[T3] Endless fuel etc probs...

["J. Jonik" <j_jonik@yahoo.com>]

[ 72 engine, FI, standard ]

Update:Ê (In hopes this all is useful to others.)

-Ê Excess fuel prob seemingly fixed by undoing Cold Start Switch.
-Ê That solved, apparently, new problems. Irregular idling, and lurching galore while driving around the block in tests.
-Ê Pressure Sensor in sync with Control Box.
-Ê Pressure Sensor VOM checks pass.
-Ê All injectors and wires and plugs checked and double checked with VOM.
-Ê BUT...(learning how to use VOM) found that
Ê a) plugs were switched between No 3 and 4 injectors
Ê b) one of those plugs had a wire with no conductivity. Bingo, I thought.
- Fixed that today. Replaced both plug ends with end sections from a salvaged loom. (Solder and shrink wrap)ÊÊÊÊ Double checked with VOM and Control Box and etc. All ok and going to the right place...according to MY checks.
- Using VOM, found that, apparently, Cold start wire plug was wrongly plugged into the Air Distributor Temp Sensor. Ê Fixed that.Ê Double checked with VOM from Control Box.

Ê Thought those major fixes would solve everything.Ê No. Ê Idling still up and down, and driving around the block is all lurching. It's still as bad as with wrong wiring. Ê How could such major adjustments produce virtually no positive effects?

Ê Used different Throttle Valve Switches (all No. 280-120-024), at all sorts of settings. Some differences...but not a fix. Still lurching and irregular idle.

Ê New thing...Starting took a couple of tries...and started weakly, not with the usual Vrooommm. ÊÊ 

Ê Re-adjusted Aux. Air Regulator to close to ' + ' side, to let more air in, I guess. It was far to the minus side before.

Ê Tried four spare Pressure Sensors. No change for any of them.Ê All of them produced worse performance when hose undone at Air Distributor. All produced better idling when hooked up with suction back in play.

ÊÊ Running out of things to check and double check or replace.ÊÊ The thing is, when cold, it idles and sounds just fine...but when it warms up in 4 or 5 minutes, THEN the irregularities happen.
ÊÊÊ SOMETHING is telling the Control Box to do something related to warm-up...and it's not consistent.

ÊÊ Q:Ê I have about a foot of fuel hose still on the 1 and 2 fuel injector pipe linkage...left over from the now-undone Cold Start Switch.Ê The hose is plugged and dry, but could that length of hose have any effect on Fuel Pressure? ÊÊ I have some of those little fuel pipe sections that have the screw plug in the center "testing" port (between 1 and 2 injectors).Ê Worth trying to change that?

ÊNext step....limp, or get towed to a pro.Ê This is maybe (?) a classic case of A Little Knowledge is A Dangerous Thing.ÊÊ 
ÊThirty and more years of fixing cars, and even rebuilding engines and so forth worked....until now.ÊÊ I've rebuilt engines on the roadÊ in Calif and Utah, and replaced torsion bars in Mexico and turned an automatic into manual, and gotten out of everything...until now.Ê If one knows what the problem is, it can be fixed.Ê This diagnosis is the hard part.
Ê 

Ê



      
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