2001 shuttering to start, won't move in drive.

Start by replacing the iridium spark plugs if they have less than 60K miles on them. If that doesn't help check the fuel injectors in cylinders 1 and 2.

It is likely that other DTC were logged by the hybrid vehicle ECU, that the code reader did not retrieve.

 

Hmm, your cylinder 1 misfire has moved to cylinder 4.

I'm not desperate to read hybrid codes at this point. It certainly won't hurt to know if there are any (there will likely be at least one from the HV ECU just saying "hmm, engine not performing as expected") but on current evidence, the patient seems to have a misfiring gasoline engine.

Running with the check-engine light blinking confirms - the ECM will blink that light when serious misfiring is detected. Again, running the engine in this state is hard on the catalytic converter so we don't want to do it too much.

I would certainly at least take the spark plugs out and take pictures of the business ends. Then clean them if they need it. As new as they are, they might not need to be replaced, but the condition of the ends can speak to what's going on in there. Will 1 and 2 look different from 3 and 4? Will some have black fluff and some not? Any signs of conductive (carbon, grease, etc.) tracking, either along the insulating body of the plugs, or of the igniters?

The scangauge can read the "bank 1" "long term fuel trim" value - a standard OBD-II parameter so no XGAUGE programming needed. Is it close to zero, or edging up near 20%, the maximum adjustment the ECM will apply?

Spark tests of the 4 igniters would reveal if any are making weak spark. If you have tools to do a leakdown compression test, that's hardly any extra work on top of taking out the plugs for inspection and spark tests.

The usual suspects for a misfiring problem are fuel induction, compression, and ignition. Ignition could be the condition of the spark plugs, igniters, or wiring. A compression problem will turn out to have a basic mechanical cause. A fuel induction problem would have to do with the intake, throttle body where you've already looked, condition of the fuel injectors, or pressure delivered by the fuel pump / lines / filter. Or impurities in the fuel.

It's the sort of puzzle that's bound to be solved just by an elimination process, which might as well start with the things that are the least work to check.

-Chap

 

Thinking outside the box . . . water on or in the igniter holes?

I'm thinking of the old blocked drain pan under the windshield wiper motor the NHW20s suffered.

Bob Wilson

 

Yes ... so you'll naturally find whether that's part of the picture, when you go to inspect the plugs.

Something to watch for - if you remove the igniters (the 4 plastic units bolted to the top of the engine above where the spark plugs go) and look down in those wells, if there's any water accumulated down there, it'll be best to sop it out before loosening the plugs, so it doesn't run into the cylinders.

-Chap

 

Behind the glove box, it works best removed, you'll find the cabin air inlet filter. If it is soaked, the rain water from the firewall pan under the windshield wiper motor hypothesis gains traction. There are drain holes that if the car is parked under trees can become blocked.

Bob Wilson

 

The filter can help but you really need to check the spark plug holes.

Bob Wilson

 

It looks lovely. How about a pic of all four in cylinder order? (Out of the socket, to look for any sign of tracking down the insulator.) I take it you did not find any signs of water in the spark plug wells? Did the plugs all seem to be appropriately torqued as you loosened them?

If they all look this good, probably the condition of the spark plugs is ruled out as the cause. In a game of elimination, ruling things out is perfectly good progress.

Probably hard starting, vibration, and misfire codes from the computer.

If you were to run some into a glass and let it sit for a spell, it would tend to stratify with the gasoline on top.

-Chap

 

1. What do the plugs from the other cylinders look like?
2. That plug doesn't look great if it only has logged 15K miles.
3. Measure the gap, which should be 1.0-1.1 mm. If greater, discard the plug (do not attempt to adjust the gap on a used iridium spark plug.)
4. Inspect the spark igniter for problems such as corrosion on the wiring harness connector, or cracking / rust marks on the plastic body.
5. Inspect the spark plug porcelain insulator for cracking or rust and replace if any flaws are present.

 

Let it run and verify it is putting a charge on the traction battery. Once it stops, turn it off.

Go back to the throttle plate and see if you can turn it by hand. High humidity is often associated with sticky throttle plate. We can't rule out the throttle plate, position encoder.

You've eliminated the spark plugs and that it now runs indicates they were marginal. Now we need to concentrate on fuel. The number one culprit, the throttle plate. However, MAF sensor could also be in trouble but I don't have Vol 1 handy. Does anyone remember if there is a MAF specific code?

As for the injectors, Chapman is the expert and I would defer to anything he suggests.

Bob Wilson

 

Was the key ON or OFF when you were moving the throttle plate? It is spring-loaded, by a sort of reasonable-feeling, not monster, spring. When you say "good bit of force to open it", was that a good bit of force, then it popped open, and felt like a reasonable spring? Or did it feel like fighting you all the way?

If it was a pop-open, that suggests it might be sticky around the edges and could be contributing to your problem. The motor might have trouble opening it too when needed.

Now, if the key was ON at the time, then the whole time you were forcing it open, the ECM was going "oh, no you don't, I said CLOSED, you...". That makes it a lot harder.

A poor-man's ignition test is to take one of the spark plugs you removed from a cylinder, stick it back into the end of its igniter, and hold it over the the top of the engine. Get some bare copper wire, wrap it tightly around the spark plug's threads, and hold it tightly to a bare metal engine part. Have an accomplice turn the key to crank the engine, and watch whether this plug makes decent, consistent sparks.

Don't hold it too close to the plug well it came out of, because during engine cranking, what's coming up out of that hole is (supposed to be) perfect fuel/air mix. So figure out how far from the hole the igniter and its wiring will let you reach, and hold the plug there. Or have somebody hold your beer and shoot video. Stop the engine as soon as you've seen enough.

If it makes lousy or no spark, there's a problem. If it looks good, you might consider repeating the test on the other three. If they all look good, it's probably ok to cross ignition off the elimination list. That'll leave compression, or fuel delivery.

I made a mistake earlier in saying the ScanGauge will show you long-term fuel trim out of the box. You need to make an XGAUGE for it:
TXD:8210F10107 RXF:031004410507 RXD:2808 MTH:00190020FF9C NAME:LF1

Then you can run the engine and read this value. It's the amount of adjustment the ECM has to make between how long it calculates it should hold the injectors open to get the right fuel/air mix, and how long it really has to hold them open according to the oxygen sensor feedback telling it when the mix is right. If it's close to zero, then the injectors are performing about as expected; if it's getting up toward 20%, which is about the maximum allowance the ECM is willing to make, then they're probably not, perhaps because of actual injector problems, or fuel pressure/delivery problems, or contaminated fuel ... anything that reduces the amount of actual fuel that arrives while the injector is open. OR, there is some way that unmetered air is getting in, which would also make the ECM have to inject extra long to achieve the right mix.

The trim could also be in the other direction, suggesting the mix is turning out richer than the ECM expects, in which case we'd need to think of things that could cause that. Injectors that leak when they're supposed to be closed would. Or maybe the MAF could just be misreading the amount of air going in, but probably not if you recently replaced it.

-Chap