ok guys here goes im at my wits end with this car...ive tried everything to get it started but its just not happening and 3 mechanics have looked at it and are all stumped

its a 350 tpi with 90k original miles

when i first bought it 2 months the previous owner said the only way it would start is if he sprayed ether into the maf (i know) and when we went to look at it he sprayed it, it started right up but ran very rough, when we went to move it it was very hesitant and idled very rough

so we brought it to the shop and got on it here is what we replaced initially

brand new southbay injectors
new fuel filter
new oil filter
new maf sensor
oil change
car ran fine when all was done although it was idling high, also when i went to start the car it wouldnt stay running unless i held the gas, then i replaced the maf and it started right up but again this time it would stay running as long as i hit the gas once also checked the idle air control and that was fine

i brought the car home parked it and figured wed figure it out the next day

the next day i went to start the car and it just started idling extremely rough
and the motor was shaking alot, i went to drive it and it again had little too no power!!

shut it down and waited for my friend to come by and plug in his scanner and this time it just wasnt starting at all, it cranked over and thats all we then proceeded to replace the throttle position sensor with a brand new one and adjust it with the scanner...still nothing

at this my we figured it may be a vats problem maybe fuel was getting to the injectors or maybe a computer problem

so we pulled the computer and found the prom was an old hyper tech chip and the part number we were told was for a 87 vette...so we just replaced the computer with a rebuilt ac delco from a gm dealer and also found a new ac delco prom for the car....installed it and still nothing!

finally today we found that the vats isnt the problem using the scanner and found no issues with the injector pulse...not to mention that the car isnt throwing any codes and we hear the fuel pump go on everytime we turn the ignition and we also have spark

so basically im lost and ready to give up and part it out

any help here will be greatly appreciated before i go to an extreme measure

 

I was Also helping him with this car before we replaced the computer it was throwing a code 51, now it has no codes.

 

There's something missing here , and ya gotta figure out what that is . Now , it should come down to checking the basics , things like have you put a manifold vacuum gauge to this thing yet (in any of the times it WAS running ?) ..... Hows about a compression check of all the cylenders ? If it truly has got fuel , not too much and not to little , and it's got a nice proper spark at the right time , well then I'd be lookin for things like low compression on all cyls as being caused by a possibly jumped timing chain ??? Or maybe an exhaust SO plugged up with carbon crap that the engine can't breathe ??? Maybe too much of the bumps worn off of ya camshaft ???

This is the thing , there are quite a number of possible causes , and to start by establishing the engine's basic internal health would be the right way to go . If you've got 8 good cylenders , good gas and spark , it should at least run somewhat , provided the intake has no mousenests and the exhaust no broken honeycombs in the catalytic converter .

Good Luck with that compression test

 

cats were hollowed out, and the entire manifold was taken down to install the injectors, a compression test is probably a good idea.

 

I would check fuel pressure before I went any further...Compression test is not a bad idea either.

 

def. check the fuel pressure. if the car doesnt start you're missing one of 4 things.

fuel - check fuel pressure. being to high or too low can cause problems.

air - probably not an issue in this case but none the less, an extremly restricted air filter and throttle blades not opening up completly, or any other type of restriction can keep it from starting

spark - check your plugs. make sure theyre not fouled. make sure they're firing. check the resistance of your wires if you have to. def. check the timing and make sure the distributor isnt in backwards or off a tooth. if you have spark but your disributors not right then the spark wont matter becuase its happening at the wrong time.

compression - without this, you're engine isnt going to run, or at least not run right. do a compression test. compare all of the cylinders. they should all be fairly close to each other. if theres one thats really low then you've got head gasket or internal problems.

 

thanks for the help guys...im gonna check the fuel pressure tomorrow and go from there
im hoping that it is just that

im worried if its bad compression on one of the cylinders, that is not something i wanna deal with!

 

We just checked the fuel and the numbers
At key on we had 11psi
At running we had 25psi by once I gave it gas the fuel pressure dropped rapidly and the car died
Which leaves us to believe it either the fuel pump or fp regulator

Is there a way we can test the regulator before we drop the fuel tank

 

that is WAYYY too low, replace your fuel pump, you should have around 45 psi.

 

FINALLY SOLVED!

 

id replace the FPR while you are at it, probably bad

 

Good to hear its fixed!

 

FINALLY SHES ALIVE!!!!!!!!!! what a relief now i can start working on the interior and paint the bumpers and do a major detail and she will be good to go!!!

i cant thank you guys enough for all your help, it really is greatly appreciated!

 

anytime, but to be honest thats really disgusting that 3 mechanics could not figure out a damn fuel pump. I mean honestly, the fuel pressure test is one of the fastest easiest test on most damn cars to try first.

 

honestly we were so concerned it was the vats and the fact we kept hearing the pump go on we ignored it...im just glad it was a simple prob and nothing major

more importantly i can enjoy it

 

Fuel pump went bad in my 91 TA TPI. I replaced it and the car ran like poop. I eventually discovered that the parts store sold me a pump for a carb'ed car. Pressure is just enough to make it run terrible.

Worst part was I had to drop the tank again to put the second pump in.