89 TR Fuel Problem

The fusebox is the immediate suspect. I just replaced one today with one of Dave Helms' (Scuderia Rampante) upgraded boxes. It's a work of art. Problem with fans immediately solved. The SR box addresses the fuel pumps as well.
Look at the white plugs in the fusebox. See any that have brown (burned) ends on them?

 

You wouldn't have an ex-lover who would put a bucket of sand into your fuel tank do you?

Not easy to explain both fuses blowing simultaneously, but no harm in putting in a new set of fuses and see if they reblow quickly. Far more reports here of "dead fuel pump" not "fuel pump fuse keeps blowing".

Did you recently replace the fuel pump relays with the incorrect type (...113) wrongly specified in most of the TR documentation? For an '89 TR (euro or US), they should be the ...101 type (and the symptom for using the wrong type is that fuse blows as soon as the relay is plugged in).

 

Blowing both fuses simultaneously and suddenly with no pre-warning / symptoms makes me wonder if you haven't simply got a freshly damaged wire shorting out or some other spontaneous ground fault somewhere in the positive side of the pump circuits downstream from the fuses ?

I would try disconnecting the fuel pumps and hook up an OHM meter to the positive terminal leads of the wire harness and see if you have continuity to chassis ground. If so, you have a ground fault / short somewhere. Try this with and without the relays installed ---- depending on where they are located in the circuit, IDK off the top of my head.

 

I'm skeptical that you can confirm/deny, audibly, if the fuel pumps are running during starter motor cranking (they, intentionally, do not run with just the key "on" and the engine not running). Remove each fuel pump relay and briefly touch a jumper wire from terminal 30 in the relay socket to terminal 87 as per this (modified) TR WSM figure:

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If things are OK, you should hear the corresponding fuel pump run (even with the key "off"). If not, give a shout back, and we'll go from there...

 

There should be no continuous "clicking" with the key "on" before engine start. One or two relays should click once when the key makes first "on" contact, and the little cabin air blower motor, for measuring the cabin temperature, should maybe "hum" quietly -- but, if you have an added CD player, that might make some clicking racket for a while at first power-up.

The next place to go on the fuel side would be to confirm/deny if the tachometric relay is trying to turn on the fuel pump relays during starter motor cranking (search on "tachometric violet wire" for prior threads), but, you should really back up in your diagnosis IMO and first confirm/deny if you have spark on both banks during starter motor cranking -- you can't fix the fuel system if it's actually the ignition system that's broke

 

That's good -- on with the fuel side...

This (connecting the violet wire to the red-white wire at the tachometric relay) is not what you should do. You need to connect the violet wire at the tachometric relay (or where it goes into the x white connector) to the +12V battery terminal or the red wire at the tachometric relay (which should also always be at +12V just like the +12V battery terminal) -- then try starting the engine.

 

With spark and the fuel pumps running, but not starting, the next suspect is the protection relay is not working (which causes the KE-Jet injection system to go lean and disables the EHA from adding enrichment at starting). The easiest way to confirm/deny is to measure the voltage on the red wire connected to the water thermoswitch on the LH side of the water "Y" at the top front of the engine = should be +9~+10V during starter motor cranking. If it isn't = then you need to dig into the triangular black box over the RR wheel well to check the 10A fuse on the protection relay and the function of the protection relay itself. If you try a search on something like "protection relay red wire water thermoswitch", you should get prior threads with photos/instructions.

 

Yes (but I think the latest available Stribel PN is 92861512402).

The 10A fuse not being blown is a good sign that your alternator going haywire is not the cause of no voltage at the red wire at the water thermoswitch (the whole reason the protection relay is used is to intentionally blow the 10A fuse and "protect" the injection ECU from a wacky alternator output).

(Since your fuse is not blown, and the alternator is probably OK,) Try removing the protection relay and use a jumper wire to connect terminal 30 in the protection relay socket to terminal 87 in the protection relay socket (simulating a properly closed protection relay). Then try restarting:

If the engine starts and runs well = investigate if the protection relay itself is bad or if an input signal to the protection relay is bad/missing -- i.e., measure the various voltages, 30-to-31, 15-to-31, 87-to-31, at the protection relay (when it's still plugged in and cranking the engine) as per the previously posted threads/instructions to deduce what's the trouble - protection relay itself (95% probabilty from prior reports here) or wiring/connection problem (5% probability from prior reports here).

If the engine still has a starting/running problem (and you confirm that you always do have +12V on the GR (red-yellow) wire connected to terminal 30 of the protection relay socket) = remeasure the red wire at the water thermoswitch (with the 30-to-87 jumper in place at the protection relay socket) during starter motor cranking. If it isn't the +9~10V during starter motor cranking = you have a wiring connection problem somewhere.

 

Glad that you are making progress, and didn't buy any unnecessary parts . Usually, the reported symptom for this fault is "it fires up, but I've got to give it throttle wacks to keep it going, and it runs really weakly". Your mixtures must be set towards the lean end of the spec (which is fine) to fully fall out the lean side to complete inoperation with just the EHAs dead.

I think Pelican Parts has been reported as having the best price lately, but the Ricambi America price isn't unreasonable IIRC (and many sources' price is way, way beyond unreasonable). Let us know if you find another such alternate source in the same price ballpark as the aforementioned.