88IROC350TPI

I just swapped from TPI to carb and just fired it up. It fires right up and idles for about 10 seconds then just dies. I'm using the stock in-tank fuel pump with a mallory regulator. When I turn the pump on my pressure gauge bounces from 5 to 7psi really fast. When the car turns on the pressure drops to like 2-3psi then once it dies it won't re-start for atleast a half hour. The fuel pump isn't turning off or making any funny sounds but do you think its the pump dying and losing its pumping power? I can't think of anything else and I really hate the idea of buying a different pump.

88IROC350TPI

Today I tried starting it and it did the same thing. Then when I tried restarting it a 6 foot flame shot out of the carb and I have gas in my oil. I just changed the oil last night and the car has only been running for like 1 minute. Anyone got any ideas?

92RS shearn

The only place I can imagine the gas getting in the oil would be the the intake manifold. Which would also probly create a serious vacuum leak whick would definitely cause the car to die. I don't know, thats all I can think of.

88IROC350TPI

That was my first thought but we changed the intake gasket and still the same problem.

Guest

Sounds like its flooding the carb. Is the return line hooked up right? And I dont know how you wired up the stock pump sans ECM, but the stock setup needs the oil pressure switch hooked up and working. I think yours has a 2 wire deal down by the oil filter IIRC. Otherwise, the car will run for 15 seconds and shut off with it disconnected.

88IROC350TPI

I didn't do the wiring for the fuel pump but my friend took out the back seats and got the wires from there. There is a chance that he left the ones going to the oil pressure switch connected but isn't that somehow controlled by the computer? The computer and wiring harness are completely removed. We have the fuel pump hooked up to the ignition so could (if the OP switch is still connected) be trying to turn it off? The pump stays running when the fuel pressure drops and the car slowly stalls.

ploegi

The switch down by the oil filter is a redundant power supply for the fuel pump. It was intended to supply power to the pump in the event of a relay failure. (turns on once pressure comes up)

If the car runs for a bit, then dies, and you have gas in the oil, I would suspect that either the regulator is not up to the task of reducing the pressure from a FI pump, or, the carb is WAY to rich.

Check while the key is on, engine off, and see if it is dumping gas.....

Good Luck.

88IROC350TPI

I completely forgot to mention that the day before I swapped to carb my car was doing the exact same thing (with the TPI I wasn't getting gas in the oil though). The last time I took it out it didn't want to idle or accelerate then once you tried restarting it after dying it would just backfire through the intake. Then it would just idle for like 10 seconds (perfectly) and die off. It must be something wrong with the fuel pump. The fuel filter is like a month old so I doubt its clogged but I'll take a look at it tomorrow. The first night we started it we had it running for atleast 5 minutes straight without this happening so I figured it was just the tuned port acting up now its exactly the same.

I guess my car is getting back at me for yanking its brain out.

Ray87Z

Hmm, no such problems with my very similar setup. The FP guage reading does bounce around a bit, but I think that is just a result of the design of the Mallory guage. It settles down after a minute or two to a solid 5-6. Has done that since day 1. No drop in pressure with the car running though. That regulator is up to the task I know, I've been running it with my stock intank TPI pump for like 1 1/2 years now.

For my pump wiring, I just ran a wire hot when the ignition is on to the fuel pump relay, and wired it in where the whole oil pressure safety switch/ECM would have normally been suppling power so the relay operated and powered the pump. IE I took the safety switch and ECM out of the loop so the relay would function and the pump would be powered whenever the key is on. Only required running one wire, relay is in the engine compartment so it's dirt simple. Best way to do it that I know of. That has worked fine so far.

I'm thinking you may have a bad carb, dumping fuel into the intake or something if gas is in the oil.

Take the carb off the intake while still being connected to everything else and put it in a pan sitting on top of the manifold or something, sitting there level. If you catch my drift. Power on the pump and let it sit there for a couple minutes, see if you're leaking gas from the carb into the pan. If it's not a new carb you may have the problem there. If the fuel pressure never goes over 7, and is in fact dropping when you start it then it isn't a too high pressure/FPR related problem. Mine runs around 5-7 psi all the time... With gas in the oil I don't see how it could possibly only be the fuel pump itself. Somewhere in the carb something is not working properly. Again, if it never tops 7 PSI then I don't see how it could be the regulator either... You may be looking at several problems occuring at once...

88IROC350TPI

Could it be by crappy summit gauge is wrong and I have the fuel pressure too high? The carb is a brand new 750 Holley so I hope thats not the problem. Since it had the exact same run for 10 seconds then stall problem with the TPI it must be either my pump or something clogging up. When you turn the fuel pressure down to about 4psi (according to my guage) the gauge doesn't bounce rapidly but once you hit 5-6psi it starts jumping like crazy. It also takes about 10 seconds for the fuel pressure to come up to 6psi

Ray87Z

Yeah, mine acts like that. I don't know why, but it always has, everyone I've talked to has the same thing with the guage jumping a bit. Again, I think it's the design of the regulator. Although mine hits full pressure almost immediately once powered up. That does suggest a weak pump. The pressure dropping after running is saying weak pump to me too. Even if the the line was completely off the carb, just dumping as much fuel as possible, the pressure shouldn't drop if the pump was powered and running right. It's gotta be weak it sounds like to me.

But, how is the gas getting into the oil? Gotta be one of a couple things. 1. Pressure too high, guage incorrect, blowing needle of the seat and just dumping gas in. 2. something in the carb itself is bad, dumping gas in.

When you initially powered it on, was the fuel pressure close to correct? Perhaps if it wasn't the high pressure screwed something in the carb up with the high pressure for a few seconds? Just guesses, I'm drawing a blank. Good luck...

Have a new fuel filter btw? Can't hurt to change it real quick before you tackle harder junk trying to troubleshoot the problem.

88IROC350TPI

I took the carb off and did the leak test and noticed no crazy leaking or anything from the carb but the butterflies were a little damp with gas after about 2 minutes of steady running. I did it really quick and late at night so I could have touched the throttle and got gas in their myself ...I'll try again tonight and take my time. I also noticed the pump wasn't making a very steady buzzing noise. It was slightly surging getting louder then quieter.