2000 explorer motor change

[Schubert2011]

I have a 2000 explorer 4.0 sohc. The timing chain broke, and Im in the middle of changing motors.

I got the motor from a junkyard, with a warranty..but in the middle of changing motors, i noticed the motors fuel rails and wire harnesses are a little different. On the new motor, there was an extra o2 sensor on the back, and also an extra plug up front. The fuel rails were also different, the new motor had the fuel rails connected in the back, and two lines comming off of it. The old motor connected in the front and only had one line. I swapped both the harness and fuel rail. I got it back together, and now the explorer starts fine, but about two seconds later it dies unless i keep pressing on the gas. It acts like the IAC is bad, but i replaced it and it still does the same thing.

If anyone could help, its well appreciated.. I only have a little while longer before the warranty is up before i can return the motor if this wont work.

THANKS!

 

[2000StreetRod]

return type fuel system

It sounds like the engine you got from the salvage yard was a 1997 or 1998 with the return type fuel system. The last 8 digits of the VIN are stamped on the rear of the block just below the left head.
VIN location
Your 2000 has a returnless fuel system. The 1997/1998 engine should work in your 2000 with the 2000 fuel rails, injectors and fuel pressure damper.

The 1997/1998 engine has a variable intake system. A vacuum solenoid activates a vacuum motor at around 3,000 rpm that changes the length of the intake runners. Your 2000 PCM does not support VIS. Which upper intake manifold are you using? It will be simpler to use the 2000 upper intake manifold. Although you should be able to activate the VIS with an added rpm sensor switch.

 

[Schubert2011]

Yes I am using the 2000 intake. I was working on it tonight, and when I started it up, it was actually idling very high, anywhere from 2,000 to 3,000. even when I would accelerate more, hoping it would bring the speed down... it still stayed the same. I swapped the throttle position sensors on the engine, thinking that would be it but that also didn't work. I never did switch the injectors...should i do that? Also i was reading that if the temp gauge is bad, that it could be causing the engine to rev high, does this sound like that could be it?

Thanks!!

 

[2000StreetRod]

Not the temperature gauge

The temperature gauge has no affect on engine operation. The engine coolant temperature sensor has a significant impact on the air/fuel ratio. However, even if the A/F ratio is very rich the engine will not run that fast unless air is available.

Make sure the throttle plate is closed at idle. A fast idle due to defective TPS is unusual. The IAC valve allows air to bypass the throttle plate. The IAC valve is controlled by the PCM. Make sure all vacuum lines are connected and none of the hoses are split or broken. See Intake manifold vacuum lines
If all of the vacuum lines are connected and in good condition then disconnect the electrical connector to the IAC valve. The engine should just barely run or die after starting.

Did you replace the upper and lower intake manifold gaskets? Are you sure that the gaskets were in the correct position before tightening the retaining bolts? When new the gaskets can easily pop out of place when positioning the manifolds.

I can't remember if the injectors for the 1997/1998 are a different flow than for the 2000. I would leave them in place for now. If they are the wrong flow that would mainly affect the A/F ratio but not result in a very fast idle.

 

[Schubert2011]

This weekend I will be changing the upper and lower manifold gaskets,also it seemed unplugging the IACv and no affect on the idle. The plug for that is tight, maybe the wires are not in tight? I talked to another guy at the Ford dealership, and he told me to go get a new computer from a junkyard.. but if i swapped the wire harnesses that shouldnt matter should it? unless its faulty?

 

[2000StreetRod]

PCM connector

I would not purchase another PCM yet. They are fairly reliable. If yours worked before the timing chain broke then it still should work now. You may want to remove the PCM connector and make sure none of the pins have been pushed back so they don't make connection when the connector is installed. Pin 83 (WH/LB wire) goes to the IAC valve. After checking the pin make sure the connector holding bolt secures the connector in place but do not overtighten - just snug should be adequate. The red wire on the other side of the IAC valve goes to a junction. There should be battery voltage at the IAC valve red wire when the connector is disconnected and the ignition is on.

Was the EGR tube O ring in the upper intake manifold in good condition? If not, did you replace it? They get brittle with age and break apart fairly easily. If there is not a good seal then air enters the intake manifold around the outside of the EGR tube.

The following thread describes replacing the intake gaskets: Starting my 00M12 Installation
It includes a link to a thread showing the 98 SOHC which you may have.

If you swapped the engine wiring harness from the 2000 to the 1998 and the upper intake manifold and fuel system and connected everything then the PCM shouldn't know that the long block has been changed.

 

[Schubert2011]

All right, I talked to a guy from a parts store, he told me the injectors where different on the motors. So I spent the night swapping injectors, i cleaned them, new o-rings. I also changed the upper manifold gaskets, cleaned as much as i could. I forgot to check that damn o-ring on the egr, so i guess thats tommarrows project. I put everything back together, fired it up and still had the same problem, Idling at about 2300 rpms. I disconnected the IAC and no change in the motor. I tested the connection and it read 14.0. I looked over all the vacuum tubes and they all seem fine. Anybody have any other ideas? tommarrow i will check the egr o-ring and those pins for the computer.

Thanks for all your help so far!

 

[2000StreetRod]

EGR valve?

Air is entering the manifold some way or the engine wouldn't idle that fast.

Do you have a code reader? If so, you should read and post the codes.

Is the EGR tube connected? The EGR valve is supposed to be closed at idle. It could be stuck open. If so, the PCM should detect and report that.

Did you replace the lower intake manifold gaskets? My lower and upper gaskets were leaking.

The engine ran fast at cold start and then slowed as it heated up. The PCM reported lean codes.

 

[Schubert2011]

yes, i put a code reader on and it dosent show up any codes. Ill check the egr today. and yes i replaced both gaskets