ive had the car for 3 years. its an lt1. ive replaced...fuel pump, fuel filter 2 times, 2 injectors, ICM, optispark, plugs, wires, crank sensor. anyways, the car is extremely hard to start. it acts like a carb. u have to pat the gas alot of times to get it to crank. once it does crank, it runs fine for a while. then if u get on it, it wants to spudder or backfire. i dont know whats wrong with it. i thought it wasnt getting gas so i primed it using the shrader valve. its getting plenty of gas and theres nothing wrong with the battery or ignition switch or anything. i just hope someone can help because everybody ive had look at it is completely stumped. it may be something easy but i just cant think of anything else.

Thanks,
Jared

 

Have you checked the fuel pressure? Pump may be new, but could be a loose hose in the tank, weak voltage to the pump, etc.

In checking the pressure, turn the key to "run" to prime the pump, but don't start the engine. How fast does the pressure drop? If it drops too fast, it will make it hard to start

"pat the gas alot of times" doesn't really do anything, except exercise the throttle blades. Does not add any more fuel. Do you have any signs of "flooding"? In that case, put the accel pedal on the floor before you try and start it, and hold it on the floor until it starts. That puts the PCM in "clear flood" mode. If it works, it would indicate a problem with leaking injectors, excessive fuel pressure, of possibly a problem with the coolant temp sensor in the water pump. If the PCM thinks the engine is cold, it enriches the mixture for cold start, and the can also cause it to be hard to start if the engine isn't as cold as the PCM thinks it is.

 

so i tried the "flood mode" u spoke of. the smell was very distinctive. it is flooding. i held the pedal down and it wouldnt crank. so i let my foot off the pedal for a second and it fired right up. havent checked the fuel pressure yet. will have to go rent a fuel pressure gauge tomorrow. will get back to u on that. thanks for your help.

 

The auto parts stores around here sell them for $25.00. Best investment you can make and use over and over again.

 

auto zone said $200.00. if i can get one for $25 then ill just buy it.

 

I've seen some very low $$ units, and they aren't really great quality. I paid $35 about 12 years ago, and its been good to work with over all those years. There is no way they would cost $200 unless its a high end unit with adapters and fuel line inserts for a wide variety of manufacturers' vehicles. All you need is a gauge, long hose with a -4AN female connector with a pin to depress the SChrader valve core, and a button to allow you to release the pressure before disconnecting it. Should not cost more than $40.

 

alright. i appreciate the help. ill get one tomorrow and get back to u about the fuel pressure

 

Actron/0-60 PSI 36 in. hose GM TB
I fuel pressure tester
Price:
49.99 Higher than I payed but years ago.

Autozone.
http://www.autozone.com/autozone/acc...questid=355223

 

so i bought the fuel pressure tester. when u turn the switch on. its jumps to 50psi. then drops to 42psi when the pump stops. idling it is holding 41psi steady. hopefully this helps so yall can help me. thanks again.

Jared

 

update. i also changed the air coolant temp sensor....still did not fix my problem.

 

man lets keep this alive I am having the same damn problem.

 

Hard start troubleshooting charts, for the LT1, from the 1996 F-body manual.

http://www.ace1252.com/1996_Z28_Fact...ts/Hard_Start/

Just as a note, a bad MAF sensor can cause all kinds of strange issues. I'm not saying it's the problem, but would be worth a quick swap of a known good one.

 

thanks for the help. havent resolved this issue yet but still working on it. to be continued.....

 

Have you checked for codes? Some don't set the check engine light. Assuming you replaced the coolant sensor in the water pump, since there are two. There is a testing procedure for the MAF that you can find on here.

 

codes: misfire cylinder 3. crank position sensor. cant find the misfire. car is definitely not missing on any cylinder. replaced the crank sensor. code did read high resolution timing but went away after i replaced the wires and plugs. im stumped!