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Lug
08-15-2023, 14:14
The saga continues. Replaced the ignition switch and lift pump. Pulled the fuel filter and found white particles/chunks floating in the fuel. Not happy about that as that is an indicator of fuel additive issues or fuel contamination. Cleaned out filter housing. Replaced the popped 10a Crank fuse. Primed filter. Still no joy. Tried unplugging optical sensor, no joy. Guess I am waiting for the manual to show. Getting ready to start robbing the 95 to finish resurrecting my 94 suburban.
Justin

Lug
08-15-2023, 15:30
Thinking DEF contamination. The FAA issued a SAIB about DEF contamination in jet fuel. Similar looking stuff.https://www.nata.aero/assets/Site_18/files/DEF/FAA%20April%20SAIB%20Engine%20Fuel%20and%20Control %20%E2%80%93%20Operation%20with%20Contaminated%20J et%20Fuel.pdf
Justin

Lug
08-15-2023, 16:00
Forgot to mention that I cracked the injector line at the #1 injector. Cranked the engine and had fuel at the return lines but none at any of the ports on the nozzle. One of the hiccups I had just before it died was an uncommanded acceleration/surge at a stoplight. Also random optical sensor codes. It has been a while, but the problems got worse after fueling at Laird River. Spidey senses were tingling telling me to use the 10 gallons I had in fuel cans, but I didn't.
Justin

JohnC
08-16-2023, 07:04
uncommanded acceleration/surge at a stoplight.
That points to the FSD or the fuel solenoid itself.

Robyn
08-16-2023, 09:38
An "uncommanded" acceleration can well be a FSD/PMD FAILING

These can fail to a full fuel situation.

These can get exciting.....Galloping around the parking lot with BLACK smoke pouring out the tail pipe.....

Foot fully applied to the brakes and a mess in your pants.....

Turn off ignition....

I have seen folks shove the tranny into neutral.....The engine reaches REDLINE instantly and the ECM will shut it off......

If the PMD/FSD is still mounted on the IP then the PMD/FSD is the prime suspect....

If you have a known good one.....Swap it in and see what happens.

A failed PMD/FSD will give a no start condition....The fits and jerk as well as stalling and restart issues are all indications of a dying PMD/FSD

PMD= PUMP MOUNTED DRIVER......FSD= FUEL SOLENOID DRIVER.....Same little box on the SIDE OF THE IP.....


If you swap the PMD....Be sure to keep the resistor chip in the PMD plug socket and install it in the new PMD

These are easy to fish out of the PMD plug socket.....

These are numbered 1 through 9 and are a calibration device to compensate for slight differences in the equipment

If you don't know what was in the thing...a number 5 will usually work....

If the ECM check down the road and complains.....It is no biggy to swap in a different one.

Using a remote cooler with and extension cable is highly recommended .....

A good cooler/heat sink behind one of the Nostrils in the bumper is a great place...

Under the hood anyplace is not good....

Lug
08-16-2023, 10:12
Three different pmd. 2 different extension cables. Pmd plugged into factory cable. If this was my 94 Suburban I would be cleaning the battery buss bar on the firewall. The 95 doesn't have one. 9 days of trouble driving across Canada the only consistent code is 49 because the light is out. But was getting optical sensor, pump pulse width, crank position, transmission gear mismatch codes at random times. But without the factory manuals I cannot go further with electrical troubleshooting. Might be a good excuse to convert to a DB2 pump setup.
Justin