I have a 1990 corvette l98. The car doesn't want to accelerate when u punch the throttle, but if you give it gas. It slowly accelerates to speed. I don't know if it's clogged cats, a bad fuel pump, a bad fuel pump filter, fuel pump regulator, or a bad MAP sensor. I don't wanna through parts at it. But I definetly need to fix the issue. Can anyone help, thank u

 

I had an issue with similar symptoms. It turned out to be a bad spark plug wire. I found it by looking at the wires while the engine was running in a dark garage. There was an arc from wire #6 to the oil dipstick tube. Doesn't run very well on 7 cylinders.

 

Hopefully it will be something simple like that, but with my luck with this car . It won't be

 

I checked the spark plug wires at night/dark but didn't see any arching

 

Check fuel pressure! Make sure you're getting spark from each wire also, you can use a spark plug tester that grounds to wherever you ground it at, or you can hold the wire close to the plug and look for arcing. If it doesn't arc, test the metal part of the plug for ground, if no ground replace the plug, if ground, replace the wire.

Ohm check your injectors, pull them out one by one and see if they flow similarly.

A injector should ohm check at around 16-17 ohms.

Pull your o2 sensor out, if it is black or rusted it is bad.

Check your timing, should be 6 degrees BTDC base timing, the est wire must be unplugged to check it.

Test the functionality of your MAF sensor, you will need a wiring diagram, and if you see a change in voltage on the sensor wire as you rev it, it is working.

Test the functionality of your CTS, you will be looking for changes in voltage as the temperature of the engine changes.

Make sure your egr valve is not stuck open, if it is make sure that you have a powered up egr solenoid, when it is not grounded, the egr flow is induced.

Check your tps voltage at closed throttle, should be .54v.

Check for vacuum leaks, you can do this by a few methods, get a cheap cigar and blow smoke around the manifold and vacuum lines and ports, if it draws in anywhere thats where there is a leak, or you can spray starting fluid around the manifold.

Pull the Pcv valves out and shake it, if it rattles it is good, if it doesn't it needs to be replaced.

Unbolt your cats, see if your car's performance improves (even just a little) it will be loud.

pull off your distributor cap and look for carbon tracing, should look like white lines on the cap, this means that the spark is going the wrong way!

Pull off your oil cap, if your idle increases, you have a leak from the intake into the lifter valley.

Check your compression, should be from 125 - 165 I believe, and they should all be within a similar range.

There really isn't anything else I can think of other than test the continuity of the wires from the sensors to the computer.

And if all else fails, replace the ECM.

 

What do you mean if you punch it, it will not accelerate? What does it do? I would suppect fuel pressure but i need more info on the symptoms. You do not have a maf so eliminate that.

 

I have a map and yes it won't accelerate if you press the gas quickly. It Boggs down and acts like it not get fuel or something. Also the fuel pump seems some what loud. I don't know if that is normal. This is my first vette.

 

i would also vote for a fuel pressure problem. check filter first, then get a FP gage on the fuel rail, and see what happens when you hit the throttle.
next, check the TPS sensor and see if its working normal when you open/close it, but with key on and engine off

 

I believe it might be the fuel pump or diaphragm on the pick up tube . Because when u fill the tank all the way up the problem goes away

 

That says a lot. It sounds like the pulsator is leaking fuel.

Another possibility is that the pulsator was replaced with some fuel line that is not SUBMERSIBLE. Regular fuel line is made to have the fuel on the INSIDE and the outside will dissolve if submerged in fuel.

Pull out the fuel level sender and check it out.

 

What does the pulsator do, what size fuel line do I need

 

The pulsator is supposed to absorb the noise that the fuel pump makes. I couldn't tell the difference myself and many people eliminate it.

The only submersible fuel line I know of is the Gates 27093:



That stuff sure has come down in price. I paid about $27.00 for a foot of it from Amazon about 10 years ago.

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It's Ruffly still the same price, I found it cheaper at other places

 

Went into work today and changed the strainer, fuel pump and pulsator . The strainer on the fuel pump was loaded with crap and the strainer on the fuel pump was crapped up also. Once I replaced everything the car came alive. Thank you all who helped me.