Tii runs poorly and lacks power, gets worse as it warms up

[Sean Murphy]

Hi all,

 

I recently returned to the world of '02s with the purchase of a '74tii through BaT.  I've had two others, both carburated, so it's a bit of a different world for me. 

Shortly after the car was delivered it started running quite poorly and eventually died, seemingly as the engine warmed up.  Allow it time to cool and it runs better, but still lacks power and pops a bit... unsure if it's backfiring.

The car has been in a shop here in Tampa for a few weeks and has some new parts, including a new coil, cap, and a new belt to the pump.  Compression tested fine on all four, and I'm told fuel pressure is good. 

So far, no change in the performance.  It's just not driveable.  As it stands, they suspect the fuel injection pump may need to be serviced.

The engine is out of a '72tii and was recently pulled while the car was painted.  

 

I'm going to invest time here in the forum and tech articles to educate myself on the pump and fuel system.  I'll be bringing the car back to my own garage in the next few days if they can't determine the issue.

Before going too nuts rebuilding or replacing more parts, I figured I would start by ensuring everything is timed and adjusted the way it's supposed to be, including the linkage.

 

My ask... if anyone has some ideas on how you would approach this one I'd greatly appreciate the guidance.  I'm a bit chapped I've owned the car a month and have driven it less than three miles!

 

Cheers

 

Edited June 2, 2023 by Sean Murphy
Removed some text

[Cruzr]

Hi Sean: the basics first. Did the shop replace the condenser, spark plugs and fuel filter? Did they try to set the timing? You mind sharing the vin for the engine and the car?

Before fiddling with the K pump, make sure all other possibilities are addressed.

[Sean Murphy]

Hi Cruzr, thanks for the reply.

Don't mind sharing at all.

Car: 2781386 - manufactured on February 21st, 1974

Engine: 2761877 - from the auction, probably a very late May 1972 build

 

I totally agree on the basics.  I'm told the timing is good, and some other bits are new as well.  

BMW Coil, Condenser, and new plugs.  The plastic dust protector had been cracked and bits were mixed in with the belt, so they replaced the cover and belt.

 

I don't have the values but was told the inlet pressure at the KF pump is good, and the output pressure on cylinders 1,2 and 3 is good, but 4 is low.  Once the car is back in my hands this is an area I wanted to examine.

 

I see there are a few other threads here that seem to describe similar issues to what I'm experiencing, such as this one.

Tii hesitation and popping...

 

[Mike G]

Check function of warm up regulator and cold start injector. Check timing on new fuel pump belt. Being one tooth off can cause issues. 

[Mike G]

My two favorite tii articles. 
 

 

[Sean Murphy]

13 minutes ago, Mike G said:

Check function of warm up regulator and cold start injector. Check timing on new fuel pump belt. Being one tooth off can cause issues. 

Thanks, Mike.
My cold start injector has been wired to a button under the dash.  My longer-term goal would be to restore that to its original state.  I haven't even started researching that future project yet.

 

I'm told the fuel pump belt is aligned correctly.  

I am curious about the WUR, and see there's a rebuild kit on the site if it wasn't operating correctly.  I'll have to dive into the specifics to see if it is adjusted correctly.

Appreciate the articles... a great read for this afternoon!

[Sean Murphy]

1 hour ago, Cruzr said:

Hi Sean: the basics first. Did the shop replace the condenser, spark plugs and fuel filter? Did they try to set the timing? You mind sharing the vin for the engine and the car?

Before fiddling with the K pump, make sure all other possibilities are addressed.

 

Cruzr, I overlooked one of your questions... fuel filter has NOT been replaced yet.  I'll have to dive into the fuel system a bit deeper and clean/replace those.

 

I do have a question if anyone knows the answer... should the electric fuel pump run continuously once the key is turned?  I can't check it at the moment, but it seemed a bit noisy and I wondered if it should turn off once pressure is built up in the line.

[Mike G]

9 minutes ago, Sean Murphy said:

 

Cruzr, I overlooked one of your questions... fuel filter has NOT been replaced yet.  I'll have to dive into the fuel system a bit deeper and clean/replace those.

 

I do have a question if anyone knows the answer... should the electric fuel pump run continuously once the key is turned?  I can't check it at the moment, but it seemed a bit noisy and I wondered if it should turn off once pressure is built up in the line.

it runs continuously as there’s a return line to the tank. They are noisy.

[Mike Self]

Since it seems to run well when cold (or as cold as it gets in Tampa) and then starts to act up once the engine's warmed, the problem could be either ignition or fuel.  I'd do electrical first, as it's easier.

 

When the engine is all warmed up and misbehaving, start with the spark plugs and work your way back to the coil, checking for spark at each point.  A coil or condenser that fails when hot can cause your symptoms.  Once you've absolved the ignition system of blame, then start looking at the injection system.  And there, as was pointed out I would suspect the cold start injector and the warm up regulator.   If you 're getting a lot of black smoke out of the tail pipe just before it stalls out, then suspect too much fuel.  

 

And just on general principles, replace the fuel filter unless you know it's new or nearly so. 

 

Let us know what you find.  All additional knowledge pertaining to the arcane world of K-fish is welcome here!

 

mike

[markmac]

There was a really good article about tii kugelfische injection in a European Car Magazine article a Loooooooooong time ago.  It was titled (aptly) ' Kugelfishin ', I have it somewhere, if I can locate it I'll post it up.  Maybe someone else has it.

[Mike G]

More afternoon light reading

 

 

 

 

[TobyB]

"BaT"

 

The engine bay has been wrapped with a bad case of runs like crap.  

The seller reports this case was specially forged in the fires of bullshit,

and lovingly applied with specialized tongans of heartfulness.

 

Sorry, tii's aren't something I know much about, but overblown marketing and

puffy, inflated fakery runs rampant.

 

t

 

[tzei]

If those plastic runners leaks then crappy running ensues.

 

start pilot etc. is your friend to find out.

Edited June 3, 2023 by tzei

[Conserv]

Although you also need to clean out 2(?) fuel filters that take the form of screen strainers (one entering the fuel pump and one entering the Kugelfischer pump), the filter most likely to bring a tii to its knees (starts but won’t run) is the filter screen on the fuel-tank pickup. And your primary fuel filter — circled in red on the first photo below — doesn’t look like anything I’ve ever seen on a tii. The second photo shows the much smaller OEM filter, snuggled up to the radiator.

 

Regards,

 

Steve

 

 

[ColinK]

There's a fuel filter on the bottom of the pick up in the fuel tank. I'd check that and possibly replace the fuel in the tank while you're at it. When my fuel pump died years ago, it went slowly and the care would barely run. 

So that could be another candidate but go with the basics first. 

good luck