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Discussion Starter #1 (Edited)
I have a project '87 Spider that has not run in 10 years or out of my operating room (garage) for 6 months. By using the excellent thread on Bosch Jetronic I did all check, replaced fuel pumps and started the engine. Seemed to work, idle, and rev so I proceeded with replacing clutch and transmission. Tried to start a few months later and no luck. Replaced more fuel pumps and tested the CSI. It did not pass any fuel so I borrowed from a helpful Alfisto a used and new CSI. The used one did not pass fuel but the new one passed a nice fine spray of fuel.

Hooked everything up and engine started just fine. A week later it would start on "starting fluid" but not on it's own or stay running. Checked CSI and it was plugged again. Got it unplugged at a fuel inj./carburetor shop and tested and installed. It would run for several seconds on starting fluid but not keep running.

Jumped the in tank fuel pump and collected fuel in a pint glass jar and there was no particulate matter at all. Tested the ohms on the "thermo time switch" and they were normal except for the resistance between "G" and "W" was 67 ohms rather than 25 to 40. I knew this originally but thought it did run a couple of times so it must be functional. Also checked with a test light the plug to the CSI and had voltage while cranking and could feel the solenoid click when connected.

Thoughts would be appreciated.

Sorry for the long/involved post.
 

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Discussion Starter #3
Yes, when I put in the new fuel pump. After that one stopped I put a fuel filter ahead of the high press fuel pump. New in tank pump with new screen. I have been resisting removing the fuel tank and cleaning. Keep thinking things will get better.
 

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Sounds rough. Obviously, if the CSI is getting clogged, the other fuel injectors likely are as well. Have you checked the fuel pressure? (fairly easy to do at the CSI hose). I know you replaced the pumps, but could the regulator be bad?
 

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Discussion Starter #5
Thanks, I have not done that. But since it's starts and runs for a few seconds on starting fluid, I assumed that the main injectors were OK.

I'll check fuel pressure tomorrow.
 

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since it's starts and runs for a few seconds on starting fluid, I assumed that the main injectors were OK.
No, that proves the ignition system is functioning OK. Now you need to figure out why it doesn't run except with starting fluid.

How are you introducing the starting fluid? I assume you are removing an air duct to squirt it in. Are you then re-connecting the air duct? All air entering the engine must pass through the Air Flow Meter (AFM). The AFM then tells the computer how much if any fuel to inject. If there are any intake air or vacuum leaks the AFM will send erroneous information to the injection computer.
 

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Thanks, I have not done that. But since it's starts and runs for a few seconds on starting fluid, I assumed that the main injectors were OK.

I'll check fuel pressure tomorrow.
Your engine needs three things to run: (1) air, (2) fuel, and (3) spark. If it runs on starter fluid, you know that it is getting spark and air. The fuel is being provided by the starter fluid. But if it doesn't run after the starter fluid is consumed, it means that you aren't getting gas through the injectors. That could be caused by a number of things, including clogged injectors or low fuel pressure. If the fuel pressure checks out okay (approximately 35 PSI), that points to clogged injectors as the problem. And given the clogging in the CSI, I'm leaning that direction.

[Eric has a good point about the AFM, but on my car, the car will start without the AFM operating, but it runs horribly]
 

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Discussion Starter #8
ghni; good catch. Start fluid just gives it some fuel. I introduced the start fluid through air horn. sloboy, I tested the fuel press, and there was none! So I guess that is my next issue. Jumped the main fuel pump and it is running. Now I'm thinking that I have ruined the press regulator by hooking up a hand vacuum pump used for bleeding brakes to release fuel press when taking out the CSI. I pulled the CSI one time without releasing press and fuel shot everywhere, at least I had press that time.

Thanks for the ideas.
 

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How did you test fuel pressure? The fact you had some pressure when you disconnected the CSI but none now has me wondering. Normally, the fuel pumps will only be powered on under two conditions - 1) the engine is running & it sends a tachymetric signal to the drive relay and B) the key is turned to 'start'. If you simply switch the ignition to 'on' the fuel pumps should not be powered on.
 

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Discussion Starter #10
Ghni:

I hooked a pressure gauge to the hose that connects to the CSI and had the Mechanic's Helper crank the engine. I also jumped the main fuel pump, still had no pressure.

Now to get the darn pressure regulator off without breaking the bracket or taking the fuel rail out.
 

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Slow down. The regulator merely regulates pressure - the main fuel pump (under the car) makes the pressure. The Fuel Pressure Regulator (FPR) is usually a sturdy, long-lasting unit. The usual failure mode is for it to leak internally. Remove the hose that goes to the plenum - it should be dry.

Remove the fuel supply hose at the plenum and have your trusted assistant turn the key to 'start' while you aim the hose into a container to catch gasoline. There should be a strong flow of fuel. If not then either the pump is faulty, is not getting power or the fuel line is blocked.
 

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Discussion Starter #12
I already pushed some fuel through the CSI line:

"Jumped the in tank fuel pump and collected fuel in a pint glass jar and there was no particulate matter at all."

However this was the "in tank" pump and not the high press pump. I'll try the main pump, but I don't think there is a blockage.
 

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If you have no fuel pressure at all, it sounds like the main fuel pump is not working at all. This could be a result of a couple of things. It might be a bad pump, it could be a blown fuel pump fuse, or it could be a bad fuel pump relay.
 

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Discussion Starter #14
Rich:
Yesterday I also jumped the main pump and it ran and pushed fuel into a jar. It was not a "gusher" but it's working. I was thinking about putting my pressure gauge on the fuel rail supply line but then it would be pumping against a "dead head". That would cut out the pressure regulator. The vacuum line from the press regulator to the plenum is dry so I guess the diaphragm is not broken.

Bill
 

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Discussion Starter #15
It occurs to me that the main fuel pump may not be as efficient when I jump it. The in tank pump is not running and I had previously put a filter before the main pump which will inhibit flow to some degree.

Bill
 

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Rich:
Yesterday I also jumped the main pump and it ran and pushed fuel into a jar. It was not a "gusher" but it's working. I was thinking about putting my pressure gauge on the fuel rail supply line but then it would be pumping against a "dead head". That would cut out the pressure regulator. The vacuum line from the press regulator to the plenum is dry so I guess the diaphragm is not broken.

Bill
When you say you "jumped the main pump," are you saying that you connected it directly to a 12V source? If it works then, but you aren't getting any pressure when it is connected through the car's electrical system, it sounds like you may have a bad relay or fuel-pump fuse. Can you put a voltmeter on the connectors of the fuel pump and measure the voltage while a helper cranks the engine? If you aren't getting a voltage, then you can confirm that you have an electrical issue.
 

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Discussion Starter #17
Rich and Eric:

Yes, when I say "jumped" I mean that an external battery is used to run the pump without using starter and all of the associated computer functions. This morning I had a pressure gauge in the CSI line and a hose on the pressure regulator return line going into a jar. Put a VOM on the main fuel pump and cranked the engine. VOM read 9 vdc, pressure gauge read zero, and there was no fuel coming out of the pressure regulator return line.

This, to me, indicates that the electrics, and press regulator are working. Voltage is low but it should be a full 12 vdc when "jumped". Keep in mind this is the third new Airtek main fuel pump that I have put on the car. On top of it all I've had the car working at least twice on it's own, but of course, I've forgotten all of the details of what, when, how.

Thank you for your patience, Bill
 

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Put a VOM on the main fuel pump and cranked the engine. VOM read 9 vdc, pressure gauge read zero, and there was no fuel coming out of the pressure regulator return line.
Bill,

I went out and measured the voltage at my main pump. During cranking, it reads 9.6 vdc and then ramps up to 11.6 vdc after the car starts. I'm not sure that this helps much.
 

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The pumps should be getting battery voltage. But due to the long wiring runs & multiple connections along the way, significant voltage drop is likely. Cleaning all connections (including & especially grounds) may help improve the situation.

The computers need ~ 10.5V to wake up and send the make sparks/squirt fuel signals. Thus due to both voltage drops & starter motor draw, it is possible for the engine to sound like it cranking over with good vigor but the engine to not start if system voltage is below the computer's minimun voltage threshold. Again, cleaning all connections is the first step to fix that issue.
 
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