Need help with my V8 swap

[2000StreetRod]

clutch pedal jumper & RAP Module?

On models with an automatic transmission and no center console there should be a clutch pedal position switch jumper located behind the left side of the instrument panel and taped to a wiring harness. It will have a pink wire on one side and a white/pink wire on the other side. If you don't have the jumper the wire will be pink all the way back to the anti-theft relay located in the relay module. I don't have an owners guide for your model but I think the relay module is located under the hood.

When you find the anti-theft relay there should be battery voltage on the red/light blue wire when the ignition switch is in start. The anti-theft relay is normally closed which means if there is battery voltage on the red/light blue wire then there should be battery voltage on the pink or white/pink wire unless the RAP module intervenes.

Have you confirmed that you have a RAP module installed at the left rear quarter panel? According to my wiring diagram not all vehicles have it. If you have one, it should be disabled from intervening with the anti-theft relay by disconnecting C338 with a light green/purple wire at the RAP module.

 

[Axial32]

I do for sure have the RAP module.. I have the keypad entry, I have the box in the left quarter panel with the keypad numbers on it... I have the full center console not just the half one... and the starter relay is under the hood on the driverside innerfender...

And If it's that easy to disable the RAp.. I'm so doing it...

Thanks a ton StreetRod...
-Axial32(Tyler)

 

[bdjernigan]

I was thinking about swapping my 4.0 for a 5.0, but yall almost have me talked out of it with these problems. I may instead either upgrade or leave my 4.0 stock. Good luck with the wiring problem. Wish I could help you out but I dont have a clue about the wiring.

 

[pwrshft99]

Ahh he'll get it sorted out then you'll have a good write up to follow.

There are options for electronics other than stock stuff, kinda depends on what you want to spend. A carburated swap would also be easier but might not be practical or legal for a street truck...

 

[Axial32]

Actually I really wanted to do a carburated setup.. I have an intake and distrib utor... Just I couldn't afford the four barrel carb. And ignition box that I wanted...
I would've been fine legality wise... And functionality would've been fine..
That'll all come later once I'm settled here at school...

 

[2000StreetRod]

carb & trans

Switching from fuel injection to a carb might be simpler but would be settling for less performance. Racers switched to fuel injection to get improved performance and better fuel economy. A carbureted dragster that only runs WOT might have comparable performance to a fuel injected one but typically for all other vehicles carbs just can't keep the air/fuel ratio at the optimum value for different engine temperatures, intake air temperatures, engine load and engine rpm.

I guess it may be possible to retain your 4R70W electric shift transmission with a carbureted engine by retaining the PCM and just eliminating the fuel injectors but I suspect there would be problems. The O2 sensor outputs would not correlate with the PCM generated fuel injector pulse width and the PCM would probably revert to open loop. Without a TPS on the carburetor the PCM would not be able to determine driver demand and would upshift and downshift the transmission at less than optimum times.

I think the best approach is just to get your electrical problems resolved. Millions of Explorers have been manufactured with the 4R70W and the 5.0L engine. It's just that none of them were a Sport.

 

[Electrohacker]

actually if you watched trucks this week they used a TCM stand alone aftermarket transmission module on project rolling thunder which could also control the 4r70w if you went to carburetor


but why you wouldn't want EFi is beyond me

 

[Axial32]

actually if you watched trucks this week they used a TCM stand alone aftermarket transmission module on project rolling thunder which could also control the 4r70w if you went to carburetor


but why you wouldn't want EFi is beyond me

Heck yes I watched Trucks this weekend,>!! I watch the PowerBlock EVERY weekend...

I am staying with the EFi, though of the problems...

If I would've gone carb.
I would've been for sure the first I've seen carb. 302 explorer sport.

If anything I would want to get a roots style twin screw supercharger for the 302 later down the road.. since I have tons of hood/capartment space.

I move into my appartment tomorrow... I'm here in Indiana at an aunt and uncles' house... I'll be headed back to home right after the move in, so I can get the problem worked out and have my own vehicle for school.

 

[Axial32]

Well I'm home... went out and cut that wire.. the lightgreen w/purple stripe... still nothing.. here's a pic of the module in the rear quarter and if you look you can see my cut wire.

So... there's still no crank from the key ignition, and no spark when key is in run with relay jumped.

 

[2000StreetRod]

anti-theft relay

Did you find the anti-theft relay in the relay module?

Did you check for battery voltage on the red/light blue wire connected to the anti-theft relay when the ignition key is in start? If battery voltage is not there then check fuse 24 in the interior fuse panel. If fuse 24 is good then check for battery voltage on the red/light blue wire between fuse 24 and the ignition switch when ignition switch is in start.

 

[Axial32]

Did you find the anti-theft relay in the relay module?

Did you check for battery voltage on the red/light blue wire connected to the anti-theft relay when the ignition key is in start? If battery voltage is not there then check fuse 24 in the interior fuse panel. If fuse 24 is good then check for battery voltage on the red/light blue wire between fuse 24 and the ignition switch when ignition switch is in start.

Umm... I didn't know that I was suppose to find a anti-theft relay in the relay module? All I did was find the wire you said I needed to and snipped it.

OK, so I need to have the key in the run or hold it in crank position??

And how would I go about finding this anti-theft relay in the relay module, and how would I get a reading on the single wire?? Do I just ground the negative on the testor.

Like I said, I don't know much about wiring... so more help the better

 

[RiverRatTech]

Correct me if I'm wrong, but from what I'm reading you are getting power to the console when you turn the key, correct? If so have you thought about doing a push button to start it, when the key is turned. I think it would just take some wiring to the starter motor. I'm not an expert in the electronics dept. but it was just a thought.

 

[2000StreetRod]

Reread post #101

Umm... I didn't know that I was suppose to find a anti-theft relay in the relay module? All I did was find the wire you said I needed to and snipped it.

Please reread post #101. It described what to do before disconnecting the electrical connector with the light green/purple wire to the RAP module. Cutting the wire should not have been necessary. I was hoping that you could just unplug the connector.

OK, so I need to have the key in the run or hold it in crank position??

There is only battery voltage present when the ignition key is in start. It is not present when in run.

And how would I go about finding this anti-theft relay in the relay module, and how would I get a reading on the single wire?? Do I just ground the negative on the testor.

Like I said, I don't know much about wiring... so more help the better

Check the owner's guide for the relay location. If you don't have one they are available online. Yes, you connect your meter negative probe to ground and the positive probe to a pin that backprobes the connector or penetrates the wire insulation.

 

[Axial32]

Well luckily I snipped that far enough back that I can resolder it... I did unplug the RAP for now... I'm working on getting some readings from relays and fuses

I checked out:
#14(maxifuse)(ignition) in relay module and it was fine, it was getting like 12.2
#2(PCM power relay) and it was getting power
#11(PCM memory and horn) it was getting power

I haven't gotten a chance yet to check the incabin fuse readings. I have to check #13,#19, #24

 

[Tufelhunden]

Nice write up OP!! I was/am contemplating a similar swap but I am not sure now. Know how, yes I have that, but I may just look for an add-on for a new 4.0 and save some headaches.

 

[Axial32]

I checked #19.. w/o the RAp.. and it had power...
I can't find the antitheft relay.. or maybe it's not label in the owner's manual.
I just can't figure it out.. why would I have no start from the key and no spark from coils.???

I had an idea to check and see if it is the computer.. but I don't know if it'll help since they things wrong I don't think are computer related... if I plugged in a friends v8 PCM would it hurt there pcm or anything like that, or would it possibly help me..??

 

[vroomzoomboom]

this is turning into a suspense thread, now!
"will he find power? will he hear it breath fire for the first time?! stay tuned!"
in all seriousness, hope you get it running soon. i have been fallowing this thread since it started. wish i could help you, but i to suck at wiring.

 

[Axial32]

this is turning into a suspense thread, now!
"will he find power? will he hear it breath fire for the first time?! stay tuned!"

That made my day..!!

Well there is no power coming through the trigger wire on the starter relay, which that explains why there isn't crank at the turn of the key, but I don't know what would the trigger wire come from...

And would that also exlpain the no power out of the coils as well???

I wanna here this thing run... jumping the relay and hearing it just crank is awesome sounding, but still not good enough... I wanna hear the roar out of the exhaust.

 

[Axial32]

So we found a couple problems....
1. Found in the top black plug and bottom grey firewall plugs some pins had slid out of the plug... So we fixed that... But it didn't help
2. Looking at the plugs... The red/light blue wire is on the top black firewall plug top row third from the left when looking straight at the engine harness side. And the female end on the firewall doesn't have a re/light blue wire in it nor one in that spot...

 

[2000StreetRod]

fuse 19

I checked #19.. w/o the RAp.. and it had power...

In an earlier post I believe you stated that you had no power to the ignition coil pack. If fuse 19 has power in run and start then there should be power to the ignition coil packs unless there is a wiring error. Check for battery voltage in run and start on the red/light green wire at the coil pack. You should be able to disconnect the electrical connector and probe the pin connected to the wire. If there is power there then the reason there is no ignition spark is the PCM is not firing the coil packs.

. . . if I plugged in a friends v8 PCM would it hurt there pcm or anything like that, or would it possibly help me..??

Until you confirm the wiring is correct, I would not risk trying another PCM.