Fuel Pump issues? 81 FI spider

[karhawk]

We finished installing the new engine hooked everything up etc. can't get the
car to fire, set rotor to #4 TDC, rotated 180 degrees still no fire. then I
realized I did not hear the fuel pump buzzing, the PO apparently bypassed the
dual relays because previously any time the key was on you could hear the fuel
pump buzzing. Now when the key is on and no buzzing. Hot wired the fuel pump
from the battery and it happily buzz's away. Is there an in line fuse somewhere
for the fuel pump? Just read an old post hear, found the in line fuse brown with white stripe cut out the old connector replaced with new in line fuse holder, I have power in and out, still no fuel pump buzz.
It has to be something related to the engine install because the fuel pump, ECU etc. was
working fine before even though it was hotwired somehow to the ignition on position.

Any thought?
Thanks
Chris
81 2000 FI spider

[adrians]

Check the AFM wiring/connector 7 pin ( mine you have to press on to get it to work sometimes), pushing of the flap of the AFM should cause the fuel pump to start pumping if the inline fuse is ok.

[lanciahf]

Hi Chris,

Here is a test,
With the key on open/move the flap in the AFM. Do you hear the fuel pump running?
If not it could be a bad fuel pump switch in the AFM, or a Bad FI Double Relay.

Ralph

[karhawk]

Hi Chris,

Here is a test,
With the key on open/move the flap in the AFM. Do you hear the fuel pump running?
If not it could be a bad fuel pump switch in the AFM, or a Bad FI Double Relay.

Ralph

thanks I will give that a shot, though I am skeptical the AFM between the time we took out the old engine and installed the new one.

[rlux4]

Is the dual relay still bypassed? How was it bypassed? If it was by a direct jumper between the red wire and the green wire that goes to the dual relay, I'd check that connection. If it was originally bypassed because of an unreliable connection through the old inline fuse holder, you may have solved it when you replaced it with a new one.
Ron

[ga.spyder]

Mine has also been bypassed,so the test with the AFM flap wont work.I am going to have to change my switch to get mine back through the double relays.It has been working fine as is for 2 years. You could always do what I did...take a pic and send it to Ron!!
Craig

[karhawk]

Is the dual relay still bypassed? How was it bypassed? If it was by a direct jumper between the red wire and the green wire that goes to the dual relay, I'd check that connection. If it was originally bypassed because of an unreliable connection through the old inline fuse holder, you may have solved it when you replaced it with a new one.
Ron

Ron
Well I cleaned all negative ground contacts, replaced the fuse and fuse holder under the dash,l cleaned the fuel pump contacts and now everything works the way Fiat intended, the fuel pump only pumps while cranking and running, weird.
Chris
You can ck some of our progress here: http://scratchybottom.blogspot.com/

[rlux4]

Not so weird. Our car's system does not have the pump running as soon as you turn the key "on". The pump gets the signal to run from the AFM. The flap opens slightly to allow air in, and this moves the meter arm which triggers the pump to run when the key is in the "start" position. Once the car is running, the air flow past the flap keeps the meter arm in position to supply a steady signal to the pump. Other FI systems do have the pump coming on with the key in the "on" position, but they'll have a pressure cut out in the circuit that stops the pump after the needed pressure is reached if you don't start the car. If you had the key on to listen to the radio for instance.
Glad to hear you're up and running normally.
Ron

[So Cal Mark]

Ron,
the pump should run for two seconds when the key is turned on to pressurize the system. I'm not aware of any modern FI car that has a pressure shut off on the pump. The system has a return for fuel to return to the tank, and they all run the pump for about 2 seconds when the key is first turned on.
The exception is the returnless systems that have just come into production in the last couple of years; these systems vary pump speed to control pressure

[rlux4]

Mark, on my car the pump doesn't run until the key goes into the start position. I had read somewhere that it would run for a couple of seconds, so when I was troubleshooting my problems last year and it didn't, I thought there was a problem. What I found was, as I described, the AFM arm moves when the key goes into the start position and this kicks in the pump. I could be wrong about this sequence, but I checked it repeatedly back then. Now, I'm away from home, so I'll check it again when I get back. I know everything on my car has no changes to the original wiring. It always starts very quickly, so I must not be getting an appreciable amount of pressure loss. My bad on the pressure cut out. I had a 79 Seville with throttle body FI and was told by a mechanic that the in tank pump only ran until the pressure was high enough to reach the other pump on the frame rail.
Ron

[jacobdbrown]

Hello,
I think I'm having somewhat of a similar problem, but since I have little to no diagnostic skills, I'm having a hard time...
Here's what I've got: the car cranks great (thanks to new starter) and will normally start right up and run fine, but on occasion, it won't start and, twice now, it's shut off randomly while driving. I did your "key on, move AFM flap" test and the pump buzzed. I also tried removing the red wire from the starter (so I could hear better) and when I turned the key to start, I could hear the pump running.
Also, a month or so ago when the car started having random starting trouble I changed the fuel filter and ran some injector cleaner through. It does not seem to have helped.
Any tips at all would be amazing. Thanks.
Jacob

[So Cal Mark]

Make sure the intake hose isn't cracked or loose. I'd also remove the distributor cap and inspect the wires to the pickup unit

[jacobdbrown]

Thanks, I'll check out the hoses. They are lookin' pretty old. I may just replace them all to be sure they're all fresh and tight.
The previous owner replaced the distributor cap, so I'm reluctant to pull that apart since I know nothing about it. I really don't think it's a spark issue though. The engine fires with starter fluid, but dies immediately, so I think it's only a random fuel problem. I noticed today that the car has a strong smell when running. Hard to describe, but it smells rich, or possibly even like there is some burning rubber, so I'm going to check into that and and just look for stuff I may have bumped around on other jobs.

I'm wondering about which sensors this could be, if any. Any thoughts? I know there is a long list of them. Since it's randomly shutting off while running, I'm wondering if maybe it's getting more sensitive to heat.

...???
Jacob

[rlux4]

There's really only one sensor that would cause the car not to run, the temp sensor in the coolant "T". The others would affect mpg and/or emmisions, but not cause it to quit running. The thermo-time switch is for the cold start valve, so it only affects cold starting. If it's an intermittent problem, it's most likely not a sensor, more than likely it's a poor connection somewhere. On my car it was the inline fuse for the dual relay. The fuse was good, but the original fuse holder wouldn't make good, consistent contact. Some other connections that you should check would be the two grounds on the rear, outboard side of the intake plenum, which are for the injectors. The air flow meter can have a sticking flap, or bad connections or potentiometer.
Ron

[So Cal Mark]

as Ron suggested, the temp sensor is crucial. Quite often the connector is broken and doesn't make a good connection. Replacement ends are available. If you're getting a odor like a rich mixture, check the pressure regulator. Pull the vacuum hose off and look for any signs of wetness. A leaking regulator will cause a very rich mixture and loss of fuel pressure.