Crankcase Breather Hose, Now Fuel Pump

[rocketbrick]

Hey crew,

My frustrations with this 1993 K75S seem to be endless. I had it running last month after swapping in some extra fuel injectors to get the bike running after bringing it up from North Carolina, where it had sat for 4 years in a trailer. I cleaned all the degraded rubber in the tank as a starting point.

I also replaced:
- Fuel pump/screen
- Fuel filter
- Fuel lines, in and outside tank
- Fuel injectors
- All brake lines (unrelated to fuel system)
- Crankcase breather hose

So anyway, the bike was running pretty sluggish, not revving over 3000RPM. I noticed and swapped the injectors back to the newly-cleaned Bosch ones, which made the bike run incredibly, when the same issue appeared last Friday. I noticed the crankcase breather hose was torn, so I put on a brand new one.

After that, I cleaned the injectors again, cleaned out the tank once more, put new lines on everything, including both ends of the fuel rail and the return line on the tank. And after that, I start everything up, and BAM - no fuel pump whine on ignition stab. It worked maybe two days ago, I'm not sure what's going on with it. Does it need a certain voltage to run? I'm charging the battery but I thought I'd ask in the meantime.

Thanks in advance!

[MIbrick]

Don't know what minimum voltage is for the fuel pump, but have you run Deoxit over the harness connector for the tank (and everything else while you're at it)? I mean, first thing I'd check is I didn't forget to reconnect the tank harness, but that's me knowing how I do things sometimes (get the big, hard stuff done, miss the small easy stuff).

[sooprvylyn]

I'd also double check the wires going to the pump terminals are tight since you've been in there messing w things.

[rocketbrick]

So, it was a fuse. Looks like I put a defective one in there because it was completely severed (not burnt out). However, now I’m not getting a start at all. It’s nearly turning over. We have confirmed fuel pressure and all! Here’s a video that will show what I mean. Any ideas? Fuel pump is getting power now. Here’s a clip of what’s going on:

https://youtube.com/shorts/cA596gIIWPc?si=XvcbCGMQdXV9-Jki

[K1300S]

Are you repeatedly pushing the start button in the video?  If so,  don't.   Push it and hold it for a few seconds...

[rocketbrick]

Yeah, tried that too. Not working as well but we’re getting a semblance of an idle. BTW, there is a new battery and properly gapped new spark plugs. I also replaced the spark plug wires to my spare set.
https://youtube.com/shorts/GtAt1Bcfygs?si=J7Jh8ivtQIZtHXeb

[Laitch]

Does it need a certain voltage to run? I'm charging the battery but I thought I'd ask in the meantime.

It needs 12V to run sufficiently. Check on both sides of the connector under the right side of the tank when the starter is running.

[rocketbrick]

It needs 12V to run sufficiently. Check on both sides of the connector under the right side of the tank when the starter is running.

Thanks for the reply, Laitch!

I figured out that issue was a defective fuse. We're onto a whole other problem now 

[Laitch]

What's the "other" problem?

[rocketbrick]

What's the "other" problem?

Not sure if you caught the above. Getting a really bad idle. See the video here:
https://youtube.com/shorts/GtAt1Bcfygs?si=J7Jh8ivtQIZtHXeb

All new parts:
- Fuel pump/screen
- Fuel filter
- Fuel lines, in and outside tank
- Fuel injectors
- Spark plugs
- Replacement spark plug wires
- Crankcase breather hose

I saw this Chris Harris trick, but I'm not sure if it's the right move for me yet.

[Laitch]

Not sure if you caught the above. Getting a really bad idle.

I caught it alright but my immune system defeated it.  Does this mean you already checked for 12V on both sides of the fuel pump connector when the starter was running?

[rocketbrick]

I caught it alright but my immune system defeated it.  Does this mean you already checked for 12V on both sides of the fuel pump connector when the starter was running?

All good

Yep! 12V on both sides

[Laitch]

Did you check it at the fuel pump connection? 

[rocketbrick]

Did you check it at the fuel pump connection? 

Yeah, checked at connector and at battery

[Laitch]

Are you indicating you checked it at the terminal of the fuel pump?

[rocketbrick]

That's correct - checked it at the terminals of the fuel pump.

However, I did shoot some starting fluid into the intake and it started up for a few seconds. That leads me to believe the fuel pressure is off, which I'm sure is what you were thinking!

So my jumping-to-conclusion questions:

- If it's the fuel injectors, what would you recommend for cleaning (again)? I've soaked in seafoam/fuel injector cleaner, and did a pressure clean w/ brake clean with one of those pulse power kits you can get on amazon.
- If it is the fuel pump and I'm getting some kind of false reading, I have a spare fuel sender, but I suppose I can always just re-solder some new wires onto it.

EDIT: Cleaned injectors with my home cleaning kit and some carb clean. Spray pattern is uniform. Everything is back together and we have the same issue. I'm at a loss for words, no idea what it could possibly be. I've done everything I can think of

[Laitch]

No magic here. Check the fuel pressure in the delivery line as illustrated below—photo from Vogel's troubleshooting manual.

[rocketbrick]

Guess I have to get a pressure gauge 

Anything in the meantime that I can take a look at? Is there something I'm missing here?

[Laitch]

You may not need to buy one. Napa, Autozone or Pep Boys might loan you one with a credit card security deposit. Earlier in the discussion it was suggested by Mlbrick that you clean all connectors and plugs with DeoxIT D5. It's the electronic cleaner that's most often recommended here; it has worked well for me. There are lots of points that interrupt fuel supply: dirty electrical connectors, loose battery connections, a dirty control unit plug, bad grounds, a faulty temperature sensor, and a faulty air flow meter. Don't worry. There are plenty of chances to get moving again.    Keep checking for results as you move along so you might discover the root of the problem.

[rocketbrick]

Thanks for the reassurance! I’ll give it a shot. The bike was sitting for 5 years before I got to it, so of course the fuel gunked everything up. I really thought I got everything, so I feel that in the back of my
Mind that it’s somehow the culprit.

I’ll see if I can borrow one. Stay tuned

[rocketbrick]

No magic here. Check the fuel pressure in the delivery line as illustrated below—photo from Vogel's troubleshooting manual.

Good news and bad news, Laitch - the great news is that I'm reading perfect fuel pressure. The bad news is that I'm reading perfect fuel pressure, which rules out the possibility of the fuel regulator :(

Check it out here, perfect PSI: https://youtube.com/shorts/9OdVeQ42cZw?si=w3Z4IjzrGf-VT1xC

What do you think should be next?

[Laitch]

The bad news  . . .

There is no bad news, yet. Discovery needs to start somewhere; in the back of your mind you thought it might be a fuel issue so that’s where you’ve started. You’re engaged in orderly diagnosis of a problem—in this case the fuel system. You’ve ruled out the fuel pump, its delivery/recovery lines, and the fuel pressure regulator as problems. Doe each injector pulse during cranking? Can you hear its pulses clicking?

[frankenduck]

Try reseating the connectors for the HES, ICU and L-Jetronic.

[rocketbrick]

Good point, Laitch!  Confirmed that the injectors are clicking. Used a flathead to listen in, and also plugged them into a rig to clean and test.

Tried researing the jettronic, where are the other two? The clip on the JT is a bit crappy so I might swap it out for the donor one

[Laitch]

If you haven't purchased DeoxIT D5, you'd better get on that. This puppy's electrical connections need to be cleaned.

Describe how the latch on the Jetronic control is "crappy." It's pretty simple. The Ignition Contol Unit is within the frame forward of the relay box. The Hall Effect Sensor Unit plug location is #3 on diagram below. Its connector is pictured in photo.