Car is an 87 Z with a 305 tpi.

New things that have been replaced-Spark Plugs, fuel filter, gaskets from intake manifold and up, injectors were tested and good. Fairly new things are cap, rotor, coil, plug wires, o2 sensor, air filters.

When you first drive the car it will surge for around 10 seconds while barely picking up any speed. This happens when coming from a stop or accelerating lightly at low speeds. After its done surging the car takes off fine. It will acelerate fine only if you keep your foot on the pedal. If you let off the pedal and then get back on it will surge, but not that bad. It idles okay when you are in park and drive, just moving around a little. When you first start it up the idle is a bit jumpy though. What do you guys think the problem is? I drove it around for 20 min. today. The longer I drove it the better it seemed to drive. I will check the IAC and TPS tommorow. The TPS sensor connector is a little messed up though, one of the little black tubes snapped off and was glued back on. I dont think that would cause the problem because the car drove fine before while it was like that but let me know what you guys think. Thanks.

 

Replace the tps connector with a new connector from Pep Boys. Its about $4 or $5 tops. Then give it a try and see. Even if that connector is fine now, its only a matter of time before it creates another problem.

 

What size injectors are in it? 19 or 23, etc.

 

stock size injectors are in it, 19 I think. The car got a code 44 today, lean exhaust. The chiltons book said it could be caused by a bad O2, and check for low fuel pressure and water in the fuel.

When one of the injectors went out it was dumping fuel so it could maybe just be a bad O2 sensor. But while it was at a shop for testing the fuel pump wasn't working too great. So I will probably replace the O2 sensor and get a fuel pressure guage. Any recomendations on a cheap guage that I can get at Kragens or something like that?

 

Go to home depot and pick up the cheapest water pressure gauge they have. It won't be a durable thing, but it would work fine once or twice. Its about $5. Then go to your local plumbing supply and get adapters and a copper line to make your own gauge. By now you are at about $8 or so. Unscrew the schraeder valve from the fuel rail, and screw in your new gauge. I think the fuel rail is a 4AN fitting.

 

I broke down and bought a fuel pressure guage today When I just turn the key the fuel pressure is 20. After I turned the key back I watched the guage for a minute and the pressure was constant. When I started the car up the pressure was bouncing between 27-29. What does that tell you guys?

Also the car is getting harder to start. Took about 10 minutes today. Then it just fired up. It ran okay for a couple minutes but then it started running rough like it was going to die.

 

Fuel pressure should be up in the 40's.I would start with a new filter,you never know,it could be clogged pretty bad.Could be the fp regulator or fuel pump.

 

We replaced the filter last week hoping that would solve our problems but still the same It seems like the pressure is holding so I dont think its the regulator. Any other things that can cause low fuel pressure, or is it more that likely the pump?

 

The fp regulator could be stuck in that position causing the low fp.My second guess would be the pump.How is the vaccum line to the fp regulator?

 

Regulator could very easily cause a low pressure problem. Pump could be weak, filter clogged, leaky injector but seriously doubt it in your case with a lean code.

 

Don't rule it out, remember the O2 sensor only reads from one bank of the engine, the other bank could have leaking injectors.

 

About a 2 months ago we had to take the car to a shop to do some diagnostic testing. They discovered the #1 injector was blown, dumping fuel and the fuel pump pressure was also low.
On the report it says the fuel pressure from the fuel pump was only 40lbs when dead head, and that it should be around 60-80. I replaced the injector so they should be good. Guess tommorow will be a long day. Are there any special tools you need for the job and how should I jack the car up, just the rear or all fours?

 

For replacing the fuel pump? Just the rear but you need to get it high enough to put jack stands on the frame rails and lower the rearend without the wheels touching the ground.
The only "special" tool you'll need is either a small piece of thin aluminum or stiff plastic. It will go next to the filler neck as it tries to pass through the box frame, the lip of the neck catches on there and you'll need to put the alum/plastic between the lip and the edge of the hole so it can slide out.

Also, get as much gas out of the car as possible before you start. When you start removing the fuel lines under there one of them is going to siphon the tank pretty much dry. Have a 5 gal. gas can under there to catch it.

 

Thanks . Tommorow I will check the fuel pressure regulator just to be sure that is not the cause. Where would be the best place to block the fuel return line?

 

Crimp the flex line in the engine bay.

 

Got it. Looks like the pump is the problem. The pressure did not change when I had the line pinched off.

 

Yeah, it should deadhead to 75psi..tank dropping time.