OK here goes,
I have a 99 2.5l engine and auto trans installed in a 48 Jaguar Mk4. I've had the car about a year and the engine and trans mostly runs well. However I get extremely bad spark knock if I accelerate modestly.

The engine is stock, all MAS sensors, air pump, dual distributor, cat, OXY sensor, ecm, etc from the doner was installed on the Jag.

However, there is no OBD port, what the heck. I have no way of knowing what's going on with the engine.

Question is:
1- I need a wiring diagram to reconnect a OBD port.
2 - Does a 99 have OBD or OBD2.
3 - Can all the smog stuff be removed.
4 - any other suggestions for tuning the engine and eliminate the spark knock.

Thanks for your time, all suggestions and reies are appreciated.

 

Welcome to the forum

The 1999 Ranger computer was OBD2
The 2.5l Lima 4cyl models didn't have PATS(passive anti-theft system) like other 1999 Rangers(V6 engines), which is a good thing

You need the EGR system to prevent ping/knock, if that's not working then that could be the issue
Mixing exhaust gases with air/fuel mix prevents ping/knock caused by higher cylinder temps that occur when accelerating, higher cylinder temps also cause higher NOx emissions, a toxic gas which was why EGR systems were first added, the less ping/knock thing was the bonus part of that, so more aggressive spark timing could be used

OBD2 plug in is called Data Link Connector(DLC), it needs 3 wires from the computer, a full time 12v wire and 2 full time ground wires

Diagram below is 1996 but same for 1999, wire colors vary
It only requires the 3 wire connection to the computer(PCM), not the other devices
And 12v and ground to power the OBD2 reader

You can also see "live data" once you have the DLC working so you can see if the system is going too Lean when accelerating, another cause of the ping/knock issue

The 2.5l can run just fine but with less power on 4 spark plugs and one coil pack, it did so for 15 years as a 2.3l Lima
So a good test is to unplug either coil pack and then start the engine
If there is a steady misfire then one spark plug on the working coil pack is not working
Then test again using the other coil pack and its 4 spark plugs
You will never know if 1 spark plug fails, so need to do this test at least once a year

Dual spark plugs were added to get a little extra power, there is no alternating or there would be no point in dual sparks, lol
So if one spark plug fails there will be a slight loss of power
4 valve heads added even more power and was a better use of head real estate than dual spark plugs, which is why you don't see that as much on newer engines

 

RonD, tks buddy. I guess what I have is the PCM not a ecm as the engine would not run without it. I find a DLC and wire it up. Will check back with results.

 

PCM is powertrain control module, it's just Ford's name for it, ECM is popular name for engine computers as well

ICM is ignition control module, spark system, after 1994 Rangers all have the ICM inside the PCM so no external/separate spark timing module

 

Disregard the below questions, I found another link that explains each pin/ wire connection/function.

RonD, tks again. Just looked at the PCM connector on my car and yelp the three wires for the DLC are cut. So ordered a DLC, be here Friday. Hopefully I'll have it connected over the weekend.

I also found a pin out for the PCM and figured out what else is not connected.

Do you have any onsite on the following differance.

I have the pin out for a 99 2.5l.

1 - pin 30, diagram shows this is blank but I have a y/grn wire connected.
2 - pin 34, diagram shows this is a dark grn/lt grn wire for flex fuel sen, this pin is capped with no wire.
3 - pin 104, diagram shows capped no wire but I have a tan/ gy wire which goes to the front coil pack

Everything else matches up although I have several wires which are cut but from the description they would not be needed in my car.

 

Pin 30 was for anti-theft which 2.5l never used

Pin 34 is not used in a 2.5l

Pin 104 is for coil 4 on the dual spark plug engines
Wouldn't be used on a 4 spark plug engine or a V6, since they don't need a 4th coil, a V8 would use this wire

These PCMs are used for all Ford engines, so just the software is changed to match engine, in most cases