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1980 633CSi No Spark

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DRiley
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1980 633CSi No Spark

Post by DRiley » Mon Dec 17, 2018 4:01 pm

My son just purchased the 1980 633CSi that I had 12 years ago and she is pretty beat up. We are going to bring her back to original glory but for now just trying to get her to run.

There is no spark at the plugs. We have power to the starter, a direct wire going to the ballast resistor, then to the ECM and finally to the coil. We are getting power to the coil and have tried multiple coils but no power leaving the coil to the distributor.

I am searching for past threads about this but want to post since I am a returning newbie!

Thanks,

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

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Brucey
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Re: 1980 633CSi No Spark

Post by Brucey » Mon Dec 17, 2018 6:46 pm

on Motronic cars there is a wire that runs from the starter motor to the ECU (pin 4 from memory). This gives a 'start' signal without which the ECU won't produce sparks, as a safety provision. The ECU also controls the fuel pump.

Your car is L-jet. I don't know of all the safety provisions on this system but there will be some for sure. For example the fuel pump is triggered by a microswitch inside the AFM on that generation of L-jet. Regarding sparks, the whole system (injectors included) is timed from the distributor. If you are troubleshooting the system for 'no spark' the first thing to check for is that you have a signal on the low tension side of the distributor.

If you are seeing pulses at the injectors (easy enough to check for during cranking) this presumably indicates that the low tension side of the distributor is working, but the that coil isn't being driven.

On some versions of L-jet there is an ignition ECU (with a map in it), an ignition amplifier, and the ECU that controls in the injectors. All these parts need power. It has always seemed to me that there are more wires going between the L-jet ECU and the ignition parts than might strictly be necessary; it is possible that some of these inhibit the ignition system under certain conditions.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Mon Dec 17, 2018 8:40 pm

Thanks! My son found the crank sensor and it is covered in grime and oil from a leak. Going to try and clean that and then if no love we will go over what you have suggested. I will post up the progress and hopefully solution.

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

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Brucey
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Re: 1980 633CSi No Spark

Post by Brucey » Mon Dec 17, 2018 8:51 pm

the front crank sensor (on all E24 built pre 6/87) is only connected to the diagnostic port, i.e. it plays absolutely no role in running the engine. It is only there at all so that a BMW service tool can be plugged into it and the correct timing settings etc quickly verified during a service. You could take a running E24, remove the crank sensor and chuck it in the bin, it won't make the slightest difference to the way the engine runs.


As I said on L-jet M30s (some models until 9/81) the primary timing signal for the spark and fuelling is derived from the low tension side of the distributor.

Motronic engines (9/80 to 6/87) use two crank sensors at the back of the engine, and have a third 'service tool only' sensor at the front of the engine, like your L-jet one does.

[BTW post 6/87 builds have a different front pulley, only one crank sensor and that runs everything.]

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

GRNSHRK
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Re: 1980 633CSi No Spark

Post by GRNSHRK » Mon Dec 17, 2018 9:23 pm

Hey Riley, reading along, as if :roll:

I do have a couple of thoughts as well, although we all know that Brucey is king =D>

Since you mention no spark at the plugs but not the condition of the dizzy cap and rotor, how do they look :-k

The only item that has troubled me when having running problems was the combo relay, which Brucey can also probably describe it's function, but it's my understanding that it performs a lot :-?

Question for Brucey, what is the "low tension side of the distributor"?

I can only think of the small connector with one green wire going to it, don't know where it comes from, however [-(
:mrgreen:
Bobbo
1980 633 CSi
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Brucey
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Re: 1980 633CSi No Spark

Post by Brucey » Mon Dec 17, 2018 9:52 pm

GRNSHRK wrote:
Mon Dec 17, 2018 9:23 pm

Question for Brucey, what is the "low tension side of the distributor"?

I can only think of the small connector with one green wire going to it, don't know where it comes from, however [-(
the small green wire has several cores and provides the timing signal for the whole engine to run; it won't run without it.

The combo relay does several things including run the fuel pump for a few seconds to prime the system.

BTW the guys on first fives are the ones to go for when it comes to L-jet systems.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Mon Dec 17, 2018 11:03 pm

Where is the combo relay? Sometime in the last 12 years someone decided to throw away the fuse box cover I bought so we do not have a diagram of what fuse/relay is what.

The cap and rotor look functional.

Since we are not getting any sign of power coming out of the coil, we haven’t really looked too hard at the distributor yet.

We will keep digging around and see what we can find.

Thanks again for the info so far (I am sure I will be asking more in the future).

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

GRNSHRK
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Re: 1980 633CSi No Spark

Post by GRNSHRK » Mon Dec 17, 2018 11:33 pm

Lower right corner in the attached photo \:D/

As you can see, it's really a dual relay with 2 connectors, nothing to do with what's in the fuse box #-o

Good call on hitting up the first fives website, those guys know their L-jet stuff =D>
Attachments
enigne left side 1-sm.jpg
enigne left side 1-sm.jpg (102.63 KiB) Viewed 1603 times
:mrgreen:
Bobbo
1980 633 CSi
Cypress Green/Pearl Beige
2011 F10 528i
2005 E46 330 Ci ZHP Cabrio
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You can never have too many BMW's

DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Mon Dec 17, 2018 11:42 pm

That relay box was loose when we got the car back. I wonder if that is the culprit! Will check on it and advise.

Thanks!!!

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

baders
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Re: 1980 633CSi No Spark

Post by baders » Tue Dec 18, 2018 2:02 am

Brucey wrote:
Mon Dec 17, 2018 9:52 pm
GRNSHRK wrote:
Mon Dec 17, 2018 9:23 pm

Question for Brucey, what is the "low tension side of the distributor"?

I can only think of the small connector with one green wire going to it, don't know where it comes from, however [-(
the small green wire has several cores and provides the timing signal for the whole engine to run; it won't run without it.

The combo relay does several things including run the fuel pump for a few seconds to prime the system.

BTW the guys on first fives are the ones to go for when it comes to L-jet systems.

cheers
Brucey are you describing the low tension side of the coil ? That is the green wire and is merely the feed from the ignition switch. Being that a coil is a transformer, the green wire goes to the primary side. Coil output going to the distributor is the secondary side. The only timing involved comes from the DME to the coil via terminal 1 (black) wire. Or have I totally misunderstood your post ?
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Brucey
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Re: 1980 633CSi No Spark

Post by Brucey » Tue Dec 18, 2018 8:12 am

I think I meant what I said; this is an L-jet car remember. The distributor looks a lot (and works a lot) like one that you might find on an older engine with carburettors, not like the motronic distributor.

Image

The base of the distributor contains centrifugal and (twin pipe push-me-pull-you) vacuum advance mechanisms, but instead of contact breakers there is an electronic pickup that works on (I think) a variable reluctance principle. Part #7 is the part that turns and its phase vs rest of the mechanism varies and so the timing vs the static part of the pickup (#8 above) is varied by the advance mechanisms.

Image
the above is a distributor from an old Mercedes but it has roughly the same kind of gubbins inside it as an L-jet distributor. And the wiring is green, too.

On a car with carbs such a distributor would be connected to an electronic ignition amplifier. On L-jet cars it is too, (#8 below)

Image

but in addition to that in some cases (post 9/81 628CSI LE-jet models certainly) the signal is passed through a small ECU that can further modify the ignition timing above and beyond what the advance in the distributor can manage.

Note that on all L-jet systems the signal generated in the distributor is used as the primary timing signal for the fuelling ECU, i.e. there is no additional pulse generator that feeds the main L-jet ECU.

On LE-jet models certainly (not sure about earlier ones) the fuelling signal is in turn fed back from the main L-jet ECU to the ignition system so that the ignition system can modify its behaviour in response to the real fuel demand of the engine as well as vacuum and centrifugal as normal.

cheers
Last edited by Brucey on Tue Dec 18, 2018 8:24 am, edited 1 time in total.
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Brucey
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Re: 1980 633CSi No Spark

Post by Brucey » Tue Dec 18, 2018 8:19 am

DRiley wrote:
Mon Dec 17, 2018 11:03 pm
Where is the combo relay? Sometime in the last 12 years someone decided to throw away the fuse box cover I bought so we do not have a diagram of what fuse/relay is what.
there isn't a diagram on the lid anyway, so you are missing nothing here. The fuse and relay allocations are given in the owner's manual, the wiring diagrams, and in the workshop manuals. Most of the really important relays that make the engine run are not in the fuse box, either!

The owners manual for cars of this date usually contains a full wiring diagram for the car in the back, printed very small. This is well worth scanning in and making a blow-up version of; it is most likely the only really accurate diagram you will find for your car.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Tue Dec 18, 2018 2:08 pm

To catch everyone up here is where we are at...

Vehicle would turn over but not start when we got it back. First checked to see if fuel was getting to engine by disconnecting main fuel line leading to engine (vehicle started by spraying starter fluid into intake) and found bad fuel pump (replaced).

Not seeing spark at coil so checked all wires leading into and out of starter, ballast resistor, ECM, coil and distributor. Checked combo relay and could hear/feel it engaging when turned over. Started getting spark to plugs (still not sure if we were just not testing it right or we jiggled something).

Determined that the fuel was not getting to cylinders so started checking fuel injectors. First connector plug disconnected and we found a spliced wire that was not even separated (both wires were only twisted together and electrical tape wrapped). Removed the other connectors and all were the same way.

Ordering new connectors from AutohausAZ (~$8 each) and son's electrician friend is going to make a new fuel injector wiring harness. Electrician said that there is a grounding issue with the injectors but wants to rewire all and then go from there. The ECU in the glove box will be looked at next if rewiring the injectors does not resolve issue.

We are using the diagram attached (thanks Bob!). Is this the best one? We have zero paperwork on the vehicle. All documentation and manuals I had with the car 12 years ago are now gone.

This vehicle has been abused and neglected and we will probably need to rewire quite a few things. Very sad that no one cared enough to try and do the right thing. She was one owner away from the junkyard I am sure.

Will update once we get the injectors rewired.

Thanks again for all of the info and support!!!

Cheers!

Riley
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80_633CSi_Wiring_Diagram.pdf
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1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

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tschultz
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Re: 1980 633CSi No Spark

Post by tschultz » Tue Dec 18, 2018 3:56 pm

So are you getting spark or fuel or neither? Need to confirm this first...

DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Tue Dec 18, 2018 4:08 pm

On a side note, some idiot decided the instrument gauge housing didn't need the plastic/glass screen (main cluster with speedo/tach etc.). Not sure how you replace that (source a used instrument housing?).

Maybe I start a new thread for this issue... I'll wait until we get it running.

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Tue Dec 18, 2018 4:12 pm

tschultz wrote:
Tue Dec 18, 2018 3:56 pm
So are you getting spark or fuel or neither? Need to confirm this first...
We are getting spark but no fuel to injectors. Vehicle cranks and when sprayed with starter fluid tries to start.

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

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tschultz
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Re: 1980 633CSi No Spark

Post by tschultz » Tue Dec 18, 2018 11:56 pm

Can you jump the fuel pump through the combo relay and get it to run? I had a similar problem in 2010 and it was a bad combo relay.

DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Wed Dec 19, 2018 4:35 am

tschultz wrote:
Tue Dec 18, 2018 11:56 pm
Can you jump the fuel pump through the combo relay and get it to run? I had a similar problem in 2010 and it was a bad combo relay.
After we rewire the fuel injectors we will look closer at the combo relay. Where is the best place for these types of parts (mostly electrical)? I have purchased from AutohausAZ and Bavarian Autoworks in the past.

Will keep you posted.

Thanks again for all the info so far!!!

Cheers,

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

GRNSHRK
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Re: 1980 633CSi No Spark

Post by GRNSHRK » Wed Dec 19, 2018 9:19 pm

Riley, been looking for the wiring diagram, nailed it =D>

This should help, if nothing else, than to ensure proper point to point, etc. :-"

Keep us posted, of course \:D/
Attachments
633 CSi wiring diagram.pdf
(241.88 KiB) Downloaded 27 times
:mrgreen:
Bobbo
1980 633 CSi
Cypress Green/Pearl Beige
2011 F10 528i
2005 E46 330 Ci ZHP Cabrio
Image

You can never have too many BMW's

DRiley
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Location: Bend, OR

Re: 1980 633CSi No Spark

Post by DRiley » Wed Dec 26, 2018 5:11 pm

Thanks Bob! The new fuel injector connectors arrived Tuesday and hope to start messing with the car this weekend. Will update outcome.

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

DRiley
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Joined: Thu Dec 13, 2018 4:57 pm
Location: Bend, OR

Re: 1980 633CSi No Spark

Post by DRiley » Thu Jan 10, 2019 2:43 pm

Update: after changing out the wires and connectors for the fuel injectors, spark plugs, alternator, cap, rotor and even the ECU she is now running!!! Haven't driven it yet so hopefully the clutch/transmission is still working right...

Thanks again for the support and info!

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

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sansouci
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Re: 1980 633CSi No Spark

Post by sansouci » Sat Jan 12, 2019 3:14 am

Riley,
Congrats on bringing it back to life. Too bad for us that you did a significant amount of parts replacement without zeroing on the actual no-start cause. Maybe you did, so for knowledge sake, please let us know.
Thanks,
Ken
Sansouci
84 E24 633Csi Auto, Bronzit/PearlBeige 6997510
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DRiley
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Re: 1980 633CSi No Spark

Post by DRiley » Fri Jan 25, 2019 6:08 pm

Sorry for not having more info and any pictures. The car is now my son's and he and his electrician friend have been spending nights working on it. I have been tied up working with my scout troop and all of the gear in our troop trailer.

He found multiple grounding issues. The biggest culprit for the no spark issue was the ECM (on PS front firewall). It had to be taken apart, cleaned up, resoldered and grounded properly. Replacing the fuel injector connectors and wires was just something that would have become an issue eventually.

The ECU actually did not need to be replaced. My son tried to return the used ebay one and they are claiming it is not the one they sent him (obviously it is as we are not exactly flush with spare ECUs!). They are sending it back and we will just keep it for a back up. Worthless ebay...

I did drive my dream car, again, for the first time in 12 years! Brakes and steering are not great but it was great to experience that again. Love these cars! Just watched Billionaire Boys Club and saw a bunch of e24s that made me happy to have mine back again!

We took apart the center console last night trying to figure out why the blower motor was not working. There were so many random wires and crap in the stereo area we didn't even get to the blower motor and just spent the evening chasing wires, cleaning up harnesses and just general house cleaning. The connecting linkage for the climate controls was all broken and we will have to try and engineer something to replace the damaged/missing items if we can't source replacement parts.

The Hazard light quit staying in and we had to "modify" it until a replacement can be found. Can't even pull the plug as the blinkers are on the same relay and quit working without the button in place...

We took it for a test drive and hit a bump and the blower turned on!

Spending tomorrow cleaning the exterior, working more on the dash and wiring so will take some pictures of the progress.

Cheers!

Riley
1980 Cypress Green 633 CSi (actually my son's car now...)
1994 Toyota Land Cruiser (my second love)

Dmckim
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Re: 1980 633CSi No Spark

Post by Dmckim » Wed Jan 30, 2019 2:07 am

I am pretty sure I have some random climate control connection rods and such if that is what you are looking for. The swivel parts that connect to the back of the panel are all brittle buy now. I got some OEM ones a few years ago from the dealer.

Dale
Buffalo, NY
1980 633CSi
1987 325is (sold)
2001 740iL Sport (sold)
2007 328xiT (Sold)
2014 320dT (Sold)
Current: 2016 M-B E350 Sport,
2007 GMC Sierra,
1972 Pontiac LeMans Sport Convertible

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