Last Tuesday (4/17/2018) my car refused to start. The starter was spinning the engine but it didn’t want to run. No CEL and no codes on the dash. I figured it’s either fuel delivery problem or ignition. I checked the cap and rotor and the rotor looked pretty worn out. I also did the fuel pressure test by removing the fuel line from the filter and put a hose on it and run the other end of the hose into a plastic bottle. I remember Bryan told me years ago that a 2L bottle needs to be filled in one minute. I had a 2.63L bottle and the pump filled it in 54 sec.
Since I bought Autozone’s brand (Duralast) of cap and rotor 4 years ago, I got a lifetime replacement guarantee. They replaced them for me for free of charge and since the fuel filter was off I bought one (Duralast $15). It was also replaced a long time ago. After installing everything the car fired right up.
My theory for the FF23 (too rich mixture) is that the worn out rotor (and maybe the cap too) didn’t always give a spark to every cylinder but in the next cycle that cylinder got a spark and it ignited double amount of gasoline (petrol since it’s a world wide forum ). That’s why I felt those pushes or fine vibrations at idling. So I guess the oxygen sensor sent the signal to the ECU about getting a rich fuel mixture and that triggered the F23 code.
The other problem was that the MAF had cracked solder joints because the engine kept running (as I wrote before) after I unplugged it when the idling fluctuated.
So what do you guys think caused the FF23 code? The oxygen sensor? If yes then it means a malfunctioning MAF doesn’t trigger any fault code (except FF12 out of range)?
Joe I think your o2 sensor is just fine, I replaced mine to “cure” the FF23 (94 cars seem to trigger this more than others as far as I can tell) but after a grueling replacement job I still got it occasionally.
I think your theory about a miss giving an extra bout of fueling, therefore “rich” is right on the money. believe me, I changed everything chasing that code, in my case I think it was a bad maf connection that triggered it, but as I swapped mafs, injectors and FPR at the same time (when I got the parts car) I can’t be positive - it might have been a drippy injector too or even the coolant sensor - my FF23 usually came on after I re-started the car when it was already warmed up, as if it went back to cold start fuelling when it was already warm.
Do you still have that parts car? Years ago I had a chance to get a '93MY BRG for parts for only $400 but I didn’t take it because my apartment complex allows registered cars only.
I know that the oxygen sensor is in good condition. What I meant to say is that it received too much unburned fuel and sent the signal to the ECU that triggered the CEL and the FF23 at the same time. We’ll see how long the “no FF23 (or any code for that matter)” will last.
Cheers!
Anytime these cars won’t start or suddenly stop while running … while cranking the engine check the tachometer. If it shows zero the problem is your crankshaft position sensor (CPS). If you get a reading of RPM then REPLACE THE CAP AND ROTOR with new ones! If that dosen’t solve your problem only THEN continue your trouble shooting…spark, fuel etc.
I don’t know what it is (although I have my suspicions) about these rotors and caps but although they look perfectly fine they more than not end up being the culprit, especially on my '89. I suspect the cap is the problem with a carbon trace but since I’ve always replaced both I couldn’t swear to it in court.
I checked the tachometer while tried to start the car. It showed 200 rpm so I ruled the CPS out. This was the first time my car didn’t start due to the rotor and the cap. I always replaced them before they went bad. Someone always keeps a spare cap and rotor in his car. Is it you or John?
I still have the parts car Joe, it was a $400 '94 sovereign with only 69,000 miles on it, broke my heart to take it to pieces but OTOH you must have read about MY parking situation (I park 2 blocks away from my place )
Here’s a pic of my parts car as she sits today, over at a VERY good friend’s house
Hmmm … my question would be “how do you know they’re going bad?”
I hate to be redundant because I’ve posted this before BUT … in the 27 years I’ve owned my car it has only failed to start once and suddenly shutoff at a stop light twice. ALL three times it turned out to be the rotor/distributor !!!
So yes Joe, I’m not sure about John but I ALWAYS keep a new distributor and rotor in the trunk … er … boot.
Larry,
That’s a nice pile of “goldmine” at least for a Jag enthusiast. What do you do with all that parts? Keeping them for your car or sometimes you sell something? I don’t think there was a Sovereign model on the US market for '94. Only a base or a VDP.
I think I just got lucky all those years. I did some preventative maintenance and replacing the rotor/cap was maybe one of them. I rechecked in Autozone the last time I bought a rotor/cap. 5/17/2014 Almost 4 years ago. Since I drive about 6k miles annually, I figure a new pair might last another 23-24k miles. 1 no start and 2 stops in 27 years? That’s impressive.
Joe - I just assumed it was a sovereign as it had a sunroof etc but maybe it was a base after all.
The previous owner had been led up a merry path of financial ruin by his “expert” Jag mechanic replacing all kinds of unnecessary ancillaries, finally calling it quits after fitting brand new injectors then being told that he needed a valve job to cure his rough idle.
I did buy the car (and spent an entire summer dismantling it) for a parts source for my old VDP but some parts I have sold on, the wheels, bumpers and fuel tank come to mind as well as some trim pieces.
I still have a whole lot though and I doubt that I’ll get round to using much of it unless something radical goes awry so I am open to selling off more stuff I suppose - anyway so far, the VDP is chugging along just fine. (touching wood as I type this )
Hi Joe, As far as FF23 is concerned, I’m starting to suspect it’s the actual fuel causing it in my case. I normally use the local supermarket when I need fuel because it’s much cheaper, however occasionally I’ll fill up at a nearby Shell station. It could just be co-incidence but I’ve noticed the CEL is a lot more frequent whenever I’ve filled up at the Shell station. I went 3 weeks with no CEL using only the supermarket stuff but earlier this week I used Shell and within two miles the CEL came back on.
Here’s the curious thing, as soon as the CEL FF23 appeared I drove to a friends garage and had the emissions tested on an official MOT gas analyzer and everything was within limits. We cleared the code before doing the test, but while waiting for the analyzer machine to self calibrate the CEL came on again meaning the test was carried out more or less at the same time the CEL came on.
The readings for a fast idle test were :
CO. Actual 0.078. (Max Limit allowed 0.200 )
HC Actual 24ppm (Max Limit allowed 200 )
Lambda Actual 1.001 ( Max Limit allowed 1.030 )
And at normal Idle : the CO was 0.095 ( max limit allowed 0.300 )
So although I still don’t know for sure what is triggering the FF23, I’m fairly confident now that my car is not running rich.
I always talk people out of owning an older Jag if they can’t repair it themselves. These cars can be money pits for some if the repair budget is not kept tight. I see a driver’s side seat bottom on top of the containers. You have a cool friend that he lets you store the parts in his garage. I wish I had a garage and time to dismantle a car. Maybe sometime in the future.
Casso, that’s interesting. Maybe the oxygen sensor reacts differently to the Shell petrol? Have you told this problem to more people? If more people give their advice then maybe there’ll be a connection point somewhere in their advice that would help you find the real cause. Did you contact the XJ40.com forum? I’ve been using Shell V Power since I bought my car (11 years ago) and have no problem (that I can notice) with it.
). That’s why I felt those pushes or fine vibrations at idling. So I guess the oxygen sensor sent the signal to the ECU about getting a rich fuel mixture and that triggered the F23 code.
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You have a cool friend that he lets you store the parts in his garage. I wish I had a garage and time to dismantle a car. Maybe sometime in the future.
