02 LW300 V6 Fuel Pump and OBD2 Trouble

[Rj 2000 LS2]

A completely broken timing belt would allow the valves to seat and as long as the cam shafts are not spinning, the engine would simply rotate and not start. Some valves could hit the piston(s). It would sound like a firm tap noise as it rotates. If the tensioner broke you would hear valves slapping against the pistons and if the engine started it would sound horrible.

I had a tensioner break and BANK 1 jumped one tooth, the engine ran but it wasn't good.

It's a 20 year old vehicle, is it the original timing belt? The plastic cover can be opened to inspect the belt. While rotating the engine, if the belt doesn't move, it's toast. These engines are interference engines where the valves and pistons share the same space being perfectly timed to not make contact.

If you determine the timing belt is broken, stop attempting to start it until you install a new belt kit.

[02LW300]

So the timing belt is good, I saw it turning as engine cranked.

Now the gas gauge works and I’m able to link my code reader. It’s pulling the same codes as before.

I’m having a new BCM programmed on Thursday.
I also ordered a new ECM that comes programmed to the VIN.

I’ll report back when something happens.

[Rj 2000 LS2]

The intermittentness of the gauges and OBD2 interconnect still makes me believe the key switch could be at fault. Why would it work once and another time not? Digital elections don't act like that, but bad connections can behave that way. Don't break the bank shot gunning parts. Eliminating potential flaws and isolating them are less expensive.

I am anxious to learn what you find.

[02LW300]

FIXED!!!


The main relay in the under hood fuse block was bad and causing all kinds of electrical gremlins to appear.

After the main relay was replaced the codes were cleared and it’s back to running like it should!

With parts and labor the repair cost me just under $500.

Now I need to do a timing belt/water pump replacement. (Way overdue!)

[fdryer]

Great news. How was it determined to be the faulty?

[02LW300]

If I understood the mechanic correctly, he took apart the fuse block to clean it up and found that the main relay had voltage on three sides. So I guess that’s how it was determined to be faulty.

[Rj 2000 LS2]

So the relay was dropping voltage across it causing the connected devices to experience low voltage hence their unpredictable behavior. Nice find!