Having some electrical issues with my new (to me) XR4TI

[EllieG]

Hey y'all! New member here, me and my partner just bought a really lovely 95k-mile mineral blue 85 a couple days ago as our first car, and it's throwing some issues that are stopping us from driving it. Right now I'm thinking our problem is the old battery (car sat for awhile before we bought it), but I wanted to reach out to some more experienced Merkur owners to make sure I'm not barking up the wrong tree.

The car is an automatic, and has a low idle that will stall it if we put it in drive or reverse while it's idling, or if we take a foot off the gas pedal right after startup or if we've been moving at low speeds (mostly the apartment's parking lot). We took a mental note and just parked it in our apartment's lot, but we haven't been able to move it from there for the last couple days.

Right now, when we try to start the car, we get nothing. The key turns, but we don't hear any cranking. Started to suspect it had a gremlin somewhere in the wiring so we turned on the cabin light, tried to start, and sure enough the light went out, which indicates a drained battery. What's making me think our battery has outright died on us though is that when we got a friend to help us jump start, we were able to jump start it once, drive it up and down the street, and re-park - but only a few minutes later when we tried to start again we got nothing. Trying to jump start it again did nothing - it wouldn't even start while the cables were connected, even though the booster car was starting fine.

What do y'all think? I'm probably going to head out and grab a new battery soon, but I wanted to see if anyone has run into similar issues with a different cause. I could see it potentially being starter motor, alternator, or even ECU issues. Car has new gas, oil, brake fluid (a bit overfilled by the dealer's mechanic, brakes are HARD), and transmission fluid. They say they charged the battery too.
Excited to join the community!

[merkurdriver]

Welcome! Congrats on your purchase! An XR4Ti for your first car? In 2021?

Car sounds familiar, I think there was really nice low miles blue 1985 XR4Ti automatic for sale (auction) in California earlier this year (?)

Onto the issues...

Instead of throwing a million suggestions at you I'll just offer a few really easy basic ones first as I always like to start with the simple stuff (thats usually the culprit).

Sounds like a battery issue to me. I would pull the battery and take it to a local auto parts store and have them put in on their charger and load tester. If the battery is dead you might have to leave it for a few hours while they charge it before it can be tested.

If the battery is bad buy a new one, easy peasy. If the battery was dead, but takes a charge and tests good then proceed as follows.

These cars are notorious for requiring extremely clean and extremely tight battery terminal connections. Start there. If its a new battery going in or your old battery thats been properly charged up - either way -- very clean and very tight connections are critical.

Lets say that a new battery or your old battery (freshly charged) start the car right up. Now I would call into question is the battery being charged by the alternator. Grab a $10 volt meter from Amazon or Harbor Freight, turn the dial to 20v DC and put the leads on the battery posts while the car is running and see what the voltage says.

The stalling out thing is probably the IAC idle air controller or a small vacuum leak somewhere. Both inexpensive and relatively simple fixes.

**Years ago I bought a dirt cheap XR4Ti from halfway across the country that "wouldn't start". Their friend came over and put a new battery in it and it still wouldn't start, wouldn't even crank, etc. etc. Hired a long haul trucking company to collect the car for me and deliver it to my house.
While the truck driver was unhooking the safety straps and putting his ramps down I popped the hood, cleaned the connections with a wire brush and tightened the clamps down like those clamps needed to hold the entire car together.
Fired right up and drove it off the trailer.

[thesameguy]

On an '85 I would also suspect the battery cables. I think the early years came with unusual batteries using "UT" terminals (I know my '86 did) and sometimes people have some up with some interesting ways to work around that issue. I pointlessly fought janky cables for years before finally just making new ones. Although I've also got an '88 with awful battery cables, so maybe it's just an XR4Ti thing.

[EllieG]

Big update day!

Quite correct from both of y'all - and some additional stuff! A friend who does some mechanic work came by to see the car last night and today, and we spent a lot of time and a bit of money on it. Battery was straightforward - Everything is fixed right now except for the low idle issue (still stalls on occasion, but nowhere NEAR as bad), old brake pads, and a missing spring on the rear hatch latching mechanism.

The battery was in fact dead - it was an old battery that as far as I could tell didn't even have branding on it, and we looked pretty close. But whoever owned or worked on this car last made some... choices. Some unusual ones . The positive battery cable had a pretty big gap where it ran through the bracket, which is probably one of the reasons it was so dead in the first place, and the terminals had seen better days. Interestingly, the sleeving they put on the battery positive was blue - not any trouble to figure out, and we were in fact jumping it correctly, but puzzling. The bracket where the bottom of the battery goes is also mostly rust - and there was a dish towel that I swear is older than I am in there . Resleeved the cables, bought some proper jumpers of our own and a volt meter, new battery terminals, probably gonna put ... something new under the battery soon.

The dealer informed us that they had a mechanic put in new spark plugs, brake fluid, transmission fluid, gas, and oil the day we picked it up, and I think the mechanic may have either been a bit rushed or a bit out of it. Spark plugs were wrong, and the gap on them was enormous. Bafflingly so - the smallest was 39 and the largest was 48. Kinda shocked the thing ran on the way home, they were new but had gas all over them. We got the correct plugs, gapped them to 30 (checked here for what people like running), and still got some knock so we took it to the gas station and got some octane booster figuring that they put regular in it. That fixed the knock in its entirety. Only 93 goes in it for now.

Thing still has a few issues, but nothing huge. Brake pads need replaced, brake fluid needs drained, low idle issue is still present but nowhere near as bad (gonna check vacuum lines and then IAC), and the rear latch is missing a spring or something so it doesn't properly lock. Starter is fine, alternator is fine, interior electronics all fine, and not much looks touched. The little battery for the key's light has "Made in West Germany" stamped on it. Oh! And the front wiper fluid lines don't go to anywhere, so we're going to do that soon .

[Ed Lijewski]

XR cables were known to conceal oxidation under the protective sheathing/insulation which was the source of electrical system gremlins.

YMMV

[EllieG]

Update 2! IAC boogaloo:

Pulled the IAC! It does in fact look pretty carbonized, gonna see if I can attach pictures. The bolts holding the sensor to the body of it are in very tight, and I don't wanna attack them too much harder since it's a philips and I'd be afraid of stripping them. Can I clean it like this? And if so, what should I use? Picked up some carb cleaner and WD40 from downstairs. IAC is on the desk next to me as we speak. Finding a replacement wouldn't be the worst hassle in the world, but would love to save the $50.

Pictures:

[MarkM]

Sounds like you're making good progress.

[merkurdriver]

I have new IAC for $25 + $6.95 ship for what its worth...
However, usually a good cleaning will do just fine.

You don't have to split it to clean it, just take carb cleaner and flood inside one of the holes until until fluid is coming out of the other side clear.
Might take an entire can before this happens.

[EllieG]

I have new IAC for $25 + $6.95 ship for what its worth...
However, usually a good cleaning will do just fine.

Might take you up on that if we have trouble! For now, the IAC is cleaned and reinstalled, but we don't want to test it til morning because it's 3am here and our neighbors would hate us. High hopes it'll work - cleaned a ton of carbon out, the can I was catching the carb cleaner in was almost black.
Gasket got damaged when we took it off so fingers crossed it doesn't leak at all. The seal feels tight, and both actual holes still have gasket around them.

[Ed Lijewski]

A vise-grip pliers (small one if available but larger one if not) will grip and turn those screws. FWIW separating the solenoid from the valve body allows one to wiggle the pintle around its seat while spraying with cleaner to get a better result.

YMMV

[EllieG]

A vise-grip pliers (small one if available but larger one if not) will grip and turn those screws. FWIW separating the solenoid from the valve body allows one to wiggle the pintle around its seat while spraying with cleaner to get a better result.

YMMV

Update 3: We actually tried that pretty early - the screws are in that tight, probably never opened. Lubricant and copious wire-brushing did nothing to help.

Cleaned IAC but still suffering. Some family visited today and offered to just outright buy a new one and new gasket, and I took them up on it. Installed, and still stalling from idle. Where do I go from here? Clean the throttle body (don't know if it's dirty, haven't looked yet)? I can do that in the morning, we picked up some cleaner, but where do I go from there? Car is shared with my fiancee and I wanna make sure she feels good driving it, ideally by Monday. Feel like this one issue is getting the better of me - but ofc I'll probably feel better after getting some fresher clothes and some sleep.

Potential other clues:

• Without pushing the gas pedal, the engine will start well, go up to ~1100-1200 rpm, start dropping, hit ~600-700, and stall.

• Car is totally fine at high rpm. Makes me think injectors are probably okay?

• Haven't checked TPS. How do I know what it's set to?

• Haven't found a code reader or timing light. Checked like 4 stores already :/ Do have a volt meter though.

• Haven't been able to find any vacuum leaks, but I'm not the best at looking. Any specific spots?

• On startup, the car does make a kind of continuous whining beep that sounds electrical, but I don't know if that's related at all, and if we keep it above idle sometimes it subsides.

• Spark plugs are brand new and I know they're good and gapped to 30

• Brakes feel spongy. I'm attributing this to old pads and needing to be bled. I think the check brake light is on.

• The dealer mechanic, who made some mistakes previously, replaced the transmission fluid

• Locking the driver door usually doesn't lock the passenger door, but did once or twice

Ideas?
Any trustworthy Dallas shops?

Edit: also I don't know if this is an admin setting but could somebody help set it up so I don't have to get every post approved? I'm trying to respond to people in a timely manner but sometimes the posts end up about a day behind.

[andyofcolumbusmerkur]

You just need the shop manual and a timing light + volt meter so you can do a tune-up.

[jkxr4ti]

Here’s a post with links to the manual and evtm. Download those both they are great resources. Check all the small vacuum lines for cracks and tears. Boost gauge vacuum line going to the back of the gauge cluster is another spot to check especially if your boost gauge doesnt work well or you hear a hissing inside the car.
I would look for vacuum leaks, clean the throttle body and then set the base idle. If that stuff doesn’t help check the tps voltage. All those things are outlined in the manual but let us know if you have questions.
viewtopic.php?f=30&t=32434&p=291532&hil ... df#p291532

[merkurdriver]

• Haven't found a code reader or timing light. Checked like 4 stores already :/ Do have a volt meter though.

Easiest code reader to use on the XR4Ti:

http://www.merkur.50megs.com/custom.html

[thesameguy]

Be sure you don't have any vacuum leaks, and I would definitely reset the idle. Especially on turbo cars, vacuum leaks are common and will be the most problematic at low engine speed.