firechicken_3

iTrader: (4)

just bought an 88 formula, supposedly only 60k on it, (looks it too) sad part is some idiot threw paint thinner at the hood and door and has a few key marks, and 2 apparently bullet holes in passenger door, (did not go to inside). and there is one broken
t-top. body is otherwise straight and as you may have guessed, the car has the 5.0 tbi lo3 engine


anyways, start the car comes to idle for a few seconds and dies, to move the car around you have to pedal it. havent had a real chance to look at injector spray or anything but at the moment its screaming fuel pump in my mind, as ive been involved with 2 blazers that had fuel pump issues and exibited similar characteristics although not nearly as bad. also the exhaust is done at the end of the cat currently rusted completely away so im sure this is having an effect how much i do not know.


does that seem like a fair diagnosis of a bad fuel pump?

also what are the mosit important first mods for this engine that are gonna get me the best gains?

thanks guys

Benm109

It is possible that it's the fuel pump, but it could be many things.

How long has it been since the car's had a good tune-up (plugs, wires, cap and rotor, fuel filter, etc.). Have you or can you checked fuel pressure? That will tell you for sure if its the fuel pump. Checking the injector spray pattern definetely wouldn't hurt either, like you mentioned. It could also possibly be the IAC valve, but I don't want to jump to conclusions just yet.

As more mods, check out the "New to TBI" sticky. There's tons of info there about all the mods you could ever want to do (almost!). The first thing to do is a tune-up, to make sure the car's running at it's best, and then get an open element air cleaner, then cat-back and/or headers. But, as you will learn, you can't modify these cars too much before you need custom PROMs, but you can do-it-yourself. Check out the DIY-PROM board and the "New to TBI" sticky for info on that, too.

firechicken_3

iTrader: (4)

thing is while it idles those few seconds it sounds smooth, it cranks when you try to start it unless the key has been cycled to prime the fuel pump. i have no idea when its last tuneup was, since i just bought the car, it only has 60k miles on it, so most of that stuff is prolly original

how can i check the iac valve,? also i need to confirm but i dont think its showing a ses light when it does run

Benm109

Since you don't know how long it's been since it's had a tune-up, I would definetely do that first. Even though it's only got 60K, it's still a 16 year old car. Get new spark plugs, spark plug wires, distributor cap and rotor, fuel filter, air filter, belt, PCV valve, new oil and filter, etc. This way you can start fresh with the car and can begin to narrow down the problem. Something else to do while your doing the tune-up is take the whole TBI unit off, clean it thoroughly, and rebuild it. That will also allow you to take off and clean the IAC valve. You can do all of this yourself, too, it's not that hard.

firechicken_3

iTrader: (4)

attempted to check injector spray pattern, as the car fired, it sprayed then all but stopped, and as the car died, began to dump fuel in.

sorta seems like it lost pressure, then regained it. maybe flow instead of pressure tho too.


i know all those things are easy to do but plugs cap and rotor etc are not likely the cause of whats happening right now.
so i think the throttle body will be checked out first since the gaskets to put it back together are only like $10, perhaps the regulator is bad although i lean farther to fuel pump now

Benm109

Get the fuel pressure checked, then. They sell "TBI fuel pressure tester" kits at most auto parts stores for about $40. You could just tap into your rubber fuel line with a 3/8" tee and fuel pressure gauge from Summit or Jegs, that'll work too. It should be 9-13 PSI.

firechicken_3

iTrader: (4)

replaced fuel pump and all is well