[spiderserie4]

so you say it starts and idles when jumping the drive/fuel relay socket, correct?
If that is true, the relay is bad. (Get a Vemo or Hüco relay to replace that big original Bosch ending in #001...not a KAE)

if it does run with the jumper, and, as you mentioned the CSI is not spraying (that is a separate system altogether, not connected to the main injectors) then the 4 main injectors must be firing.

 

[spiderserie4]

No, I have not yet gotten it to idle, even with my jumper wire running the main fuel pump.

I believe the big Bosch relay is dead and I will have to replace it before driving. Thanks for the tips on alternatives.

View attachment 1749474

The good relays are HUCO 13 2019 and the VEMO V20-71-0001

if it does not run with fuel relay jumped, then I'd be checking:
both the pumps: put power to the pink/white (middle) contact on the in tank pump (leave the pink/white connected) that runs both pumps....listen that both are working

if pumps are running then is fuel getting to the rail?
fuel delivery: remove the hose entering the fuel rail....does fuel pump out whilst cranking?
the main injectors: do they pulse with the noid light?

 

[spiderserie4]

so the csi is good, spray pattern for 4 secs looks good from here

the in-tank pump sounds as if it is bad
Remove it (6 screws, make sure you note the orientation of the float so it goes back correct) and inspect
make sure the filter sock comes out with it and check condition inside tank with a flashlight..also check the small rubber stepped hose, that needs to be in good condition or the pump sucks air when gas level is sort of below half.

the dim noid at #4 sounds no good either.
there is no problem testing voltage at the injector connector...choose one of the pins and test to ground...then test the other pin likewise to ground (KO)
what voltage do you get?
(what you do not do, is test ohms for anything on the ecu side of the loom)

those square spring clips are difficult to get hold of
you can afaik, only buy them complete, then use the clip onlythis is a set of 4, for instance
Bosch EV1 Style Fuel Injector Connector w/Terminals and Boots (4 Cyl pack) | eBay

securing the csi with a twist tie sounds an ok solution for now....often you find fallen down missing parts at a later date

 

[spiderserie4]

that doesn't even look that bad...a few crystals forming from stale gas
but the lack of filter sock is a shame...that is the only filter before the main pump.

have you tried tapping the pump to try get it started...might just be slightly stuck. (btw. it - and the main pump - should not be run when its dry, the fuel serves as a lubricant)

you took a photograph of the top before you removed it.....can you post it here, to see if the orientation was correct in the first place

 

[spiderserie4]

The output hose reaches over the power connections, and the float arm in the tank is pointing toward the passenger rear wheel.

View attachment 1749697

yes orientation looks correct
you'll have to finagle the pump sock through the hole, it likes to try fly off, but can be done with care...
(the PO probably tried a few times then said to heck with that and threw the sock in the trash 😁 )

 

[spiderserie4]

bypass this thing (inertia switch) it is a safety switch left over from spica days, which they didn't bother to remove for the first years of the Bosch spiders .....just jump the wire

a little later alfa removed it and added this nice little connector to join the wire.

when that grey inertia switch goes bad, or trips (the grey tube is the earlier type, more susceptible to failing), your fuel gets shut off.
You want that failure point out of the equation whilst you are trying to diagnose this no start.

With the correct relay, you do not need it. The 'tachymetric' fuel relay you have ordered shuts off the fuel in event of an accident.

ps. that stepped hose is toast....just get a new one when you fit the new pump/gauge. You will find if you have to replace the gauge sender that it doesn't just fit back into that metal cage so easily.
Just get it all done in the tank so you can close that and move on to the next step in the diagnosis...my advise

I know it is 30 bucks in USA!
but, half price in UK
FL121 CONNECTING HOSE IN TANK FUEL PUMP

 

[spiderserie4]

I tried to test the fuel level gauge by measuring resistance between the two terminals that connect to the sensor (getting infinite resistance), but probably one is for fuel level and one is the low-level indicator

correct
fuel gauge sender is the violet wire
grounding that should make the dash gauge go to max (that at least tells you the dash gauge is ok)

low level is the white/black wire
so grounding that should make the low level warning light go on.

 

[spiderserie4]

voltage either side of injector to ground is correct.
the resistance, 2,6 ohms sounds correct too for the jetronic injectors. (Motronic injectors would be 16 ohms)

next step is the 2 flywheel sensors:
do one at a time so that you do not mix up the connectors (grey is lower sensor, black is upper sensor)
1.do a visual under the car, check they are both secure in place.
if one looks like this, you found a problem 😁

2. check the ohms resistance on both (as per jetronic guide), especially the lower one (injection ecu signal)
3. check signal pulse: same as ohms test, but set your voltmeter this time to Volts AC......you should see a couple of volts when your trusty helper cranks the engine (one might only show a fraction of a volt)
If you find a bad sensor, replace (about 60$)

the relay positions, well, that is alfa.

the horn sounding continuously (with a good relay...the power window relay should be the same) will likely be the wire going up thru the steering shaft has come loose and is shorting.
take off the centre and see what wires you have (or don't)

if the wire has slipped back down the shaft, you should be able to fish it out again.
But first check there is a wire entering the box as here:
Hellebore wood steering wheel install.

 

[spiderserie4]

I can't match the relay in the lower left to anything in the wiring diagram. Maybe a PO feature? This car does not have air conditioning........
While digging I found the connectors deep in the nest, marked here.

close to the plenum like that, it could be a starter relay fitted by PO (a good thing) just follow the wires and see if a couple go to the starter motor/solenoid.
It's possible someone changed your sensors ages ago and got some with shorter leads....(sensors fit porsche etc, but have different length leads, depending which vehicle)

To check voltage I'll

1. Set multimeter to ACV.
2. Connect probes to the same two terminals used to measure resistance of the sensor.
3. Crank engine and confirm some non-zero voltage while engine turns.
4. Repeat for other flywheel sensor.

Does that sound right?

yes.

 

[spiderserie4]

so flywheel sensors both seem to test good.
the relay 'sounds' like a starter relay by the description of where the wires go

you have spark and you can get it to run a second or two on starter fluid (even with inop CSI)......so basically your injectors are not firing.

As the car was sitting between 2016-2021 (if I understand things, reading back thru the thread)
either your injectors have gummed up and need a rebuild
or the ecu is bad

 

[spiderserie4]

OP is getting some action on the noid, just not near enough
this is way too dull, inspite of good full battery power to both pins.
you want a solid fast flash

Might even be worth having a friend crank the engine whilst you gently tap the injectors with a long screwdriver and tap hammer (leave the sledge in the box!)....you want to tap the injector itself, not the fragile bosch connector

you need btw, solid clean connections on the coil. The shielded yellow especially, that signals the ECU to pulse the injecors.
If you haven't done so, undo all the coil wires and clean them and retighten.

and can we presume your coil is wired correct? (the green/blacks are on the positive side and all other wires on the negative side)

 

[spiderserie4]

my guess is that stray black was likely bolted under the coil bracket....best put it back

when you do the mounts, definitely replace those injector hoses, they look like a fire waiting to happen...

 

[spiderserie4]

The fuel injector repair kit is out of stock, but it looks like I can just cut some fuel hose to length and reuse the existing end caps.
Tradition appears to dictate storing the motor mounts at home for several months to allow them to acclimate before attempting the replacement.
Anyone have suggestions for "while you're in there" work? Probably the starter could benefit from some attention.

if you buy the hose and cut to length and are going to re-use the factory "ferrules" (those little cup things) then you need the correct size hose.
BMW sells 7,5mm FI hose that experts on here say fits perfect
or if you went to find your own hose, just make sure you get hose that is FI rated, has an ID 7,5mm and OD (important) of 13,5mm and it'll fit the ferrules
I have seen the length of these 4 injector hoses mentioned here on BB to be anywhere between 52 and 54mm.
There was a BBer who said the centerline hose (has 14,5mm OD) does not work for use with the ferrules, but can obviously be used with FI hose clamps, as some prefer. I, personally, like the cleaner original look.

But, is it not worth having the injectors cleaned and flow tested by a company, as you are going to remove them?

Not sure I believe leaving the engine mounts a while to acclimitise (unless you were joking?)....they have probably been sitting in the shop for months/years already! And anyway they undergo a normal acclimitisation, because we buy the mounts and then put off the job of fitting them, time and again, because we know what a pita that will be

whilst in there: certainly a general clean up, yours looks awfully grimy down there! All those starter connections should be undone and cleaned. Maybe check the starter mounting bolts are still tight. If Oil pressure gauge is not working, a good time to replace the sender.

 

[spiderserie4]

well, that is something completely new I have learned today .....
I always thought both pumps only operate when ign. key is turned to position 3 (ie. cranking)

tbh. I cannot see how the fuel relay and wiring thereof can distinguish between the two pumps........but ok, if the book says that, then it must be.

if your fuel gauge needle is overly jumpy, check that you have put the in tank pump back in the correct orientation.
My rule of thumb: if the ground spade is facing to the right of the car, so facing the spare tire, then it is OK (as that means the float - as seen along the length - is roughly parallel to the spare tire)