Hi Matt

With the CPS unplugged if you put your Meter on Ohms what reading do you get?

Also your reading of 2.945 Volts if that is Volts AC that might be good instead of bad

But if that 2.945 Volts was DC then maybe you have a dead short or something going to ground somewhere that was caused by the Water, which may also explain the permanent Tacho reading, to me it sounds like something is going to Ground but Grant will know

 

Matt, that is one real upset CAT, and washing it has stirred it up.

That 2.9...V is part of the problem, and that is simply an Ign Feed Voltage from the relay I mentioned, albeit an X300, but as I also said, the layout would be very similar.

The connector at the ECU would be carrying the "Signal" from the CPS to the ECU I reckon.

Not being there to see the wash, I suspect many loom connectors. The main would be where the loom exits the engine bay, and passes through to the cabin, we call it the Bullhead Connector. It that got seriously wet, or flooded, havoc will reign supreme.

The fact it RAN, you washed the engine bay, now it dont run, or even cough, and the Spark has gone AWOL, is a connector somewhere that is still not doing what it should.

Being AJ16, and 1996, AND, not wanting to mess you around at all, look in the X300 Section. There is a member there "Parker2", and he is the AJ16 Electrical Guru in my opinion.

My only experience with this engine is my X300's, and one got drowned in a flood years ago, and it took 3 days of drying every connector I could find, and slowly but surely it came to life. The stupoid connector for the CPS, the vertical one on the timing cover, was the 98% cause of all my grief.

 

I am not near my manuals, but the signal voltage is often 5V. So unless you’re getting 5V or 14.x volts, something is amiss.

Please double check that you are reading DC Volts.

 

So went the through the wiring loom and found a bit of moisture. Also a white wire that is connected to the CPS but is just tapped off. Picture below. Any idea?

Also in worse news pulled the ECU to check her out. Only pulled the red connector before this time pulled the black and found some corrosion. Looks likes 2 pins completely gone. Strange thing is it looks like pin 13 and 26 which, per diagram, goes to fuel injectors. Think a way to fix or need new ECU at $1K + ?

Also no water at all so strange how cleaning the engine could cause this

 

Hi Matt

I think the Crank Position Sensor is the least of your problems, as I was saying earlier that on these Cars water can get into them and then trickle down to the ECU which is a well known issue and seems to have been happening for quite some time in your Car

Where after looking at the state of that ECU socket, all I can say is no wonder she won't run and all the drying out in the World isn't going to fix it, as the socket on the ECU is supposed to look as clean as this (see photo)

So your best bet is to get yourself another ECU from either a Scrap Yard or Ebay unless you can find an electrical Shop to recondition it for you

Sorry I can't be more helpful but that ECU is in really bad shape and needs to be fixed before we can help any further

 

In Post #30, you said you checked the ECU pins and that they were dry, shiny and bright. Now this?

That ECU needs to be reconditioned. There are people that claim they can do it. I’d look into that. Replacement ECUs are expensive in the secondhand market.

An alternative solution could be to use an XJ6 ECU, which are much more common and I believe work. I forget whether using an XJ6 in and XJS sets a constant security light, or Vice versa, but I believe it functions fully.

 

Yes. Sorry about that Vee. I did think I was looking at all the ECU pins. The black connector release was reverse so I honestly thought that was connected piece and the red connector only had a release. Also didn’t want to disturb it much... but found that when I took it fully out last night once I started tracing wiring.

I have someone looking into the repairing the 2 pins. All other connections looks fine and the rot is only on the outside not fully into ECU.

 

That’s great. It really isn’t an unusual problem to repair and fix. It’s a simple pin repair.

I believe you can still buy just the 36 pin make piece, but that would mean resoldering 36 connections inside the box.

I believe it’s part number 346350-5 made by Amp.

 

HI all. Sorry haven't replied to your wonderful responses. Haven't been with the car to continue troubleshooting since the last posting.
I have checked all the usual places mentioned and my ECU connector looks no where near what Matt's looks like! It's both clean and corrosion free on both the ECU connectors and the car's harness connectors. I did a bit of tracing where 12V and grounds should come from. The outputs of the EMS power and fuel pump are good and are present at their destinations. The fuel pump works as I have flow into a bottle at prime position. The one question I am not sure of is when does the "ECM Controlled Relay" get energized by the ECU. Power is there on one side of the relay coil and waiting for the neg side to be energized by the ECU. I can't tell if it only energized during cranking or all the time in the "Run" position. I would think in Run and crank as the MAF is energized by the "ECM Controlled Relay's" relay's output. For it to be controlled by the ECU, the ECU must be looking for something before it gives the command to provide the ground for the relay to pull.
From what I can see:
1. ECM Power relay= Provides 12V input power to the ECM
2. ECM Controlled Relay- A relay that is controlled by the ECM to pass 12V to various sensors or devices such as, MAF, Purge valve, fuel injectors and another 12V path back into the ECU
3. Fuel Pump Relay- Powered 12V by the EMS power relay output but neg side controlled by the ECU only under certain conditions, (Brief prime just before crank and after valid running)



Measured for voltage at the Cam sensor, (three wire) I have two of the three wires with 12V, unloaded and the other shares a ground with a few other devices. I also have 12V on the red wire at the Crank sensor. So I know the wires coming and going between the sensors and the ECU are good.
When I checked for spark on one coil No spark. I have fuel at the rail from a good prime, but I haven't checked for fuel spray from the injectors. When do the injectors get their signal to open?
Question, does spark only happen when cam and crank are happy? or does spark happen when cam is happy, or when crank is happy, or both?
This is where I am.

 

So does anyone know a place that will repair my ECU pins? I tried 2 places and both said they could not assist me. Both places were listed on other Treads.?


C&P - My first start was Replacing ALL the Light Blue Hella Relays. They are allllllllllll over the car from Start Relay to Horn to Headlights. There was a Jag recall on them as they can collect moisture in them. I found some online at that JagBits.com place for $11 each but have later found that that place is more pricy ? Not sure if your tried that route yet. There are like 8 (5 Right and 3 Left) in the Engine Bay, 2 Back at the Fuel Pump, and 2 at the panel passenger side ---- Atleast on my '96 model.

 

Hi Matt

I'm not sure I would bother as I feel that it may be quicker and cheaper to get one from a Breakers/Car Dismantlers or someone who is breaking their Car for Spares

As long as the Pins are Shiny it would probably be ok as they are generally thought to be pretty robust although susceptible to water damage as you have found out

 

Yes OB I have been looking for one but 1300 vs 300 or so for the fix is worth it. Was thinking about trying to fix myself worse comes to worse I’m in the same place in the end.

 

Hi Matt

Here's a couple of places you could try

ECU Rebuilders Remington

The ECU Doctor

 

Matt,
Staying with the relevant blue relays, (the two under the glovebox for ECM power and ECM Controlled) I did swap them and also was able to open both up and work them with 12V and ground. Both work and pull on their own outside of the car. What I'm not sure of is the "ECM controlled" circuit which as described, pulls when the ECU wants it to (when everything sensors are working). I want to be able to probe the intended and expected ground to it to know if A. the ECU is doing its job of supplying the ground. ...or... B. If all the sensors are communicating to the ECU for the ECU to be satisfied in order for it to supply the ground out to pull the the relay. ...and then there is the matter of the ECU supplying the grounds for the coils to fire and injectors too.
The ECU connectors are categorized by "inputs' and "outputs"., High power side(Black), and low power side(Red).
I'm redrawing the relevant circuit to make it easier for me to understand. I may have it finished in a minute to share and commiserate over.

 

Hmm Ya I guess I haven't gotten that far into it myself as my exploration stopped at the bad ECU. I have found some people to look and service the ECU at around $300-$350 and if no issues is found they only charge $50 service.

 

I’m no longer sure what is what. It seems like this thread may have gotten hijacked by someone else with a similar issue?

in any case.

Ive posted a part number previously that can be purchased and then when you call ECU repair places, you can explain to them that you have the replacement part that’s needed to solder in.

Once more, you might also find a computer repair guy that can do this for you. It’s a straightforward replacement that anyone comfortable with computer motherboard repair should be able to do, if provided with the right replacement parts.

please note, the part number I gave you was for the red male connector. You’ll need to find the part number for the black male connector.

 

All, I apologize for the hijack. The intent was to offer additional areas to check based on the similarities of the problem I was having as well...which matched the no start issue with the OP
I will start a new thread Again, apologies.

 

Thanks VEE for getting me that part. I am looking acouple Pin Repair Kits that may be simple fix to see if that even is my problem, the ECU.


C&P no issues I understand we are looking at a similar problem... but it maybe in your benefit to start your own thread as you have a different year. Post your link back in this thread so we can all still contribute.

 

Matt, I will. Unless I'm wrong, I think 95 and 96 are pretty much the same with regards to the AJ16 engine. My VIN is 199019

 

Yes. Sorry I thought you had a '94.