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Upgrading 1998 Explorer 4.0 to 2000 5.0 Issues

kchartier

Member
Joined
May 18, 2016
Messages
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City, State
Fort Worth, TX
Year, Model & Trim Level
1998 Ford Explorer
help please here is the story:

I had a 1998 Ford Explorer 4.0 SOHC that I replace the timing chain guides that eventually the timing chain broke. I decided to do away with the guides by installing the 5.0 L and that is where a lot of issue occurred.

After installing the 5.0, it was discovered that the engine was a 2000 year model and not a 1998. two things happened, the anti theft kept flashing and from my readings on here I needed to get keys programmed. Well, that was done by a locksmith and it doesn't flash anymore. it operates as normal.

I have sprayed starting fluid in the intake and the engine does run with that....So it looks to be a fuel issue. We actually had two 5.0 at one point but took one of them back. the wires on the fuel injectors were different so we took off the wires on one and spliced them and put them on the harness we are using. There are also some componets that are nnot plugged in and I don't know what is essential for it to run. I know that something don't have to be plugged in and will run but it would run like crap. I cant even to get it to run like crap yet.

I took to ford to see if they would flash the computer or get past the anti theft and they would not even touch it because of liability issues....which I think is crap.

another note: there is a possiblility that we are using a 1998 motor with a 2000 computer

so my question is, what are the essential componets that are required to start the vehchicl even if it run like crap ie. cam position sensor, O2 sensor, MAP, etc? also, was there a big difference between fuel injectors from 1998 to 2000?
 



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There are a couple differences between the '98 Expo and '00 Expo along with PATS that need to be addressed:

Pretty sure the '98 uses an electromechanical VSS at the back of the transmission for the speed signal. The '00 uses the ABS system so there's a fair chance your '00 powered '98 has NO speed signal -- the PCM needs a valid speed signal as does the speedometer and cruise control module.

A quick scan of the wiring between the two shows a wiring disagreement at pin 13 on the 42 pin connector between the engine and body harness -- The '98 has the ground for the VSS, the '00 is expecting the "check fuel cap" warning indicator.

The really big issue is the likelihood that the fuel pressures between the '98 and '00 are too different for the PCM to compensate for. The '98 probably uses a 2.5 bar EFI system (38 or so PSI), the '00 uses a 4 bar (60 PSI or so).

Still, from your description, it sounds like you've got no fuel pressure at all so I'd start with a pressure check at the fuel rail to verify the pressure there.
 






we pushed that value thing on the fuel rail and the fuel spertied out. don't know if that helps
 






I just want to get it to start.....I know that the map sensor o2 and other sensors will make it run smoot, I am just trying to get it where it runs on its own..crapy or not.
 






what would be recommended if the injectors are my issue? replace computer 1998 or replace the injectors. don't know where to go from here.
 






What pcm are you running? The pcm from the 5.0 doner vehicle with the same 5.0 wiring harness (with different injector connectors).

I'm no expert on this subject, but with pats sorted out and the right pcm I'd think you could at least get the motor to fire.

If your trying to use the 4.0 pcm with the 5.0 you have a problem. The 98 body is a returnless fuel system, so it sounds like you have that sorted out.
 






I Think it is a 2000 pcm and a 98 motor because the motor has the return
 






Did you seal the return side of the fuel rail? The 98 body would not have had a return fuel line, correct?
[MENTION=61294]vroomzoomboom[/MENTION] has done a swap from the 4.0 to 5.0. He might have some great tips for you.
 






do you know which motor harness you have?. there are 2 main connectors. one to the pcm on the firewall, and the other behind the intake near the windshield wiper. you might have to get a service cd, and check pin for pin that all of them are feeding the signals to the correct spots. it wont matter if you have a 2000 motor in a 98, its all about the electronics. if it runs with you spraying starter fluid into the throttle body (or infront of the MAF) then there still is a problem with the injectors not pulsing, or not pulsing in time the way they should. as mentioned before, there might be a difference in the fuel pressure when you do get it running (never thought of that before, but it is possible). the vss in a 98 is picked up from the rear diff however.
you will have to look closely at your pin outs. to give you an example, i have a 96 trans in my truck. it is a 98, and i am using the 96 trans harness. when i put power to everything the first time, i had a page of errors. i had to repin the 96 harness to match the 98 harness. the problems you have can be fixed with some time. bluka also did a v8 swap in his sport using 3 different truck harnesses. he pretty much ended up repining the entire truck so that everything worked.
 






The computer, which is in the firewall on passenger side, is a 2000. I looked that up by the part number. What happened was I purchased a motor from salvage place and when get go it back we saw some problems. So we took it back to get another one but not before we took its wire harness off because the new engine did not have harness. the second engine I think is a 98 because it had the fuel return lines. the body harness is a 98 from original 4l

where and how do I obtain a ford service CD?
 












Ii called the salvage yard and they have a 98 computer.....if i swaped that out and goto pats to work....it shoukd work correct?
 






If using a 98 PCM you'll need the matching vehicles PATS, GEM and wire harness. Since you'll be using a 98 harness you will need to swap to return style fuel injectors and fuel rail.

To keep the returnless fuel system, you'll need to use the 2000 pcm, pats and harness. There are also a few sensors ( cam sensor being one) which needs the appropriate year harness.



2000 cam sensor is 2 wire-1998 is 3.

You'll also need to use a 99-up returnless fuel pump.

In other words, everything must match from the same year. best to use whichever style of injectors you have.

early ( up to 99 return style) has orange injectors.

99 up returnless system has white-light gray injectors. Return fuel injector harness plugs will not connect to returnless injectors and vice versa. They will look like they are plugged in, but they will not be.

So, you either need to change the engine to 98 by swapping the injectors and some sensors, or, convert the truck to a 99-up by changing the harnesses, pcm, PATS stuff, GEM and fuel pump.

There is more i have missed, like HVAC fitting and lines, battery harness Etc.
 






Trans wiring is different 98 to 99-01. Your BEST option is to source a 98 harness and swap it onto the engine. Then get a locksmith to reprogram the pats.
 






I'm betting you really didn't expect this much misery simply swapping a motor. Ford sure didn't make it easy.
 






My injectors are orange and I have a return line. this is correct for the 98?
 






My injectors are orange and I have a return line. this is correct for the 98?

Yes but also 96 and 97 was like that. The way you can tell for sure it's a 98 is the TPS sensor on the throttle body. If it's a 98 the wiring will plug into the sensor on the throttle body. 96 and 97 both have a 6" wire w/ plug coming off the tps sensor.

You never mentioned what year your transmission came out of
 






Update: I got the 98 computer and theft light is not flashing but car will not start. I pink eye and can't work on it
 






Everything is 98 now, except I am not sure of tranny and tranny harness. But that would not keep motor from starting? It still will not start.....I am 2 steps away from hauling this thing to the recycling place. I just lost my job and my ex needs her car back (which I am driving until mine is fixed). Is there anyone in fort worth area that could stop by and give me a hand before it is turned into coke cans?
 



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when you turn the key to the on position, and all the dash lights come on, can you hear the fuel pump cycle for a second or 2 then shut off.
 






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