I fully agree with the concept of root cause analysis. Often people treat the symptoms without determining the true root cause and correcting it.

That said, I would appreciate some specifics or a good source to read up on the GEMS to acquire that understanding and some specifics of what signals to read, and possibly where to place the meter probes and related info. Do you know of any good sources or possibly some troubleshooting flow charts?

I have a 97 Gems that occasionally throws a similar code but it is running stronger than ever.

I did recently salvage some electrical equipment and have a few test panels that I am in the process of tearing down if anyone needs a few potentionmeters, test jacks, there's a few 0 to 10 vdc Simpson panel mount analog voltmters. I have toyed with the idea of building a Breakout Box type tester that could be used to dial in specific resistances for some of the sensor inputs. Just did not have much reference data to go on.

 

Look here for a great insight into the GEMS system.

http://www.gomog.com/allmorgan/GEMS/GEMSbyPoole.pdf

 

And here.
http://www.g33.co.uk/images/PDFS/LR_...ionSystems.pdf

Plus a ton of other sources, like britishv8 and so forth.

 

Damn, I have a GEMS ECU I don't need. That would be perfect to pull the board out of and use as a breakout box, plug the harness in and probe! Just need to make a label to put inside to indicate where the pins go. Thanks for the idea. Probably not going to happen until my truck breaks though, no engine issues in 2 years though.

 

Thanks Higgs. Good info.

 

The person doing the educated guesses has already read those documents and website mentioned many times, in addition to many other resources, and consulting with Rover technicians with fancy diagnostic systems. Steps taken have been based on this. Being familiar with this document, it suggests the CKP as being a likely culprit. However, it is spotless, shows no signs of contact, and sits perfectly centered between the 4.5 spaced reluctor tabs. I've also visually inspected the wiring and found no issues. I already own a DVOM but am not aware of a test procedure for the CKP.

 

The CKP would be pretty much the same for a D2, in the D2 RAVE engine management section there is a volts vs RPM chart for the CKP. Would have to attach probes over at the ECU, perhaps skin back wire ever so carefully, or use straight pins poked thru insulation, etc. Could also be an issue if the shield of the CKP cable was not connected at all to earth. In a D1 the tach is driven by the alternator AC volts frequency, but the engine rpm on the OBDII port is derived from the CKP. So if watching the code reading scanner, and holding rpm constant with the calibrated Mark ! right foot (size 13), if rpms are "wandering" while other indicators, like throttle % and ignition advance remain constant.... guess you could also wedge something in the throttle body stop to idle it up and know that your foot was not moving the throttle.

 

Well I repaired the CKP wire insulation and within 5 minutes I get P1313/P1314 again. So I clear it again and it pops right back up.

Should I be noticing the misfires? It idles smooth about 630 RPM, and revs smooth through the entire RPM range. The OBDII RPMs are very smooth as well, with no inconsistencies between the various gauges. I suppose if it was off just a fraction or a rotation it could misfire though.

I'm about to just take this thing to the local LR shop and say use your fancy tools and fix it

 

If CKP wires are reversed somehow that will make timing off 3 degrees..... but if you don't have cats anymore, don't see how the O2s can not detect that and cause some sort of code (perhaps these) to pop up. They are testing to see if they are there and performing to federal standards, hell, they've been yanked off by rocks on the trail...

 

Lie to your ECU by simulating the presence of the cats.

Perhaps try removing the post cat sensors and zip tie them out of the way. You should be able to find something to plug the holes with at a hardware store, short bolt or something. It may be as simple as the ECU being super sensitive to the sensor readings.

This will at least eliminate or confirm that the issue is caused by the sensors.

I'm not sure a shop can help you, pretty sure it is illegal for them to work on a vehicle that has had the smog stuff gutted out.I doubt they would be willing to commit a felony for whatever they would make on the repairs.