I'm working on a 91 Dakota SWB RC 4x4 with a factory 5.2. My cousin bought the truck with the engine removed, although it had been rebuilt. The last owner said the engine was pulled by the friend who owned the truck before him because the rear main seal kept leaking. The truck sat for at least 4 years - long enough for the mice in the radiator overflow into turn to gel. The interior smelled almost as bad because squirrels and/or rats had moved in and eaten the seatbelts, although NONE OF THE WIRING was damaged. We pulled the dash to confirm.

I pulled the oil pan and discovered the cause of the leaking rear main - the thrust bearing was in the wrong spot (#1 main). Fortunately, the crank wasn't damaged and I replaced all the mains. Everything else looked good internally.

The motor is now installed but there are a couple of gremlins that I can't figure out. Gremlin #1 - the starter will engage the engine but it will not fire. I've checked the ASD relay with a multi meter and it's good. It opens/closes with 12 volts and has minimal (0.1) resistance. I've also swapped relays around but can't get power to the coil. I can jump the ASD relay and get power to the coil, and I've verified continuity from the relay box to the coil. The harness has been checked and there are none of the common corroded or broken splice areas. If I put gas in the TB with the jumper to the relay, the engine will run for a few seconds and die, which brings me to...

Gremlin #2 - The tank was dropped, thoroughly cleaned, and a new fuel pump purchased (cheap insurance). Currently the old pump is still installed and working very well. The tank is not currently in the truck but the pump is in a 3 gallon bucket about 1/4 full of gas, which it sucks up without problem. There is fuel coming to the TB but not coming out of the injectors. Before re-assembling the engine I took the TB apart and used 2 cans of TB cleaner cleaning it and the injectors. Do they need to be bled or will they eventually purge air? I have power to the injectors (if I jump the ASD relay), power at the TPS, and at the AIT sensor, but zero spray. The TPS and AIT do not illuminate the test light as bright as the injector connection. I haven't checked voltage, but are they a lower voltage (5 volt or 8 volt) connection?

I've been checking the ignition switch and there is one connection - I believe it's a seven wire plug - that is giving a higher, scratchy tone when checking for continuity. The connection has two input wires going into one receptacle. I hope to trace this and see if there's a fray, and if so, it solves the problem. If not, I'm about out of ideas. Any input is welcomed and appreciated.

 

Borrow/rent some noids lights from your local parts store. Check and see if you are getting injector pulse. Sounds like you aren't.

 

Also, pick up the 1991 factory service manual (used paper on eBay, or new disc off Bishko Books's web site Bishko Books, Repair Manuals, Owners Manuals, Parts Books & Sales Brochures (autobooksbishko.com) or through Summit Racing or the dealership) so you have the wiring diagrams.

RwP

 

When you first turn the key to "on"(not cranking the motor) the fuel pump will prime the system. If you take the air cleaner off and look down tb (and have somebody else try to stat it) You will see if you are getting any fuel out of the injectors. Since it never had been fired up since all the work floor the throttle when starting if there is any air in the system it should purge it.

 

Got the truck started this weekend. The first problem ended up being a short in the ignition switch. By jumping the relay the short was bypassed. I pulled the connector and messed with the wire where we got the scratchy continuity tone and that seemed to work. I'm hoping the wire was not fully seated in the switch connector.

On the fuel issue, I am fairly sure the fuel problem was due to the old rubber lines. I knew fuel was making it to the TB because I pulled the line. Also, gas started to drip from the injectors while cranking, but we never cranked the truck over with the fuel line off to see just how much pressure there was. A leak developed right at the entrance to the filter so we replaced all the rubber lines to and from the tank. After doing that the truck fired up and ran on its own.

Which created Gremlin #3. The tach is not working, neither is the oil pressure gauge. I am positive I put the rear main bearing with the oil hole in the right spot, but now I'm second-guessing myself. I have a mechanical gauge I will put on tonight after work - fingers crossed.

 

The fuel tank is in and the new pump is installed. The oil pressure gauge started working after I fooled with the sending unit. No tach yet and the fuel gauge isn't working, although it was before putting the new pump in. There's almost 5 gallons in the tank so it should show. Will check the usual fixes if more gas in the tank doesn't do it. Still getting rat nest residuals out of the exhaust, but she is coming along.

Thanks to all who provided insight and comments.

 

]I would check your instrument cluster connections. Seeing how the Tach and fuel gauges are not responding . Not uncommon for a loose connection on the cluster wiring harness to cause the gauges as well as instrument panel lights to not operate correctly. For years I would have to tap on my dash to get them to start working. A while back I read on here that it is usually caused by the connectors being just loose enough to break the connection. There is a note about it in the section with service manuals and common issues. Hope this helps. As for the fuel gauge, there is another common issue with the sending unit/fuel pump not reading correctly. I had mine replaced and a year later, same issue. I just track my mileage, I’m not trying to pull my 22 gallon tank down to fix it. Again.

 

I pulled the new pump out and found the float was not floating. Put the old float on and that cured that problem. And the tach started working too, after I pulled the cluster and checked the connections. Little bits of progress each day.