engine is running. If Intake Manifold and/or Gasket leaks then often Engine Coolant coolant is Leaking and often suck into #4 cyl. #4 spark plug often will be Cleaner then others. If true, use only Felpro gasket that's make to prevent this problem. Can leak w/o coolant leak but use the Felpro gasket. If Piston Rings etc have problems... whole different thing and may need a rebuild. But If Oil doesn't drain right from upper engine... could be just block drains. That will make oil "leak" thru valve guides because upper head had too much oil. Plug drains are common w/ people using RTV Silicone and "boogers" get loose and plug them. Felpro makes a better gasket, VS50179T, that Doesn't need any sealer. If cover is wrecked, buy DORMAN 264905 that comes w/ a new screw fill cap.