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Discussion Starter #1
Is anyone familiar with the older (looks like a carb)pro-injection system? I have the 900 cfm on a built up 402. The problem is that the car dies every now and then, usually when I am idling, but sometimes at part throttle. It seems pretty well adjusted, because if I adjust any of the controls in the car it runs worse.

Worse yet is that sometimes it won't start for several minutes after it dies. Its like it is flooded or hot. It will turn over, it always fires once and die. Over and over again. I used to think it was just a hot start problem. But I had it happen twice yesterday under 190 degrees. The fuel injection is kinda cool, but hard to trouble shoot. Would appreciate if anyone has had any expereince with this thing. Ground problem? Fuel supply problem?

BTW, it was tuned by a pro a couple months ago and it runs great except for this.

Pat
70 SS396
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Early systems were plagued by fuel pump problems. Most guys replaced the Holley pump with a factory replacement inline pump as used on F o r d products or an aftermarket pump. Hard to say for sure but you might look into this first.
 

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I've heard of these system's creating a vacuum in the fuel tank, when the vacuum get's too high, the fuel pump can no longer overcome it. I wish I knew what the cure is, I'm sure someone else will pipe up with an answer.
By the way, what do you think of the system as compared to a carburator? Good luck, Nick.

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Nick P.
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Make sure the fuel tank has a good vent in it. You cannot use the original vapor return line as a retrun and vent at the same time. You might check the return line pressure, shouldn't have more than 10 lbs pressure in the line, prefferably no more than a couple of lbs return line pressure.

There is a switch inside some of the Pro-Jection systems when the end plate is removed, that changes the initial running of the the system from small block engines to big blocks. Might check to see if it is in the big bolck setting.

Also, make all the usual checks of the electrical feed system, one relay on my V8 Vega is prone to voltage loss, and when it does it, the injection goes into fuel dump, then needs to have the throttle opened into the clean out mode before it will start, and I just have too much to do and haven't got my relay replaced.
 

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Pat,
I don't have ananswer for your problem,but have been strongly considering buying an 900 4di system.I would be very interested in hearing your opinion on this setup.Not alot of people have it so it is hard to get first hand info. If you have some spare time. Thanks John
 

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Discussion Starter #6
Thanks for the replies. Here is a little more info. I drove the car 400 total miles this weekend to Daytona. It died several times at highway speeds and a couple times slower. It will always start right back up after it dies as long as I am in PARK. But in neutral I only got it to start once. Now keep in mind that my car has been switched to an aftermarket TH400 (setup for strip) from the original Muncie. The first time it died I looked under the hood and fuel gauge read 10lbs. The gauge is after the filter. The Holly runs at 15lbs. But 10lbs lead me too believe that it was still getting gas. And several times when I got pulled over and into Park, it started like it was flooded. So I started thinking ignition instead of fuel? Any thoughts? It has not died in the last 75 miles I drove it. I did look for poor connections. Did not see anything. The car has a Mallory coil and distributor and MSD 6A box. And yes it really has a lot of vapor lock when I remove the gas cap.

Pat 70 SS396
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Discussion Starter #9
What does the nuetral safety switch do? And where is it? The shifter is a Turbo Action Cheetah. The reverse lights don't work either. Those are the only things I have noticed wrong. I bought the car with the transmission setup. I know very little about transmissions. Being able to restart in N would be a big help!
Thanks.

Pat
 

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Pat;

You said that the first time it died you checked under the hood and the pressure was 10psi. Does your pump run continuously after you turn the ignition on (without starting the engine up)? The pump should cycle for a few seconds when you turn the ignition to 'on' and then stop. Your fuel pressure should then bleed down rather rapidly back through the pump. If your pump is running continuously then you have the wire that goes to the starter on the wrong terminal. Also, check your return line pressure. This should not be more than a few psi.
 

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Discussion Starter #11
I'll check to see that the pump only runs when the key is on the on position. I am pretty sure that it does. The guage takes a few minutes to go down. To be honest, I have not found the pump. I will have to lift the car and trace the line all the way back to confirm that it is in the tank. I can't hear it whine. But you would never be able to hear it when the car is running. You can't her anything!!!
Keep in mind that nothing has really changed on the car and it has ran fine for me in the past. The last ten times that it has died it started right back up. Just died while driving down the highway. Still had headlights etc.
Thanks again guys.
 

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Pat, when you said your tranny was swapped and you couldnt start the car in neutral made me think of a problem I had some years ago with a car I had.I would be driving along and the car would quit,just like someone shut off the key.I would have to pull over,put the shifter in park because mine wont start in neutral,it would then start again and I would be on my way until the next time. this when on for several weeks while I checked everything I could think of to fix the problem.Finally I took the car to a shop that does rewiring.The mechanic and I took the car for a drive and about one mile from the shop it quit. The guy pulled over, slammed the shifter in park a couple of times got it start and back to the shop we when.when we got back he reached under the dash and pulled the connector off the neutral safety switch and jumped it with a paper clip and said try that.I drove that car for six years after that and it never happened again.I know that the neutral safety switch shouldnt have anything to do with the motor after its running,but it fixed the problem.after that I just had to be careful when starting it because it would start in any gear.

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Pat,
First of all, if your neutral safety switch was bad, the starter would not turn the motor over at all. That does not sound like the problem you are describing.
The Holley projections came with an external pump, but that does not mean someone did not install one in the tank. If it is the one that came with the system, it is probably mounted along the frame rail somwhere near the back of the car.
It is very easy to tell if lack of fuel is the problem. Take off the air cleaner, have someone try to start the car, and see if fuel is squirting out of the injectors. They pump a bunch so you there will be no mistake about it if there is fuel.
If you are getting fuel, then ignition is the next test. If you can carry a timing light with you, when the car dies, hook the timing light up and see if it flashes. If not, then you have no spark...start looking at the ignition system.
I am fairly sure that your 70 should have a vented gas cap on it, make sure someone has not replaced it with an unvented cap. That could be causing the vacuum you mentioned when removing the cap. If it went 400 miles though, I think you are looking at an intermitant, probably wiring related problem.
Hope this helps,

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Bill Koustenis
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Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100
 
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