Help Needed - No juice to fuel pump - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 10 (permalink) Old 06-09-2019, 11:01 AM Thread Starter
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Help Needed - No juice to fuel pump

1989 Spider Veloce with a little over 100K miles. I replaced the clutch and in the process removed the intake plenum to get at the starter motor. Replaced the rubber connectors between manifold and plenum, belts, plugs, cap, rotor, valve cover gasket, fuel filter, oil/oil filter, and remediated the air intake bellows. When all done, it would try to start but that's it. Prior to my work, it started every time. I read through different threads on this forum. Battery is charged and cranking voltage is over 11v. The CTS has just under 2K ohms resistance (ambient temp between 80-90). The TTS shows reasonable resistance between G and W. The AAV is clean and I can see a small opening. Both fuel pumps run when jumpered to a battery. They are not getting any voltage when cranking. If I put a battery to the tank pump, the car immediately starts and runs perfectly. I've taken the main relay out and bench tested it. While I don't know the load on the circuit, when the control is activated, there is clear connectivity between the dependent terminals (30 and 87?). I've tested the circuits to the tachymetric (aka pump) relay. With ignition on, there is battery voltage at terminals 15 and 30. Terminal 31 shows continuity to ground. In start position, terminal 50 shows 9.9 volts (or enough to run the fuel pump I think). Yet and still, there is no voltage to either of the fuel pumps when cranking. The 8amp fuse is perfectly clean and there is continuity between the external leads of the fuse holder. The engine grounds are tight; the passenger compartment grounds under the package shelf are clean and tight. I haven't tested the CSI but since the engine tries to start and runs for a second or so, I'm assuming that it's fine (and it runs perfectly with the tank fuel pump powered up by an independent power source). The leads on the coil are clean and tight.

Interestingly enough, I found an engine ground that was free. When I connected it, the car started immediately and ran for about 10 minutes. I turned it off and later it refused to start. That's when I started chasing the relays. I don't know how to test the tachymetric relay, but I'm starting to think it is in intermittent failure mode. Also, I can't figure out where the pink and white (or is it black) hot wire for the fuel pumps picks up it's juice. The wiring diagrams in the Alfa factory manual are not a lot of help. They don't even show both relays or the ECU. I'd appreciate any thoughts on this. Thanks in advance
Eric
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post #2 of 10 (permalink) Old 06-09-2019, 12:30 PM
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If the fuel pump fuse (the 8 amp one near the FI computer) is the 'bullet' style and it is of unknown vintage I'd suggest your replace it. The bullet fuses - especially the ones with an aluminum strip - can somehow look OK but fail to allow electrons to flow. The brass strip fuses are better. Best solution is to replace the entire fuse holder with one that takes a blade type fuse.

Since the fuel pumps are wired together, I suspect that when you jump 12V to the in-tank pump you are also powering up the main pump.

If not that fuse, it sounds like you've checked all the usual suspects. Now it is time to check for an unusual one. Long story - the early model years had a fuel pump inertia switch. This was likely a left over from the pre-EFI models. After a few years it was determined that the drive relay (the one that gets the tachymetric signal) would serve as a fuel pump cut off device - it would cut power to the fuel pumps if the engine stalled (as might happen in an accident) so the inertia switch was deleted. However, Alfa didn't change the wire harness - they just connected the wires that used to go to the inertia switch together and buried that connection inside the wire harness covering. There have been a few cases where that connection failed (loose, corroded, etc) and the fuel pumps then did not get power. Short story - buried in the wire harness along the firewall near the hood latch is where that connection is hiding. IIRC, you're looking for a red w/white trace wire that connects to a pink wire.

One other thought. Have you checked the flywheel sensors? Even if they test OK with the ohm meter I'd suggest removing them to check for physical damage. I helped a guy with a no-start Spider. Everything checked out good but it would crank but not start. We then removed the flywheel sensors and noticed that one had a dent in the end that faces the flywheel. We replaced it with used but known-good sensor and the engine started with up.

- - Eric
don't read this
~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


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post #3 of 10 (permalink) Old 06-09-2019, 12:45 PM Thread Starter
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Thanks, Eric. The fuse container shows connectivity and fuse itself looks new and has connectivity. As to the flywheel sensors, I could see them being an issue if the car didn't start and run perfectly when the fuel pump is powered up. When I took the clutch out, I was very careful with the 2 sensors and their probes were clean. I will look to see if there is something to the firewall wire.

What troubles me is that the other day, when putting the missing ground wire (near the valve cover) in place, the car started and ran on its own, revved, had power. I was thrilled and thought the problem was solved. However an hour later it wouldn't start...well it actually started, revved, and then spooled down, quit, and wouldn't restart. That's why I'm thinking the problem is related to the pump relay, which should be the source of power to the pumps. I also tested the main relay circuits. There was battery voltage on terminal 86, 85 had ground continuity, and 30 had battery voltage.

Eric
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post #4 of 10 (permalink) Old 06-10-2019, 02:37 AM
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not of importance quite yet, but what fuel relay do you have? KAE, or Bosch original..?

jump the fuel relay plug terminals between #87 and #30:
that should make the pumps run continuously (and tests fuel pump wiring, fuse etc)...do they?
If not, the relay is bad.

the ground wire you found near the valve cover, was it just a single braided wire with a hoop? If so, you forgot to replace that on the plenum
https://www.alfabb.com/bb/forums/505873-post20.html

if otoh, it is a small bundle of grounds, then likely belongs under the AAV bolt.

the main ground bundle on head near cyl. 4 has 7 grounds in all: 2 single, one double, one triple...they are all there I presume?....you could remove them and clean them if not already done.

further relay tests:
https://www.alfabb.com/bb/forums/996584-post31.html

I have one of Papajam's supurb coloured wiring diagrams for an '88 if you need it....unless someone has one for an '89 on file for you?
(send me a PM with your email if you want the pdf)

you'll get there in the end, we all do, somehow...

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #5 of 10 (permalink) Old 06-10-2019, 08:17 AM Thread Starter
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Good news and not so good news

Thanks to both Eric and Dom for suggestions. I've got the car running on its own, but I'm not exactly sure what I did to encourage it back to normal life. I strongly suspect that I have an intermittent issue with my BOSCH tachymetric/FP relay. I jumpered 87 and 30 on the FP relay (easier than typing tachymetric over and over) and both pumps sprang to immediate life. The car started and ran perfectly. All of the connector circuits for the FP relay checked out with correct voltages and grounds. I then touch-jumpered 15 and 1 and heard a clicking at the coil. I then took the FP relay and applied an external battery source to terminals 15 and 1...no clicking sound. I decided to reinstall the relay...et voila...the car started, revved, ran perfectly. I turned it off, waited a minute or two and tried again and it started instantly. Did that a few times and finally backed it off my lift, out of the workshop and down the road to my attached garage.

Dom, Eric already sent me the colored wiring diagrams from Papajam (Jim, R.I.P.) and I'm going to do what he suggested and have them blown up and laminated. I have similar ones for my 65 Healey 3000 and 71 Etype and they're great to read.

Now the question is where can I get a Bosch replacement. I've read others that say the KAE alternative is not a good choice, although I'm not clear if it just doesn't work or if the cutoff switching mechanism is a problem....or what. I don't want to trust my current relay to keep running if I really wish to drive the car and not get stuck.
Eric
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post #6 of 10 (permalink) Old 06-10-2019, 08:31 AM
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glad its working...it does sound like an intermittent relay problem....perhaps just pulling the relay and replacing it cleaned the plug contacts a bit? Maybe clean them some more with contact spray and a toothbrush

You could just buy a new KAE relay and keep it in the glove box in case your good old original Bosch (pn: 0280230001) ever lets you down again.

The problem with the KAE (pn:3.304.500) is - not always the case, but you often read about it on here - it keeps the pumps running with KO, rather than cranking/engine running as the relay is designed (so, not the safest idea!)

if you have a good pick and pull near you, check out the BMWs, the identical relay is on several older BMWs.
Centerline's shows the correct Bosch, but recently someone ordered it and got the run of the mill cheapo KAE...go figure
https://centerlinealfa.com/catalog/f...injector-relay

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #7 of 10 (permalink) Old 06-10-2019, 08:39 AM Thread Starter
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I did exactly that....I ordered the one from Centerline which clearly shows a Bosch with 02 280 230 001 on the case. If they send me a KAE, I'll complain to them (but probably keep it in my glove box). I have a couple of junk yards near by...an LKQ in Durham and a Pull-a-Part in Winston-Salem. Do you happen to know around what year BMWs I need to check on? The older the year, the less likely the yards are to have them. I guess that they figure that these are the good old days :-).
Eric
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post #8 of 10 (permalink) Old 06-10-2019, 08:52 AM
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from what I see on german ads, where the bosch is listed, they say for
BMW E30 E23 E24 E28 M30

all sort of 1990's models I'd guess...

example (edit: USED):
https://bmw-haifisch.de/p/bmw-e23-e2...sch-0280230001

btw: a new KAE is about 30 bucks, not 90!

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #9 of 10 (permalink) Old 06-10-2019, 09:06 AM Thread Starter
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Thanks for the BMW info. And Centerline ripped me off is what you're saying :-) Oh Well...there's a sucker born every minute ain't there. Must have been my minute in the barrel.
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post #10 of 10 (permalink) Old 06-10-2019, 11:57 AM
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Originally Posted by ghnl View Post
If not that fuse, it sounds like you've checked all the usual suspects. Now it is time to check for an unusual one. Long story - the early model years had a fuel pump inertia switch. This was likely a left over from the pre-EFI models. After a few years it was determined that the drive relay (the one that gets the tachymetric signal) would serve as a fuel pump cut off device - it would cut power to the fuel pumps if the engine stalled (as might happen in an accident) so the inertia switch was deleted. However, Alfa didn't change the wire harness - they just connected the wires that used to go to the inertia switch together and buried that connection inside the wire harness covering. There have been a few cases where that connection failed (loose, corroded, etc) and the fuel pumps then did not get power. Short story - buried in the wire harness along the firewall near the hood latch is where that connection is hiding. IIRC, you're looking for a red w/white trace wire that connects to a pink wire.
Glad your pumps are running again but you may wish to do a little additional troubleshooting before you rule out poor connections as the source of the original problem. I had the same issue several years ago on my '88. After reinstalling the engine, the fuel pumps would not run. The problem was a drop of three volts at the pumps compared to voltage at the junction box in the engine compartment. Cleaning the connection between the two wires Eric references above and the connection at the the G73 connector improved the connection at the pumps by 2 volts. Cleaning the relay connection yielded another half of a volt and is where I stopped. I have not had any additional fuel pump problems in nine years and 50K miles.

Rich Hanning
'65 Sprint GT, '78 Spider, '88 Quad
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