dcramer67 Posted May 4, 2016 Share Posted May 4, 2016 Can anyone tell me why the PO might have put in this jumper wire between the fuel pump relay and fuse? Also, whenever I turn the key over, I get a high pitched whining noise coming from this box next to the air filter box. What could be causing that? Link to comment Share on other sites More sharing options...
gogmorgo Posted May 4, 2016 Share Posted May 4, 2016 That box is the ECU... Probably not great that it's humming. Which pin on the relay is the wire going to? Could be trying to put power to either the fuse or fuel pump. Looking at those two wires twisted together with the marette, I suspect he was having fuel pump issues he was trying to correct. I'm pretty sure those are the wires for the fuel pump ballast resistor. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 4, 2016 Share Posted May 4, 2016 The "OP" has a 60A maxi fuse jumpered to what looks like the fuel pump relay. Using a wire nut confirms the "OP" was/is an idiot. Whining noise from the ECU usually indicates it's pulling a hi-amp load it shouldn't be. First thing you should do is disconnect the battery and remove the PDC (that's the relay/fuse box where the jumper is). There is enough slack in the cables to partially flip it over and inspect the wiring underneath. Verify that there are no fried wires, relay sockets, fuse contacts, etc. Link to comment Share on other sites More sharing options...
dcramer67 Posted May 5, 2016 Author Share Posted May 5, 2016 The "OP" has a 60A maxi fuse jumpered to what looks like the fuel pump relay. Using a wire nut confirms the "OP" was/is an idiot. Whining noise from the ECU usually indicates it's pulling a hi-amp load it shouldn't be. First thing you should do is disconnect the battery and remove the PDC (that's the relay/fuse box where the jumper is). There is enough slack in the cables to partially flip it over and inspect the wiring underneath. Verify that there are no fried wires, relay sockets, fuse contacts, etc. By "OP" (original poster), do you mean me? I am not the one who ran the jumper wire, or have done any of the wiring on this vehicle. That is why I am asking these questions. Looking through stuff, it seems there is a bunch of jerry rigged wiring, and I am not sure where to start with making things correct. When my jeep wouldn't start and I couldn't hear the fuel pump click on, I first checked the fuse box. This was the first time I opened the fuse box up, and that is when I saw the jumper wire. I will check the fuse box tomorrow and make sure nothing is burnt up/melted. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 5, 2016 Share Posted May 5, 2016 Crap. I meant PO (Previous Owner) not OP. :dunce: My bad. I transpose things all the time..... Link to comment Share on other sites More sharing options...
dcramer67 Posted May 5, 2016 Author Share Posted May 5, 2016 Crap. I meant PO (Previous Owner) not OP. :dunce: My bad. I transpose things all the time..... It's all good :) If memory serves correctly, that 60A maxi fuse should actually be a 20A anyway right? So something was definitely going on with the fuel pump. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 5, 2016 Share Posted May 5, 2016 What year truck are we talking about? I just noticed your signature shows an 87, yet you are showing a 1991 PDC (Power Distribution Center) in your pics. The 87-90 Renix models didn't have a PDC. It also looks like an HO ECU beside it. Was your 87 converted to HO? The below is a pic of my 91 PDC, so the 60 fuse is correct for a 91. 92's are configured a bit differently. Link to comment Share on other sites More sharing options...
dcramer67 Posted May 5, 2016 Author Share Posted May 5, 2016 What year truck are we talking about? I just noticed your signature shows an 87, yet you are showing a 1991 PDC (Power Distribution Center) in your pics. The 87-90 Renix models didn't have a PDC. It also looks like an HO ECU beside it. Was your 87 converted to HO? The below is a pic of my 91 PDC, so the 60 fuse is correct for a 91. 92's are configured a bit differently. How can I tell for sure if they did a swap? The only other jeep I've had was a 96 zj so I'm not familiar with renix. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 5, 2016 Share Posted May 5, 2016 The truck I am looking at in your pics is either a 91 or 92 MJ model. That's a good thing. Hopefully someone will chime in and run your VIN to verify the year of manufacture ......... Link to comment Share on other sites More sharing options...
mikekaz1 Posted May 5, 2016 Share Posted May 5, 2016 look at the door sticker for mfg date? Link to comment Share on other sites More sharing options...
dcramer67 Posted May 6, 2016 Author Share Posted May 6, 2016 look at the door sticker for mfg date? The doors are not factory. It has the 97+ style doors. The truck I am looking at in your pics is either a 91 or 92 MJ model. That's a good thing. Hopefully someone will chime in and run your VIN to verify the year of manufacture ......... The title I have says it is an 87, but there is a good possibility a swap was done. Here is a photo of the engine compartment...anything you see proving it was swapped? Or will I have to look at something else? I checked for burnt wires and everything seems to be in good shape. I tried starting it with that jumper wire removed, and it wouldn't turn over or anything. Is that fuse/relay actually for the starter somehow? Link to comment Share on other sites More sharing options...
Keyav8r Posted May 6, 2016 Share Posted May 6, 2016 If that is the ECU right by the air filter box, this looks like my 91 AFTER I re-located the washer fluid bottle from the left fender well to the right firewall. I moved it to make room for the eventual dual diaphragm brake booster upgrade and replaced it with a later model XJ bottle (which is what yours looks a lot like). Post you VIN and maybe someone can decode it for you. BTW - that's not the stock location for the vacuum reservoir. It's usually mounted behind the front bumper on the right side. Link to comment Share on other sites More sharing options...
Minuit Posted May 6, 2016 Share Posted May 6, 2016 Looks just like my '91's engine bay, except my washer bottle is on the opposite side. Maybe a 92 or later donor? Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 6, 2016 Share Posted May 6, 2016 You have the HO oil filter sticker and the HO vacuum diagram on the firewall. If it was a swap it highly unlikely someone would swap over the aged stickers. The water pump is HO, the thermostat housing is HO, you have an HO truck. Plug your VIN into this decoder, it works for me: http://www.cherokeeforum.com/vindecoder.php Link to comment Share on other sites More sharing options...
Minuit Posted May 6, 2016 Share Posted May 6, 2016 Look on the big white sticker on the driver side of the firewall. What model year does it say? Don's right, that looks almost completely factory. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 6, 2016 Share Posted May 6, 2016 I'm taking bets it's a 92 due to the PDC configuration........... Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted May 6, 2016 Share Posted May 6, 2016 It's had a swap done , you can see where the c101 mounting bracket has been removed directly below the HO sticker . If there is still a sticker on top of the ECU that will give you a ballpark as to what year swap was done . Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 6, 2016 Share Posted May 6, 2016 I guess we'll never know................... :yes: Link to comment Share on other sites More sharing options...
dcramer67 Posted May 6, 2016 Author Share Posted May 6, 2016 You have the HO oil filter sticker and the HO vacuum diagram on the firewall. If it was a swap it highly unlikely someone would swap over the aged stickers. The water pump is HO, the thermostat housing is HO, you have an HO truck. Plug your VIN into this decoder, it works for me: http://www.cherokeeforum.com/vindecoder.php I used that VIN decoder (1JTMW6416HT191051). The jeep is an 87, but was also originally 2WD. It definitely has had a motor swap. I will have to see if I can find another VIN on the motor, and see what year it came out of. I store it in my Dad's garage since I do not have the space here at my house. I will look into this a lot more over the weekend. Link to comment Share on other sites More sharing options...
DirtyComanche Posted May 6, 2016 Share Posted May 6, 2016 You have the HO oil filter sticker and the HO vacuum diagram on the firewall. If it was a swap it highly unlikely someone would swap over the aged stickers. The water pump is HO, the thermostat housing is HO, you have an HO truck. Plug your VIN into this decoder, it works for me: http://www.cherokeeforum.com/vindecoder.php Unless your eyes are way better than mine, that looks like the "Attention! Warning! Vorstich!" (or whatever it says) sticker for the oil filter threads being metric. And I can't read the vacuum diagram well enough to tell what it is... But the Renix ones had the diagram there too. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 6, 2016 Share Posted May 6, 2016 You have the HO oil filter sticker and the HO vacuum diagram on the firewall. If it was a swap it highly unlikely someone would swap over the aged stickers. The water pump is HO, the thermostat housing is HO, you have an HO truck. Plug your VIN into this decoder, it works for me: http://www.cherokeeforum.com/vindecoder.php I used that VIN decoder (1JTMW6416HT191051). The jeep is an 87, but was also originally 2WD. It definitely has had a motor swap. I will have to see if I can find another VIN on the motor, and see what year it came out of. I store it in my Dad's garage since I do not have the space here at my house. I will look into this a lot more over the weekend. Look for the block casting number: 1987-90 53005535 1991-95 53008405 1996-98 53020569 1999-04 53010449 Location is the front left side of the block: You can also ID the cylinder head to see if you have a Renix or HO head: 1987-90......2686 1991-95......7120 1996-98......0630 1999-06......0331 Image Not Found But since the body is an 87, it's a conversion. Adam nailed it. :cheers: Link to comment Share on other sites More sharing options...
dcramer67 Posted May 6, 2016 Author Share Posted May 6, 2016 I would also like to just thank everyone here for their help and input! You guys are awesome. Link to comment Share on other sites More sharing options...
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