hello all-
new to ECC (been reading it for years) but driving EC's for 27 years-'72,'80,'83 and an '86 since 1991

it's a1986 4.3 TBI 200R4 trans? w/270,000 miles and only a valve job all this time.Has never quit on me,so a little atttached to my baby.

About a month ago-started surging(at will) going 45MPH w/o foot on the pedal-for about 2 minutes and then back to normal and then would do it again(at will).Then it wouldn't start w/o a tromp on pedal or gas down TBI.

Replaced EGR,TPS,fuel pump,filter,fuel pump relay,fuel pressure regulator -now it will start(on occasion) and run great-until you turn it off and then no start until fuel down throat.then it starts fine and runs for a short while and then just stalls and no start until gas in TBI.Now,it will start but as soon as turned off...no start.

So,I checked the fuel injectors and upon starting,only dripping gas (or not) until gas in throat,starts right up and injectors spray as they should.Runs for a while and then a stall.

What am I missing?
seems like fuel pressure but what do I check now?

thanks for your insight...
fattjak

Check fuel pressure , may be a bad pump

Welcome, jak. Glad you decided to join. It sure does sound like a pressure, or lack there of, problem. What pressure it makes, bleeds off when it is not running, then the no start. EFI needs a standing pressure.

Sandblaster said it..fuel pressure......if the fuel pump has never been changed, it's just worn out. And if you replace it, take the old one apart, and after seeing the inside of it, and you will wonder how it ran that long!:smileyb:

The pump runs for a few seconds when the IGN is turned on, to prime the system for start. And if it's not the pump, the regulator in the TBI may be bad, like with a leak in the diaphram etc..

YEP WHAT HE SAID:beer:

how do you do an EFI test?
is it worth it to replace fuel injectors? since i already replaced the fuel pump,filter,relay,EGR,TPS,fuel pressure regulator...

thanks for all the help
fattjak

The idle could be the idle air control valve(IAC)if it carboned up or the soleniod in the valve is weak you'll have problems with idle and stalling.
http://www.autozone.com/autozone/parts/Duralast-Idle-Air-Control-Valve/1986-Chevrolet-El-Camino/_/N-ij1fdZ9gsof?counter=1&filterByKeyWord=iac&fromString=search&itemIdentifier=2987_0_0_
Look here to see what it looks like ,if you take it out to clean with carb cleaner do not spray towards the electrical end and let it air dry before trying it out also make sure the seat for the valve inside the throttlebody is clean and not damaged this stand for if you replace the IAC also.
If you don't have a manual I suggest you get one, even a Chilton or Haynes is better than nothing.The Chilton 28440 has a breakdown for the throttlebody on page 5-42 in that breakdown item #11 is a small screen that gets plugged up and cause it to starve for fuel.On page 5-44 shows you how to get to the screen under the injector.
Your Elco also has a oil pressure switch that if it is malfunctioning will cut power to the fuel pump relay keeping the fuel pump from working, it is usually at the back of the block to the drivers side under the distributor.On page 5-46 fig. 67 will show you two oil pressure switches one that looks like a small can with an electrical connection on it is the sensor for the dash guage or oil light.

Don't remember the exact procedure for EFI test. Remove fuel line at throttle body ,put line into a catch can, crank motor , something like so many ounces of fuel in so many seconds .

What Kerno said. A manual is most necessary if you take the TBI apart. And kits are available for them. The factory manuals say not to take the regulator apart, but most kits I've used have parts for the regulator, and they go together OK.

fattjak, when you turn your car on, you should hear your fuel pump running for two seconds, and then stop. Sounds to me like this is not happening. Putting gas in the
TBI and starting the car is building oil pressure, which then turns on the fuel pump.

If this is the case, I would check the connections to the FP relay, and maybe the relay itself. You may be able to test the relay by applying 12v to the bottom left ALDL port. This should energize the relay, and turn on the FP ( I'm guessing that it is the same as TPI ALDL connections). You could also have connectons issues at the ECM itself. The pins are notorious for getting "Loose". It's the ECM that sends out the signal to the relay for those two seconds, so that is also something to consider. Howevder, if it is running OK otherwise, look for a simple solution ( connections or wire to the relay).