01 3.8 to 98 3.8 swap

Discussion in 'SN95 V6 Mustang Tech' started by william1315, Jan 17, 2010.

  1. I have swapped in a 01 3.8 into a 98 stang and am having problems with it running correctly or very long at all. The car will start then it starts running rough then dies so i am assuming that it runnin in limp mode then when the computer is taking over it is dieing and will not start again. Is there any known tricks to fixing this. I am using the engine harness from the 01 the body harness and computer from 98 the computer and body harness from 01 will not work because of plug issues. I have heard that i need to switch the cam sensor but i dont see how since the one off 98 is 3 wires and the 01 is only two wires so any help would be greatly greatly greatly appreciated.

  3. The answer to your question is in the OP.

    In 1999, the Mustang under went a major rework. There were major changes in the electrical system. The number of circuits almost doubled.

    The PCM is made to work with the wiring harness. By mating the 01 harness with the 98 PCM, any of the differences will become problematic.

    Note: to start a motor think FAST. Fuel, Air, Spark, Timing. Few sensors are needed to start. Many more sensors are needed to make the motor RUN. Do you have access to an ODB2 scanner? It will help to monitor the operational PID's so that we can tell what is going on. Help locate missing sensor input.

    Help me understand why you didn't just use the wiring from the 98.

    Pictures would be nice.

    The easy answer is to use the wiring from the 98. Otherwise, it will be necessary to compare the pin out of both harness and resolve the differences. I am afraid that the cam sensor is just the first.
  4. Ford TSB 02-22-1 cam sensor sync tool use

    Found a Ford TSB that may provide some insight into your problem. It states that two different cam position sensors have been used (2 wire/3 wire) and that they are not compatible with each other. The TSB also talks about the importance of using the correct tool to sync the cam sensor.

    Bottom line, you are going to have to use the cam sensor that matches the PCM.

    Engine Controls - Engine Surge/Rolling Idle/DTC's Set
    Article No.



    1994-1997 THUNDERBIRD
    1995-2003 TAURUS
    1996-2003 MUSTANG
    1995-1997 AEROSTAR
    1995-2003 RANGER, WINDSTAR
    1996-2000 EXPLORER
    1997-2003 E SERIES, F-150

    1994-1997 COUGAR
    1995-2003 SABLE
    1997-2000 MOUNTAINEER


    Incorrectly installed gear driven camshaft position (CMP) sensor synchronizer assemblies may be hard to diagnose. Vehicle may exhibit poor fuel economy, driveability Diagnostic Trouble Codes (DTCs) P1336, P1309, P0340 with MIL light on. Loss of power, surge, hesitation and runs rough on acceleration may also be present.


    New diagnostics have been developed for WDS to diagnose incorrectly installed gear driven camshaft position (CMP) synchronizer assemblies. Refer to the following Service Procedure to diagnose a possible mis-installed synchronizer assembly and proper installation procedure.


    Items Covered In This Article

    ^ "Hall" vs. "VRS" sensor function
    ^ Vehicle history scrutiny for past service of the synchronizer assembly
    ^ WDS - Power balance test
    ^ WDS - CMP and CKP wave signal comparison
    ^ Wave Comparison chart - CMP vs. CKP
    ^ Correct (CMP) synchronizer installation tool application & installation procedure
    ^ "Top Dead Center" (TDC) alignment
    ^ Synchronizer installation tool application chart

    Hall - Effect (Hall) and Variable Reluctance (VRS) CMP Sensors

    CMP sensors are used on all current model year engines, regardless of fuel system or ignition system type. The CMP sensor provides the Powertrain Control Module (PCM) with cam position information to indicate # 1 cylinder, on the compression stroke

    There are two different types of CMP sensors:

    ^ The three-pin, Hall-effect sensor (Figure 1)
    ^ The two-pin Variable Reluctance sensor (Figure 1)

    Although the Hall-effect (three-pin) and the Variable Reluctance (two-pin) CMP sensors perform the same function, their signal appearance is quite different and they are not interchangeable.

    ^ The three-pin Hall-effect sensor uses a Hall effect device and a magnet to generate a digital square wave signal (Figure 2)
    ^ The two-pin Variable Reluctance sensor is a magnetic transducer, which uses differential voltage across windings to generate a voltage waveform that is similar to a sine wave (Figure 2)

    Both sensors provide a switching voltage as the engine rotates.
  5. Reply

    I am using the 98 Wiring and computer but it wont run right i was going to put in the wiring from the 01 but the wiring under that dash is totally different and i would have to totally rip out the dash i figured it would be cheaper and easier to just have a shop put a custom tune on the old computer to make it run right. The intake system is a little diff along with the injector setup. The car will start but when computer takes over it dies and will not restart for a long while but it runs EXTREMELY rich. Its like the MAP sensor and O2 sensors are causing problem but i dont have my computer with me its all in New Mexico.
  6. Unless I don't understand the manuals, the 01 came with a 2 wire cam sensor. The 98 would have a 3 wire sensor. Did you use a 3 wire cam sensor? Did you use the correct alignment tool to sync the cam sensor? How did you perform the sync?

    Did you have any issues putting the 98 engine harness on the 01 engine? Did all of the sensor connections mate up? Confused because your original post stated that the 01 engine harness was used.

    What is the difference between the fuel injectors used on the 98 verses the 01? Could the fuel injectors be a different size? This may account for the rich condition. Have you considered using the injectors from the 98?

    Refresh my memory. Does the 01 3.8 have a split intake manifold?

    OBTW, if the engine dies right away, it is doubtful the PCM has switched from "open loop" to "closed loop" mode. The O2 sensors are used during "closed loop" operation only. IMO, it is unlikely that the O2 sensors are the cause of the no-run condition.

    Try unplugging the MAF sensor and see if it starts and runs. Note: when a sensor such as the MAF fails (or is disconnected), the PCM replaces the missing data with "default" data. Post the results.
  7. I have the same swap, I put a 99 3.8 into my 96 3.8 body. I still have a few air/fuel ratio problems myself but i've been driving it for 8 months and its still running. I used the ECU and wiring from my 96 body but i used the engine harness from the 99. If i understood correctly that is what you are doing as well. . . . Anyway i thought i could give you a few tips that may help you. Factory air box is an easy fix, buy the custom intake parts from an outoparts store. Wiring is tricky but the simple way to explain how to do it is to. . . . disconnect to engine harness at the main connector in the engine compartment. Unbolt the lower portion of the connector from the firewall so it is possible to see the color of each of the wires beneath. The upper portion of the connector that is to your 01 engine harness should be taken apart so that the pins can be moved to match the pins in you 98 connector. This should fix your problem for the most part. Be careful not to leave any vacuum hoses unplugged because there is one on the intake manifold underneath the throttle body that will make your engine die if it is not plugged off. Good luck and post again if you have any questions.
  8. So how did you handle the differences between the CAM sensors?
  9. Thats my air/fuel ratio problem, i only had three days to do the swap and have the car back on the road again. I haven't had time time deal with my cam sensor untill now. I was searching for some ideas to fix my problem when i found your post. But i have some ideas that I'm planning to try this weekend. I know the sensors are completely different and the older ECU or (PCM) cannot read the signal from the newer sensors. So I'm planning to cross reference other sensors to see if i can find a Hall-Effect that will fit the 99-04 3.8 V6. I don't think i will find any, so we will probably have to change to the new (PCM) and do more wiring changes. I'll post again if i figure something out this weekend.
  10. Hall effect or VR?

    Some of the 3L Ford v6 (Taurus & Explorer) had both types of sensor ( Hall effect & variable reluctance) at one time or another. So the question becomes, can the EEC be reprogrammed just for the difference in cam sensors? the harness would have to be altered for sure. Anyone have a Tuner & can shed some light on this?:shrug:
  11. The PCM can not be "re-programmed" for the differnt sensor types because it requires a different analog to digital converter circuit. The D/A converter are hard wired into the PCM.
  12. Ok, I was limited on time as usual but I did manage to make some progress. I swapped my 96 camshaft position sensor and syncro assembly into my 99 engine. I had to make some wiring changes but its possible to make it work. My computer is still throwing a code for the cam pos sensor, but its because i didn't have time to get a syncro tool to put it in perfect. But its not to very far off, and to be honest I could tell a difference as soon as i started it up. It was running rich on bank 1 and 2 as well as throwin a few other codes. Now its much smoother at an idle and mid RPM's. Although I still have some hesitation at full throttle. I did my swap fast, so i may have overlooked some detail that is causing my problems. But if you decide to swap your 98 cam pos sensor into your 01 let me know how it works out. Oh and as far as the wiring goes. . . . just cut the plug off the 01 and connect the red wire from the 98 plug to the grey/red wire, connect two blue orange wires together and ground the black wire. I'm pretty sure that is what i did with mine. I strongly suggest buying the syncro tool to make sure you put it all back together right. Good luck, I hope that helps a little.