I might need a new fuel pump. Here's my symptoms.

[92es]

Weird stuff happens and its never consistently repeatable.

Sometimes there's a very small fluctuation in acceleration after I first start it. It goes away after the motor warms up.
Sometimes it doesn't start at all. It will just crank. When this happens, sometimes it will start and idle real low. It won't even register on the tach. After about 30 seconds of rough idle, it dies.
Sometimes it will start fine, but for no reason at all, the RPMs drop to zero and back to normal real quick. It will do this for a while until warm.


A little info on my car...

New battery
3 month old IAC
My AC clutch is shot which might hinder the start process?
Power/Eco switch is stuck in Eco setting
New relay on the passenger side of console


I think its the fuel pump but would like someone experienced to agree before I change it.

What is involved in upgrading to a VR4 pump? Do I need larger injectors or any other upgrades? What is a good price for a fuel pump?

Thanks for the help. ;)

[Racer 007]

Before you change out your pump, you should check your fuel pressure. It should register around 36 - 40 psi. If it is lower, you may want to hot wire it prior to changing just to ensure that full voltage is being sent to the pump. I can't remember what I was told but it should be over 10 volts of power. If that doesn't work, then you may need to change it.

The fuel pump switch is extremely easy. You can go to http://www.stealth316.com for complete instructions on how to change it. It took me about an hour or so to switch mine out.

Regarding the fuel pump, I purchased one at AutoZone for around $150. It was a Bosch or some other type but not OEM. When I installed it, my hesitation problem became worse. I didn't think it was the pump at the time because it was brand new. After a bunch of troubleshooting, we tested the fuel pressure and it was registering at 14 - 16 psi, even under load. Very unacceptable. I purchased the OEM fuel pump and we were back in business with the pressure coming up to 38 psi. The OEM fuel pump was extremely pricey though at around $530.

I don't think it would be necessary for you to switch to a VR4 pump and injectors. I spoke to Matt about that also because that is what I was looking at doing also and he stated that the added pressure plus the larger injectors will just bog you down. You will be injecting more fuel that what your engine is capable of burning causing you to run extremely rich and your hesitation problem will not go away.

I am planning on upgrading to a different fuel pump though since I am running 11:1 compression and at the higher RPM ranges, I feel a little hesitation also. That is due to me not getting enough fuel at that high up area.

If you end up switching out your fuel pump, you might also want to switch out your fuel filter. This will be to ensure that your entire fuel system is clean and unclogged. You may also want to clean your injectors or even at that, send them to RC and they can balance them for you.

Hope this helps.

[92es]

Yeah, that helped a lot. Except for the $530 price tag! :eek:

I'll check the pressure first. Thanks for the help! ;)

[92es]

What about Denso for a fuel pump?

THE PARTS BIN (http://63.89.49.212/partsbin/new/wizard.jsp?partner=partsbin&year=1992&make=MI&model=3000-GT-001&category=E&part=Fuel+Pump&usemake=&returnurl=catalog.thepartsbin.com&appDescription=w%2F+Filter&usemake=&returnurl=catalog.thepartsbin.com) has it for $202. That's a lot more in my price range. ;) Whaddya think?