I did a search and found a couple of things, but nothing really matched my issue. 91 RS 305 TBI - stock everything

1.) this 3rd gen is a new experience for me, I'm use to 2nd gens, carbed, no computers. I've had the car for about 3 weeks, probably driven 30 miles

2.) last week I changed out a bad oil sending unit and inadvertently popped the fuse by the battery. At the time I did not know there was a fuse by the battery and obviously had starting issues. Before the fuse was replaced, I noticed that the fuel gauge was pegged past full and no SES. Gauge returned to normal after replacing fuse-at 1/4 tank, and I read about the loop to the ECM and now have the SES check at key on again.

2.) a few days later fuel gauge is pegged past full again, car still starts & run well, but i've only driven it around the block checking things out.

3.) this past weekend while sitting on my angle driveway, car will not start, not getting fuel. I looked for stuff for awhile, still thinking I have 1/4 tank. Finally I go get 3 gallons of gas, car starts right up, so I take it to the gas station and fill it up, it only takes 12.3 gallons of gas and I'm puzzled, till I get home and read that they are only 15.5 gal tanks. So I was out of gas at what appears to be 1/4 tank when the gauge worked - logged as mental note. Thought maybe full tank would fix the gauge issue, but no still pegged.

4.) Sunday I have the steering wheel off to fix some previous owners breakage of the all the stuff on the turn signal. Take the car for a spin afterwards, all is fine, except that dang fuel gauge.

5.) I drive it to work Wednesday this week, car runs fine, take it to the AC shop and find out AC system is shot (but can be fixed for $1300 - I pass), coming home from work, I drive over an unusually tall trench cover plate at about 50mph, at about 100 feet after that, car begins to run rough, low idle, and hesitates badly upon throttle and won't accellerate very well. I make it home and the car will not idle at all. Car will start then die. Sometimes I am able to keep it running by feathering the pedal, but it wont stay running with out doing that.

6.) Since then I have check for gas in the tank - good, replaced the fuel filter, and today replaced the fuel pressure regulator. I can hear the pump come on during the time delayed pressure up and I checked the voltage out of the regulator (grey wire) during pressure up (13+volts) and when I was feathering the pedal (15+volts). Just for kicks, I checked the voltage at the connector before going to the tank, same as before.

I have not done an actual pressure test, but I have performed a shadetree flow test at the out side of the filter, with adequate results I thought during the pressure up cycle.

So with all that crap above in mind, is it the fuel pump? even though it will pressure up. Dont they just generally die?

Why would the fuel guage be pegged? all fuses are fine and all other gauges work.

Did the hard bump/hit do something I am unaware of? Knock something loose somewhere, but what?

And I do not have the "G" pin on the ADAL. Don't know why, but its not there.

It has not thrown any codes.

Sorry for the long typing, but I figured the more info I provide the better my chances of getting it figured out.

Thanks for any input.

Mark

 

Well as for the guage, it sounds like the sending unit is going bad. It also sounds like you need a new fuel pump so when you drop the tank for it you can change the sending unit while you are there.

 

In my experience, get a pressure gauge and check the pressure from the fuel pump. Mine did not die completely but read about 5-6 psi. New to this like you, I disconnected lines and still had pressure, but not until I checked the actual pressure did I realize, after a lot of needless diagnosing of other items, that the fuel pump was the culprit. I installed a new fuel pump for little cost and everything ran beautifully. The fuel gauge is, I believe, a different issue. Good luck.

 

ANSWER found and it makes sense (now).

After pulling out the pump and being disgusted at the condition of the strainer, I found a 1/2" slit in the small hose that connects the fuel pump out to the fuel line, thus the car would run until it needed more pressue, then it would just dump back into the tank.

I was hoping the sending unit would correct itself, but no.

I did do the fuel pump access hole thing, so...

Thanks for the input everyone.