2002 RD688S Crank no start after starter change.

[McDonald24]

I have a 2002 RD688 with E7 400 that will only crank but not try to start. I just installed a new starter because the old one was starting to hit and miss due to a loose ground in the starter itself.  I’m 99.9% sure all wires are connected back as they were originally. I did break the oil pressure sensor when changing the starter and replaced it with a new one. I am showing oil pressure when cranking but I also got into the wires of the oil temp sender but appears to still be intact and I put some hot glue to make sure they don’t touch obviously I can’t tell if it’s still working due to it not running but I’m assuming the temp sender only runs the gage and maybe a warning light but wouldn’t think it would cause a no start. Had a tech put a computer on it last night and showing “Short to earth” on a couple of the EUP’s but the fix for this is to basically check every single connection and electrical component on the truck and I don’t have any idea where to start. Any help or general area to start checking would be great. I also would like to know where my VECU is located which is one of the components it said to check. 

[The Heinz]

I don't have a lot of experience, but if you're checking the EUP wiring, I'd start at the EUP's themselves. They're on the right hand side of the engine with lines going into the heads above. They're in a high-heat area, so we've seen some wiring getting brittle before. Could also have issues with the EUP/injectors themselves, but you'll want others' opinions over mine for that.

As for the VECU, the engine module should be on the RH side of the motor as well, below the heat shields that also cover the EUP's and forward of the air compressor. Here's a diagram from a 2000 RD:

[fjh]

2 hours ago, McDonald24 said:

I have a 2002 RD688 with E7 400 that will only crank but not try to start. I just installed a new starter because the old one was starting to hit and miss due to a loose ground in the starter itself.  I’m 99.9% sure all wires are connected back as they were originally. I did break the oil pressure sensor when changing the starter and replaced it with a new one. I am showing oil pressure when cranking but I also got into the wires of the oil temp sender but appears to still be intact and I put some hot glue to make sure they don’t touch obviously I can’t tell if it’s still working due to it not running but I’m assuming the temp sender only runs the gage and maybe a warning light but wouldn’t think it would cause a no start. Had a tech put a computer on it last night and showing “Short to earth” on a couple of the EUP’s but the fix for this is to basically check every single connection and electrical component on the truck and I don’t have any idea where to start. Any help or general area to start checking would be great. I also would like to know where my VECU is located which is one of the components it said to check. 

Ground from starter to frame?

[JoeH]

On 5/1/2024 at 8:42 AM, The Heinz said:

I don't have a lot of experience, but if you're checking the EUP wiring, I'd start at the EUP's themselves. They're on the right hand side of the engine with lines going into the heads above. They're in a high-heat area, so we've seen some wiring getting brittle before. Could also have issues with the EUP/injectors themselves, but you'll want others' opinions over mine for that.

As for the VECU, the engine module should be on the RH side of the motor as well, below the heat shields that also cover the EUP's and forward of the air compressor. Here's a diagram from a 2000 RD:

2002 has the Left Side Redesign, (started in 2001) the EECU is on the intake manifold on driver side of engine.  VECU is on the passenger seat kick panel, it's common for the windshield seal to fail on R models and let water in to cause VECU issues. 

How are your batteries? What does the voltage do when you crank? EECU shuts off at 9.5 volts, so weak/failing batteries will result in a crank/no start situation.

What blink codes do you have? Key on, cruise control off, press the set/decel cruise rocker down. Hold til lightning bolt blinks, then count the 2 digit code it blinks to you. Repeat set/decel request until codes start repeating themselves. Example code: 9-5. Share the codes here and we can point you in the right direction.

[Joey Mack]

Check fuse 40 in the fuse box on the fire wall, top center below the wind sheilds . EECU fuse, 25 amps,  clear in color.

[The Heinz]

8 hours ago, JoeH said:

2002 has the Left Side Redesign, (started in 2001) the EECU is on the intake manifold on driver side of engine.  VECU is on the passenger seat kick panel, it's common for the windshield seal to fail on R models and let water in to cause VECU issues. 

Woops, I hit the V when I should have hit E again! Good to know, we haven't had too many EECU complaints on the "older" trucks, didn't know they relocated. Learning something new. 

Edited May 7 by The Heinz