86 Ranger TFI Relocation **** Up

[Frankenstein86]

So I got a relocation kit to move the tfi module off of the distributor, got a new module whole nine. Right off I see there's literally no where to put this damn heat sink so I go with the only place it would fit and also the only place I probably shouldn't have put it..... Right above the heater fan airbox on the firewall. I went to try to start the truck and when I put the switch to the on position fuel pump comes on properly lights in the cluster come we're good. Turn the the key all the way to start and you lose power immediately. You have to take the power wire off the battery and put it back on to get power again. It blew the EEC Power Relay, so I took the relocation kit off, placed the TFI back on the distributor, got a new Relay. Still the same thing. Now this is where I think I truly ****ed up. I grounded this bastard with one of the screws holding the heat sink to the firewall as the manufacturer suggested, but at the time I didn't think about the fact that the ECM is grounded to the same bit of steel on the inside of the cab. Before I jump to conclusions thinking I have fried the system I'm hoping someone might have some insight.

 

[Big Jim M]

Grounds all are the same. Everything in the vehicle is grounded to the same ground. Doesn't matter how close to another item you are it would be the same if it was at the other end of the vehicle.
THAT ISN'T YOUR PROBLEM!
Big JIm

 

[Frankenstein86]

So NONE of my grounds need to be specifically placed (i.e.- this should be grounded to intake plenum, that should be grounded to the frame, etc. etc.)? Is there still a possibility of shorting the ECM regardless of the EEC Power Relay acting as the failsafe?

 

[Spott]

Relays don't really act like fuses, they're more like switches. If you're frying relays there's something significantly wrong with your wiring; fuses should always be the first thing to fail.

There's always a small possibility of frying the EEC if you wire things up wrong enough, and we can't tell from here what kind of wrong you've got.

You really need to go back and double- and then triple-check any wiring and connectors you've worked on during this project. Make sure everything is connected only to what it should be. If you don't have a multi-tester, it's well worth it to spend $15 for a basic one; you'll find it very useful for all sorts of troubleshooting and repair in the future, after you finish this job.

Once you get the wiring sorted and verified, you can finally hook the battery back up and see if the EEC is still happy (you're not doing electrical work with the battery hooked up, are you? You know better.)

 

[Frankenstein86]

Definitely not working on any of it with the power hooked up, I'm pretty experienced as far as industrial electrical just not too privvy to any automotive electrical. I've checked, triple checked, removed the relocation kit and placed everything back to factory just to check it. Still it kills the power when you turn it to the on position. It seemed simple enough. 3 wire hook up 4 wire screw up. I'm at a loss because the connections are back like they were and still the same result.

 

[Frankenstein86]

Apologies it kills the power when you turn the ignition to the START position.

 

[Big Jim M]

Agreed! Franken did his wiring incorrectly and needs to spend some time reconsidering the project. Unless his screws into the firewall found a wire bundle or some such.
Big Jim

 

[Big Jim M]

I cannot think of anything you could have done wrong that would cause this happening at the START position except a direct short. Which short most likely comes from installing wires wrongly.
Big JIm

 

[Spott]

Well, if everything you've worked on its back the way it was, and everything you've tested is correct, then there's got to be something tangential going on. It won't be something obvious, but a couple possibilities might be damaged wires a ways down the harness that got cranked around when you did the initial work, or, as Jim mentioned, maybe you drilled or screwed into a wire somewhere. It might be something else similar, too, that I can't think of right now.

 

[Frankenstein86]

Okay I pulled the dash out and the firewall back and i didn't get into any wires..... So for shits and giggles let's say that I crossed a wire somewhere either at the distributor stator or the tfi, what could happen?

 

[Big Jim M]

I think you have found the answer to your question! Just what is happening could happen!
Big JIm

 

[Frankenstein86]

Obviously, but what components could it take out?

 

[Spott]

That depends on what wire is crossed. It could cause no damage at all, or it could light your truck on fire, or anything in between. We can't tell you what it is because undetermined wiring will cause undeterminable results, and because we can't see your truck from here.

You need to stop worrying about what could be wrong and what could get damaged, and start finding out what is wrong and what is damaged. Don't guess what is happening based on advice, but observe what is going on based on tests and measurements.

If you want instructions for testing, we're happy to provide them, but you have to actually do the tests and report the results. And the instructions will certainly start with "Acquire and learn to use a multimeter" and "Get a complete wiring diagram (book) for your truck."

 

[Frankenstein86]

Okay I know how to use a meter, also I have a wiring diagram that half ass resembles what's in the truck, from this website... The wires that could have gotten crossed would have been the wires on the extension from the distributor to the tfi module.... It would have been the two outside pins, the best breakdown I can find says that would be the Ground and the PIP IN wires. I have check the battery 12.4V, checked the 3 fusible links coming from the starter solenoid for coninuity. I removed all the wire looms and checked for bad wiring it's not great but it ain't bad either. How do I test an EEC Power Relay to tell if it's still popping them?

 

[Spott]

Not sure what you mean by "popping" a relay.

There's two parts to a relay: an electromagnet coil and a switch. In this case, if you put 12V across the coil, it makes a magnetic field, which moves a piece that closes the switch.

To test things, take the relay out of the socket. If you measure the resistance across that coil, that is, between pin #85 and 86 on the relay, you should measure about 50-200 ohms. If it's open or infinite or over-range, you've fried the coil. This would likely be caused by hooking up something in series with the coil and trying to draw power through it. This might be what you mean by "popping" the relay.

The other thing that could happen is that the switch contacts get fried. If you try and draw too much current through the switch part, it could make a big arc which could either blast metal off the contacts so they don't make contact any more, or weld them together so the switch never opens. These relays are rated for pretty high current handling, like 20-60 Amps, so the only thing that's really likely to overload the contacts that much is a dead short to ground.

To check the switch portion, test the resistance between pin #30 and 87 on the relay, it should read open or infinite resistance or over-range. If those two tests measure correct, then hook up pin #86 to battery+, pin #85 to battery- (it should click as soon as you complete those connections), and measure the resistance between between pin #30 and #87 again; it should now read close to 0. If those 3 values measure out correctly, then the relay is working properly.

Next, hook the battery back up (leave the relay out of the socket still) and make sure your battery terminals are clean and tight. Measure the voltage between the socket connector for #30 (yellow wire) and ground (use the negative battery terminal or a clean bare spot on the body or engine when I say "ground); it should be 12V (battery voltage). If it's 0V, then you've probably blown Fuse Link L in the yellow wire. Test the resistance between socket connector #87 (red wire) and ground, and it should be a couple dozen ohms minimum. If it's open, you've probably blown Fuse Link M in the red wire. If it reads close to 0 ohms (or whatever you get when you touch the probes together directly) then you've got a short to ground somewhere. However, if you have a short, I would expect a fuse to blow long before you fry the relay contacts.

Measure the resistance between socket connector #85 (black wire with a light-green stripe) and ground, it should read really close to 0 ohms, as that terminal should be hooked to ground. If not, you've got a broken wire or a rusty/dirty ground connection. Turn the key to "run" (remember, the relay is still out of the socket) and measure the voltage on socket connector #86 (red wire with a light-green stripe); it should be 12V. If it's not, then you've got a bad ignition switch, or ignition switch connector, or you've blown Fuse Link E in the yellow wire to the ignition switch.

Let us know if you find anything different than the expected values on any of those measurements, and we can proceed from there.

P.S. If you register on www.autozone.com, they'll let you access their service manuals for any vehicle. They're not quite as thorough as the factory service manuals, but they're better than a Chiltons or Haynes. That's where I'm getting the wiring diagrams and wire colors I'm referencing above.