Good Morning Folks.

I feel like I've been absent a while. New job, new house, new level O relationship moving in with ME Lady. Lots and,,,

Anyways. I'm hoping folks will give me some hints before I dive in.

I woke up my 1990 yesterday and she started right up. Went to pull away and I got a GOOD dip in revs, had to hit the accelerator pedal a bit and things went back to normal. Happened x2... Off to work no further issues. After work (and it's getting colder here) car started right up and I noticed a few dips in the rmps while warming, sitting still.

This ALL happened before coolant temps came up enough for NEW e-fans installed a few weeks ago to kick on. For all intent and purpose new fan set up is independent of all other electronics - except where the 12v comes off of the POST fire wall in engine bay. Before today, I had noticed no side effects of the e-fan change.

So, drove away after work and within 50yds car stumbled hard. Hit gas peddle - recovered-ish. 75 to 100yds later, car stumbled and stalled completely. Got to the side of the road. Opened hood, jiggled some wires around, looked for things. Car would start right back up, then stumble again - parked. Removed and reseated plug for CTS - removed and reseated several times to "clean" a possible bad connection. Started car and it seemed to run better. Drove home without issue. Idled fine. But now I'm a little afraid to drive her.

CTS? A distributor issue? Main relay or fuel pump? I DunnO. CPS?

I'm all ears... Which direction(s) should I go in first?

 

It sounds like damp getting into a connection, JJJ. AS a guess, most likely an amp connector, a crank position connector, or a coil connector or the white wire to the ECU. I cannot see the fan setup causing it if they are not running.
What state are the HT leads in, and plugs?

 

Good Morning, Greg!

HT leads are just 1yr old (give or take) and from memory were resistance tested, reported to all of y'all, and said to be spec. I never had a problem. Plugs are new-ish and gapped and stuff. Maybe I should have a look under the cap (which is new-ish as well but not Marelli). I never sawed off the post under the rotor arm.

4yrs or so ago now I placed a new front CPS, never the rear, but I have a spare CPS (fly wheel position sensor) in the cabinet behind the seats. Maybe I should install it?

I will have a close-r look at ignition amps, the white wire, and coil wires (coil wiring I redid no too long ago). I've had problems more than once with BAD after market coil wire connectors...

I hate issues like this.
​​​​​​

 

Hi Jay

You probably know this but the White Shielding Wire (dreaded white wire) goes to Pin 24 of the ECU the important bit being the Shielding Wire is Grounded ONLY at the ECU end and NOT the Under the Bonnet/Hood end

Maybe dampness is causing an under Bonnet/Hood Stray Earth?

Alex

 

Heeeey Alex...

New house 😳. Mother in-law here for 2 weeks 😳😳😳

Lol. I will definitely have a look at that and check the ground(s). I don't know if it's that, but I think it's something like that. Thank you. I think I will pull the ol girl into the yard this weekend and start poking around HOPING I can reproduce the studders and stalls. It's usually how I am able to zero in on things. I'll get it!

Be back soon enough. This is definitely on my mind

 

Yeah, I agree and I see an afternoon of checking/cleaning connections in your future and sometimes gently jiggle-testing can help reveal a problem. Don't forget to include the ignition switch. Maybe you'll hit paydirt, maybe not. But you gotta begin by checking relevent connections and wiring.

Cheers
DD

 

So, I'm poking around today and this is as far as I've gotten.

Had to jump the car. Battery was never a thing before install of the auto cool guy e-fans - but it has been COLD-er here so the battery problem may just be a seasonal thing - time for new battery? At the same time my intention today was check for parasitic draw - having to do with the e fans for my sudden weak batter after just 3 or 4 days of sitting.

It's an AGM battery. Will these cars struggle if there is a dead spot in the battery once the car is started?

Anyways.

I jumped the car and it started right up. Went into idle warm up routine and as it warmed idle speed slowly started to fall. I started noticing the studders, the almost complete shutdown, and just before she stalled, she recovered. I drove the car from the street to the driveway. I used my hand to turn the capstan to rev the car once in driveway. Released the capstan, took a step back (car was fairly warm at this point) then it stalled flat!

I couldn't restart due to dead battery - but the last time it shut down like this it would start right back up.

This seems electrical to me. A while back I had a problem with the ignition switch innerds and I "repaired" that and she has been fine since.

Something strange is going on here.
I'm all ears.

I have a new CTS I think I will install that - I don't know what's going on, yet...

 

Hi Jay

Have I got a Video for you!


Not my words but advice from someone who did

 

It's too late for this. But thank you

 

Hi Jay

I just thought you might be able to pick up something from this that might help with what you are doing

 

Got ya, and I appreciate it. My short response kinda had to do with me being under the hood. I'll take a peak.

 

Alex... That guy is a nutt job! And what he has is not what I have. This doesn't mean that some sort of problem will not show it's self in the near future, it just means that it will not be his lead that I follow. Anyways,,,

I did 2 things. Don't know which gave me the good results I have so far.

One, there is a wire that comes up at the RH back of the motor. It's 12 or 10 gauge wire, red and white, and is included in the loom that comes up the back of the engine from the starter. It is in the loom with a 1 or 0 gauge wire/cable that comes up and is bolted to the B+ bar on the fire wall BUT it does not tie in there. Instead, it comes off the 1 or 0 gauge loom and is connected with an OEM spade connector type plug (plastic encased plug) and continues on. Mine is rapped from that point in tape and I have NO IDEA what it feeds or where it goes. I didn't chase it. Anyways, the spade style OEM plug had seen better days, so I cut the spade connector out and soldered the two ends of the white red wire together. Much much better connection...

I am REALLY hoping someone can tell me a bit about the white/red wire described above.

Then two - I replaced the CTS. This one looks OLD. I swore I'd changed it in these 4 or so years of running this thing. But it appears to be older than that. I honestly don't know.

Anyways, I started the car up (a new battery is in my future) and SO FAR the stuttering is gone. No stalling. Seems smooth. I don't know which was the "fix" - of it's fixed. I just hope it lasts.

 

Hi Jay

Dunno!

But that could have been the problem, let's just hope it lasts

 

I hope so. Might have just been time for the CTS.
I don't feel as lucky, though.

So, I also did some tests for parasitic draw and resting, key out of ignition, interior lights off, the car was drawing .40 amps? Is that just way off?

Goodness knows I've chased parasitic draw on the 2000s XKs and from memory, they were lower at rest. Low 20s if I remember. I poked (not for long) at the auto cool guy controller on the low voltage control wires and got nothing when the key was off, but I will do more testing (most likely discon the grounds) to see if the draw is affected.

It just never ends, 😂

 

.4 amps!!. Should be under .02 amps (20 milliamps). Check any non-stock accessories and disconnect them to see what happens; I'd start with your new electric fans and controller.. I don't recall when the power door locks changed, but if you have the older solenoid type, the capacitors in them fail and start drawing a lot of current. Could also be alternator diodes failing. You can try taking out fuses and see which ones have any effect.

 

I always struggle with the readings on my DMM...

So, with the dial set readings int the 20amp range, on the screen I get .40... I will be back at it tomorrow and try to get clearer on what I think I'm seeing.

 

Yep, that's 400 milliamps, 20 times what it should be.

 

Jeeeeeze Louise... Better git my pitchfork and shovel. Time to start digging... smh 🤣

I hope it doesn't turn into a situation where (if it is the controller O fans) the draw can't be cured with the electric fans.

 

I don't know WHAT I was going on yesterday. I was tired and cold, may have been I had a damn door open while I was testing...?

Anyways, doors closed, this is what I'm looking at today. This is with the hot cable of the battery disconnected, the meter set to amps, being the bridge between the electrical and the HOT post on the battery.

I need a new battery. 170$.
Didn't see that coming!!!
(slaps forehead)

 

Yeah, that's a lot better. Often pays to come back fresh and retry things.