87 TR Power Less

If it was able to be driven, but with little power, then the problem is probably that one of the fuel pumps have quit on you. This is usually due to the wiring at the circuit board. Check the fuel pump fuses.

 

Probably fuel or ignition. Be sure to check your coil wires to see that the connections are good. If one were to "slip" or have a bad contact then you could loose 6 cylinders, but run on other 6 very sluggishly. Don't jump to any conclusions right away...hopefully it's nothing major. Please keep us informed of your progress, and if you can provide more details about the car. I'm sure the great people here can help you through this trouble.

 

I have an '88 TR. The symptoms you describe are exactly those that would indicate that either one of the fuel pumps or one of the coils is not functioning. Probably a fuse. If not that, still probably something simple that you can find yourself.

 

Sounds definitely like a dead bank, but you've got to first determine whether it's spark or fuel:

1) Use a timing light to check whether or not you've got spark on each bank.

If that checks OK, then:

2. Measure the voltages on the beige and beige/black wires leaving the "y" connector (you might also unplug the "y" connector to see if one of the connections for the beige or beige/black are badly "baked" -- see jpeg below.)

If #1 and #2 measure OK, then you can manually jumper the fuel pump relays one at a time (engine off) to check if you can "hear" each fuel pump running, and if that's OK then you've got to make a functional output supply pressure measurement -- but get past #1 and #2 before worrying about this later stuff.

 

Lou -- the TR fuel pumps only run under 2 conditions:

1. During actual starter cranking (i.e., key in the "start" position and the starter solenoid plunger energized, moved, and closing its internal switch)

or

2. Key "on" and the engine actually running (i.e., the ignition system feeding pulses to the tachometric relay which, in turn, closes the fuel pump relays).

Just didn't want you to expect that the TR fuel pumps should run with the key "on" and engine not running -- good hunting...

 

a clogged catalytic will also drop your power, so will water in the gas

 

This could be 2 issues:

1) bad coil allowing it to run on one bank.

2) In addition, you have the overheated connector causing the discoloration (but not necessarily causing the problem at hand)

 

Yes, that's trouble, but I'd agree with Patrick that discoloration doesn't necessarily mean "no function". Does that mean you confirmed #1 (spark) is OK on both banks and that the beige wire terminal was not going +12V during engine running?

The bottom line is that you need to add a high-current capable wire (AWG 12 gauge would be best IMO) from terminal 30 on relay "R" (which is the vertical top tab position) to the beige wire (and similarly, from terminal 30 on relay "T" to the beige/black wire if you want to take care of that side too).

I've added such "bypass" wires for the fuel pump, AC, and radiator fan circuits internally to my relay/fusepanel, but this is more difficult as the internal mods must be able to withstand relay insertion/removal (top jpeg below). The added wires are then connected to wire branches added to the target wires.

Ben L. had a simplier approach where he directly soldered the wire to the desired relay tab -- leaving enough of the tab still exposed so that he could still partially plug the relay into its socket. The other end of the wire is connected to the target wire. (bottom jpeg below - but in Ben L.'s jpeg it shows the wire added to the 87 terminal of a different relay).

PS The reason you can run on one coil and not the other is that only one of the coils supplies the pulses to the tachometric relay -- which runs the fuel pump relays -- which run the fuel pumps. When you unplug the coil running the tachometric relay, both fuel pumps shut off.

 

Lou -- Those measurements sound pretty conclusive.

"would it make a difference after it warmed up" -- not really, except that it could be intermittent/random for a time (although it can only get worse over time). When my beige/black wire connection was going bad, a couple of times it started up on only one bank, and then after 15~30 seconds, the vibration was enough that the second bank came up. The third time it happened, I wiggled the "y" connector and got it to run (but after that "event" I made the repair because I knew it would go downhill fast).

 

Your coils are fine if you've got spark.

The method can vary, but you need to:

"...add a high-current capable wire (AWG 12 gauge would be best IMO) from terminal 30 on relay "R" (which is the vertical top tab position) to the beige wire..."

If the male tab on the PWB is still in good shape (but I doubt it will be), you could try to get a new female end tab for the beige wire in the "y" connector -- but that leaves you with the same (poor) design.

 

Lou -- restoring those mods is OK -- but they address having a different problem between the 30 terminal and the male tab (i.e., having a broken trace on the PWB). Your problem now is the connection between the male tab and the female terminal on the beige wire in the "y" connector. You'd need to somehow extend one of those wires so that it reached directly from the relay "R" 30 terminal to the beige wire, but that would work (and the other wire from the 30 terminal of the "T" relay to the beige/black wire if you wanted to do that side too).

PS You've actually only removed the back cover of the relay/fusepanel. The wires I added are "inside" between the front side of the PWB and the top plastic cover. The jpeg below shows more internal details of my mods for the AC and radiator fan circuits only (before I did the fuel pump circiuts too).