Slow and steady ,get the front of the car in the air,look up,oil filt sticks out the side of the engine block.on the left.

The oil pressure is high on these cars,mine make 100 PSI on startup,or about 7 BAR on your guage,later cars,the guage will just sit at center,no matter what the oil pressure is doing.

Misfiring,check one thing at a time,distributer cap and wires,clean and tight,with the idling engine,pull one plug wire a a time,isolate the misfire.

Fuel drying up over time might take some time to clear the injectors and fuel rail,avoid revving the engine in park,could damage the transmission pump.There is a spec,2 grand max i think.

Never hurts to pull off the intake tract,and clean out the mung that can build up. look around the threads,lots of glossy pics on that.

Check the TPS,see that it is set properly,.6 v at idle position,the hanes book says somthing else.lots of threads on that too.

Keep us posted,Jim

 

Can anyone point me in the direction of the location of the oil pressure sending unit?

I'm thinking the pressure relief valve in there must be stuck or gummed up.

The car ran great the first start, perhaps as the oil was moved around the unit got stuck or clogged?

Would the high oil pressure be related to the rough running?


STILL waiting on my repair manual to arrive. >_<

Changed oil+filter, as well as air filter.

 

The oil pressure sender is the little pot,just in front of the oil filter,as you gaze at it from under the car.It has a single wire going to it.

The oil pressure relief valve,is in the oil pan,to the front of the car,some pans had an access plug,some not.High oil pressure is not an issue on these cars.

Have a look at "oil pressure sender" thread.Rough running would not be caused by high oil pressure,IMHO.
Sometimes when Champ car acts up,it's cause is a sticky injector.We get some crappy fuel here.

A little injector cleaner,and a good redline shift run clears things up for me!

Hope your manual arrives soon,Good luck,Jim.

 

Hi Doug,

First of all, I highly doubt that your oil pressure sender is related to your rough running, and I'm also suspicious that you really do have a high oil pressure problem, unless the new oil filter you installed is defective somehow.

To answer your question, the oil pressure sender is mounted on the left side of the engine block (as viewed from the driver's seat). It is just to the left of the oil filter adapter. On our '93 I've installed the later switch-type sender, which has a small black cylindrical body with a single blade electric terminal protruding. You can see it near the middle left edge of the photo below. Your car probably still has the original transducer type sender, which is a larger metal cylinder:




Access is very difficult with the intake manifold installed, though I've managed to change the sender with a crows-foot wrench by just removing some of the air intake plumbing, but it wasn't my first time to change the sender so I had an idea of what I was doing blind.

But as I said, I'm skeptical that you have an oil pressure problem. It's more likely you have a problem with your oil pressure sender or its electrical connector, and that the cause of the rough running is something else.

BTW, while you are waiting on your service manual, you can download the Haynes manual and many other helpful documents from the 'HOW TO' quick links thread near the top of the home page of this XJ40 forum. Also, jaguarclassicparts.com is a great place to look up exploded parts diagrams and part numbers.

Please keep us informed.

Don

 

I had not changed the thermostat when flushing the coolant, could this be faulty? The temp gauge is remaining very low (2 bar) when the engine is running. RPM is at around 900 with slight surging.

Also pulled out spark plugs to make sure the were properly gapped, and I observed the electrode ends were coated in an oily residue. I cleaned them and reinstalled.

Exhaust is puffy ?whiteish?, blackish water droplets while running.

Installed new plug wires, cap/rotor.

Thanks for the guidance!

 

Still on the right path,I have changed out the thermo's on both our cars,makes a world of difference on how they run.Your guage should sit at almost straight up,and not waver when warm.easy and cheap.lots here on that.

Look at the threads concerning cleaning the 10 pounds of oily goop out of the intake tract.world of difference,and FREE to do!

Clean and reset the throttle position sensor,see the XJ40 book,to have a good read on resetting the idle.It is in quick links,top of forum page.FREE to do!

All these little things add up over time,and that's why some people park them.

Stick to it! Cheers,Jim.

 

+1 on all Jim's advice. You really do need to change the thermostat before you can rule out other possible problems.

Regarding your whitish exhaust with blackish water droplets... Is the whitish component similar to steam? Are you still having rough running?

Have you driven the car long enough to get it good and warm? Our '93 typically warms up quickly while driving (5 minutes or less) except on very cold days, but if just left idling it can take a long time to reach operating temp. If you can get the engine to operating temp and the exhaust is still whitish and the engine still runs roughly, please let us know.

Cheers,

Don

 

Yup, totally agree,add,RUN,the car!

 

Hello again!

Changed the thermostat unit+gasket, topped coolant.

Ran a little rough at start, but temp gauge read in between the lowest and the middle bar. The unit must have been stuck open.

Took it for a drive down my road, and temp gauge remained normal, and apon arrival home, engine was running normal, no surging RPM or rough idle. Also white-ish smoke went away, clear exhaust now.

Question, what is the normal idle RPM on these cars?

Looking at getting tags/plate next week, and then enjoying this wicked cool driving machine!

I'm sure Ill be frequenting the forum from here on out, so many great resources here. I would also like to thank the community for all the amazing guidance getting this older cat up and running.

Local foreign car "expert" wanted 4000$ upfront to work on this car, Ive been able to do exactly what they were going to do for pennies on the dollar.

Don, Jim, special thanks.
If you are ever in Mid-MI, beers are on me.

 

Niiice!it's good to have success for pennies!

I have our cars set up for 600 RPM,hot in drive.when you push on the go pedal,stuff happens fast!

There is a procedure to set up idle,XJ40 book,in quick l;inks,step by step.
Free and easy!

Continued success!I'll have a beer for ya!Jim.