Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
'96 rodeo/passport fuel pump not getting volts
05-15-2013, 04:59 PM
Post: #21
RE: '96 rodeo/passport fuel pump not getting volts
I ran a wire to replace the pink/white one that had no continuity. The new wire has continuity from the relay to the PCM but car still won't start. It continues to turn over but won't start and the fuel pump doesn't turn on. I am at a loss. What should I check next?
Find all posts by this user
Quote this message in a reply
05-15-2013, 08:42 PM
Post: #22
RE: '96 rodeo/passport fuel pump not getting volts
Did you check for the proper Power & Ground at the 85 & 86 terminals with the key on? Is everything plugged back in properly? Did you try a different relay?

Without knowing what all you have tried & checked along with the results it is difficult to offer any more suggestions.

Thanks for using the forum,
Garner

Interested in Mining? Look here: Coal Mining, PA
Visit this user's website Find all posts by this user
Quote this message in a reply
05-15-2013, 10:25 PM
Post: #23
RE: '96 rodeo/passport fuel pump not getting volts
I did plug everything back in and tried several different relays. My test light turned on going from 86 to + terminal on battery, No illumination going from 86 to - terminal or from 85 to either terminals. I turned the key while doing all tests, 86 to + terminal turned light on with and without turning ignition on. Should I assume that due to the test results 86 is the ground and 85 should be getting power but is not?
Find all posts by this user
Quote this message in a reply
05-15-2013, 10:49 PM
Post: #24
RE: '96 rodeo/passport fuel pump not getting volts
Almost sounds as if you are back to square one. 85 & 86 need to supply power and ground to the relay coil in order to trigger that pump. It should only trigger for a couple of seconds when you first turn the key on and then go off again. It should also power up during cranking and go off again a second or two after you stop cranking. Presuming the engine runs if you jump power to the pump that usually means the main EFI relay is good. (power to the ecm and injectors) Can you rig the test light so you can see while working the key? What happens?
Find all posts by this user
Quote this message in a reply
05-16-2013, 06:10 AM
Post: #25
RE: '96 rodeo/passport fuel pump not getting volts
It sounds to me like 86 is Ground & 85 “should” be power and isn’t. I am thinking that either the key switch isn’t sending the signal to the computer or the computer needs replaced. You could look on a wiring diagram to see what path the power takes from the key to the computer. Test that circuit to see if the computer is getting power. If the power is actually getting to the computer & it has a good ground then the computer is probably the problem.
What do you think, Rupe?

Thanks for using the forum,
Garner

Interested in Mining? Look here: Coal Mining, PA
Visit this user's website Find all posts by this user
Quote this message in a reply
05-16-2013, 05:37 PM
Post: #26
RE: '96 rodeo/passport fuel pump not getting volts
Rupe I am not sure what you are suggesting that I test with my test light. The tests I spoke about in my last post where done while turning key. None of The tests done were effected or changed when I turned key. The only test that "lit the lamp" did so with and without key turned.

Garner thanks for your input, i am trying to make sense of the wiring diagrams in the shop manual I have.

I refuse to let this beat me!
Find all posts by this user
Quote this message in a reply
05-17-2013, 11:16 AM
Post: #27
RE: '96 rodeo/passport fuel pump not getting volts
My suggestions were based on the reality that most people can't get to the test light fast enough to view it within that 2 second window where it will have power, which is why I was suggesting that you rig it in such a way to see it while you work the key switch.

That said, every system I have worked on (both Bosch based and GM) use the PCM for the ground side of the relay coil, which means the other terminal will be the hot side. Test light should come on going from battery neg to that terminal with the key on. The other terminal should switch the ground side, meaning clip your test light on bat pos and probe the other connection while working the key.

Let's think outside the box for a moment... are we sure the various plugs are making good connection at the relay and the PCM? Can you find a ground wire in your wiring diagram and add a new connection to chassis ground just to be sure? At 17 years old that could be a distinct possibility. Rust never sleeps!
Find all posts by this user
Quote this message in a reply
05-17-2013, 02:11 PM
Post: #28
RE: '96 rodeo/passport fuel pump not getting volts
What does it mean, if anything, that the test light lit up without turning the key while touching (+) terminal to relay (non PCM side of relay coil)?
Find all posts by this user
Quote this message in a reply
05-17-2013, 10:36 PM
Post: #29
RE: '96 rodeo/passport fuel pump not getting volts
If it was fully bright (verify full bat voltage with a meter) then that means the plug location goes to ground. You should be able to follow that up using your wiring diagram. If that terminal location is really ground then we need to bark up another tree because something has changed over the years since I worked on stuff like this regularly. If it is not full battery voltage and the diagram does not go to ground then there's another issue causing weird readings.
Find all posts by this user
Quote this message in a reply
05-18-2013, 09:16 AM (This post was last modified: 05-18-2013 09:21 AM by Garner.)
Post: #30
RE: '96 rodeo/passport fuel pump not getting volts
OK, I need to step back & look at everything again to see if we are all on the same page.

Post #8 : You said that Terminal 86 connects to the PCM via a Pink w/white stripe wire. You attached a wiring diagram that was helpful but for some reason I can no longer open it?

Post #10 : You said that Terminal #85 connects to a body Ground via a black wire. Every test that I have read that you tried on this terminal seems to confirm that it is a constant Ground & does not go to the PCM.

So far, that information seems to say that 85 is NOT the problem. It would seem that 86; Pink w/White stripe is where we need to focus our attention. It would also seem that this wire should supply power via a PCM command.

Post #19 : I think that this may be the problem. You said that you were going to Piggy Back a new wire with the old one. If the old one is still connected and is damaged it could be causing the problem? You may need to eliminate the old wire completely?

So; if I am understanding everything correctly, here’s what I would do:

First I would re-check every fuse in the car incase that bad wire caused one to blow. Then I would cut the old Pink w/White strip wire out & solder with shrink tube the new wire. Test this connection both for continuity to the PCM & NO shorts to ground. Try it. If the car runs, you’re done except for posting back to us so we can celebrate along with you.

If the car doesn’t run I would get a short jumper wire. Fashion it so you can connect terminal #30 to terminal #85 with the relay in position. I think that I would use 2 pieces of wire with both ends bared. Put the end of one wire in the #30 slot & the other in the #85 slot and carefully install the relay. Now you should be able to touch the two bare ends together and hear the pump run. If it does this still leads me back to thinking that the key isn’t sending power to the PCM or the PCM is faulty. If that happens to be the case we can figure that out in new posts. I don’t want to provide a lot of information on that right now as it would just add things to confuse you. Let’s go one step at a time.

What do you think, Rupe? I don’t want to go down the wrong path.

Thanks for using the forum,
Garner

Interested in Mining? Look here: Coal Mining, PA
Visit this user's website Find all posts by this user
Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)