Hello,

My 1999 xj8 is my weekend driver and gets out every now and then. Last weekend i changed the battery (car sat dead for a few weeks) and drove about 60 miles no problem. The car sat a week and the temperature has been dropping.

I started it yesterday and it started right into restricted performance mode and once i put it in drive and pulled out a little the check engine started flashing. The car idles rough and i moved it a little around in my driveway and got it to idle normal right before shutting it down (still was RP and CE flashing). Although the RPMs drop low when i take my foot off the gas on idle and come back up to ~700.

On my OBD reader I am getting: P304, P1313, P0351, P354, P0356, P1000. I did a quick look under the hood and all the air hoses look good.

I changed my coil packs and plugs about 1.5 years ago. Any help and suggestions is appreciated.

 

Change fuel filter the disconnect the maf harness and see if engine runs better it might be bad maf clean it it might work those are easy things to do if no improvement . Since it's 1998 it might be the timing chain itself hopefully it's not other things it might be vacuum leaks and clogged injectors or maybe just bad spark plugs
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Clean the MAF; check the pins are not bent on the MAF connector. Maybe need to clean the throttle plate and bore. But my guess, given the weather has turned cold, you temperature sensor is bad (sits in the cross over pipe; new crossover pipe usually comes with a new sensor): the ECU thinks it is cold outside (or hot) and is enriching too long and dumping raw gas . . . over time this will destroy the catalytic converters!!

 

I did not review all the codes you posted -- but strange things can happen with these cars when you have weak batteries and when the cars get batteries changed out. The flashing CEL is telling you it's missing to a degree that you are getting misfires .... possible raw gas to the converters ... so that's not something you want to drive with.

I would use the reader and clear the codes -- you may have to do this a couple of times. I always push my gas pedal 50 times every once in a while to keep the TB sensors clean -- with the car and ignition off. Turn on the ignition w/o starting and see if you get a clear dash alert. If not ...clear the codes again. If you keep getting the warning ... try and start the car and see what happens. I have had the RP and a few cycles of the ignition clears it .... and other times it takes resetting. Once you get all the codes it typically takes a couple of the resets.

The car will not run correctly in RP -- so that will get you going down the road to all the codes. If you start the car and it run rough with the RP coming up .... shut it off and restart.

 

I went ahead and tried to clear the codes a few times with the key in the 2 position, proceeded to turn it on and clear a few more times. The car starts sluggish and jumps into RP. When i read the codes again it makes the CE light flash and reads P0351 P0354 and P0356. Could it be my cheap ignition coils i put in about 2 years ago? maybe they didn’t like my new battery and zapped? or possibly my new battery needs a charge up (although ran good only a week ago when installed)?

I will add a new fuel filter and check the Maf/temp sensor to my list.

 

The vehicle should not be operated under conditions that cause the MIL to flash as catalyst damage is occurring.

 

Switch the affected coils around and see if you get the same codes. I had some cheap coils go out a few years ago after 40K miles before I went back to the Densos.

 

I swapped the coils to see if the codes would jump but they are sticking on the same coils. I cleared the codes prior to starting the car and got the same result. is it possibly the spark plugs or fuel injectors?

is there a relay or fuse that be blown?

 

Hi Dan,

Sorry to join your thread late but you've already received some excellent input.

Just to add to the discussion, here are the definition and published possible causes of the P035X codes:




Here is the schematic for the coils:



Since you have misfires in multiple cylinders, a wiring issue could make sense. Battery/Alternator voltage arrives to the coils from the ignition coil relay on the Purple wires with White tracer stripes (color code PW). If you confirm that you have good voltage at all of the coils for which you have codes, check the ground side of the coil circuit. There are two splices, a connector, and a ground stud. The locations of the splices are not given in the manual, but the locations of connector PI1 and ground stud EM8R are given in this list:



Here's the diagram of the engine bay ground points. In order to read the text you may need to right click on the image, select View Image, then hit Cmd+ or Ctrl+ to enlarge the image. This was as large as I could get it all on one screen for the snip:


A problem with the coil wiring and the resulting misfires could also trigger the P0304 and P1313 codes. The P1000 code simply means that the diagnostic readiness monitors have not all reset - which they should do automatically after you've resolved all the diagnostic trouble codes (DTCs), which will replace P1000 with P1111 (all monitors completed).

Cheers,

Don

 

Thanks - I am no electrical expert by any means, but I have a multi meter and would like to check the charge come to each coil pack. Would this consist of unplugging all the packs and turning the car on to test the voltage?

Also, when my battery was dead i used the terminals under the hood to open the boot, could this have caused any damage?

I have pulled and swapped the boots, cleared the codes, and tried starting up a few times. Codes keep sticking to 1, 4, 6. This makes me think it’s an actual problem vs. the car just being confused with a new battery...

 

Fault for multiple coils is not usually coil problem. Especially when coils are place swapped. You can measure voltage from the coil plug atleast with engine running. But maybe with key on not engine running. There should be battery voltage between pin 1 and 4 on every coil. I'd prefer measuring by poking thin needle through silicone pin insulator. That way measure is taking the coil load in count too. Multimeter is not suitable to measure the coil dwell signal from the ecu. But a led voltage tool is. With that you have to go thru the insulators with engine running.

If you have led voltage tool you can test te coil load signal by poking between 2-3 where 2 should be 5V. Of course you can measure the 5V with multimeter.

 

You can test the voltage either by back-probing the connectors with them still connected to the coils, or by disconnecting one connector at a time.

If the voltages at the coil connectors are plausible, you could pull the coil from cylinder 1 and inspect the spark plug well for oil. Oil on the plug threads interrupts the ground path for spark and will typically trigger P030X codes rather than P035X, but it's worth ruling out. If no oil is present, it would be worth swapping the #1 and #2 coils, clearing the codes and running the engine to see if the P0351 code changes to P0352. If the code moves, suspect your cheap coils.

Next steps might include:

Pump about 1 liter of fuel out via the fuel rail Schrader valve into a clear container. Set it somewhere safe to allow it to decant for 30 minutes or more. Then check for a separation line in the fluid indicating a layer of water at the bottom, either from receiving contaminated fuel at a fill-up, a clogged fuel filler drain and leaking fuel cap seal, accumulated condensation in the tank, etc.

Perform a compression test to rule out problems with valves, valve timing, rings, head gaskets, etc., and a test for combustion gasses in the coolant.

Cheers,

Don

 

Thanks Don - I will attempt these steps. Now that you mention the coolant, i realized that my coolant was pretty low, i opened the cap and the system gargled a lot and the level in the reservoir sank down. I refilled the coolant to the top(filled almost whole reservoir).. I was shocked to see how much coolant the system was low on as I didn’t see any leaks. I had the coolant changed last year and it was good for a while...