ozbon

tii Starts then stalls

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Hi, I posted this in another forum and no help/response after a week. Hopefully someone here can help.

 

Searched the net and was encouraged by a thread that resembled my problem. The ehow thread (non-BMW or tii specific) referred to a faulty fuel pump relay. On further searching I discovered that the tii did not utilize a fuel pump relay. I found this site and hope to get some help here.

My 74 tii is normally only driven once or twice a week, a stock restoration in good condition, no known problems. After a 2 month 'holiday' it started without problems, drove it a few times and on the last occasion it just decided to stall while driving and just wouldn't start again. I had it towed home. Had not done anything to the tii and now a few weeks later I tried starting it and to my surprise it started after a few cranks but died a couple of seconds later. Tried it a few times with the same result. 

My thoughts at this stage: it starts, therefore the ignition, timing and cold start must be ok. So it must be fuel related? Checked the fuel return to the gas tank (per McCartney's book) and it checked out (>850cc in 30 seconds). So that means the fuel pump is ok? 
Any thoughts on what to check next?
TIA

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(edited)

Hang in there, someone definitely more knowledgable than me about K fish injection will chime in but from my lay position the starting and then stalling would indicate that your cold start injector (it is a single, separate injector) is working but your k fish pump is not. I am pretty sure that there is a filter screen behind the incoming fuel Union to the pump. This may be blocked (but perhaps not if the fuel is readily returning). 

 

Lots of info available on here by searching. 

Edited by Simeon

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49 minutes ago, Simeon said:

Hang in there, someone definitely more knowledgable than me about K fish injection will chime in but from my lay position the starting and then stalling would indicate that your cold start injector (it is a single, separate injector) is working but your k fish pump is not. I am pretty sure that there is a filter screen behind the incoming fuel Union to the pump. This may be blocked (but perhaps not if the fuel is readily returning). 

 

Lots of info available on here by searching. 

Simeon, thanks for the encouragement. Yeah, I read the posts about blocked filters (tank, fuel pump input, fuel filter, FI input filter, pressure regulator filter). I figured if the 850cc was returning to the gas tank, then the filters should be ok? And it's starting so the ignition and timing should be ok? Someone help clear my confusion!

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(edited)

I'm NOT one of the "tii whisperers" that frequent this forum, but it might be something as simple as the filters, starting with the fuel tank filter (screen).  Then there's a filter (screen) at the pump, the primary filter next to the radiator, and another filter (screen) at the Kugelfischer pump.  I'd search the forum not only on "tii troubleshooting" and "tii filter", but also look particularly for a thread by user thehackmechanic (Rob Siegel) where Rob step-by-step diagnoses running issues with user achman's tii: it's an excellent example of an approach to tii diagnosis.  There are lots more, but that thread stands out.

 

Good luck,

 

Steve

 

This might be the thread: it's long!

 

 

Edited by Conserv

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(edited)
On August 2, 2016 at 9:11 AM, ozbon said:

....I figured if the 850cc was returning to the gas tank, then the filters should be ok?....

 

I hear you but if my tii exhibited the same problem, I'd probably immediately pull and replace/clean (as applicable) the filters starting with the in-tank screen, just to: (a.) assess the amount of crud in the fuel system; and (b.) eliminate the filters -- low-hanging fruit -- as a cause.  Certainly, the pump drive belts wear out and injection nozzles accumulate debris, but I can't see attacking those types of items before I've even examined my car's filters.

 

Regards,

 

Steve

 

Edited by Conserv

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10 minutes ago, Conserv said:

 

I hear you but if my tii exhibited the same problem, I'd probably immediately pull and replace/clean (as applicable) the filters starting with the in-tank screen...

Thanks Steve. Night time here in oz, I'll check the filters tomorrow and report back, and probably also have a look at the pump drive belt. I'll check out the link you provided as well. 

Cheers.

 

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Sounds like a broken KF belt. You can loosen the top bolts holding the black plastic belt cover, and pull the cover back a bit. It you see only the toothed wheel, the belt is broken. The car will start via the cold start injector, but immediately die since no fuel to injector. Pressure from electric pump just sends fuel through the return back to the tank. Best of luck--Fred

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5 minutes ago, FB73tii said:

Sounds like a broken KF belt. ..

Thanks Fred, hope you're right! I'll check tomorrow.

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Sounds like fuel.

my Tii used to do the same. It may be more than one issue, but fuel sounds very possible.

1. Check a constant fuel flow

2. Blow through all pipes

3. Clean and or replace all filters, does yours have the large metal filter by the rad?

4. For the cold start, make sure your warm up regulator is functioning correctly, if not it wont run after the cold start injector has finished its job, Mikes book tells you how to check and set it.

5. Check the pump belt

6. Report back and let's us know

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(edited)

+1 FB73 ..... my first guess is a broken KF belt, because that's the easiest to diagnose and fix.

       A broken belt is the "main" symptom of happened to you:  you're out driving, then the engine quits, and won't start again ..... and because the engine is hot, you won't get the "cold start gas spritz."
        Then, when the engine is cold, you get the spritz which will fire the engine very briefly, and nothing more.

 

Cheers,

 

Carl

 

Edited by OriginalOwner

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13 hours ago, OriginalOwner said:

+1 FB73 ..... my first guess is a broken KF belt, because that's the easiest to diagnose and fix..............

Hi everyone, Guess what? I found a broken KF belt! Fred and Carl: you were both spot on! Quite relieved but I have not replaced the belt as yet to confirm that's the problem but it's a good bet me thinks. It was quite a mess in there - belt was twisted, broken in 2 pieces with strands wrapped around the crankshaft end. I've set all the timing marks (TDC etc) in readiness for the belt replacement. Now need to get the lower belt cover off so I can clean up all the mess for the new belt. I'll post again when it's up and running. Thanks all for your support.

Cheers.

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Maybe you've already got this covered, but make sure TDC is with #1 valves both closed, i.e., ready to fire on #1. The camshaft can be 180° out of sync using the external timing marks only.

I think you've nailed the problem, it should run fine with a new belt.

Jerry

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6 minutes ago, JerryC said:

Maybe you've already got this covered, but make sure TDC is with #1 valves both closed, i.e., ready to fire on #1. ..

Thanks Jerry. Yeah, I had the valve cover off to confirm TDC is with #1 valves both closed. Also took the opportunity to re-check valve clearance on all 8 valves - all spot on at 7 thou. Quite surprised as the last time I set them was some 15 years ago LOL!

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tii's back on the road and purring like a cat with the new KF belt. Chewed belt... Did someone mention scheduled maintenance? Got what I deserved with the lack thereof. I'll be paying more attention from now on!

Cheers

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TOTALLY AWESOME !!!!

 

speaking of KF belts and scheduled maintenance ...... I never ever once gave a thought to replacing mine and I drove the original belt until it broke somewhere beyond 200,000 miles.

 

Cheers,

 

Carl

 

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