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Discussion Starter #1
This is kind of long, so please bear with me.
I have a '72 spider which has been running fine since I bought it in 1991. The Spica pump and fuel supply pump were replaced in late 1991 or early 1992. Other than the MarelliPlex and headers, the engine is stock.
Last December, in the middle of my morning commute, the engine died at an intersection. Ever since then, I can start the engine but it will only run for about 10 seconds. It doesn't matter what RPM it's running at, it will only run for that length of time (ask me how fun the 5-mile drive back home was).

So first I changed out the fuel filters with no change in behavior.
I wired a relay and breaker into the fuel pump circuit, no change.
I bought a new fuel pump from IAP (the LJet pump), it acts exactly the same.
I pulled the ignition switch and cleaned up the contacts, no change.

Before getting the new fuel pump, I verified that there is actually fuel flowing through the injection pump, but don't know about the actual pressure, hence the new supply pump.
The engine is getting spark up to the point that it dies, which leads me to believe that it's fuel related. However, the fact that it starts at all and while it's running sounds normal bothers me.

The only other weird thing is after starting and trying to run a few times, the headlights won't turn on (although I can hear the relays click) and the fuel pump won't run even though there's voltage at the battery, which has been connected to a charger since December. When this happens, the solenoid won't even click. And yes, all of the fuses are OK and there aren't any melted wires. After a little while, it'll start and run for 10 seconds at a time.
What am I missing?

Mike
'72 Spider
 

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Does your fuel low pressure light come on for a couple seconds, then go out when you first turn the key on? Try the troubleshooting tip below, but it's likely that you're going to have to find out what the electrical problem is for the power to the fuel pump. Check the ground wire to the fuel supply pump first.

Quick and easy, try this --- Remove the #6 fuse in the main fuse box and try a start. What we're doing this for is to remove power from the fuel cutoff solenoid due to a possible short, thus energizing the FCS constantly. During the start cycle with the key switch in "START" (starter motor energized), the #6 circuit is de-energized thus allowing fuel pressure and the engine to start, then when the engine fires and you return the key switch to run, the engine dies.

Report findings.
 

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Discussion Starter #4
Thanks for the suggestion, John.
I removed #6 fuse and started it again. It runs for about the same length of time and then dies. I did try that before (removing the connector from the top of the FCS). I have also tried removing the connector from the cold start solenoid - it won't start at all (If I remember correctly).
In answer to your other question, the low pressure light stays on until the engine catches, then goes out and stays out even after the engine dies. That sort of answers Roger's suggestion about the rear filter clogging. After a few minutes, I can turn the key again and the low pressure light will be on again.

Mike
'72 Spider
 

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The fuel light should go out after a couple of seconds with the key switch on. Don't try and start the engine unless the light is out.

I would investigate the voltage AT the fuel pump itself. Make sure you're not getting voltage loss. I'm trying to think how the other electrical problem could be related.
 

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My 2 cents. Seems like a SPICA pump issue, rather than electrical. Sounds like its only running on the fuel kicked in by the Cold start solenoid, so there something going on in the pump. I'm wondering if you might either have a stuck micro switch or the internal spring on the rack has broken. Since you really need to pull the pump to check the micro switch, I'd check the rack first through the cover by the throttle arm.
 

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Don't need to pull the pump to check the microswitch. That can be operationally checked with a test light. To change it, yes, the pump has to come off the engine.

Until the fuel supply system and electrical system is functioning normally (i.e. the low pressure light), it's premature to suspect the injection pump. Although, checking the compensator link spring is quick and easy to do.
 

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John, it's been a long time since I've played around with a SPICA pump. I was thinking that if the micro switch were frozen you'd need to remove it to check rather than using a check light. Could the fuel cut solenoid be seized? Maybe removing it would be something to try.
 

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No, you can just use a test light to make sure that it only comes on under throttle-off decel, then goes out at about 1600-1300 rpm to allow the engine to recover to idle. If it doesn't come on at all, or stay on all the time, then it's broken.

To check the FCS, run a wire from the positive terminal on the battery and touch the spade terminal on the top of the FCS. Listen for a "CLICK" as the solenoid pin pops out. The guide I wrote should show that test and pics of the inner workings that are happening. The FCS is spring loaded off, so a failure of the FCS is almost always failed OFF, meaning no fuel cutoff during decel. A lot of owners never notice a failed microswitch if it fails OPEN (i.e. OFF).

If it fails closed (i.e. ON) then constant current will be sent to the FCS causing fuel cutoff. The roadside fix to that is to remove the #6 fuse and cut power to the microswitch/FCS altogether.
 

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Discussion Starter #10
I had a thought about the CSS yesterday. I started the engine and before it died pulled the CSS wire off. Unfortunately, no difference.
It won't start without the CSS, either.
I think at this point that I'll have to get a fuel pressure gauge to make sure that the injection pump is getting enough pressure.
Since I put the relay and breaker into the circuit, I know the pump is getting enough voltage.
I'll look into making sure the rack spring isn't broken, either. I doubt this would be the case, since the engine idles just fine and also runs at high rpm, although for only 10 seconds at a time.

Mike
'72 Spider
 

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Discussion Starter #11
I did your test just now. I applied 12 volts to the FCS and couldn't hear a click.
I have another FCS that I can try later this week. I can check my spare microswitch as well.
Mike
'72 Spider
 

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Discussion Starter #12
So here it is 4 months later (more or less).
I emailed Wes several times trying to find a solution to my spider's problem, to no avail.
As a last resort, I decided to pull the 255 pump and put the 260 on that I got a few years ago.
After setting the 255 on the bench, I decided to look at it a bit (I really didn't want to put the other pump on it, not knowing its condition).
I checked out the CSS action and it looked normal. The rack spring and compensator spring looked OK, too. Since the gasket over the plunger section was stuck on very well, I decided to look at the FCS (which the 260 pump had donated).
After removing the FCS and confirming that it was OK, I looked at the arm that it acts on.
I couldn't make it move by pressing on it with a screwdriver, so I took the FCS housing off (three 8mm bolts).
I found that the spring that's supposed to keep the arm up would just spin around on the shaft. The tail that keeps the spring from rotating was so badly worn that it couldn't hold the arm up anymore.
I got a new spring along with a new pump mounting gasket and o-ring from Wes. Wes told me that he has never heard of that spring failing.
I put the new spring on the arm (after marking the arm's position on the shaft), remounted the pump and I'm back on the road.
The thing that frustrated me from the beginning was the fact that the engine RAN, and ran well, but only for about 10 seconds. As it turns out, it takes about 10 seconds for the CSS to return to its normally closed state. After that, with the FCS arm all the way down (closed), the engine was getting no fuel at all.
Unfortunately, this wasn't the easiest problem to diagnose, but it came to a satisfying conclusion.

Mike
'72 Spider
 

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Great job running that to ground.

Well if Wes has never heard of that failure, you can bet I haven't either. Wow, that one's crazy.

Thanks for posting your resolution. Since it's actually happened, I think I'll update the Roadside Guide with that possibility.
 
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