NOW!!!, NOW!!!, NOW!!!, Highhorse. Our xk8s and xj8s are beautiful cars, but when my wife or daughter drive them they are even more beautiful. But I do miss driving the xk8. I need to finish up one of my projects if I want one to drive.

 

Would you. E interested in parting with the heads off of one of the supercharged models? I have a 2001 xjr-r1 that the valve seats dropped out and I need just heads to make the kitty suck gas and haul ads again

 

Check with VDPNYC, his just got rear ended and he's parting it out.

 

We shouldn't hijack Jaghag00 thread. I sent you a private message.

 

Good point, no sense mixing issues.

 

 

I don't want to be Donnie downer here but I got a lot of the same codes before I figured out the valve seats fell out of the heads....

 

Same here jaghag staring at the only r1 I have ever seen disgusted by the fact I may have to replace the original heads on a numbers matching all original r1 that no one actually has...enjoying an adult beverage here as well

 

Also is there proper voltage? Another reason I got multiple misfire codes is that the alternator was not generating enough current...no less than 14.4 volts at an idle...if the plugs are wet then the alternator may be weak too

 

I'm new to these hot rods but when the coils are separated from the ignition module, it typically is one more link to fail. If moisture got in the ignition module it could cause it to fail. I read that a couple had the valve seats detach from the heads but I do not think that is your problem as you'd never maintain compression in the cylinder. If it were me I'd go after the ignition modules.

 

I think this is a AJ27 and the coils are fired directly by the ECU.

 

RJ237 is right: on the AJ26 the two ignition modules are separate from the eight coils, but on the AJ27 the ignition modules are integrated into the heads of the on-plug-coils. The coils receive a constant ignition-switched 12V supply and are fired by the ECM connecting them to ground in firing order.

Regarding the P0327 and P0332 knock sensor circuitry codes, doesn't it seem unlikely that both knock sensors would fail simultaneously and far more likely that their electrical connectors were contaminated by coolant leaking from the valley hose?

jaghag00: I may have missed it, but I don't see that you've measured the battery voltage while cranking. If it sags below about 10.5V the ECM will not trigger the ignition to fire, and even if the battery is good, corrosion on the battery power connections and grounds in the car can affect the voltage seen by the ECM.

Cheers,

Don

 

So if I understand correctly as long as the voltage does not dip below 10.5 during Cranking I can safely assume that the ECM is supplying signal for each coil to fire at the correct time. Meaning there aren't any separate ignition modules. Would you measure voltage while cranking at the battery?
The battery is brand new as well as completely topped off. I thought the initial codes were because the knock sensors got wet from the leak and after pulling them and cleaning them as well as everything else, most codes did not reappear.

 

That's exactly the pointed information I needed to hear so I could put to rest the possibility of a faulty ignition circuit. The injectors seem to be firing which I think are also signaled by the ECM. Thanks Don

 

Yes, you want to measure voltage while cranking the engine, but you need a meter capable of reacting quickly enough to measure the true voltage sag. Many digital meters don't react quickly enough so a good old analog meter may be a better choice, or a professional battery-starter-alternator tester like those used by good shops.

But just because the battery voltage does not sag below about 10.5 volts while cranking doesn't mean the ECM is properly grounding the coils to fire. For example, if the crankshaft position sensor (CKPS) is not providing the correct signals to the ECM, the ECM won't trigger the ignition. And if the camshaft position sensor (CMP) is not providing the correct signal it may take 30-45 seconds of cranking the engine for the ECM to use the CKPS signal and trial-and-error to determine correct ignition timing.

Yes, the injectors also receive a constant 12V power supply and are operated by the ECM connecting them to ground for the length of the pulse or "on time."

Cheers,

Don

 

I read somewhere that if the tach indicated approximately 500 rpm while cranking, that it would indicate a functioning Crank positioning sensor. Mine does.
Tha cam positioning sensors I'm not as confident about. But I think default should allow her to start. Like many of us I've been busier than a working girl when the ship is in, but I continue to check in here in the hopes that there will be that light that goes on when with the help of you all this humble wrench turner gets her to purrrr once again.

 

The rule of thumb is that if the CKPS is working, the tach will show about 200 rpm while cranking, but there have been reports of the tach showing 200 rpm but the CKPS being discovered to be failing, and there have been reports of the tach showing 0 rpm but the engine starting, so it's always possible that yours could be one of the rare exceptions to the rule.

The way the Engine Managment System (EMS) works, the Engine Control Module (ECM) first refers to the camshaft position sensor (CMP) to determine ignition timing within less than one full rotation of the crankshaft. If the ECM does not receive a plausible signal from the CMP, the ECM then refers to the CKPS and uses trial-and-error to determine when cylinder 1 is at top dead center (TDC) on its compression stroke so proper ignition timing can be established. This can take 30 seconds or more of cranking, so if you haven't already tried a long crank on your car, it would be worth doing so.

Cheers,

Don

 

There's always something to be gained when someone lends his view and I thank you for yours Don. You recommended a long crank to give the ECM time to find the correct parameters should one of the sensors not be providing the required signal, and although this didn't result in Doobie's Cat starting, it got me thinking.
Although I had iridium plugs installed I decided to replace them with Platinum which gave me an opportunity to check my compression once again. My dry test revealed what I expected, or hoped for, and that was no cylinder was without compression. Someone mentioned valve seats falling out and that spooked me. I did have a couple that seemed sub par, 60psi as compared to the norm of 120psi.
But to get to my point, the long crank had all cylinders over 100psi, indicating to me that Nicosil or not, bore wash or not, compression was being achieved.
STILL WON'T START!!

 

Hi jaghag00,

I was just re-reading your thread and I may have missed it, but I didn't see anywhere that you have actually verified that you have spark.

Inexpensive coil-on-plug spark testers are available at many auto parts stores, but you may be able to test without one by pulling a coil and plug, laying the coil on the head and reconnecting it to the harness, inserting the plug in the coil, then connecting the plug threads/ground electrode to a good ground point. You should be able to see a strong spark while cranking.

If you've already verified that you have spark, forgive me for missing it.

Cheers,

Don

 

It really gives me comfort that we seem to be on the same page. Today I used a test light to interrupt the coil and the plug starting with the forward plug on the drivers side.
First thing I noticed while cranking was a continuous spark but weak and orange in color and then it started. It ran for 10 to 15 seconds and then stalled. I used the test light on the rest of the bank and observed the same orange color spark, not the blue snap I had hoped for. I've been cleaning battery leads and body grounds but nothing yet. What say you?