Jump to content
anthony920

No Start

Recommended Posts

Any ideas? Checked continuity and voltage on all wires at VECU. Also, checked continuity and voltage on all wires at ECU. Checked all fuses and relays - all good and voltage good. Ohm'ed J1939 wires all good. Installed good test VECU and ECU still no start. Have good fuel pressure. Computer will not talk to data link. Any suggestions will be appreciated.

Ok my gynisis computer wont talk with going to try prolink tomorrow. I have also tried a new cam sensor still no start. First day checked out wiggled wires and disconnected plugs on trans and after a bit it started. Drove to yard and died at yard. Next day cleaned all battery terminals and positive and negative on chassis. Truck started, killed it and then would not restart.

Share this post


Link to post
Share on other sites

Something else driver said truck was running rough the day it started all this and the electrical light was on. Also now while starting no smoke from stack.

Share this post


Link to post
Share on other sites

Any ideas? Checked continuity and voltage on all wires at VECU. Also, checked continuity and voltage on all wires at ECU. Checked all fuses and relays - all good and voltage good. Ohm'ed J1939 wires all good. Installed good test VECU and ECU still no start. Have good fuel pressure. Computer will not talk to data link. Any suggestions will be appreciated.

Ok my gynisis computer wont talk with going to try prolink tomorrow. I have also tried a new cam sensor still no start. First day checked out wiggled wires and disconnected plugs on trans and after a bit it started. Drove to yard and died at yard. Next day cleaned all battery terminals and positive and negative on chassis. Truck started, killed it and then would not restart.

I think trying to use the Prolink on step 10 software and higher is supposed to corrupt module data. Is you diagnostic connector 6 pin or is it 9 pin? I've seen some problems with the 9 pin connectors not communicating due to damaged or unseated pins. If your EML is flashing a 6-4 the problem is likely in the wiring to the engine or in the power up sequence of the modules. You probably have no communication on the J1587 datalink as well as on the J1939. It kind of sounds like power relay #3 may be sticking which causes incorrect power up of the modules or no power up at the engine ECU.

Share this post


Link to post
Share on other sites

It is a 9 Pin. I have checked the voltage across all 4 of the big relays with key on and they are ok. Does this have a timing sequence that may be off.

Share this post


Link to post
Share on other sites

It is a 9 Pin. I have checked the voltage across all 4 of the big relays with key on and they are ok. Does this have a timing sequence that may be off.

The modules have to power up in sequence, VECU first EECU second.

Check fuse 16 for power with the key on. This is the fuse that supplies switched power to the VECU. The VECU puts this power out on wire VJ3-13 as the control wire to the coil on the power relays. If you have power at the fuse with the key on check to see if you also have power at pin 85 on the power relays (you should). Next check that there is no power at pin 85 of the relays with the key off (you shouldn't have power there with the key off). If everything so far is ok, check pin 86 for continuity to ground (should have continuity to ground). If the coil wires (pins 85 and 86) are correct then check to see if you have power at fuse 40 (EECU power). This fuse outputs power to the EECU on wires EJ2-10, EJ2-22, and EJ2-41. If you get power here with the key on check for continuity to ground on wires EJ2-12, EJ2-24, and EJ2-43

If you don't want to do all of these checks you might try replacing the power relays and checking the female terminals in the fuse panel for a loose fit, I've seen that happen more than once.

Share this post


Link to post
Share on other sites

I have checked all fuses and they have power with key on. Also VJ3-13 it has voltage,fuse 40 is good. I think I check for voltage on the EJ2 at pins at the middle three large pins i believe, and check for continuity on the bottom three. I have removed all harness protectors and checked all wires from bulkhead to EECU. Sorry I have tried to check all this, I am just at wits end don't know what else to check, thanks for your response. Could these relays just be sticking as you said, and be coming on but too late. I also switch all four of them around several times.

Share this post


Link to post
Share on other sites

I have checked all fuses and they have power with key on. Also VJ3-13 it has voltage,fuse 40 is good. I think I check for voltage on the EJ2 at pins at the middle three large pins i believe, and check for continuity on the bottom three. I have removed all harness protectors and checked all wires from bulkhead to EECU. Sorry I have tried to check all this, I am just at wits end don't know what else to check, thanks for your response. Could these relays just be sticking as you said, and be coming on but too late. I also switch all four of them around several times.

I wouldn't think all four power relays would go out at once. It's more likely that the pins in the fuse panel are loose, but that's not necessarily the problem either. Try checking the grounds at the engine block, frame rail, cab ground breaker, etc. Check the 15 pin connector that is over the top of the transmission too. If you have another truck you might try swapping the ECU's around.

Share this post


Link to post
Share on other sites

I cleaned the grounds at the block frame the cab ground braker on post is good although I wenta ahead and put the two wires together. I swapped the ECU with one from salvage yard not sure if its good for sure though. I checked all fuses by removing and checking for voltage then raising fuse and checking voltage on both sides. I also removed the positive cables at the frame and cleaned, they were loose and corroded so I thought I had finally found the problem. I checked the pin connector over trans and ohm'ed wires on each side of plug all ok.

Share this post


Link to post
Share on other sites

Tried ProLink today and it won't talk to it. Also, Engine Shut Down Light does not come on.

If you can't communicate with it your J1587 is not functioning either. One or the other of the datalinks has to be operational to start the engine. Check for worn wires on both datlinks that may be shorting out. I am doing the same thing right now. The datlink wires for the J1939 were still intact but the insulation was rubbed through allowing an intermittant short that was causing a fault.

Share this post


Link to post
Share on other sites

I replaced the VECU with a 1999 model and this is a 2006 - could that be the problem?

The VECU software will not match with the EECU software and will cause a 6-4 code unless the VECU is programmed with the software and datafile for the truck by a dealer.

Share this post


Link to post
Share on other sites

just to mention, I didn't add the VECU and EECU, until after the 6-4 code, and I checked all powers and grounds and all where ok.

Share this post


Link to post
Share on other sites

I’m having the same problem.After the starter motor was replaced,the engine just cranks and will not start.Fuses good.Power and ground to VECU and EECU good.Any help would be appreciated.Thanks.

Share this post


Link to post
Share on other sites
Posted (edited)
4 hours ago, C1065 said:

I’m having the same problem.After the starter motor was replaced,the engine just cranks and will not start.Fuses good.Power and ground to VECU and EECU good.Any help would be appreciated.Thanks.

Go back in the chassis, dig around and find the power leads or ground run you did not attach to the starter post. Not everyone is getting fed.

Edited by Mack Technician

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...