Engine on 89 TR running rich.

What is your engine family number -- it's on top of cylinder #6 (something like F113A040, F113B, F113A, etc.).

Very few things can take out both banks at the same time (e.g., no +12V power on a KE-Jet system or a fault in the common leg of the water temp thermister). Never hurts to check/reseat connectors in the engine bay, but if you give the engine family number I can be more specific about some preliminary tests.

 

F113A040 is a US version KE-Jetronic with Lambda.

Are you changing the reported symptom? Does it run perfectly well (revs and has power) after an overnight cold restart until the water temp gets up to ~160 deg F and then the problem starts? Can you confirm/deny if the bad running always starts at the same ~160 deg F water temp after an overnight restart or if it's just random? -- a water thermal switch "opens" at that ~160 deg F coolant temp (if it's previously closed itself by being cold enough) and changes the KE system from running (dumb) open-loop to closed-loop (using the O2 sensor voltages for feedback), or please re-explain your symptom if it's something else.

 

OK -- I almost like that better (more broken).

The first thing to do is confirm/deny if the fused relay C in the triangular black box (item 18 of Fig 48) is closing properly during starter motor cranking or engine running. When this relay closes properly it puts +12V to run the injection system. The easiest place to measure this is at the red wire on the water temp switch that sticks out the LH side of the water housing at the front of the engine (this water temp switch is shown as item 20 "water thermoswitch" in Fig 48 of the TR OM). If you measure the voltage between this red wire (leave it plugged in) and the engine block (ground) during starter cranking or engine running it should be +12V. If not, you'll be needing to check/test what's going on (or not going on) at relay C.

Please see this thread (and the other thread mentioned in post#4 of this thread) for more information on relay C.

http://ferrarichat.com/forum/showthread.php?t=69889
Image Unavailable, Please Login

 

George -- see post #5 in this thread:

http://ferrarichat.com/forum/showthread.php?t=69889

You need to get to relay C inside the triangular black box (item 18 in that Fig 48 jpeg). If the fuse is not blown, you'd follow the same strategy in that post #5 -- "jumping relay C" and then "jumping relay C and the fuel pump relays" if just "jumping relay C" didn't work.
If when you jump the relay C socket, the 30 terminal and the 87 terminal are at +12V during starter cranking but the red wire is not, it becomes a harness or connector issue like LVG's trouble.
If the 10A fuse on relay C is blown, you can just try a new one (that would be an incredibly lucky fix), but more likely indicates an alternator over-voltage problem -- let's hope we don't go there (and don't do the relay C jumping if the fuse is blown)
Based on the results of these tests we should be able to find the Gremlin.

 

Glad you're getting it sorted out -- they should've included a multimeter in the KE-Jet TR toolkit

To really confirm that relay C is bad, when you have the 30-87 jumper in place at the relay C socket and the engine running, measure the voltage of the wire coming in to terminal 15 at the relay C socket:

If the terminal 15 wire is +12V, relay C is bad for sure.

If terminal 15 is not +12V, you have a wiring problem in the connection from the tachometric relay output to terminal 15.

Most likely your relay C is bad -- but, as I said before, I like to be sure before buying expensive, non-returnable electric gizmos.

Try Sponsor RicambiAmerica for that protection relay -- Daniel just recently added it to his inventory when another TR Owner reported trouble finding it elsewhere.

 

Glad to help out George -- you got off easy

 

Hello, I'm troubleshooting a TR (KE w/ 02 sensors). Relay C fuse blows after driving for a bit. Alternator charging 14.25 volts. Am I looking at an over charging issue? Thank you, Charlie

 

I would have to say "yes" that your first concern should be the alternator. When you say "Alternator charging at 14.25 volts", does that mean that it's at that value at idle and at higher engine RPM, or is that is just at idle at it (wrongly) increases with engine RPM? Also, have you tried measuring the AC voltage at the battery with the engine running at idle and say 3000 RPM? Should be a fairly low AC voltage (something like 1V AC or less? -- your homework to search the internet about this ). A large AC voltage there would be a bad sign for the electrics inside the alternator.

The other possibility is that the Zener diode inside the Protection Relay is not working properly, and is allowing a large current in the 10A fuse at voltages below ~22V, but I wouldn't go here until I was rather sure that the alternator was OK.

 

This thread should really be posted in the "Boxer/TR/M" section - Not the 308,328 section

 

"Report" the first post in this thread and ask a Moderator to move it (the Mods don't actively check for such things being in the wrong section).

 

Thank you for the response. The car is charging 14.25 volts at idle, but doesn't increase too much at higher rpm. I will check the AC voltage.

 

Hello again. There's no (or very minimal) ac voltage across the battery at 3k rpm. Once I replace the protection relay fuse the car runs nice for about 20 minutes or so and then blows the fuse while it's running. Also, this time I read 14.5-14.75 volts at that fuse while idling.

A little detail on the car, it's a US KE with Lambda, but with Euro headers, Cats deleted, Cat temp sensors deleted and O2 sensors deleted. Also, the tall black relay (PN 280230012) in the box with the protection relay was disconnected (the fuse blows with it connected or disconnected)

Seems like my next step would be to send out the Alternator for testing.