Nope, it’s not Miku colored yet. Quit asking.
It’s hard to believe that I only went on the Great Van Escapade a week and some ago. Between then and now, I’ve done many hours of disassembly, testing, and debugging. I think I’ve finally rooted out the problem, but am waiting on some more advice and recommendations before proceeding. Why am I even buggering with fixing the ICE engine, with all its attendant pre-OBD-but-post-CARB Mitsubishi-only oddities, when I’m just going to unbolt it all and drop in an electric power system? Not quite sure, but some of it has to do with curiosity in figuring out exactly how much of a complexity nightmare ICE vehicles are, and others because I have 20 more days of temp plates left. Getting in some driving feel would be immensely helpful too.
Mikuvan lives in the enclosed underground parking garage under my apartment block, next to a Honda CR-V, a Volkswagen Golf, a Prius, and (among other cars) a 1963 Mercury Comet. Good, I’m not the only project car sitting in a pile of its own parts. Looking down the row of parked cars is amusing – all you see is hoods and headlights…and then there’s this.
At least it’s not on-street or outside. But the downsides of this arrangement include the total lack of AC outlet power nearby, poor lighting, and a lack of Wifi or cell reception. The nearest outlet is 75 feet away, necessitating some extension cord creativity. I have a 500W halogen work light to relieve the lighting issue, but it is still only one source. The latter issue means I often neglected to bring cameras or camera-enabled things with me into wrenching sessions. Hence, even though there were plenty of cool photo ops, this post will sadly be mostly text.
Hey, so is my air filter supposed to be furry?
The story of digging in around in the
drivers seat engine bay is centered around consulting with people who know a thing or two about what cars are, then vaguely following their suggestions but ultimately falling back to the Official Strategy Guide / Shop Manual to figure out through its well-drawn but extremely narrow view diagrams where the parts in questions actually were.
It’s often said that you need 3.5 things to get an engine to work. Spark, fuel, compression, and when-does-the-spark-fire (i.e. timing the spark, the 0.5 part). I basically began by checking the ones that were easy: spark and compression. To check the timing properly would have involved exposing the timing pulleys, which, as far as I could tell necessitated removing the radiator and cooling fan shroud, then also removing the distributor cap which was more accessible. I did not feel like attempting this in the dark with limited tools. In Pennsylvania, we already verified compression, so I started by checking the spark plug lines.
I bought 2 of these in-line plug checker lights from Harbor Freight (not sure why I just didn’t go ahead and get 4). The firing order of the engine is 1 – 3 – 4 – 2, so I started by putting the lights on 1 and 3 to verify the order, then 3 and 4, and so on. Basically to make sure that 1) there was spark even if it may not be the correct timing, and that 2) the cables weren’t switched around or something.
The sparking order checked out fine, so I began reading up on fuel injector testing and cleaning. My suspicion at this point moved to the injectors, since they were really the only element left. I highly doubted it was a timing issue in that somehow the timing belt (which is in great condition as far as I can see – it must have been replaced fairly recently) skipped 1 tooth or the distributor cap rotated enough such that I got completely inconclusive cranking – even a late spark would give me some kind of ‘puff’ and an early spark would cause premature detonation and horrible noises.
But I couldn’t help but think that all 4 injectors failing or clogging at once was extremely unlikely. In my experiences with watching friends tell stories of problem cars and from a few trouble vehicles my family has owned, engines don’t just suddenly stop working unless either something
- catastophically failed on the mechanical side, which I would certainly know by now, or
- a single electrical point of failure such as a sensor is preventing the ECU from running the engine properly
My money was moving towards some stupid sensor failure. For instance, if the crankshaft position sensor, used for fuel injection timing and electronic spark timing (the ECU fires the ignition coil when it feels like) is out, then the ECU won’t know when to do either of those things. If the throttle position sensor, which is potentiometer based, was broken or worn, it could be reporting a completely nonsensical value, though this seemed less likely since you’re never supposed to step on the throttle while starting, unless you know exactly why you have to. There’s other sensors involved too, like the mass air flow sensor which the ECU uses to determine how much fuel is metered into the cylinder.
With all of these things having to work in synchrony, I’m amazed cars function at all.
Here’s the scene of the crime, lit up by the aforementioned 500 watt halogen light. It kept the area reasonably warm, as the rest of the garage is unheated and basically settles to its own temperature by thermal inertia alone (surely it will get unbearably hot during the summer). At this point, to access the fuel injectors and high pressure fuel rail, I have the passenger seat slung up, the driver seat removed, and the underframe of the driver seat also detached but just shuffled out of the way a bit since it has the parking brake lever, fuel door lever, seat belt anchor, and a host of other stuff on it I don’t feel like dropping into the engine.
Here’s the whole mess from the other side. The shop manual has been my reading material of choice for the past week. It’s extremely informative, but at the same time I can tell it was written by mechanics for other mechanics. I assume that the unlabeled detail shots require some background in wrenching to understand where to insert the thingimadoodle and how many degrees to turn the whatchamadoosit. There’s other info missing such as sensor pinouts right after it tells me what voltage this or that sensor should read…
…While the engine is running. How about a little help for the other case here, guys?
Before taking even more things apart to get to the injectors, I decided to see if it could tell me what was wrong.
Okay, now I’m seeing something familiar. My van debugs like a Kelly controller or Hobbyking controller!
It predates OBD (“OBD-1”), so it has multiple means of debugging available. You could buy the $500+ “multi-use tool” which is like a form of proto-OBD scanner, or you can debug with a voltmeter. Not a digital one – an analog one. It puts out little pulses of voltage so you can see the needle move (digital meters do too much time-averaging to see this effect). If I added an LED to the circuit, I literally could have watched it blink. It probably would have said “FREQUENT RESET” or something, knowing the average Kelly controller.
So an analog voltmeter it is. It took me a while of digging in MITERS to even find one of our crufty analog voltmeters, and I ended up having to make hardwire leads for it anyway.
But it worked! The key has to be turned to ON (not start) for a few seconds for the ECU to start putting out pulses. The result is:
Oh, come on.
My guess is that since the vehicle has not been started since my new battery was connected, the ECU doesn’t know what’s good or bad. The engine must run, no matter how crappily, for a while before the ECU can recognize something is out of range or nonresponsive. My mission now was to try and get the thing started no matter what. If the injectors were clogged, then I’d have to unclog them.
One thing I was told to try was to drop carb/throttle body cleaner (i.e. vicious, surely carcinogenic, and highly volatile solvent cleaner) directly into the fuel rail, mixed in with the gasoline, to try and dissolve anything which might be causing injector blockage on the spot. Basically you cycle the injectors bathed in disgusting solvents and let it sit for a while, then try again. Rinse and repeat. I bought a little can of Seafoam on recommendation from friends, which appears to the most disgusting of the disgusting solvents since it claims to clean everything. Seems legit, right?
The procedure was to disconnect the high pressure fuel line from the rail, get most of the fuel in there out, and replace the rest with Disgusting Solvent #81289. I wicked fuel using a few shop towels, which were promptly lit on fire for my own amusement (this process does not have photos associated), and mixed in Seafoam about 50/50 into the rail. Next, I gave the engine about 10 seconds of crank to get the new mixed drink into the injectors. During this time, the engine sputtered a few times.
An hour later, I came back to give the engine another spin. 10 more seconds of excited cranking and sputtering later, it took off.
It was shaking like crazy and white smoke was everywhere (allegedly a sign of the cleaner doing its thing), and the revs were unsteady for the first few seconds of run. It seemed to settle into an idle, though I was both too excited and scared shitless to check the tachometer for functionality. Something was happening.
I was under the impression based on checking the dipstick in Pennsylvania that the engine was very low on oil. It was also running with zero coolant. Fearing causing damage due to lack of lubrication, I shut the engine off after about 20(ish) seconds of running.
it did something
Unfortunately, that was the only run I got out of it that night. I regrouped thoughts for a bit to formulate the plan of attack if it started and ran more than once. On the next shot, there was some more sputtering, but no consistent behavior. I gave the air intake a dose of starting fluid to no avail. By the next few tries, the battery was wearing down too low to crank effectively. I’d have to bring in my charger and top it off before trying again, so I cleaned up for the night.
That was when I noticed that the air flow sensor wasn’t connected at all. Remember the air filter shot? I opened the air cleaner box to remove and replace it with a fresh one, but neglected to reconnect the airflow sensor. So, the engine running must have been pure luck – or the cleaner/solvent making for such a volatile mixture that any small amount was sufficient for it to keep turning over. The air flow sensor is a “hot grid” type sensor (looks like this) used for air mass calculations. If “disconnected” also means “off scale low”, it means the ECU would think that there was no airflow. No airflow means no air mass to calculate fuel injection quantity with. And no fuel means no combustion except if you’re basically mainlining Seafoam. My exhaust system is probably really clean right now.
Yesterday evening, I tried re-adding some cleaner to the fuel rail (in lesser quantity) to try and confirm this theory. I got the engine to sputter some times, but no starting and running was observed. I also noticed that the ECU code had finally changed to:
Air flow sensor.
It was definitely connected. I even abraded the pins a little and recrimped the socket to increase contact pressure just to make sure it had connectivity. I couldn’t tell if the element was damaged (it looked good, even clean) or the entire sensor had just stopped working or what. I cleaned the grid element with some rubbing alcohol and let it dry under the halogen lamp for a while. No obvious changes were noted, nor were any starts effected. Maybe “disconnected” is a totally different signal from “porked”.
A new-used MAF sensor costs about $120 on eBay, so I went ahead and ordered one. Even if it’s not the problem, I now have a debugging chain to follow instead of shooting in the dark. The airflow sensor being problematic would corroborate my theory that some critical sensor failing is causing the ECU to not control air, fuel, or spark properly. We’ll see how this goes.
With these new developments, I decided to do some staging and preparation. First, I wanted to get the disgusting sludge oil leftovers out of the engine and put in something fresh. On the same Harbor Freight trip earlier in the week, I anticipated needing to do this eventually so I got an oil filter strap wrench and a waste oil container, the kind with the integrated drip pan. I ordered a new oil filter off eBay (the best auto parts store!) last week already.
The oil drain plug and filter were clearly designed to be accessed from an auto lift. I didn’t have this, so luckily the thing has a massive front nose cavity…
The plug and filter aren’t visible in this picture, but they’re right behind the front suspension arms. The radiator to the left is the A/C condenser – it’s the first thing to hit if you drive over a tall curb or something.
I also noticed while I was under there that the transmission oil pan is basically the first thing to hit the ground if I go over an enthusiastic speed bump. I’m not sure how they expected this to navigate the rough streets of the U.S. while loaded with seven U.S. sized adults. Maybe everything was smaller back in 1989…
It was black. ALL BLACK.
Around 5 quarts of entirely black oil poured out of the crankcase. Like, this stuff was basically the color of the filter. So it did have oil after all! “Oil”, anyway. I think we must have read the dipstick wrong in PA, since we swore it had very low oil.
Always a good thing to find in the drip pan – little metal particles. And chunks of sludge.
I let both filter and drain plug ports drip for over an hour (while waiting for the battery to charge) before refilling it with some new 5W-30 from the gas station. I didn’t bust money on premium oil since I figure it wasn’t going to stay in the car for too long anyway.
Oh, also, the oil filter had basically no torque on it. I didn’t even need the strap wrench – just the torque of my hand trying to engage the strap loosened it. No wonder there is a thin sheen of oil all over the underside – it must have just been leaking forever. I made sure to crank it down when I installed the new filter.
The game right now is to wait for the new airflow sensor and see what happens from there. I’ve pledged to give an honest debugging effort to this thing even if I’m not keeping the engine for long, and I’m willing to spend some money on it. I’ll make sure to take more pictures of everything in the future.
This is also the first post in the new Mikuvan build thread. Oh boy, I’m in deep now…