Once again I have crossed swords with the infmous pink wire (pink/white actually) that supplies power to the electric fuel pump (or, is meant to supply power) on the 75TS. I thought I had this weakness fixed by bypassing the connectors in the loom (RHS fwd of firewall and behind above fusebox) and securing/heat shielding the four EFI relays on the LHS inner guard. But last evening, far from home, it stopped without warning. After checking all the usual things a call to an experienced friend yielded a temporary solution - lift the back seat and connect the yellow tail light wire to the pink fuel pump wire (requires cutting wires of course). And off we went, as the first drops of rain started to fall and the sun set. I owe you a bottle of your favourite Julian.
So, I'd like to ask the collective wisdom is there a definitive fix for this problem, or a recommended approach to re-wiring the fuel pump circuit completely, before I start re-inventing the wheel?
I recently purchased a 75 twin spark that had a wire running from the battery to a switch in the cabin and then down to the pumps.... no fuse of course.
What I found was that the pink/white wire had simply come off its terminal on the back of the fuse box. I gave the terminal a squeeze with a pliers and reattached it and all is now well (with the fuel pump wiring anyway....)
I hope you find something as easy to fix as this!
Yes, I have heard of the permanent just-in-case wire - I was hoping for something a little more elegant! My thought was carry an emergency jumper wire that plugs in to the rear cigarette lighter socket that will reach to a blade connector on the pink wire under the seat. Not elegant either and fails the beloved wife test. I'll search further re. fusebox and miscellaneous connectors. I read a blog about a guy and his Ferrari (testarossa) from this vintage - sounded very similar with scorched connectors and plastic trim turning to goo. Apparently they sometimes even catch fire!
I had huge problems with this but the final thing that actually solved the problem for me was replacing the green black wire that goes from the ignition switch (well, actually the brown wire when it comes out of the first plug) to the set of four relays. Mine had got old and hard. It was obviously struggling to carry the current to feed the fuel pump relay. I just fed the wire from the ign switch plug, through the firewall grommet, across the back of the engine and down to the relay.
In the mean time, a quick fix (if you need to get home) is to disconnect the lambda heater as it is fed from the same fuel pump relay and uses precious little electrons!
To make my response clearer: I too was not getting current through to the fuel pumps. I ran a new wire from the fuse box to the pump direct (bypassing all plugs). Problem returned. I ran a new wire from the relay direct to the other new wire. Problem returned. Installed a brand new pump. Nope. I then discovered if I disconnected the lambda heater it would sometimes work. So I looked further up the tree and discovered the relay is fed by this green/black wire. Changed that and have not had a problem since, including reconnecting lambda heater and routing new fuel pump wiring through the fuse box as per the original.
I suspect most of my work was a waste of effort as the real culprit for me was the green/black wire.
Thankyou GTVeloce for the description. I'll have another look at it tomorrow. Thanks all.
Sorry, couple more questions....is this a 75TS only problem, or do the V6 75/Milano also suffer? Or, is it only RHD 75TS??
It can be limited to the TS because of the specific relay setup. But it depends where the fault lies. The V6 does feature a pink/white power wire to the fuel pump originating from the Combi Relay in the engine bay.
Craig's Place description of TS relay sequence: http://www.users.on.net/~craigf/ts_start.htm
Generally, I think it's a good idea to upgrade the power supply through the pink/white wire, by using a relay. The pink/white wire can trigger a relay (ie: go to terminal 85 on a typical SPST Bosch-style relay); then take a dedicated power supply to feed through the relay. You can take a power feed from the fuse board and mount the relay in that area which is also where the pink/white wire passes, so it's all relatively within easy reach.
:)
Thanks Shiny, I've trawled Craig's 'site quite a few times, and this one http://www.alfamilano.com/. Haven't found a TS-specific wiring diagram yet anywhere on the web, only older combined 1.6/1.8/2.0/2.5 manuals and diagrams. Relay sounds like a good idea, but need to find my fault in the pink/white wire yet. I have a short after fuse #13 somewhere.
http://david.alfa-romeo.eu/alfa/AlfaRomeo75/
and
http://david.alfa-romeo.eu/alfa/75/
lots to download and sift through!
http://david.alfa-romeo.eu/alfa/75/75_ee_diag_e.zip
this file contains the diagrams below as well as the key to wiring diagrams (E-119 to E-125) and wire colours (file E-003 to E-004)
excellent, thankyou.
These may help as well. Especially if you are chasing fuse 13. IIRC the output of fuse thirteen goes into the loom above the fusebox and down the drivers side (RHS) of the floor all the way to a plug underneath the right rear seat. It then splits into two with one going to either of the pumps. I quick check with a multi meter will tell you if there is an issue in the continuity of the wire. Also, check the earth to the main pump at both ends. On the pump itself and where it connects to the body which is also under the right rear seat. No harm in giving them a good clean and spray with contact cleaner while you are there.
Too big for one post.
thanks, I was wondering about the routing of the pink wire. I definitely have a short in that run, and plan to retire that wire from use. Found the pump wire earth point on the inner sill - all clean now. Also pretty sure that connector H6 on the back of the fusepanel is the supply to the pump/pink wire. My current plan is to run A NEW CONTINUOUS WIRE FROM h6 that switches a relay under the rear seat. Then, take pump power from the rear cigarette lighter circuit (maybe) or run a dedicated power wire from the battery, or the L connection on back of fusepanel. Thoughts?
Job done, lets hope it lasts. Used the original wiring/fuse 13/H6 to activate a relay behind the fuse panel. Power via an in line fuse from the L connector on the back of the fuse panel, to the relay, then under the carpet and along the sill to the pump wire under the rear seat, all hidden and tidy (used heavier gauge wire also). Now to relay the headlights.
Just purchased a 1988 75 3.0. One of the minor electrical gremlins infecting it is a 13% drop in voltage from the battery to the fuel pump. I'm assuming this car only has the one pump given the fuel tank is behind the rear seat. On two occasion's now it has developed a lean surge - only during 30C+ weather. The most recent last Sundays AROCA drive - after almost 300k of trouble free running!
I understand one of the fixes for the voltage drop caused by the low cross section wiring is to run a significantly heavier +12V cable between the starter motor stud and a terminal block on the RHS of the engine bay adjacent the "Bosch Combination Relay". This is a logical fix given the apparent loading of the existing conductor, however I have concerns as this heavier cable does not seem to be protected. Does the 75 3.0 or any 75 for that matter feature a Fusible Link between the battery +ve and the rest of the car electrical??
The previous owner installed a high power sound system - now removed. There are two glass 10 x 38 fuses on the LHS of the engine bay adjacent to the battery. Could these be the fusible link/s? They look to have been added post manufacture. Maybe they are the feed for the now removed sound system. I'd rather feed the Combination Relay from a protected source especially if the new cable will have four times the current rating! Thoughts?
Can't say WRT a 3L, but in the TS power for the fuel pumps comes from a relay in the engine bay, through fuse 13 in the main fuse box (under dash) and on to the fuel pumps. I would imagine the 3L should be fairly similar in nature.
Do you have the original manual? It should tell you what the fuses are for as a starting point.
The electrical schematic for the respective cars is similar but not identical. F13 feeds the fuel pump. F13 is fed by via SB1.5 so the majority of the fuel pump wiring is 1.5mm section - pretty thin given the current draw of the fuel pump. I'll check the SB1.5 and F13 connections. Probably end up replacing SB1.5 with a 2.5mm or 4.0mm cable and be done with it.
I installed a new fuel pressure regulator last night and drove the car tonight - all good! Maybe the regulator was suspect, however I'll still attack the wiring nevertheless.
I ran a better (and newer) wire from the relay to F13 and then on to the pumps to replace that 1.5mm SB. From memory I just used 2.5mm. Seems to be holding up fine so far (after about 18 months).
Maybe Mr Bosch had it right but the bean counters at Alfa had it wrong. The new electric fuel pump I installed came supplied with blue (2.5mm) crimp lugs!!!
hope you have solved the problem, I haven't been on here recently! The 75TS has TWO fuel pumps, one in the tank and one out. The same power supply goes to both. I found on mine that the in-tank pump was NOT connected to the power, so only the external pump was working, and then was intermittent! A bigger wire direct activated by S13 (as per original message) to the pumps, bypassing any factory connectors, seems to have cured my ills. good luck. currently chasing stray electrons in a '95 Maserati - more fun:(
Hi ALF750,
My 75 is a November 1987 build 3.0 with the tank above the boot floor / behind the rear seats. Appears to have only the external fuel pump under the floor. Only wiring to tank seems to be for the fuel level sender.
I replaced the infamous pink wire with 4mm OFC cable when I installed the new pump and filter. The significantly shorter earth / return wire I changed to 2.5mm. Only seeing a 5% voltage drop now.
A future project will be to increase the conductor section of the cable between the starter motor and the fuse box via that connector / terminal block on the r.h.s of the engine bay. Under high electrical load the existing cable causes excessive voltage drop to the fuses and effectively the majority of the car electricals.
Methinks the lean stutter issue when taking off in high ambient temperatures was(?) / is a sticking Air Flow Meter flap. Engine idles fine, however when you open the throttle to drive off under load the airflow increases however the flap sticks or is slow to move causing insufficient fuel flow via the injectors / very lean mixture. The ECU still thinks the car is idling! Have to wait for the hot weather to return. Bloody cold in Melbourne at the minute!
Colin