84 XJS/350 LT1 Oxy Sesnor Light
 

heya everyone, Ive had some problems with my cat lately, engine light on, knock sensor replaced, bad timing, got most of it sorted out then the Oxygen Sensor light came on and she would stall out when I accelerated. I had a couple mechanics take a look but no luck, till the last one got the timing right and made the car purr again but still the OxySensor light is on.

Would this mean I should look at replacing the sensor or is there a way to reset it? Is there anything else I should troubleshoot?

If the oxygen sensor light is still on the original Jaguar circuit it can be turned by pressing the reset button on the interval counter...which as I recall is in the trunk.

Cheers
DD

There are 2 350 LT1's. The 70's corvette solid lifter and the 92 to 96 which is the last and most modern small block Chevy, and my personal favorite for swaps. Ask a machinist about them, they are so tough they make the boring machines ring with a sympathetic harmonic, as the tool struggles to go round. It's common place to open up one of these engines with over 100k mile and still see the factory cylinder hone marks.

I presume it's a 94/95 LT1 with a stand alone harness because these were the go to year when doing any conversion. Typically on converts the installer would use the Oxy sensor lamp to stand in for the "Check engine" lamp. Have a look at your PCM. If it says 16188051 or 16181333 its a 1994/1995 and will require a very specific ODB1 scan tool to get the trouble code. A self diagnostic trouble code is a good place to start.

Post some pics of the PCM and engine so we can see what exactly you have and then you can be pointed in the right direction.

Hi, thanks for the info to you both. It's a 94/95 LT1. The car had 40k miles on it before the swap and has another 45k mile on it now, so the Jag has about 85k but the engine/transmission only half that.

We did several ODB1 scans. They continued to show Knock Sensor even after the Knock Sensor was replaced. After the last bit of work and the timing set right, the code went away. Another thing is, the original owner who did the swap added an engine light wired in just below the passenger side dash where it is visible by the driver. Once the timing was set and a few other things under the hood were jiggled, the check engine light went away, still, the Oxy Sensor light remains on.

Another interesting thing, when we were first troubleshooting the problems the other day, before adjusting the timing, we would lift the vacuum tubes and wiring that laid on the top passenger side of the engine, as we moved them about, the engine would act differently. We did this 3 times in a row, but on the 4th and afterward, it stopped reacting. perhaps we wiggled it into the correct position lol, strange and we couldn't figure it out so we moved on.

@Doug, I will give the reset a go this afternoon and report back. Thanks guys!

What exactly do you mean by setting the timing? 94/95 LT1 is timed by a non-adjustable optical sensor wheel inside the Opti-spark. There is no external adjustment of any sort.

Sound like you have a loose wires somewhere. Jiggling wires should not produce changes in operation.

Ground is very important on these conversions. There should be a ground wire from the engine harness, this must be attached to a bolt the back of the head or to one of the intake manifold bolts.

GM had a few different knock sensors those years which all appear similiar, make sure you have the right one to match year make and model of the tune in you PCM. For example if you have a corvette tune and a camaro knock sensor it wont work becasue corvette has a different 2 sensor knock system.

I had to check with my mechanic, he said he adjusted the timing by turning the distributor to advance or retard. Maybe I have an older LT1 then? I will get some pics and post them, that may help even myself get a better grasp on the situation

It is not an LT1 93 or later. If it is, the spark plug wires are down and under and work forward to the Optilite on the front of the engine, just under the water pump.


And, as a V8, it should have at least two O2 sensors. One for each bank.


The Jaguar O2 lamp on the fascia of my car is now wired to the PCM and relabeled, "check engine".


Can we see a picture of your "LT1" ? We might be able to figure out what it really is.


That wiggling of wires causing things to happen is not a good thing!!!!


And, yes, when the LT1'a are right, they are a great match for the Jaguar chassis.


I love mine....


Carl

Perhaps, it is an L98, a TBI engine.


Or a much older unit? But, SBC, nonetheless.


Carl

Thanks for your patience, here are some photos, hopefully, this could shed some light on things a little.

The attached photo with my hand in it is to show which group of wires I was moving around that was causing the engine to rev differently. this wierdness did eventually stop and I could no longer replicate it

I do not believe you have an LT1 Hard for me to ID, but, I suspect it is an L98. A TB injected engine, but, many have been more than pleased with them


Carl

Interesting. the previous owner told me it was an LT1 and to be honest, thats all I had to go by as I didnt start working on cars until I owned a jaguar heh heg