I'm missing 9 volts. :p

What makes me mad is that the relay chart in my owner's manual doesn't mention anything about a separate injector relay, only mentions the fuel pump relay. So for all this week, I've been working AROUND the problem, and all I had to do was look at the relay chart provided by 928 Specialists. Another stupid thing I've done.

Which pin is giving you 3v? Are you getting 12v at Pin 87 (FI relay)?

Also, check contacts at Plug W on the CEP for clean.

Just keep asking...

Yes, I'm getting a solid 12 volts across 30 to 87 as I should. But the voltage that controls the coil is giving only 3 volts. I'm gonna go read again, but to a known good ground to verify.

tell us where the measurements come from...if you are losing voltage from coil 15 you may have a failing ballast resistor. I am not sure what you should read from coil 1 which comes from the Transistor Ignition unit.

I think he's talking about the coil within the fuel pump relay --- that is supposed to activate the relay.

I verified that I can get solid 12 volts by jumping the coil hot to a good ground outside the CE: door hinge.

So I jumped the coil 12 volts to ground, tried to start the car hoping to energize the injectors, no joy. Same old gripe, starts, explodes five times, stalls.

I've taken the battery out and put on a charger. Will try again on Saturday, will continue to study and research.

Oops, I may have messed up again. I think I jumped the wrong socket and subsequently sent no voltage to the injectors.

I need to eat some food, think some more, and try again when I get a good charge on the battery.

Next try, I will jump the hot 12 volts straight to the injector output socket. Sheesh, I'm feeling scattered right now.

Nonetheless, at least I verified the high resistance is in the output circuit, and not a power supply problem.

Which kind of leads me to the injector ground on the passenger side head.

Now I'm gonna do some more resistance readings.

I have a nice little set of extra ground cables that came with the voltage stabilizer. I may put one or two of them to use this weekend.

There are instructions for tracing these circuits buried in your manuals --- did you find it?
Don't risk burning up your electronics.


The injector relay has two 87's. Its a complex relay. You should build the three legged jumper wire and jumper it. Do you know which relay and how to jumper it? It needs 30 to 87 to 87. These relays are known to fail on one side and cause lots of problems.

Just had a good idea. I wonder if I have high resistance in the ignition switch?

I put the key in the ignition switch, rotated slowly and watched the resistance of around 70 ohms slowly reduce as I got closer to the crank position. In run/crank, I get 20 ohms. As I back away from run, where I know the car shuts off, I get slightly more than 20 ohms. So if I'm only getting 3 volts for injector power, and it goes through the ignition switch, and the switch is resisting by 20 ohms, and it only takes a little more to kill ignition, it seems to me that the switch is preventing the injectors from getting full power.

Yeah, 20 ohms seems like it shouldn't be enough to prevent the injectors from operating, but at the kill position, I'm getting just a little bit more resistance.

I read out the injector ground. At first, it gave 20 ohms, too, but with a better ground on the water bridge, I was able to get .01 ohms. So I'm thinking the injector ground is okay.....for now.

I think I have multiple small problems. I've dealt with this before on Hornets. A bunch of small imperfections all worked together to create one big, ugly gripe.

High resistance in the ignition switch, weak fuel pump (have not verified yet), degraded fuel pressure regulators and damper, and very likely, grounds that have degraded after a year of operation.

The ignition switch has given more problems the entire year, but solely in the accessories circuit. With power on, tilt steering wheel upward, lose power to the stereo, but comes back on shortly. I've reached under the pod and wiggled the switch harness, but could never duplicate. It only happens when the wheel is tilted upward to the full stop.

I have to keep reminding myself that there is an ignition control unit in between the CE and the injectors. So I focused on the power supply circuits, and was happy to see the switch rotation showed another small issue.

There are a few mechanical point-type contacts inside the switches. I'm sitting here staring at one that was taken apart. They are know failure points. Shouldn't you replace that? Grounds cleaning, panel cleaning. It'll all get better like on the plane

My understanding of the FP relay...DIN
30 always hot (some have a dedicated in-line fuse on the relay) from Bat.
15 Switched Power 12v to a Transistor within the relay that steps voltage down (unsure of the v) to energize the internal coil (to the FP) closing the circuit allowing 87 to pass voltage (12v from 30) to the FP. Independent of the FI relay.

Did you replace the any/all TEMP, O2, Airflow, Throttle (2) sensors and/or confirm their values...these directly interact with the Control Unit??

as Landseer said, You are running a serious risk of burning up your electronics.
How about posting a picture of the wiring diagram you are using, and showing us exactly where you are jumping, measuring the resistance, etc.

Great question..
I'm using as a reference http://www.cannell.co.uk/928_Workshop_Manuals/1982%20Current%20Flow%20diagram.pdf

The alarm will interrupt it.
So will corrosion at fuse 22.
Or problems behind the panel.

The panel needs to be removed, cleaned and re-fused.
All grounds cleaned.

All the rest is futile til that's done.


Don't make me drive down there, Maleficio. ( wish I could help, but have stuff here that needs to be done this weekend)

I'm using the workshop schematics that came with the car.

Hatch alarm connection is disconnected. Was having random alarm activations.

Right now I'm focusing on running loads of small tests to accumulate as much odd data that I can. I have no care to get the car running right now. I want to drag a fine-toothed comb across the systems and refine them all, then worry about final operation. Thanks for the suggestions, very much appreciated.

I wished the schematics were similar to what I'm used to: Hornets, in which the entire system is laid out in one long schematic.

These are broken apart, linked only by power supply lines. I feel I could move so much faster if they were laid out like Hornet schematics.

I'm accustommed to studying a schematic, and efficiently pointing a gun at a possibly failed part and being right the first time. I find myself wrong at every turn. But it's a challenge that I need.

I was reading a thread on Bannlist today about my exact problem. Three sharks were healed within that thread, and all by a failed injector relay. My relay is solid. A relay couldn't be more simple: a coil circuit, and a power circuit.

My problem emulates a bad relay problem perfectly, but the issues lie elsewhere.

I'm looking at the ignition switch as an obvious culprit, robbing voltage from the injector circuit, over-riding the control unit's control.

But whenthe car was running, the intermittent cuts in fuel flow indicate a broken wire moreso than high resistance. Nonetheless, a new switch is required.

I remember when you guys were talking me into buying this car, you said the issues were 75% electrical. You were right. And I feel right at home.

Don't even bother continuing with measurements. Its all wrong until you clean.

+1...start with the W plug, the related contacts at the Control Unit (CU), sensors, the FP and FI relay paths. And confirm the Alarm is properly connected or dis-connected.

Since you have good/persistent 12v at 87 of FI relay a key problem is in the other side of the Injectors which come from the CU and prior to CU the sensors or between Plug W(2-5) from 87 (FI).

Here's a nice writeup on how the fuel pressure regulator works:

The regulator's job is to keep the pressure in the fuel system to a constant psi. Id does this with the spring-loaded diaphragm that controls a valve. The valve, when opened by excessive pressure in the fuel lines, uncovers a fuel line that returns excess fuel to the fuel tank. The vacuum connection is there to help reduce emissions during deceleration. During deceleration, the vacuum connection serves to open the fuel return valve wider, which reduces pressure in the system and prevents excess hydrocarbon emissions due to less fuel being injected as a result of the lower pressure in the system. This is very nicely designed device in that it provedes for an automatic self-adjusting pressure regulator and emissions control device all rolled into one. The simplicity of the design also contributes to it's reliability.

I've lost track here, we are talking L-Jet - it is not such a difficult system to troubleshoot - but you need to get back to basics and start over - you are hitting so many different areas you will never figure it out - listen to Chris ( Landseer) and get the grounds sorted, then get into the FI. Don't worry about the functional description of how the regulator, works. Get the electrical side right first then the fuel, the the spark - and you may have a shot at getting this running before winter sets in.
If Chris, or I or many others were close enough to you we could have you running in a day or so, I believe ( at current shop rates, of course :-)

I'm researching and learning as much as I can while it's still freaking cold as hell outside. When it FINALLY starts to warm up I can get serious about going through the car. I am so sick of winter!

Where exactly is 'your hell' must be way north !
PM me and i'll send you the Bosch manual on the L-jet - may help you out.
Neil

I'm in Virginia Beach. I have to do all my work on the car outside.

Do you have an electronic copy of the Bosch manual?

Ha, my daughter is moving up to Yorktown in May, with her 84 Euro! I'll be bringing it up there. from South Carolina.
Yes, I have an electronic copy, pm me your email and i'll send it to you.
Neil

Ha ha with it sooooo cold out , its like you post for a answer so you can run right out there and fix , just cant stay out there very long, ive gone from 3sec of death at a time jan/feb. and now march 15 minutes. when you can really move around when warmer you tend to want to dig in and can dig in you solve alot of issues but soooo cold out now, New Hampshire.

I wouldnt rule out the fuel injector relay its completely possible that you need a new another one and another new one. And when you start the car move the finj relay up down side different positions. I got my ice scraper as arm extension to start it. And when you pull the ce panel forward the long green wire? on left can get pulled out along with pliers in that area push any back onto pins if loose. if you follow finj relay one of the leads spaghettis through to the left bottom of panel.

Speaking of cold , the pcar is also , i say, you get alot of symptoms when cold that just simply arent there when warm season gets here. i think the pcar just fakes it and wants somebody out there to cuddle with her in the cold. lol.

:D

Thanks, Fausty.

I honestly do think my ignition switch is the main culprit. I will continue to clean grounds, etc.

The cold start valve is powered by the battery, and it works, which is why the engine tries to light off, but can't run because the injectors are not powered up.

The cold start valve is driven via a known-to-fail block thermoswitch located on the passenger side of the front of the water bridge or block. If it fails, it floods the car. It will allow the car to start and run usually flawlessly until it gets, say cool below 50 or so and then it causes trouble.

Replace, preemptively if your values allow it.

Chris, that switch has a transistor in it, I don't know how to read it. But you're right, it's probably bad, too.

The best-bet money in these is replacing sensors and wear parts, and the time investment in the systematic cleaning of electrical.

I've worked trying to make sense of things, but realize I never will. It doesn't matter whether A, B, C, D or E is causing the problem on a 29 year old car. Replace them all if possible, because if its A this week, it'll be C & E next week.

Go thru the lists that we and the guys before us have empirically identified as wear parts or causes. Its the easiest answer and ultimately the most economical.

Yes, I'm pissed that I don't know the root cause. On the other hand, I seem to have headed-off so much stuff that others complain about.

Not an expert, just an adapter. Keeping 5 running everyday has been an experience.