VincentBanuelos

The car does not have a place for a scanner under the dash, and i have checked all fuses and have had my lil bro go under the car while cranking it. The fuel pump does keep running while cranking. I plugged up the schrader valve thinking it was letting out too much pressure, because it was leaking, but that wasn't it. also i tried disconnecting the mass air flow sensor, didn't work either.

bruiser

If it fires using a starting fluid, then I'd look at the fuel pump.

VincentBanuelos

Thats what i thought!! i was just wanting to confirm it. the idiot i talked to didn't really sound like he knew what he was talking about anyways.

I guess I'll have to take it to someone to get the pump in because of the exhaust, I don't have access to a welding machine.

unless anyone lives near San Antonio, Texas. and wants to come help out.
hah
it could also be the lines right? cause the pump doesn't sound like its bogging or anything. sounds fine. Fuel is getting to the front. guess its just the pressure.

cardoc

Did you ever mention what the fuel pressure gauge was reading.

VincentBanuelos

the gauge was reading about 50, but when i turned the key the pressure dropped. I talked to my mechanic, he saying it sounds like either injection fire, or VATS system wires. I need to get a node light, see if i can test one of the injectors.

think thats a good idea?

mack1

Hi Vence,

When you turn the key form off to on ((Not start)) you will get about a 2 second burst from the pump. Key off then back on, you would get another burst. That's where the 50 psi is coming from. When you turn the key to Start (( the pump susposed to come back on while starting)) If it don't, it will never start and the pressure will drop fast. Put someone under there while you hit the starter and see if the pump runs while starting. If not, fix the electrical problem.

Mack1

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Raylo

Vince,

Did you ever determine the actual fuel pressure specs for your car? I had a problem with my 4.3 L S10 CPI where the fuel pump didn't fail outright but wouldn't put out full pressure. The FP specs on that motor are pretty high and if the pressure is 15 psi low, like what I had, you get a no start. That one was a bear to diagnose because I could hear the pump running and discounted it as the problem, until I actually looked at the specs. Getting a gas tank off a truck is a lot easier than a Camaro, though. I can't wait until my Z28 FP dies. <fingers crossed>

So, yes, get a noid light to check injector operation. But you really need to find the fuel pressure specs for your setup. Haynes manual or similar should have it.

cardoc

If you continue to crank the engine how far does the pressure drop.Fuel spec on that engine is 41-46 psi.If pressure drops while cranking sounds like pump is not running after prime signal.If you can try pinching off return line from the fuel rail.You should see a marked increase in pressure probably to 80 or 90 psi with a couple cylces of the ignition.This is the reserve pressure unregulated (another test of the pump).I think this car is too early for the factory VATS system.They have a security light in the dash.Some VATS systems would shut down the fuel pump during cranking for antitheft.If your handy with wiring you good jump the fuel pump relay as a test.
Keep posting,Cardoc

VincentBanuelos

doc, the car does have a vats system, has the chip in the key with the orange wire with two white wires inside under the steering column going to the computer. I think i may just end up changing the fuel pump. its sounds to me like its that, but the fuel pump does continue to run while cranking the car. so lets go over this again, if the car fires with starting fluid, the timing is correct? we have spark? the injectors are firing? so the last and pretty much only option is the vats or fuel pump right?? just trying to clarify with myself, i got like 5 people telling me different things.

cardoc

Correct.I kow how you feel.Thats why I was interested in the pressures while cranking because of ths hassells of changing the pump.Got to narrow it done to one or the other.Although it does sound like the pump.You didn't happen to try a secound key.I know the VATS can be weird.Remember that the VATS can shut down the pump as well as other things.

VincentBanuelos

I dont have another key. i heard of people bypassing the vast system by wiring a resistor of the same ohms as the key into the vats wire.
but i may have to just wait to get someone to install the pump. cause its a !$@#$

ganna go buy a noid light today, to check the injectors just for the hell of it.

mack1

Hi Vince,
Looks like you are going to learn all our tricks before this is through. Cardoc's trick about clamping the return fuel line is a good one. Often, however, you can't either get to the hose or it isn't the type you can clamp.

Here's another trick that can tell you something about the pump. When I heard about this one, I said "yea, righttt". But I tried it on a 95 Ford pickup with a failing pump and it worked. To know if it works, you have to know what the low pressure you get while cranking the engine over long enough for it to settle out. Then, get two friends to help. While cranking, let one watch the fuel pressure gauge while the other gives the bottom of the fuel tank some firm hits with a flat piece of wood. (It's ok to say "yea righttt" at this point) See if the bottom pressure increases. If so, it might even start. That's not necessarily good news, because it means you will have to replace the fuel pump. Some pumps get sluggish while failing and this trick will sometimes jar them enough to run faster, thus more pressure.

Here's another thing everyone should be aware of. The fuel is used to cool the pump. If you routinely drive with low fuel level, you will reduce the life of the pump. It's a lot better on the pump if you keep the tank near full.

Hope this helps,
Mack1

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VincentBanuelos

hmm, not bad...

I may have to try that, and you are correct, the return line looks like a fuel line. metal and not flexible.

mack1

Hi Vince,
And by the way, be careful and use the flat side of whatever you stike the tank bottom.
Be extra careful if the tank is plastic. You don't want to bend up the bottom of the tank. The pump probably reaches the near bottom of the tank.

Mack1

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cardoc

Oh yeah,we get a lot of vehicles in the bays with that trick.Beats pushing and it's cheap diag.You wack the tank with a rubber mallet,it starts,you know it's a bad pump.Still wondering what the fuel pressure is doing.

VincentBanuelos

im wondering the same, pressure is good till i turn the key, and it drops to like 15psi.

cardoc

It really sounds like the pumps not running when crankingTry juming power across the fuel pump relay.You will have to see the wires and jump the 2 heaviest wires preferably with a fused jumper lead.This is getting down to the nitty gritty

cardoc

According to the locator I just tried it's near the master cylinder on the firewall.