85 245 LH 2.2 Tank Pump delay

[Parc]

SOLVED (See 10th post)

Long history

Symptoms: Currently No Start, prior Hard cold start, fires right away but violent misfire for 20 seconds then runs fine.

Identified: Tank pump not running with ignition when cranking (Main pump runs when cranking).

Runs with Jump at fuse panel
Runs with Jump at fuel relay

000.0 Ohms on Y-R wire to Main Pump
000.3 Ohms on Y-R wire to Tank Pump (Is this my answer?)

FPR Switching with ignition and second pole with crank (viewed with white cap off). And no change with New FPR

Wondering where to look next or if not looking right. Hall Sensor, ICU?
Promise to post when solved.

 

[Khrrck]

You say it currently doesn't start. Which systems are still functioning?

Does it still crank?

Are the spark plugs firing?

Are the fuel pumps running during the start attempt and are the injectors getting triggered?

 

[Parc]

Thank you Khrrck, will get back

Yes it cranks
Will check spark again next (hadn’t done that since hard start problem)
Main pump runs during start attempt, Tank pump does not.

 

[Khrrck]

If you jumper the tank pump, can you hear it running?

If you try to start it while the tank pump is jumped, does it start?

 

[Parc]

Yes jumping tank pump causes pump to run.

Will try starting engine with jumped pump tonight. Thank you

 

[cleanflametrap]

Because the tank pump and the main pump share the same circuit, but not the same wires, the only explanation I can imagine is the tank pump is binding or offering excessive mechanical resistance, making it imperative it gets full voltage to run. This may be lacking during cranking, or the voltage is dropping within the sender wiring where you can't monitor it externally. Still, you could check voltage (during cranking or while the pumps are run with a jumper) as close to the sender as you can get physically -- piercing the black wire or at the connector, without disturbing a possibly corroded connection. Voltage drop under load always trumps multimeter resistance readings. http://cleanflametrap.com/transferPump.htm Still, a stalled tank pump (in Vancouver) is an unlikely cause of a starting problem. But testing it by starting with the tank pump already running is a good idea, provided you jumper it at the trunk so it is the ONLY pump running.

 

[bobxyz]

Try spinning, or replacing, fuse #4 (tank pump)

 

[cleanflametrap]

^^ Yes, this. I'm an idiot.

 

[Parc]

Ok back at it

To cover a few bases:
1/3 Tank of Fuel
Battery Voltage 12.5
Fuse #4 rolled/new (thought I might have ruled it out by jumper at relay)

Khrrck, jumping pump did not start (So now onto the engine bay...?)
Art, I've learned much from you over the years, thank you so much, I tried jumping ONLY the tank pump by removing the fuse to the main pump, I hope that was sufficient a test. Cranking Voltage at BOTH Pumps is 10.2V, Jumped (at fuse box) Voltage is 12.2V at Main Pump and 11.6V at Tank Pump..........What I hear with a stethascope on top of the tank pump cap while partner cranks is the faint whir of the Main Pump. No change by knocking it. While there is weirdness at the pumps, I guess this means they're on the backburner for now...?

To the engine Bay:
Good Spark (with spare dry plug) on all four
Pulled #1 plug and it is gasoline SOAKED
Rotated to TDC and things appear to line up, (concerned may have skipped a tooth, was running great after recent valve shim reset)
Yellow Top Injectors recently replaced Black Tops
Fuel Pressure Regulator apparently functional,
Idle Control Valve New.

Recent Stalling Issue cause by freyed exciter wire at D+ on Alternator
Now suspecting this stressed the ICU (again)....

hope this is helping you help me keep this daily driver going
Marc

EDIT: Wrote this under pressure and tired, will be checking distributor and reading about no start diagnostics some more.....

 

[Parc]

SOLVED

Crank No start caused by fault in Ignition Control Module (Chrysler 1346107). Not sure whether it's the vacuum bladder/sensor or something else within it. Installed a used one from ebay that looks like hell but works. Before, I was only able to start the car by manually rotating the distributor counterclockwise (retarding?) working off the premise that if there's fuel and spark than it must be air or timing.

Rough or erratic Idle caused by cheap Fuel Injection Temp Sensor (AMR, sold by IPD). This was the big headache in more ways than one as I presumed (because it was new) that it was good and because it was one of the first things I changed without properly checking the old one, it sent me chasing red herrings for days. A simple ohm reading across the poles read 20,000 Ohms (It should have been ~2,000). This sent a signal that it was -30 celcius when it was +30 ...So I reinstalled the Bosch sensor and bingo.

Tank Pump seems to be operating now, I had gone through ALL the grounds and cleaned the fuse panel and I can only assume there was something dirty or loose.

More lessons learned and it lives another day!

 

[Khrrck]

Rough or erratic Idle caused by cheap Fuel Injection Temp Sensor (AMR, sold by IPD). This was the big headache in more ways than one as I presumed (because it was new) that it was good and because it was one of the first things I changed without properly checking the old one, it sent me chasing red herrings for days. A simple ohm reading across the poles read 20,000 Ohms (It should have been ~2,000). This sent a signal that it was -30 celcius when it was +30 ...So I reinstalled the Bosch sensor and bingo.

Are you sure you got a LH 2.2 temp sensor instead of a LH 2.4 sensor? LH 2.4 sensor is actually two thermistors (uses block for ground) and measuring between the two pins gets you them added together. LH 2.2 sensor is a single thermistor (uses harness for ground).

 

[Parc]

Are you sure you got a LH 2.2 temp sensor instead of a LH 2.4 sensor? LH 2.4 sensor is actually two thermistors (uses block for ground) and measuring between the two pins gets you them added together. LH 2.2 sensor is a single thermistor (uses harness for ground).

Good to know. It appears LH 2.2 are blue and LH 2.4 are black. No continuity between either pole and brass on this one so it seems the right part, but bad (I know it's a cheap meter too, but it could clearly tell the difference).

 

[Khrrck]

Good to know. It appears LH 2.2 are blue and LH 2.4 are black. No continuity between either pole and brass on this one so it seems the right part, but bad (I know it's a cheap meter too, but it could clearly tell the difference).

Color isn't reliable but no continuity to the body means it's LH2.2 - just a bad one. Good catch!