alright im having issues i really need help with my 91 z28 with the 5.7 tpi will not start unless you have the throttle pushed about half way than imeadiatly dies once you let off the gas but while you hold the throttle to keep it running you can smell a strong odor of gas and it burning rich and if you unhook the map sensor it will start up and stay running with out any help iv already replaced the map sensor and new plugs but still no fix any suggestions

 

ok after thinking about it iv come to believe its fuel related it fires up with help from the throttle so its getting spark so it has to be a fuel injector shooting too much gas causing it to flood anyone know how to test a fuel injector and also since it is a 91 there is no 9th injector for a cold start am i correct and is it possible for the fuel pump to be bad in a reverse way and sending too much gas when it is suppose to be priming

 

still no one has any ideas not even a retarded answer like "check the carburetor belt"

 

Ohm check your injectors. with the engine off, simply unplug one injector at a time and measure the resistance across the two injector terminals. I believe the spec for new injectors is around 14-15 but will likely be around 12, if they are good. Measure them all, and look for one or more that is less than the rest. Also, have you checked the fuel pressure? You can rent a fuel injection test kit from autozone. should be around 37-ish IIRC. pressure should hold after the key is turned off for about 10 minutes or so. it's ok if the pressure decays over time but you don't want it to drop to zero as soon as you turn the key off.

 

in the last couple weekends of it sitting iv already replaced the fuel pump the map sensor and all three temp sensors checked the fuel pressure regulator no gas leaking out the nipple with the key on havnt ohmed the injectors just yet

 

make sure your TPS voltage is whiten spec as well.

 

well i pulled off the cap to have a look at the ignition modular and to my suprise the terminals on the inside of the distributor was solid rust not to mention the actual distributor was also just as rusty i tried posting pics to give you a visual but i was unsuccessful so i bought a replacement from oreilly auto which came with a new distributor cap rotor and ignition modular all for $112 so now the car fires up but after 5 minutes of low stumbling idle it dies i was thinking the IAC valve but wanted to get opinions since a new one is $102 at oreillys

 

sound like you have one or more bad fuel injectors. I would also change the fuel filter.

 

If the throttle is held open more than X% when cranking, the ECM shuts off the injectors because it "thinks" you are trying to clear a flooded engine ;
which most likely you have if the injectors are faulty and leaking fuel into the intake

 

if a injector is faulty would unplugging the maf allow it to fire up without pressing the throttle im going to test the injectors tomorrow with a volt meter just gotta do the research on how and what the readings should be if there good

 

http://forums.corvetteforum.com/c4-t...nal-video.html

 

you need a multimeter and test for ohms

 

heres a update so far iv replaced fuel pump fuel injectors fuel filter rotor cap ignition moduler plugs wires ecm distriburater all three temp sensors and map sensor runs like crap when i can get it started very irratic high idle stays running longer now though the timing is dead on still no codes egr valve is fairly new if you unplug the iac valve it makes a definate change for the worse so im guessing thats good does anyone have a clue im running out of options and time i need my its been over a month 4 shops refuse to look at a tpi motor and i paid one shop $100 to keep it for two weeks just to tell me there stumped as well

 

is it running like its stuck in diagnostic mode?(like when you jump ALDL pins a and b) Is it pinging under acceleration? Mine did that and i replaced the prom chip and it ran normal again.

 

The ECM I replaced mine with was from a perfect running 91 z28 with the 350 tpi in it the guy was parting it out do to severe body rot unfortunately the whole motor was spoken for when I got there but I was able to hear it run before I took the ECM just to be sure it was good as far as pinging the only pinging I hear is after the motor is shut off you can hear a slight noise from the top end almost sounds like it's coming from the runners also one thing I did forget to mention is once it's running the passenger side exhaust emits severe smoke

 

You will prob get better response if you start a new thread outlining what you have done

 

And where would you suggest starting a new thread at to get the most veiws helpful to me

 

check for a leaking fuel pressure regulator.
just pull the vacuum hose and pressure up the fuel rail and look at the regulator hose fitting. if you see any signs of liquid fuel, its bad.

 

what color smoke is it. blue or white or black

 

bluish white

 

Do a compression test on every cylinder.

 

had the shop do that everything turned out fine

 

issue solved despite the shop saying it had perfect cylinder pressure i double checked and found number 8 was completely dead well i figured i might have severe problems i got to thinking that my dad asked me how tight the valves should be when he was doing the passenger side valves and i was doing the drivers side so i pulled both valve covers off loosed every valve once i got the car running once i got them all chattering the car seemed to come back to life after getting the valves to stop chattering now every cylinder has around 130psi and the car sounds and runs amazingly thanks for all the advice im going to start a new post on a new issue that came up