86 TR Won't Idle

when you drive you have full power or less than normal?

 

Copy and pasted from earlier post. But this solved my idle prooblem:

The idle speed is adjusted with air bypass screws located at rear of the throttle bodies. It's a large brass hex bolt. What ever you do, make very small adjustments. The TR's motor runs like to 6 cylinders engines, so it would be good to know if your fuel mixtures are balanced. Do you have access to a gas analyzer?

 

You didn't look hard enough

For a sudden change from good running to the exact symptom that you describe (and assuming it's a US version), the first thing to do is confirm/deny if the protection relay/fuse is working or not (i.e., measure the voltage on the red wire at the water thermoswitch when the engine is running or cranking). Do a search on something like "red wire protection relay" that I've posted for prior threads with pics and instructions.

 

The symptom is weak idle that only stays running by pumping the gas pedal and no power. The instructions include a way to test without running or cranking the engine:

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Wrong connectors -- those are the TTS and 2-channel thermister mounted on top of the water Y-pipe. The water thermoswitch is mounted on the LH side of the water Y-pipe sticking out horizontally and has two spade connectors (one red wire and one orange-black wire). You should be able to touch your voltmeter "+" probe to the red wire terminal without unplugging it (and just touch the "-" probe of the voltmeter to the bare cylinder head or engine block).

 

That's good and bad news -- are you sure that you aren't running on just one bank? I.e.:

1. Do you have spark on both banks? (you'll need your assistant).

2. If you unplug the fuel pump relays and touch a wire from the 30 female metal terminal in the relay socket to the 87 female metal terminal in the relay socket do you hear the corresponding fuel pump run? (PS the labeling of who's who on the fuse-relay panel relates to where the fuel pump is mounted -- not which bank it serves.)
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I'd go with the plunger in one of the fuel distributor being stuck/not moving freely (I'm not sure just what condition you made your observation -- at idle it would only be barely opened, at higher RPM more). One thing that you can do is crack open the cold start injector connections to release the fuel pressure (wrap with a rag and be careful as some fuel will squirt out), then depress each airflow plate down with a finger to ensure it moves easily, smoothly, and returns to the proper rest position (make sure they "feel" about the same). The deflection of the two airflow metering plates should be very similar at any RPM.

 

then I would say the engine is only running on one bank. now have to check left or right and if it will be a fuel or an ignition problem

 

At 3000 RPM, the "barely open" airflow plate is bad.

This isn't such a valid test if done after shutoff as there is no guarantee that the residual fuel pressure is exactly the same on both banks at any instant in time. Also, the force on the airflow plate required to overcome the residual pressure and move the plunger is very high so hard to detect the difference in mechanical drag of the two mechanisms, and the residual fuel pressure helps to return the airflow metering plate to its home position much more than just the gentle return spring -- best to do a zero fuel pressure.

If the two airflow metering plates both seem smooth and OK mechanically (at zero fuel pressure), another thought is that the pressure regulator may have failed, and during running, the fuel pressure on the bad side is way too high -- this would also reduce the deflection of the airflow metering plate during engine running. But no need to go here until you've checked the airflow plate/plunger mechanical motions (at zero fuel pressure).

 

That's good for the airflow plates and plunger mechanisms -- so if they have wildly different deflections at the same engine RPM = I'm back to thinking that the regulated supply pressure should be checked (and the bad side, where the airflow plate doesn't move much when the engine is running, has too high a supply pressure).

This is more an indication that your right side is not holding residual fuel pressure like it should after engine shutoff. With the two banks on a TR, when one bank goes bad for this, the engine will still have good warm restarts on the good bank. This isn't really a runability problem, but something that isn't really correct (i.e., the fuel pressure on both banks should be ~3 bar at engine shutoff and remain near that for at least 20 minutes).

 

I'm 95% sure that the thread size for the KE-Jet cold start injector hardware is M8x1P (often shortened to M8x1). There is another port on top of the fuel distributor that can be used to measure the regulated fuel supply pressure, but I don't know the thread size or if it is different -- just going by the size of the hex head on the plug (which looks to be 12mm AF vs the 14mm AF for the banjo bolts on the injector lines), it might be M8x1, too:

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you are right steve: the head with 12 mm is on all K and KE jetronic M8 x 1

 

I have an equal set but there is in a M8 x 1,0
the other side of the connector goes to the gauge with a hose between
with all those adapters and hoses you will be able to make a Y- connection to the upper arrow on steve´s photo