I have a 1996 freightliner fl70 with cat 3126. we didn't start this for about 8 months and normally it starts right up but this time it cranked fine but no start. started on ether but died. so I guess no fuel which is controlled by the ECM? (mine is the 40 or 42 pin though I don't know how you remove the connectors. my check engine light comes on when key is on and then goes out after being on briefly.
THEN while we were trying to start a second problem happened:starter engaging and not stopping every time you try to start.
there are all white wires on the back of the start switch (1 large plug and then 2 individual wires which maybe I got on the wrong connector)...I had a really worn key so I took out the switch and bought a new one thinking it was preventing starting.
Here are things I have done or checked so far on these 2 issues:
* new batteries (fully charged) * cleaned ground connectors and posts at engine/starter and battery * checked the engine oil (full) * took starter to shop and bench tested fine * confirmed check engine light comes on when I turn on the key and then goes out as it should * fuel is 6" deep in tank but filters are not very old.
* bought new engine speed sensors (not installed yet until starter not disengaging fixed??)
*ordered new mag switch for firewall (don't know how to check old one or what a faulty one would do but with the mag switch disconnected the starter still didn't disengage??)
I did not check voltage or ground at the ECM plug yet (40pin type) (I don't know if you poke your lead prong through the wires or if the plugs come off? I don't see how the connectors come off unless there is a bolt on the engine block side of the ECM I cannot see?
I am real frustrated with this thing and want to get it running. It is hour drive from service tech so wanted to do all I can before paying to have CAT mechanic drive out and back.
maybe I did something to the wiring connection either at the ignition switch or at the battery??
Any suggestions on the 2 problems:
1. starter not disengaging (want to fix first) before no start issue if I can fix this I will change the speed sensors to hopefully get fuel for starting
Most likely lost prime if you don't have a primer pump on your fuel filter I would strongly suggest getting one (p/n 105-2508 pump & 1P0436 gskt.) the pump will get very hard when the fuel is full in the filter. The pressure regulator in the back of the head will hold fuel for awhile but not months. We generally prime most of the Caterpillars after summer break. As for your starter problem low voltage at the solenoid could cause the contacts to stick in not letting the starter disengage. Once damaged they tend to stick more often even after low voltage concerns are repaired.
Ok, the local parts guy didn't think this good part number would work with my fuel system (high pressure oil)?? Do you mount these for 3126 engines? I hope I just lost prime. I am taking in my starter to get it rebuilt to eliminate that problem (hopefully that will correct that not disengaging problem).
I think the oil pressure system is really high pressure and I don't have the right test gauges, I may just have to pay for cat mechanic to drive out here and look at it. they will have the software for checking codes etc (if they are retained after battery removal).
Look at the top of your fuel filter mounted to the engine,does it have a cap with a 1/2" and a 7/16" bolts in it? Remove the cap and install the primer pump there. The pump will work with any Cat fuel system. Do you have Cat ET to check out the system?
fl70 with cat 3126 not starting...
Posted - 06/04/2015 : 1:06:32 PM
