2001 S-Type V6 140k Miles. New Transmission at 80k Miles

Well I don't have a good feeling about this one.. I've spent a lot of time trying to figure this out but now I'm out of ideas and worried that the PCM is toast.
So I just recently replaced my water pump after failure and coolant tank. Hooked everything back up went to start back up and it cranks but wont start.
Car ran fine before the repair.

I have JTIS and proper wiring diagrams for this car.

What I know
Cranks as normal
Battery is just under 12.6 Volts Charged
Fuel pump whirls when turn the key to on position
Fuel sprays out at schrader valve
Throttle opens on startup
No Spark or power to coils
No Rpms on gauge during crank
Checked Crank Sensor Wires for break to PCM but good
Tested Crank Sensor all the way back at PCM connection but good
Replaced Crank Sensor just for sh*ts but nothing
However when I tested Crank sensor inputs at PCM at 5v supply I'm getting 1400 ohms to Ground and Ground to Chassis Ground the same reading
Also getting 1400 ohms to ground on 5v supplies to cam sensors directly from PCM
No Codes
Checked all fuses multiple times but all were good
Pats Light comes on for 2-3 secs then turns off when key is in on position

Please someone help me! I have to move in a month and can't bring this with me broken down =(

 

Hello everyone!
I’ve got my first real situation that I can’t seem to figure out and I’m worried it might be the PCM.
So I just recently replaced my water pump as well as coolant reservoir due to leakage. Then I put everything back together and now the car cranks but wont start. Here’s what I know so far on the situation.

The car ran fine before the repair.
Battery is fully charged at 12.6
Cranks as normal and doesn't sound any different
There is fuel at the rail and fuel pump whirls in the on position.
No Spark
No RPMs showing on Tach during crank
Checked Crank Sensor and wiring but all good.
Getting 1400 ohms of resistance at 5v supply at crank sensor input at PCM back to chassis ground as well as the ground for crank sensor and cam shaft 5v supplies.
PATS Light comes on for 2-3 seconds in on position then turns off so don’t think its some kind of security lock out?
The throttle opens at startup as well.
Checked all fuses multiple times
No fault codes


Please help I have to move in a month and really love this car but can’t take it with me like this. =/

 

Pretty much guaranteed it is NOT the PCM.

 

Well I did end up taking the PCM out of the car and bench tested it and in the wiring diagram I have pin Pl 1-56 which is sensor ground for CKP and did a continuity test back to the ground pins at Fh-1 24-27 but its giving me that same resistance reading of 1400 ohms. So am I wrong in thinking that there is a short to ground on the 5v supplies? I mean if its ground and it goes back to the other ground pins there should be no resistance correct?

 

If you like to worry, I'd suggest finding a more plausible source of anxiety. For example, what if Nancy Pelosi figured out how to clone herself? Now that's something to really cause worry. Your PCM being the problem? Nah, the odds are infinitesimal.

Big clue, good to know. You have to pretty much figure something important was disturbed during the recent work.

Can you please 'splain exactly what you were checking and how? Is the 1400 ohms reading through the CKP sensor, measured from the PCM connector? That's a very simple out and back circuit, with nothing else branching off.

If you were reading the resistance through the CKP sensor, I have no idea if that is a good value. Even if resistance specs are published, or you have a spare sensor for comparison, a "good" resistance value doesn't conclusively mean the sensor is good. I deal with similar sensors at work (aviation), and even if a resistance check passes, the sensor can still act up. If resistance is out of range, yep, that's bad, but being within range doesn't prove it good. I do not care to discuss how I learned this...

A bad CKP sensor can prevent the engine from starting, but I forget the exact chain of events. IIRC, the CKP sensor tells the PCM that the crankshaft is rotating, which enables the fuel pump. If no rotation signal, the pump is shut off.

I don't believe a CKP problem will shut off the ignition system, though. You mentioned no spark, but how exactly are you testing?

For a no-spark condition, try a click test at relay #3 at the fuse panel under the hood. When this relay is energized, it supplies power to the 6 coils and several other circuits. Place you finger on the coil and have a helper cycle the key on an off. You should feel this relay click on and off. Other relays may click at the same time, so make sure you're not feeling a vibration from an adjacent relay.


This can be normal for a no-start condition. OBD fault codes are primarily for problems affecting emissions. With a no-start, even if the computer knows exactly why, it just crosses it arms and doesn't tell you any details via OBD because it's not required to do so. It's kind of like getting in the wrong line at the DMV.

 

Heh. You do realize all these people running the government are puppet clones right?

I can tell you for a fact its not the CKP I tried to put a new one in it just for sh*ts and checked both wires for continuity from CKP Harness back to PCM Harness then I toke a screwdriver hooked the ckp back up and rubbed it on the magnet and got voltage back at the PCM Harness

I checked spark by pulling a coil and spark plug and watched for a spark but nothing stuck it engine metal nothing. Both PCM relays are clicking #3 and #14. Hell I didn't even need a helper I just turn the key to on position and stick them in and out. Read my last post about testing the PCM though if you haven't... My real worry is that the water pump is directly above the CKP Sensor and it was spewing out like a son of B when it went out so I'm worried it could have potentially shorted the PCM when it did since there is no fuse between the PCM and CKP wiring.

 

Also worth mentioning I replaced all ignition coil's and spark plugs with brand new to spec about 3-4 months ago and the cars been running good ever since.

Car has 140k Miles new transmission at 80k miles.

I've also checked the reluctor gear for any play but it's solid. Also just checked the boot for corrosion on rear control module and there was some corrosion on the case (prob from the tailight leak a while back) but the connection's and the inside were clean.

 

Making some progress. Where were you grounding the test plug? The valve cover? I don't think those are grounded well at all. They sit on a rubber gasket, and the bolts pass through rubber isolators, IIRC. Not trying to bust your butt, but do want to make sure we have a valid failure and not a false indication induced during testing.


The current through the various sensor circuits is milliamps at most. Even if fuse protection wasn't warranted, I'd highly suspect the engineers anticipated external direct shorts, such as the wires rubbing together or touching ground. I'd certainly think the PCM could handle such faults without damage.

Another thought along the same lines: If the coolant leak did somehow manage to kill the PCM, shouldn't it have done so before the repair was accomplished, leaving you stranded somewhere? If you drove the car into the garage for this repair, that tells us all was good electrically up to that point. Power would have been off from then on, so there was no juice available to damage the PCM. Once again, not trying to bust your butt, but am merely trying to make sense of the timeline.

 

Hmm. What brand of coil did you install? Lots of trouble on the forum with Chinese specials and store brands from the discount chains. Top quality brand names seem to be the way to go. The typical fault is the output of an individual coil will fail and cause a misfire code for one cylinder. But if one coil had a partial internal short on the input side, it could pull down the available voltage to the other coils (without blowing a fuse), below the point where they would fire.

Still unknown is why it happened just now. Did you have the coils out or disturb their wiring for any reason during this other recent repair work?

 

Just checked on my '02 V6. This is normal. The needle didn't budge from zero with the starter engaged.

 

See your other post https://www.jaguarforums.com/forum/s...001-v6-260166/

 

I've merged your two threads. there is no advantage to two threads on the same issue.

 

Hey everybody sorry for the late response I just got back around to the car the other day and haven't had much time to post. Apologies for the double post as well I didn't see my original post the next day so that's why I did that. Oh and thanks for your help and wisdom Karl I really appreciate any feed back and would never resent that also your absolutely right! I feel like I messed something up or missed hooking something back up somewhere and I keep looking but nothing is out of sorts. I toke your advice though about testing the spark on the valve cover bolt and checked it with my meter back to ground and it was no good. So I hooked up my ignition coil test light just to be sure there was no spark and what do you know on the first crank I get a spark and the engine tried to start... Then I put the coil back in and it tried to start a few more times then it went back to nothing but cranking again. After that I hooked the test light back up and there wasn't any spark! So thinking there was some sort of short in the ignition I followed the JTIS diagnosis for the ignition. I tested all the coils which all tested between .8 ohms except one at 1.0 ohms which was spec according to JTIS. All of the supply wires have over 12v with key in on position. Then I did a voltage test with the meter hooked up to a coil positive and negative but got 0v when cranking so that tells me that the PCM is NOT sending any ground signal to the coils. I already checked every single coil wire between the harness and pcm harness for continuity. I tested relay grounds for both PCM relays as well as 12v supply and signal wire from ignition is 11v. I'm not sure whats going on here very confused especially with it randomly trying to start. The car did drive home but I ran it once more in the driveway before repair just to confirm where the leak was coming from which I really shouldn't have done. I also rented a pressure test and pressurized the coolant system to check for other leaks and that's how I found hair line cracks in the coolant tank. I thought maybe it could be the alternator since water got on it, but I tried jumping the car as well but still didn't get any spark the car did sound like it was turning over a little to fast with the jumper cables on though? I did an amp draw test to see if there was a short and I got 740 milliamp's, anyone think that's to high for this car? I didn't feel like pulling all fuses I just pulled the ones in the front fuse box. Anywho.. I hope everyone is having a wonderful night and I really appreciate what everyone is doing here to keep this site running and helping out average joes like me!

 

As it tried to start you know the PCM is doing the right thing so I think your tests are fooling you.

740mA is way too much if you waited the about 40 mins first, to let the modules shut down. There are threads about quiescent current that give detail.

 

You may not realize it, but you're making progress. Don't give up.




What's with them negative waves? Is the PCM a giant magnet and you're made of cast iron? Is it a candle and you're a moth? You already had some positive response from the PCM, as your ignition worked briefly. I'm willing to stake your reputation the problem is something external to the PCM, such as reduced power input to the coils and/or injectors.

The 0 volts you've measured? You're not going to see a steady voltage between the two terminals. The PCM switches the ground on/off at a very rapid pace. Nearly all meters can't pick up such a rapid spike. In fact, most meters have special circuitry to ignore such spikes. You'd most likely need an oscilloscope to see what is happening. So I'm afraid the 0 volts you've measured is not a valid test, and is rather misleading.

So let's imagine it's several months in the future. Nothing you've tried has worked. You've given up and sold the car at a fire sale price on Craig's List. The next buyer, a tall handsome guy who likes to tinker with cars and is rumored to smell nice, knows nothing of the history for this particular car. I'll have to begin my troubleshooting from scratch. Here are the first things I'll be doing when I get the car off the flatbed:

1) Charge that poor battery. No mention if you've been keeping it charged, so I have to figure no. Even if the starter cranking speed seems okay, don't let that trick you into thinking the battery has an adequate charge. I'll hook up my automatic charger overnight and let it run until the happy little green light illuminates.

2) Go back and make sure the battery is fully charged.

3) Repeat steps 1 and 2.

4) Verify proper fuel pressure. This is very easy to do on an early V6. There's a test port on the injector rail, near the oil fill cap. I'll hook up my mechanical gauge and verify pressure is within specs. (Don't rely on the thumb test, i.e. there's some pressure present. No way to know if it's even close without a mechanical gauge.)

5) Check for a spark, using a tester connected to a known good ground.

6) Notice I haven't said anything about checking the PCM...



Put away your jumper cables. Those are for emergency use, such as if your battery has gone dead while parked at a strip club, and the only person available to come get you is your Mom. In that case, get the engine started and get home. Then figure out why the battery went dead so it doesn't happen again. Charge the poor battery while you're at it. You should never need to use jumper cables during normal troubleshooting.


Is this a test of total amp draw at the battery? If you waited the full 30 minutes or so for everything to go into sleep mode, that's very high. However, as long as the battery still has a good charge, the car should start and run well.

One last thing to check. Powertrain Control Relay 2 (confusing labeled R3 under the hood) sends battery power to the coils and injectors. You previously did the click test on it, which is only part of the story. The click test only means the relay is getting the signal to close and send power to the coils and injectors. It does NOT confirm power is actually getting there. The easiest way to test it is to swap with a known-good relay of the same size and see what happens. Make sure your front fog lamps work correctly and swap with relay #7.

 

Another quick test you can run, to check the power supply to the coils. This will measure the voltage with the circuit under load. I think any previous measurements were taken with the circuit unloaded, which can lead to potentially misleading results.

Pick a coil, whichever one is most accessible. Identify the power supply wire on the coil connector. This wire will be green with a secondary marking (stripe?) of a second color. The secondary color varies by cylinder and is not important. (Just for reference, the base color for the ground side, switched by the PCM, will be brown.)

Leave the plug connected, and backprobe the green wire with the (+) lead of your meter. You may have to use a short piece of stiff wire as a meter lead extension to make a good connection inside the rear of the connector. Connect the (-) meter lead to a good ground connection. (Remember, don't use the valve cover for a ground.) Have a helper turn the key to start while you watch the meter.

Under the massive load of the starter, it's perfectly normal for battery voltage to drop close to 10.0 volts. What do you get for a reading? If you get less than 10.0 volts, that's a big problem. There are more tests we can do to isolate the fault, but let's begin with this reading.

You can also test the power supply to the injectors in the same fashion. The base color for those wires will also be green. The base color for the switched ground wires is black.