2000 5.7 gsi problem

[SD2600]

hi guys, So I rebuilt the top end on my 5.7 gsi. I put everything back together and when i went to fire the motor to adjust timing my fuel pumps didn't click on for 2 sec like they normally do prior to the rebuild..

So digging into the fuel pump relay I think I have found some problems....

Testing the ground 85 I don't have a ground with the key on or off.
Testing 86 I have power with the key on and off

Should 86 only be on when the key is on?

I ran a ground from the backside of the relay to the batt and the fuel pumps kick on and stay on.....

Im pulling my hair out on how this works... what to try to trouble shoot and why this all of a sudden happened...

I have tried to troubleshoot it per clymers manual but I haven't gotten any where....

I pulled and cleaned where the wiring harness grounds to the block and all of my components have ground minus the fuel pump relay on 85

I added a new alternator, could something here be the culprit?

Any and all comments are greatly appreciated..

thanks dustin

 

[alldodge]

Pins 85 an 86 are across the relay coil, side 86 goes to ground and side 85 goes to the ECU, The ECU applies voltage to 85 which energizes the relay and closes contacts between 30 and 87. Side 30 receives 12V power thru a 20 amp fuse/relay, and side 87 supplies power to the fuel pumps.

If you apply a ground to side 86 then you have a bad ground

 

[SD2600]

hey dodge, thanx for the reply,

When I pulled a good ground and tied it into the backside of the relay harness I attached it to 85. this is when the fuel pumps came on and ran continuously.

Should I pull a good ground and apply it to 86 instead? would this allow the ecm to control the relay and only apply the pumps for 2 sec when the key is on and then run continuously when the motor is running?

I thought 85 was ground and 86 was hot....

 

[alldodge]

Your correct, 85 is ground and supplied by the ECU, drawing is hard to read.

So if the ECU is not grounding 85 (Pin J1-23) then something is either not right with the ECU or something is not being supplied to the ECU so it will not let the pumps come on. Is the ignition relay supplying power to the ALT and the Purple wire?

 

[SD2600]

the ignition relay i believe is working properly.. it sits right next to the fuel pump relay behind the low pressure fuel pump... when the key is turned on it clicks like normal...

i did put on a new alternator. is it possible i have it wired wrong or it is faulty?

 

[SD2600]

how can i check J1 23 to see if its ok? thanks for the help

Would an ohm reading from 85 to slot 23 be sufficient to check it?

 

[alldodge]

Ohm out the wire is good.
Probably going to need to have your motor scanned for codes.

 

[SD2600]

ey dodge, i haven't been able to rule out then wires from the ecm to the relay yet,, but if in fact i have a bad ecm, do you know of where i can get it replaced or refurbished?

 

[alldodge]

Give Bob a call at OBD Diagnostics. He can advise what he can do and cost
https://www.obd2allinone.com/mefiecms.asp

 

[SD2600]

thanks

 

[SD2600]

ok. i have continuity from j1-23 to 85 on my fuel pump relay.... huuummmmm? now what.. im stumped

 

[alldodge]

The ECU applies a ground to the fuel pump relay and you have continuity between 85 and J1-23. This says the ECU is not turning on the pump. Either the ECU has an issue, or something is not getting the correct signal which in turn tells the ECU that everything checks out, turn on the pump.

Maybe a ground not connected that once was or something else not connected or making good contact. If everything is as it should be then only thing left is scan motor for codes, and if no show up have the ECU tested

 

[SD2600]

Thanks for the reply dodge... I have checked all the grounds... that i know of and all check out good. I tried to check for codes via the data port... but when i turn the key to the on position I don't get a light at all....nothing... I inserted my led light to ports f + and E - and nothing.. i even tried jumping port A and B with a paperclip to see if it would light up and nothing....

Im shipping my ecm to bob to have him run it and see if i have any issues....

 

[SD2600]

ok, so i sent my mefi3 to bob. stand up guy, very prompt and knowledgable. anyone with Mefi issues shouldn't hesitate to use him. So the ecm checks out fine. which is good and bad. good because they are costly little devils, but bad because im still in the same boat. I should have the ecm back tomorrow so stay tuned for more questions. I plan to start from scratch to trouble shoot..

 

[alldodge]

Good its not the ECU, we missed something simple, just need to figure out where

 

[SD2600]

yup, once i get my ecm back im moist to start fresh troubleshooting the relay and associated wires...I think i have a better understanding of the system.. at least i think.... ill post my tests and hopeful results... stay tuned

 

[SD2600]

ok, so i started from scratch and cut open the wiring harness. I think they used a dozen rolls of electrical tape....I chased all the wires and found the culprit..... drumroll..........nothing. i didn't find anything..... so i decided to re install the whole harness. when i went to turn the key my fuel pumps kicked on..... Im not sure if i did anything differently but hey they are working...

now its time to fire her up and see where im at from there.... this is my first top end rebuild any pointers

thanks dodge for your help!

 

[alldodge]

Ya did nothing but it started to work, bummer, man I hate those Gremlins, they will show back up, just don't know when. I'm going to say it is probably inside on of the plugs. Reason to say this, is seen it happen a few times. The easiest one found was my trim pump connector.

Chased wires an found it work fine until the wires were just in the right spot, then it would loose connection. Turned out the bad connection was between the wire and pin connector inside the plug. In this case I ran another wire around the connector

As for top end rebuild, I'm not sure you need it, but will not hurt. Pull the heads and have a valve job done, you've already taken care of the other issues.

I need a top end rebuild on one of my motors because of the high lift cam, but the old Rinker motor has 600+ hours and doing fine

 

[SD2600]

I just rebuilt the top end... fuel pump relay issues showed up after i put it back together, I’m trying to start it up right now.... it cranks but hasn’t fired... I just verified my firing order and plug routing. Still no fire. All new cap rotor plugs and wires. Any thoughts

 

[alldodge]

OK, my misunderstanding

My documentation of the GSI indicates it has the Delco EST distributor and not cam or crank sensor. If this is the case then check for spark from the coil. Then see if its making it to the plugs.

If no spark check 12V on the Pink and Purple wires at the coil