I need some help - I've got rough starting issues. This has been intermittent for the last few years but has been happening pretty steady for the last week.

Truck is a 5-speed 1985 4Runner.

Battery is good (bought a year ago, load tested last month, and on a tender all night, every night), starter is a month old, and a couple of months ago I installed a starter relay (the truck didn't come with one and I was getting intermittent starter operation).

Codes are 6 and 10:
It cranks ok, usually catches pretty early when cranking but then seems to run on only a couple of cylinders for a while. After a bit you can hear something that sounds like a relay click then it smooths out. When it's running rough I have to add a lot of throttle to keep it running. When cranking, if I don't catch the first firing with some throttle it'll die quickly then it's a lot harder to start (the video is of a second starting attempt).

Once all this shenanigans is done it runs really well.

Here's the video:
Any ideas?

Thanks!

 

Inconsistent cranking speed, check.
​​​​non-MIS-firing cylinder, check.

Diagnosis, terminal...

Alot of stuff going on here. Firstly you've got some bad engine and or tranny mounts, based on the vibrations showing up on that shift lever. This can both be caused by or causing your misfire and inconsistent cranking speed. With the engine moving this much you can't be certain the ground and power wires aren't suspect due to the vibrations. Also this inconsistent torque is hell on the rubber bits of the mounts. Replacing the torn mounts, after you inspect them of course, won't solve anything since its a by-product of the misfire most likely.

There are two factory grounds that are being stressed here, your primary ground (large wire attached near the lower front of the block which supply's the starter), and your EFI ground wire from the ECU (attached somewhere on the joint between upper and lower intake sections). Make sure these are clean and have a tight connection, also that they aren't routed such that they strain when the engine rocks around. (Loose grounds here will cause inconsistent injector pulses or power supply issues for the starter)

That's all kind of an aside to your misfire in my view however (from way over here at the other side of the internet, so take it with a pinch of salt.)

You've got a wet sparkplug based on the fact it clears up with some time and rpms. This is an injector, leaking valve seal, or head gasket issue. Either fuel fouling the plug, oil, or coolant respectivly.

Disable the efi (pull the fuse), disconnect the distributor from the ignitor/ignition. Now you can crank over the engine with out fuel or spark. If it continues to have the inconsistent cranking speed you've isolated it to a compression issue such as piston rings, burnt valve, bad head gasket. This should show up on your compression test. It might not be out of the 10% deviation from cylinder to cylinder (which indicates more a bad gasket than valve train problem, but from here I would say you've got one that will show way out of spec).

So bottom line I would start with the compression test, then pull my valve cover and inspect the camshaft, and finally inspect my sparkplugs regardless of the other results to confirm which cylinder isn't behaving. I expect you should find a sparkplug that's steam cleaned(head gasket, or other coolant leak like a cracked doohickey), or one that is carbon fouled (leaking valve seals).

 

Thanks for the feedback!

Last time I tried to tackle this problem back in 2016 (thread here: https://www.yotatech.com/forums/f115...59/index2.html), I was CONVINCED it was an electrical or electronic issue somewhere. Heck, I almost bought an MegaSquirt PNP ECU because of it.

After reading your response last night, I payed closer attention this morning when I fired the truck up (and with a more open mind). I can definitely see this being a mechanical issue.

Last time I noted a marked difference in exhaust manifold temps against the head right after a stumbling idle start-up. Cylinder 4 was the coldest, with #3 close in temp. 1 & 2 were both hot.

This weekend I'll try cranking without fuel or spark and see how that sounds. I also have a compression tester, so I'll try to make some time to knock that out - cold and then hot if I have time. I'll plan to check the plugs immediately following an incident (shutting down before it smooths out). I inspected the cam (as much as I could see) last time I adjusted the valves and didn't see anything, but I'll put it on the to-do list.

And yeah, my mounts are pretty bad. I keep meaning to replace them but haven't gotten to it yet.

 

Here's some pictures from the last time I changed my plugs:
Old Plugs:
Attachment 115825

Attachment 115826

I wonder if the problem is getting worse lately because the plugs are getting caked again.

 

Well, I just got done running the starter without fuel and spark and it cranked consistently. Weird. I guess that points to oil fouling, or injectors?

No time tonight for any more work. After work tomorrow I'll pull the plugs to look at and clean them (I'm sure they're all ashy like last time) and if I have time to grab my tester from the hangar I'll try to do a compression check as well.

Anyone know of a good valve stem seal replacement write-up?

 

These all were wet? The threads look wet. You are definitely getting some some substantial build up on those due to oil "coking", coking is bad, thing really hard carbon (you know like diamonds only not quite that hard) this is essentially sand paper (OK really cheap sand paper) and not good for things like your rings and piston bores. The third one doesn't look to bad, but it also looks like you spun the wratchet a few extra turns and I bet it would have looked more like the first on the left. They also show signs of one or both of a valve cover leak and an exhaust gasket failing based on the rings around the boot area and the first ones body looking quite wet/shinie..

I wager if you put a new set of plugs in it fires right up atleast the first time. I also would suggest you don't run those acdelco plugs regardless of the cost and what the "shirt" at the counter says, pay whatever the difference is and get the spark plug specified in the FSM (from memory this is a bpy5s), there are plenty of recounting of the 22R/RE not likeing other sparkplugs. This won't solve the issue but it will run closer to the engineering spec and fire up much smoother for a while.

..

You say it cranked smoother and at a steady pace with the EFI disabled? This is a good sign that in addition to the oily plugs you in fact do have some wiring issues which are magnified by the bad motor mounts. This might just be the wires that run to the ignitor from the distributor, the wires from ignitor to ECU are also suspect. Both of these path near the exhaust and get failure of the wire sheeth, you'll find they are extremely brittle and hard as well as probably already show cracks and exposed copper. If you don't have loose connectors, this is a good candidate for your NE signal to ECU trouble codes. But you might also have some issues with the injector splices. (start with the simple, cheap, and fast things like new clean plugs, then decide if you want to tear into the wiring and rebuild)

​​​​​Also worth going down to the Toyota dealership and getting a good quality PCV valve (they are like $10), worst case you get piece of mind you don't have a crappy plastic PCV valve and best case it will help with your crankcase pressure. High crankcase pressure stresses things like bad ring seating and valve stem seals..

There are some signs you might of noticed like your oil going black or having to top off the system between scheduled oil changes. Do you have to add oil to the system regularly, do you check your oil level and quality on atleast a semi regular basis?



...
Bottom line. Throw some new sparkplugs and a PCV valve from the Toyota parts counter at it, it's gonna cost less than a tank of fuel, and see where that gets you and how long it stays running smooth.

If you love your Toyota think about starting to save up for some engine work and down time.

 

That was a couple of years ago so I can't remember if the threads were wet or not, but I don't think they were. Right after I pulled those I replaced them with some NGK BPR8ES plugs. That all went down when I was getting some pretty ridiculous highway detonation even with retarded timing. I ended up changing a bunch of stuff towards the end of that issue, but somewhere between the new plugs, disabling EGR, and replacing all my vacuum lines I was able to fix that problem.

I check the oil every couple of days, since I keep the battery on a tender and have the hood open anyway. The oil goes black really quickly and I always have to top off between changes. Its probably burning oil, but it also leaks pretty good from a few places on the engine. I started running Rotella 15W-40 and it slowed the oil consumption and leaks a bit. In fact, I'm a little overdue for an oil change so I'll knock that out this weekend, too.

This engine is not the original to the truck, and the engine swap looks to be cheaply/poorly done. I've been "maintaining" the state of this engine for 5 years now and I've always been able to keep it running about as good as when I bought the truck, but I don't have plans to do any major work to this particular engine. When my son is old enough (a couple more years) I really want to do an engine swap with him helping. I had been thinking about re-wiring the truck at the same time, but I think every wire under the hood needs replacing at least. They're all pretty brittle. The good news is that the sheaths are still intact and no copper is showing, but I'd bet that doesn't mean there isn't issues under the wire sheathing. I love this truck, but this particular motor has been a pain compared to my last 22RE. It's my DD because I like it so much, but I've got an Outback as a third car.

I'll put some new plugs and a new PCV on it and let you know how it goes. Thanks again for all the help!

 

Interesting turn of events: this morning I ran the starter without fuel and spark and while it was fully cold-soaked it cranked IN-consistently. Weird.

Next steps are:
1) new spark plugs (NGK website says I need BPR5ES - I think I have BPR8ES in there now. Looks like they're just a couple of steps hotter.)
2) cold and hot compression test this weekend.

 

Those old spark plugs don't look good, a little like mine, unfortunately.

These are the recommended spark plugs from the Factory 1985 Toyota Truck & 4Runner Repair Manual:

 

Any chance you have a digital copy of that FSM you could email me?

 

I’m running an ATF treatment on it today. I was going to run a compression test cold then hot but left my tester at the hangar and won’t have time to go get it this weekend.

I got my vehicles mixed up - the BPR8ES went into another car. The 4Runner had another set of auto lites in it. The plugs looked a lot like the ones in the pictures above, and the threads were wet. New NGK BPR5EY plugs and an oil change tomorrow as well.

 

Yes!

I just send you a Private Message.

 

thanks!

 

I’m interested to hear read your version of an ATF treatment.

https://www.yotatech.com/forums/f116...r-head-307764/

Not saying that’s the right way of doing it, or suggesting that’s how you should do it, but that’s how I did it and it is still running fine. I mean it still consumes oil, just only when accelerating hard.

 

I pull the spark plugs, pour some ATF into the cylinders with a funnel or a syringe, put some paper towels and whatnot over the plug holes (also, be outside, and not next to anything you like), then run the starter (no fuel, no spark) for 5-10 seconds. When you run the starter you’re going to shoot ATF a bit. If you’re prepared you can catch most of it with shop towels. Repeat the process a couple of times, then let it sit for a day or so.

Be warned, it’s going to smoke like a forest fire when you crank it up.

This won’t fix issues with valve stem seals like you replaced, it’s more for freeing up potentially stuck rings and things since it looks like I somehow have an intermittent compression problem (That can’t be right!). Anyway, I figured it couldn’t hurt.

 

The ATF treatment restored some midrange power and I think the new plugs are helping the rough starting. It got a lot warmer here lately so I’ll have to see on the next cold snap. Unfortunately my truck still smells like ATF, but it’s fading every day.

Someone else thought I should check out the circuit opening relay, so if the starting problem comes back inThe cold I’ll see if I can do some troubleshooting to isolate a problem there.

I agree though, I think it’s likely that the engine codes were caused by the motor shaking and disturbing grounds. No codes since and I’ve never once noticed my CEL come on.