Mrmerlin

use a 194 bulb to test the signal from the harness.

get a 9 volt battery and solder wires to it use it to test the installed injectors ,
NOTE if the injectors are not clicking then they are stuck.

IcemanG17

Kibort a couple thoughts as the Estate was an L jet car. The water temperature sensor is VERY sensitive. On the Estate it was faulty....which makes the resistance too high or run very rich. It was a hot day, we bypassed the sensor with a small piece of wire and it ran fine (hot is low resistance) pull the wire it would instantly stall.

Another issue I found is the various resistances of the AFM are important too....I had one measurement that was barely off the acceptable range like 100 ohms off and car ran like crap....swapped a rebuilt AFM in and it ran perfect.

dr bob

Mark -

Waste no time worrying about the green wire from the distributor. Its purpose is to carry the ignition trigger from the distributor. Since the engine runs on starting fluid, the ignition is functioning.

If the noid light shows no triggering while cranking, .and. (that's a LOGICAL "AND") you see battery voltage continuously at the all injector wires referenced to ground, then there's either a short in an injector or wiring, .or. your injection controller isn't able to pull one side of the injector circuit towards ground. IIRC, the early injection like yours still depends on the ground point at the rear of the engine itself, top rear right in the V on the right side cam tower (right is passenger side of US cars). Pull the air cleaner housing, clean out the mouse nests, test that ground integrity from the controller end after clean/repair/etc. as needed after the visual check that it's still there.

As far as testing with a meter... In your drawing you can see how the top (positive) ends of the injector loops are ganged as two groups of four, with those common to the relay inside the CE panel. On the bottom end at the injection controller, each of the two groups of four are further divided into groups of two. If you suspect a wiring fault in those injector loops, you'll want to unplug the injectors in a test group, or maybe just unplug them all so you can test each circuit individually for shorts to ground or opens or shorts within a specific loop. You can do all that testing from the footwell, with CE plugs disconnected and the controller plug out and exposed. Good time to verify the ground path to the engine too, although the real test will only happen under injector load.

Mrmerlin

DrBob his injector grounds are on on the right hand cam tower. there should be 2 of them, 16 V
The S4 grounds are at the back of the V, 32V

dr bob

Thanks for the clarity. It's been a long while since a 16V was in my workbay. Hence the "IIRC", which I obviously didn't.

GregBBRD

These L-Jetronic systems are literally "See Spot Run" simplistic stuff...well with-in your wheelhouse, Mark.
The fact that you (Mark) are still struggling points to something "very abnormal" going on.
Seems like Scott (and you) might benefit from an intervention of a mechanic who really understands this ignition/injection system.
Is there such a person local to you?

mark kibort

ICE< there is no clicking.. i was pretty experienced with that Phenom... remember, we had reversed the water temp and tempII connector, which cooked the tempII and then we had to prop up the AFM to get it running. then, we talked about it, i measured resistance..... INFINITE, so put in a few hundred ohm resistor and it started..... bought a new temp 2 and problem solved. the real problem is NO clicking!!!! injectors have voltage but not being sunk to ground

mark kibort

yeah Greg... helpful as recent-usual.... (i liked the old greg better, fyi).... they are pretty simple and have had many many years of using it, modifying it and trouble shooting it.... UNTIL now. so, why not try and help rather than be a dick? is that possible??

GregBBRD

Whether or not you appreciate it, that is the best help I could offer...find someone with basic knowledge of the system to fix it.

'Cause, if everything you say is true, it would start and run.

Maybe this will help...

Internal combustion engine review:
---Compression with valve events occurring at the correct time.
---Spark at the correct time.
---Fuel in combustion chamber.
Engine runs.

mark kibort

yep.. and that was the first thing we did was to clean and replace them... however, they looked very nice and clean..

mark kibort

i know you mean well most of the time... but you and i have this thing going and i get it. you are puzzled how i could have raced a 928 for 24 years with no engine issues. Seriously, i think you also get that these electrical issues are offen hard to figure out, unless you take everything apart and rebuild with known good components. one time i did this, and the problem was the connector just not being seated in the ECU LHJetronic.. spent hours doing all the tests..... turned out something simple. what about my fuel pump issue at the runoffs?? who would have thought the suspension could break a fuel pump power wire by smashing into it. it was intermittent and would kill the engine on track.... however, it idled fine....... cut out at certain compression points on the track until the wire was actually cut!

this will be something like that....... im sure its just one connection, maybe at that fuse panel, that will be the culprit. we have narrowed it down... lets see if when i measure the continuity of all the injectors to ecu, what i find. THEN we can start thinking about getting a professional to help.

ok, lets review your help
:
"Internal combustion engine review:
---Compression with valve events occurring at the correct time.
---Spark at the correct time.
---Fuel in combustion chamber.
Engine runs"

yes - compression, and valve events timed correct
yes- spark at proper time
NO - No fuel in combustion chamber
NO - engine doesnt run

REAL helpful, thanks greg. you told us ^^^^^ what this entire thread has discussed for 2 pages... so , you are really trying to help?? doubt it. .

try again................ so, car runs on starter fluid.. injectors show voltage 12v on both terminals, but its not pulling to ground when start is attempted.

someone here, i think Dr bob gave the best idea...... he said that if ONE connection of the injectors/harness is open, that would effect the entire group.... so thats probably a great guess.. how about you?

dr bob

Mark --

I know the whole engine doesn't start thing can be really frustrating for you. At the same time, a [shrinking] group here is more than willing to help you, but we are a bit hamstrung by the fact that we are trying to help you diagnose based on the very narrow and often skewed/distorted bits of info you choose to share. Equally frustrating is your habit of questioning, rethinking/improving many of the diagnostic steps shared, rather than just doing them and reporting the results as requested. I appreciate that you are smarter than I am on lots of 928 stuff. I ask you to appreciate that there are a few areas where the knowledge experience and perspective of others might compliment your 928 knowledge where there are gaps. Beating on/berating/belittling those who respond to your requests for help will get you crickets in the future. There's a limited and shrinking pool of folks who have direct 928 and related diagnostic knowledge. Each time you alienate one directly, you also warn off others who don't want to endure you.

If you would rather not receive advice from someone here, ask them to kindly stay away from your threads. Most everybody will honor a simple request like that. You always have the "golden rule" option of putting them on your ignore list, as many I'm sure have done for your posts. You can then decide whether you want to look at what they have to share on a selective basis. Consider that posts, threads, questions about the cars are shared in the open here so that others in the future can learn from them.

In the meanwhile, understand the frustration that many have trying to answer your questions or share their knowledge and experience when you ask. If you'd rather not hear the suggestions, don't post the questions.


My too sense...

mark kibort

Dr Bob, i welcome all posts , even the ones that are critical of me or my ideas/descriptions. my only response back to greg was that it was NOT helpful and he is perpetuating the tension between us. i dont have any, but i just fire back when fired upon. that last thing in the world i would ever do would be to block someone. ive tried to be clear on my analysis... yes, it might have pieces missing, but keep in mind.. im doing this for a fellow 928'er, not my car. and ive invested a LOT of time on his project, not mine....... gregs advice wasnt meant to help it was a jab.. and it was cute and funny, and i responded with my own funny response. do you think i needed the
:Internal combustion engine review:
---Compression with valve events occurring at the correct time.
---Spark at the correct time.
---Fuel in combustion chamber.
Engine runs ????????????????????????????

Now, what "skewed" or "selective" information have i shared? i started out being very clear about many of the results of the investigations.... starter fluid was able to start it, but then i got advice on "green wire"etc.. Brian talked about "tempII" and again, i had to remind all about the fact that the injectors were not clicking. maybe im jumping ahead when you advise me to put a noid light on it, but this function could be and has been served by using the AC function on the DMM, its not clicking. there is no pulling the voltage to ground to allow the injector coil to flow current and release the fuel under pressure. Pump running, cycling, flow is about a half of water bottle in 2 seconds........ i dont think ive been selective on anything thing ive posted. your information has been best and VERY much appreciated btw, so thank you for that. (and all the others, because even the ones i know about not being the cause, its nice to hear others bring them up and ask so i can confirm my list of things it might not be, like "green wire" for example) So, this shouldn't be that hard . i havent looked at the wiring for a long time and forgot how the injectors fired on being pulled to ground by the ECU. i also didnt think about one wire in that bundle being able to stop the injectors from being pulled to ground to fire....... so, let me now go back with the electrical drawing and do a few logical continuity tests and get back to you . thanks again, mk

dr bob

Mark, these aren't "guesses", they are pointers to help you think about the system as a whole, and maybe how some simple damage in storage (mouse damage?) would offer the symptom you describe. The injection controller needs a solid very low resistance path to ground, sufficient to sink current through all the injectors firing at once. The controller does that through the ground connections directly to the block, pretty much the lowest-impedance path to alternator and then chassis ground. The injectors are functionally wired in parallel, and are batch-fired in parallel. You can apply a little basic Ohm's Law to determine how much current needs to pass to the ground point, if you know the resistance/impedance of one injector. The actual wiring is ganged to injectors in groups that start with eight in parallel, splitting into two groups of four inside the CE panel on the power side, and splitting into four groups of two by the time the circuits terminate at the injection controller. Testing those circuits is amazingly simple -- just follow the groupings in the wiring diagram. Since you have no injectors firing though, and have battery voltage everywhere on the loops with the injection and fuel pump relays closed, it would make a certain amount of sense to focus on the path(s) to ground back to and through the controller. Simple enough to look for voltage at the ground terminals on the controller while cranking; if none, it's grounded well and/or the controller isn't trying to sink the injector current. What causes the controller to try and sink that current? It depends on the connected sensors including air and coolant temp, key is on (circuit 15), engine is spinning, and eventually volumetric airflow and manifold pressure (1/vacuum) to decide how much fuel to share. The list is amazingly short and direct, therefore easy to test everything. Test. And report back what you find please. Clean every sensor connection you open for testing, verify for shorts, opens, and faults to ground WYAIT.

Problem solving is a disciplined technique, a method that has you test for and sequentially eliminate all possible causes. Start with the easiest, cheapest, and most common known causes of your symptom. The knowledge and experiences of others who have gone this way before you is quite valuable for determining the order to test. In your case, the sensors except for CPS are all easily verified with a DMM. You have an oscilloscope for testing the CPS signal while cranking, and everything terminates at the injection controller connections so you don't even need to open the hood to get clues about what's not working correctly. Got a good tach signal while cranking? A needle bounce would move the CPS lower on the list but not off of it. What did you fiddle with last on the car? Move that up in priority on the possible-causes list. This is not rocket surgery.

With the wiring diagrams and the car in my workbay, it would take much less time to find your problem than it takes to type this description. The Good News is that this post will hopefully help many more than just Scott's car.

Edit: No CPS. The LJet cars generate the tach signal from the reluctor and Hall pickup in the distributor, sent via the Green Wire to the injection controller. The fact that the car runs on starting fluid rules out the whole trigger circuit to the ignition. Does the tach move when running on starting fluid?, that would be a clue that the signal might not be making it to the injection controller either.

GregBBRD

Mark:

You wouldn't recognize "help" if it ran you over....your giant ego has a really tough time accepting any help.

However my "review" of the internal combustion engine was a good review, for everyone (including me)....sometimes it takes a giant "reset" to get up to speed.
Forget the green wire. Forget ignition. Forget the tach bouncing. Forget Temperature senders (for now.)
Concentrate on the issue.....try not to be distracted by shiny objects.

Pretty much everything you need to know, at this point, is in Dr. Bob's post #48.

But here's how to do it:

1. Build a noid light. Steal a noid light. Buy a noid light. Just get a noid light for Bosch injectors in your hands...somehow.
2. Disconnect all 8 injectors (Every single one.)
3. Put you noid light on the injector wire for #1 cylinder. Pulses or no pulses?
4. Now do that for #2 cylinder. Pulses or no pulses?

If the noid light pulses:
1. Hook back up the injectors to #1 and #2. Crank the engine over and see if they "click".
2. If not, they are stuck from lack of activity/bad fuel. Remove all of the injectors and have them cleaned.
3. If they do click....well that would be weird, since you've said they don't.

If the noid light does not pulse:
1. Get a 12 volt test light and see if there is 12 volts at each of the injector wires with the key on....check them all.
Power present, but no noid light:
1.The ground path from the injectors to ground on the other of the control unit is bad....somewhere.
Power not present:
2. The 12 volt power path from the relay board to the injectors is bad...somewhere.

Report back and I'll continue to try to help...if you can get over yourself and accept help.