88 TR Cylinders 1-6 No Fuel

Need your help please and apologize in advance for the length. Bought a US 1988.5 TR last month. Runs/drives fantastic--until last week. I have been doing some very minor, non-intrusive (cosmetic) engine bay cleanup, removing paint overspray, excessive rustrproofing gunk, road grime etc. I decided to pull the Jetronic ECU boxes/shelf out so I could clean along the wheel arch. I disconnected the two ECU connectors as well as the two connectors on the "triangle" box aft of the ECUs (all with power off). After wiping down the area and dusting off the ECU's I reinstalled all. Was very, very careful with the ECU boxes, knowing the replacement cost. The connectors did take more fiddling than I would have liked to get them off, mostly me learing how they are retained. Did a little more cleaning then started the engine to confirm I had everything reinstalled correctly.

Immediately noticed a different tone, idle was down to 900 rpm. Lagging response while gently revving motor. Low power evident, did not try to drive. Shut down and re-checked all the connections. Started again, same response. Checked everything I could see/think of 3 or 4 (OK 5 or 10) more times with no improvement.

After 3 days of reading every related post, today I tried to isolate what I have induced: I have good spark on all 12 cylinders, verified with a timing light. There is no (raw) fuel smell as I run the motor, exhaust pipes are dry. I checked exhaust manifold temps with a thermal heat gun, manifolds for cylinders 7-9 and 10-12 both read ~175F after a few minutes running, 1-3 and 4-6 both consistently cold at about a steady 70F. I pulled the ECU connectors again and none of the female connectors are recessed or "gapped" and no corrosion, they all look very good. Boxes were not dropped or handled roughly. Male connector "tabs" are all perfect. Same for connections on triangle box. Cleaned all just to be sure with spray electrical contact cleaner, low pressure air dry. I cold-swapped the ECU boxes with no improvement. With engine running, when I disconnect the forward-most ECU connector engine stumbles and drops (by ear) maybe 100 rpm. When I then disconnect the aft ECU connector (front still disconnected), no change, and does not stall motor with both ECUs disconnected. When I disconnect either of the plugs on triangle box, engine stumbles, RPM drops, but also does not stall. When all is reconnected, idle improves, RPM back to ~900, but 1-6 still dead. I can't imagine what I could have done. Did not touch ignition system at all or the rest of fuel system--pumps, accumulators, filters, etc. Electrical connections at themostat were not touched and I visually confirmed they are connected. Admittedly I have not isolated the fuel pump for 1-6 to ensure it is working (both pump fuses are good) and I suppose I could have had a very coincidental pump failure or something else upstream/downstream of the ECUs but that would be one heck of a coincidence. All I disconnected or touched was as outlined above. I don't see any broken grounds or anything else obvious. I was nowhere near the actual fuel distributors (FD I think) ar any of the on-engine wiring or connections. Double checking ignition I also cleaned coil connections on both sides (both coils) and cleaned the two connections under the expansion tank. Didn't get back near the Stribel relay on the triangle box.

As for the fuel pumps, sometime in the past my fuse panel suffered the normal meltdown at the white connectors and has been repaired with off board (isolated) circuitry/relays for both fuel pumps and the AC relay. Not as clean as the Dave Helms repair and does not address the oil coolers, will do the full DH repair this winter. Both pump fuses are good.

I definitely don't like the flimsiness of the ECU connectors from the rubber boot to the plastic conduit, and may have damaged when I removed as it takes at least a 45 degree bend to get these clear. Seems like the weakest area I touched while cleaning and most suspect (to me), though I am second guessing now that I see the motor will run without the ECUs connected (on default mapping?). Anyway, I pulled both connectors gently apart to see if there was an obvious broken wire and saw nothing, though I did not dig around much at all. There could still be issues in those connectors.

Aside from the obvious question (whats wrong?) can you help me understand:
1) Does each fuel pump singularly feed only one bank of cylinders? I think so--please confirm
2) Does the forward ECU run/tune cylinders 7-12 and the aft 1-6?
3) Can a bad/broken connection on either of the ECU connectors cause the entire bank not to run?

I have some notes from Steve Magnusson on performing an EM Pressure Actuator Coil Resistance test, as well as well as checking for 12V at the water thermoswitch which I will do when I get home tonight. Beyond that I am at a loss, perplexed to say the least. 30 years of Air Force fighter maintenance taught me not to "fix" things that aren't broken but my OCD will not let me live with a dirty engine compartment. Oh, and no need to point out what a dumb a*s I am, my wife and two children beat you to it.

I truly appreciate any/all help you guys can provide.

 

Shouldn't be a shock to anyone but Steve called it right. My LH fuel pump was not operating. Upon further inspection my fuse panel has had 3 circuits repaired but it was AC and the two water radiator fans, not the fuel pumps as I had thought (still figuring out what has been done to the car for the last 23 years). Failure mode was the standard burnt white connectors and gapped fingers on the female connectors. I was able to pinch the fingers closed and reseat the white connectors, pump runs fine (for) now, back to a TR vs. a Fiero. The other pump wire is similarly damaged. This will accelerate my Winter project to upgrade the fuse panel. My car has almost 40K miles and as mentioned 3 of the 6 common failed circuits have been repaired so I suspect those pump connectors have been burned for awhile and the LF pump connection finally let go last week. The PO(s) likely only wanted to address the issues as they arose, I'll be more proactive.

Also, thanks Mr. Chairman for your insight as well, I have cleaned and checked those additional connections as recommended. Gold connector kit is on the list, I plan to tackle during my next major when everything is really accessible. If I continue to have problems (unlikely I think) I will also accelerate the connector swap.

So in the end it did turn out to be a big coincidence the pump connection failed when I was cleaning around the ECUs, but it serves to remind us not to take anything for granted. I came out fairly unscathed, could have been big $$ as Steve mentioned.

Thanks for your help.