bill50cal

has anyone found a good source for having an ECM repaired? i think mine has an issue. it can take anywhere from1 to 10 seconds to trip the fuel system relay and turn on the lift pump.

Fordzilla

You can't run a redundant circuit from an ignition source?......Ben

AlpineRAM

He could, but it's not advisable. If the ECM takes a long time to boot you have a host of other potential problems.

In his case I'd check first if the ECM boots OK with sensors unplugged, sometimes a short to ground can stop the boot process.

Fordzilla

Good advice, Markus......Ben

high bid

Look over the entire vehicle, find every ground you can, remove it, clean it and re-install. These trucks are very sensitive to ground issues, I'd make sure they are all clean and tight before replacing an ECM.

robert78.5

Where would ground be for the ECM

high bid

Start with making sure battery connections are clean and tight, there is one ground on the passenger firewall and I think 2-3 grounds on the body underneath the battery trays. From there look all over the frame and back towards the transmission grounds. Any questions as to the ECM, I'd make sure all of these are checked first and are clean and tight. From there check the connections to the ECM also making sure they are clean, tight and no issues. I'd then wrap the main alternator wire with aluminum foil and then electrical tape. This will help reduce any electrical interference issues. These are all free to check before ECM replacement. Good Luck!!! After this point, I'd continue reading on here for ideas/items to check.

bill50cal

well now in the last few days all is OK. the last 2 mornings there was no wait to start light but after unplugging and pluging back together connectors 125 and 126 a couple of time the wait to start light is OK also. these dont appear to be great weather proof connectors and I might replace them with the deutsch brand. thanks for the help on this.

but it looks like no one has a recommendation for ECM repair IF needed

AlpineRAM

There are some ECM repair shops, even advertising here.
But I don't have experience with them.

All of the trucks I fixed did not need a new ECM, main problems were wiring, especially grounds, and in many cases sensors or bus wires shorting to ground.

With a factory service manual for your year of the truck (very important, they seem to have changed wiring annually ) seek every ground splice and connector, check that all wires attached to it have good ground.
I do not want to count the number of faults in some wires that go together into a bushel of common ground on these trucks. Many times the cables were corroded to green-black dust up to 2" from the connector.