Fuel Injection Bobbing

[buckweber]

1974TII with fuel injection hasn't run in 15 years.   I got it running after a year and a half.  Car idles fine.   Car will not wrap up and bogs down when the throttle is mashed in all gears.  Most articles in forum troubleshoot carburated cars.   Is there any links to how I can troubleshoot a fuel injected car.    Any help would be most appreciated

[jireland2002]

More info would help.  After it boggs does it eventually reach a reasonable speed?  Most "fuel" problems are actually ignition issues.

Rig up a switch to apply 12 volts to the cold start injector.  Activate it when you step into the gas and see if it makes a difference.  If the car takes off well you have a fuel shortage.

 

[chargin]

As another possibility, maybe the electric pump could be week and not able to supply fuel at higher loads.

Could be a good time to visit a experienced professional. After I put mine together I sent it to a Pro to get it dialed, I was VERY happy with the result and figured it was well worth the money.

[PaulTWinterton]

Here we go again.  At first glance, I'm thinking of all the crud at the bottom of the tank and the dry seals / dirty filters along the fuel route.  THEN I think of all the adjustments to the MFI that likely need to be made to make the car run properly throughout the rpm range.  Air leaks?  Injectors clean?  Ignition timing?

 

You could read through the Kugelfischer (MFI) maintenance manual (BMWtii_pump_guide_v1.pdf) and clean your fuel system filters, including the one in the  tank.

 

Or you could take it to a Pro like Chargin says and get it taken care of.

 

Good luck!

[Adamha]

1- Fuel delivery within spec to the pump? Search the forum for the test. It's easy. Then check your pump screen.

2- Spark. Should be working to factory spec.

 

Those two things solve 90% of the issues. After that it get's more interesting.

[Mike Self]

Find a copy of McCartney's second 2002 restoration book.  It has a very comprehensive tuning/troubleshooting section for the Kugelfisher injection system that doesn't involve using unobtanium factory tools to work on or adjust the system.

 

mike

[buckweber]

Thanks for all the responses: 

More Info:

-pulled gas tank and had it treated at a radiator shop.

-replaced screen on pickup in gas tank.

-replaced all soft and hard gas lines from tank to the kugelfisher

-upgraded fuel pump as recommended on another site.  (I believe a 3 series pump)

-removed and cleaned all fuel injectors.

[buckweber]

I am struggling with the timing.   It appears to be in time utilizing the crank pully and indicator on timing change cover.

However, I do not see the ball on the flywheel as indicated in some of the documents.

I will work through it again as I am thinking I may be doing it wrong.

I did take off the valve cover and at tom dead center I do see a white line on the flywheel.  not sure if it is the ball or not.   I am old and vision isn't what it used to be.

[buckweber]

The car does eventually get up to speed and picks up to a higher RPM.  It just stumbles over time to get there.   A previous owner did hot wire the cold start injector to a switch for some reason but it doesn't have power.   I will look at that and then try  what jireland2002 suggests.

[saaron]

I put a mark on the crank pulley so I could time it off the front.  I had to find TDC on #1 first, to make sure I was putting it in the right place.  The ball method never worked for me.  

 

I'm not an expert, but the distributor can have issues - I've heard things like the spring/weight system inside wears, so the timing doesn't change the way it is supposed to as RPM increases.  Advanced Distributors will rebuild your distributor for a few hundred bucks.  Many folks love the 123 programmable distributor, but it is more money, and there is a "tinker factor" - you have to program it, etc.  Some people love that, some people don't appreciate that.  

 

Rob Siegel wrote this post on the tii:

 

Keep working on it, you'll get it.  

 

Scott

 

[thehackmechanic]

If you've:

--Done the back-to-front cleaning of the fuel system, including the screen in the inlet to the fuel pump, the one in the Kfish pump, and replaced the canister filter

--Verified that fuel pressure is at or near 29 psi

--Put in fresh plugs and timed the ignition properly and verified that the distributor is advancing

--Verified that the warm-up regulator on the pump extends and that the "verboten" screw is sitting on its stop

--Ruled out vacuum leaks

 

Then it's time to pull the injectors and take them to a shop to be tested for leakage and spray pattern. Any diesel injection shop should be able to test them.

 

If they fail, that's a different question.

 

Rob

 

 

 

Edited May 24, 2017 by thehackmechanic

[buckweber]

i ,messed with it some and got the cold injector to work manually.  It is pouring rain so I will give it a shot tomorrow.

The car idles fine and when in neutral Revs freely with no issues.

is there an electronic ignition distributor that that can replace the existing.  

It appears that soemone may nave changed tou the points distributor as when I went to purchase a rotor and cap the cap recommended for the 74 does not fit.  

The model number says it came from a 68.

When I replaced the rotror, cap, points and condensor the car wouldn't run.   I put all the old stuff back in as it was in pretty good shape and the car cranked right up.

 

Thanks to all for the help as I don't have the cash available to take it to a shop.   I will keep banging on it.

 

 

[thehackmechanic]

The "123 Ignition" distributor is fully electronic -- both electronic triggering and electronic advance. Folks love them. But they're steep -- about $500.

 

The Ireland distributor has electronic triggering and mechanical advance and is inexpensive -- about $170 -- but the electronic triggering module (which is not a Pertronix; it's a different brand) appears to have a high failure rate.

 

The Pertronix electronic triggering module is cheap -- about $70 -- and is every reliable as long as it is installed correctly, but you still need a distributor whose mechanical advance is working properly.

 

You can paint the TDC mark on your crankshaft pulley, take a timing light, shine it on the mark, rev up the engine, and if the mark doesn't move, then your distributor isn't advancing. If it moves, then, to a first approximation, your distributor is working, in that it's advancing. How accurately it's advancing is another question; you'd need to use the timing light more carefully to tell.

[buckweber]

i marked the pully and it does appear advance.  Have no idea how to measure actual advance.

Could a bad coil cause this behavior.   It looks ancient.   I tested it with a volt meter as documented and it tested ok.

[thehackmechanic]

It's possible, but coils are usually pretty long-lived. When they go bad, they usually die completely or exhibit intermittent behavior with heat or vibration.

 

I would set the timing, then see where you are. The timing ball can be very difficult to see through the inspection hole. You can use the timing mark on the crankshaft pulley instead, but you need an advance timing light -- a timing light into which you can dial an advance number. Then you can check the "total advance." You can dial in an advance number of 32 degrees, then rev the engine up to highway rpm -- say, 3500 -- and time it so that the TDC mark lines up with the pointer. In this way, you're setting it so that the total advance is 32 degrees. 

 

I'd be surprised, though, if it's a timing issue.

 

When it's idling, put a finger on each of the plastic injection lines and make sure you can feel fuel pulsing through each one. If you don't feel pulsation in one line, then fuel isn't being pumped through it. If you pull the spark plug wire off that line, the engine will idle no differently. If you find that, report back. It's pretty simple to check for a stuck plunger in the pump and to free it. That's certainly possible with a tii that's sat for years.

Edited May 24, 2017 by thehackmechanic