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Discussion Starter · #1 ·
Hi there:

My 88 SPG started lossing power one day. The next day it will start, but it will stall after a few seconds. I pumped gas and it seemed like it wasn't getting any. I have done quite a few tests:

I have spark on the plugs all the time.
Most of the time I have no voltage at the injectors, but I always have voltage on the fuel pump.
Fuel pump seems to work all the time.
Fuel rail has fuel, I checked by opening the banjo, fuel starting spraying
Replaced fuel pressure regulator with a good one
Tested and replaced ignition module.
Checked for continuity from hall sensor to ignition module and wires seem to be well connected.
Checked ignition coil, voltage is good.
Tested a good working distributor and still I got no voltage on the injectors.
Pin tested and tried a couple of working ECU's and still the car wouldn't start
Fuel filter seems fairly new
AIC valve was replaced not too long ago
Checked and installed a working TPS
Pushed the car and it started, but it stalled as soon as I let off the gas pedal.
Sprayed carb choke in the intake, but again, it died after a little while. By then I had voltage on injectors. After trying to start the car a few times, it will crank but won't start, again, no voltage at injectors. Is there a safety system that prevents the injectors from working after the rail gets flooded with fuel?

Checked the boost pressure and it seems to be fine, it gets voltage (very little) in and out, and when unplugged there's continuity between terminals.

At this point I am not sure what else to check for. It's been frustrating, but I do want to get my SPG back to life. Have you guys any hints and something that I may be missing?

Any help will be greatly appreciated.
 

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What type of meter are you using to measure voltage?

Using a digital one on things like injectors is a bit of a pain. An Analog one works much better for that sort of thing.

The fact that you have gotten the car to start (albeit poorly) says the injectors should be functioning fine.

You have spark which is good, which is also why the fuel pump is working. (the fuel pump doesn't turn on until LH "hears" something from the hall sensor in the dizzy)

Have you tried another MAF (mass air flow meter).
You can also try unplugging the MAF and see if it starts.
 

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Discussion Starter · #3 ·
I use a digital voltimeter, but I clearly got battery voltage when I tested the blue/red wire from an injector with the other lead of the voltimeter to a good ground. That's when the injectors used to get voltage.

Is it normal for injectors to stop getting voltage after the engine has been tried to be started several times? I had the battery recharged and still got no voltage at the injectgors.

When I got the engine to run, I tried to unplug the mass airflow meter, but the car died. I'm not sure it it was going to die anyway, because I stopped pumping the gas, or because I unplugged the MAF.

Is there any way to test the MAF without having the car running?
 

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Discussion Starter · #5 ·
I increased the resistance on the MAF and the car started and stayed on for about 10 seconds and then stalled. I then tried a working MAF and it made no difference at all.

Next, I got a pressure gauge from Autozone. I hooked to the fuel rail, try to crank it, and no pressure. Turn the switch on, and zero pressure. Then I ran the pump from fuse 30 and the needle in the gauge didn't even move. I still got some gas on the rail, so I'm surprised the gauge didn't register anything. To be sure, I tried both sides of the rail and tighted everything snug and still got zero reading.

Is it possible to have a reading of zero fuel pressure even though there's some fuel in the rails and the pump works.

Assuming I have zero pressure, what's next to do? My fuel filter looks almost new, but who knows.
 

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slice open the wiring harness where it does the 90 degree bend around the head (by the a/c compressor) and check for chafed insulation on the wires. Also try the coolant temp sensor in the intake manifold.
 

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Discussion Starter · #7 ·
I did tested the coolant temperature sensor first since it had given me issues in the past. I replaced it with a newer one and secured the connections. The fact that I'm getting voltage to the injectors tells me that the ECU is sending the right signal. I can also hear the fuel pump work and get some fuel on the fuel rail, but the pressure test came to be Zero.

What could cause zero reading on the fuel pressure gauge? I though I hooked everything correct? Is it possible to have zero pressure and still have some fuel on the rail?
 

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88 still runs the Bosch pump (I think?) and usually if they make noise, they're pumping fine. Actually, if it's a Bosch pump with 2 seperate spade connectors, pull both connectors off the pump and jump power to the fuse. You should still hear the "feed" pump buzzing with the main pump unplugged. How full is your gas tank? It'll literally run out of gas between 1/2 and 1/4 tank if the feed pump is bad
 

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Discussion Starter · #9 ·
Bingo! It seems like low gas level is the issue. Even though my gas gauge indicated I had 1/4 of gas, the fuel had no pressure. I decided to add a couple of gallons to compensate for the one lost during the fuel pressure test. Once I added more gas, I cranked the engine, pump the gas pedal and vroom, vroom, the SPG starts running. I immediately drove to the nearest gas station to fill it with premium gas.

The lessons learned, are: never let the tank drop below 1/4 and don't trust the gas gauge, which seems to be acting up along with other instruments in the cluster.

So, do you guys think that a failing pre-pump will cause the car to run out of gas at about 1/4 of the tank? Can this pump be installed independently of the main pump?

Thank you all for your advices.
 

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You need to pull out the main pump assembly to change the feed pump. Pretty easy though, just disconnect the fuel line and elec. connectors, loosen the big hose hose clamp around the rubber boot and pull it up. It's a tight squeeze at the bottom. You'll need to tip the whole thing to get it through the hole. Feed pump is on the side of the assembly, just 2 screws. You may need to reach inside the tank and unplug the wires for the feed pump, I can't remember if it'll come out while still plugged in. Or just always run on the top half of the fuel tank.
 

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Discussion Starter · #11 ·
I think I can do that. I will take out the auxiliary pump, test it and if bad I will look for a replacement, hopefully not too expensive. I know in the long term I will go below the 1/4 mark on my gas tank, so I don't want to be stranded again.

Thank you all for the tips, they've been very helpful.
 
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