Engine running lean.

[Torn Mind]

Swapped some spark plugs after a P0171 popped up on my mom's Toyota Matrix. The plugs do look whitish(even with two of them having oil on the threads), suggesting a lean condition. I do not believe the intake manifold gasket is an issue, since i replace the defective version with the corrected version. I did a brief OBD check and the long term fuel trim is about 12% at idle and increase when the accelerator is pushed. On a test drive, the long term fuel trim goes up to 20%, indicating that the code was caused by not enough gas getting into the mix. The code is gone after the new spark plugs, but the poor cranking at start up and poor idle at startup is still around. The poor cranking first popped up after one time I overfilled the oil. The poor idle has been happening for almost 100k miles.

I'm thinking fuel injectors or coil packs, more towards the injectors. The engine code is gone but the whitish spark plugs are still a concern plus it's still guzzling fuel to compensate for the lean running conditions.

I'll probably spray down the MAF but I don't think it's the main issue.

 

[NutBucket]

IMHO you'd be surprised what a dirty MAF will do. Might also want to check fuel pressure if possible.

 

[Torn Mind]

IMHO you'd be surprised what a dirty MAF will do. Might also want to check fuel pressure if possible.

I can address it, but the main issue looks like something before it becomes even relevant. Cold startups are the first priority because I don't want to be chewing through starters all the time even if I can replace solenoids on the cheap. It needs 5-6 rotations, so that's why I've narrowed down the first targets to the injectors and the coil packs.

Plus, if the computer is reset by disconnecting the battery, the factory defaults always result in a complete stop at idle until the computer "learns" the proper ratio; this has been going on for years.

While normally I would not buy China direct, certain car parts leave me considering it. The dealer markup for a battery terminal is huge and in the past, the Ebay china version seemed like a exact replica, possibly overstock. So the fuel injectors with Denso stamping on Ebay might actually also be overstock and the markup for an OEM injector is about 190-200 dollars. https://www.ebay.com/itm/126089870189

Fuel injector #4(closest to the passenger side) is interesting in that an oily liquid is present in the in the connector area but it seems it is about the valve cover. But spark plug #4 is probably the best looking out of all of the spark plugs.

The car has seen plenty of cheap gas so that might be why the injectors are clogged. I can't totally eliminate a fuel pump because it did run dry about three times in its life.

 

[mindless1]

The most common cause of a system too lean is a vac leak. You stated the code went away after the spark plug change (which is odd in itself, a bad plug should cause a misfire on that cylinder, not a lean code), but, are the long term fuel trims still at 12% and higher?

If so, it could be insufficient fuel, in which case check the fuel pressure, or it could be too much unmetered air, in which case clean the MAF sensor, and check for vac leaks. If all else fails, smoke test to check for leaks. A vac leak can definitely make it hard to start and idle poorly as this is when the throttle is closed most of the way with engine producing max vac.

You stated cranks bad, but cranks means the turning of the engine so is it spinning slower than usual? If so, check battery clamps for corrosion, that it has a good ground, and holding charge, battery not dropping too low during cranking.

A failing upstream O2 sensor can cause a false positive too lean condition too, usually not the downstream sensors besides a trouble code, but on newer vehicles I wouldn't rule them out either.

It certainly wouldn't hurt anything to dump some fuel system cleaner in your next tank of fuel, something with a lot of PEA in it. Coil packs are unlikely, tend to fail badly enough that you'd get specific cylinder misfire codes.

$29 for 4 fuel injectors? I would not trust them at all. I'd see if I could find the correct Denso injectors cheaper than the oem rebranded ones, not sure if this is the right part # but an example:

NEW Denso, Corolla, Matrix, Carina, 1.8L, 1ZZFE

<style>#html-body [data-pb-style=JRQCNMI]{justify-content:flex-start;display:flex;flex-direction:column;background-position:left top;background-size:cover;background-repeat:no-repeat;background-attachment:scroll}</style><div data-content-type="row" data-appearance="contained"...

www.fiveomotorsport.com

I would not get (even) brand name injectors on ebay unless you really trust the seller. I'd still try fuel system cleaner and everything else mentioned above, before replacing the injectors.

 

[Torn Mind]

The most common cause of a system too lean is a vac leak. You stated the code went away after the spark plug change (which is odd in itself, a bad plug should cause a misfire on that cylinder, not a lean code), but, are the long term fuel trims still at 12% and higher?

If so, it could be insufficient fuel, in which case check the fuel pressure, or it could be too much unmetered air, in which case clean the MAF sensor, and check for vac leaks. If all else fails, smoke test to check for leaks. A vac leak can definitely make it hard to start and idle poorly as this is when the throttle is closed most of the way with engine producing max vac.

You stated cranks bad, but cranks means the turning of the engine so is it spinning slower than usual? If so, check battery clamps for corrosion, that it has a good ground, and holding charge, battery not dropping too low during cranking.

A failing upstream O2 sensor can cause a false positive too lean condition too, usually not the downstream sensors besides a trouble code, but on newer vehicles I wouldn't rule them out either.

It certainly wouldn't hurt anything to dump some fuel system cleaner in your next tank of fuel, something with a lot of PEA in it. Coil packs are unlikely, tend to fail badly enough that you'd get specific cylinder misfire codes.

$29 for 4 fuel injectors? I would not trust them at all. I'd see if I could find the correct Denso injectors cheaper than the oem rebranded ones, not sure if this is the right part # but an example:

NEW Denso, Corolla, Matrix, Carina, 1.8L, 1ZZFE

<style>#html-body [data-pb-style=JRQCNMI]{justify-content:flex-start;display:flex;flex-direction:column;background-position:left top;background-size:cover;background-repeat:no-repeat;background-attachment:scroll}</style><div data-content-type="row" data-appearance="contained"...

www.fiveomotorsport.com

I would not get (even) brand name injectors on ebay unless you really trust the seller. I'd still try fuel system cleaner and everything else mentioned above, before replacing the injectors.

The code popped up after a hard rev in the 3000 rpm range(after multiple previous hard revs).

The objective numbers appear to eliminate vacuum leaks. LTFT increases from idle 10% to 20%. With the new spark plugs, the idle % dropped from 11 to 9%. But hitting the accelerator easily puts it into the 20%. From the vids I've seen, the numbers go down if it is a vacuum leak.

I have used Berryman B12 in the past but at least one injector demands replacement. There is this brownish oily liquid in the connector power plug socket. It's probably some fuel because it's above the valve cover and the power connector is a pretty tight fit.

Bigger gauge aftermarket Ground cable was installed years ago after an "auto-lock" gremlin appeared. OEM ground was corroded. I have a thread or post on that here.

Battery got greased up and I chose a Deka built Duracell.

It's a calculated risk to Ebay the parts, but given that the Chinese were dumping loads of negative battery terminals with the exact same designs as an OEM Toyota for a pittance, I'm banking on desperate warehouses in China dumping excess inventory. for these old Densos no one wants because Toyota updates part numbers, rendering these old things obselete.

I believe the injectors might have been choked up for about 10 years and 100k already, because way before any of this new stuff popped up, the car already stalled out after a "battery disconnect", meaning the default computer calculations were off. Could be cheap gas because my mom is extremely price sensitive(Asian growing up in famine times). The Matrix does not have a fuel filter though, so the injectors getting clogged might be a designed eventuality, along with intentionally designing the engine to go "lean" so that people go buy a new Toyota.

 

[RLGL]

You need to have this checked by a mechanic. Whitish-looking plugs could the normal color (they need to be looked at by someone who knows what they should look like). Crank times could be a faulty fuel pressure regulator

 

[Torn Mind]

You need to have this checked by a mechanic. Whitish-looking plugs could the normal color (they need to be looked at by someone who knows what they should look like). Crank times could be a faulty fuel pressure regulator

I changed plugs at 89k to 100k(OEM to Ik16TT) and around 175k(Denso Ik16TT, which ran better on acceleration, to OEM dealership again). The first OEM plugs were what mechanics would call "normal". No white, no black, but the usual inbetween gray. Three of the IK series look mostly dark grey but with the ground strap having a tinge of white, suggest lean running already. The three better IK plugs look like they still could run another 10k because the electrode ground look ok. The one I marked "2" (which might be cylinder 3 because I start from the passenger side), was whiter hand and bumpy deposits. These plugs are clearly whiter. The new plugs are ruthenium, and they feel better than new OEM stock plugs, but the engine will have to "learn" for me to determine if it is better than the IK series.

The car is at 219.5k, and the wear on two of the plugs is so rapid that the electrode is totally gone. So, the plugs are whiter and they are dying faster than the first batch of OEM plugs or the IK series plugs. Only 55k has passed.

The Matrix is a budget car. This is no fuel filter. The regulator is part of the fuel pump itself; I can get another one and I feel confident that a junkyard OEM pump would be just fine, but given 220k and passed and it has been running abnormal already (but without codes) for maybe 10 years, I'm thinking injectors.

The delta between cheap gas and name brand gas in the local area is about 30-40 cents. But 17 years of unfiltered name brand gas might not have been that big of a difference.

 

[Steltek]

From what I understand, a good source for Toyota OEM parts is Standard Motor Products. Supposedly, most of the parts SMP sells (at least as far as Toyota parts are concerned, anyway) are rebagged OEM parts that are way cheaper than dealer prices. And, certainly better than the Chinese knockoffs or Dorman crap.

 

[Torn Mind]

I did swap out a starter solenoid and put in new brushes harvested from a previous remanufactured Advance Auto starter(which died pretty quickly, possibly the old Toyota Tru-2 being a contributing factor).

The removed brushes in the suggests that the I would have needed new brushes very soon or imminently, as they were worn down. I had a no start condition three days ago and had to whack the starter. This was the replacement to the "quickly dead" Advance Auto starter.

Solenoids have shot up in price and not easy to find. So somebody liquidated some cheap WAI solenoids. One thing is that the included spring is much softer than the reman'd Advance springs. I think a lost my one connector due to the shape not being exact with OEM. I bought four for about 8.90, but one is clearly not a compatible unit but the other three are.
Right now, the remains of the cracked connector remains in the starter so that I don't have to worry about disconnection until a few years down the the line.

As expected, the computer at factory fuel mix will get close to stalling and the short term fuel trim immediately goes up to 20 percent. After computer learning, it seems it is at 14 percent for the long term fuel trim.

 

[Torn Mind]

The starter is much louder and faster in its turns. Vr-vroom-vroom-vroom-vroom.

Still takes five turns to "catch" but the starter is wailing like a champ, lol. Battery must also be good enough then.

LTFT was at 14 but on the last return trip, it wouldn't go below 20. The air temp is in the 50s right now though.

 

[RLGL]

Back to the spark plugs, have you done a leak down test? Possibility the head gasket is leaking.

 

[Torn Mind]

Back to the spark plugs, have you done a leak down test? Possibility the head gasket is leaking.

I don't have the equipment for that. The oil is not chocolate milk though.

I also said the sparks plugs are white and bone dry. So if there is any liquid the leanness of the air/fuel mix is currently overpowering such effects.

 

[RLGL]

The oil is not chocolate milk though.

Another reason to have a mechanic look at it, a leak down is one of the first tests to perform.

 

[Torn Mind]

I have replaced the injectors. There is some improvement in the overall ability to scoot about and at times, the start up is slightly better. One time, it almost instantaneously started after the engine was stopped and restarted, but it wasn't frequent, suggesting that further upstream parts like the fuel pump or separately, the ignition coils are also contributing to the issue.

Valve cover gasket has failed and needs to replaced so I can eliminate oil on spark plugs being a potential variable.

The Ebay set did not provide the injector insulators on the bottom, so I had to use the dirty ones off the old injectors for now, which means a mega vacuum leak. Going to pick up some new insulators tomorrow.

The electrical connectors slid on just fine with the new compared to the old, leading me to believe these are indeed OEM overstock dumps from China.

 

[Torn Mind]

I tightened down the air hose clamp. That least stabilized the long term fuel trim at 29%. I hammer the accelerator, it stays pretty much stable at 29% (without load, haven't driven out).

I reinstalled the injectors with new Carquest insulators, removed the dirt with a combo of brake cleaner and air, and that didn't fix the problem.

Startup today is much better than before the injector swap.

Air intake hose is probably at the end of its life, I see cracking on the hose. Maybe disturbing that is the cause of the current overload of unmetered air at idle.
Crankcase ventilation hose has harden to the point you need a lot of muscle to shove it onto its engine port. I'll be replacing that too.
Since I did remove the intake manifold, maybe the gasket can't recompress any more and I need a new one.
The reason I had to take off the intake manifold was to blow out a piece of plastic that fell down into the piston.

 

[Torn Mind]

I got around to doing the valve cover gasket. PCV hose decided to show it was not removable anymore by snapping into two pieces. The longer segment and the one still stuck on the PCV valve. I had no choice but to shove the shortened old piece into the hose so that there is some sort of connection temporarily.

Two new hoses ordered and a new air intake hose.

The one new ignition coil on plug and the old ones show considerable discrepancy in ohms. Like one pin had 30 megaohm and the old one had only 4 megaohms on the same pin. Installed the one new coil and three old coils....I only started the car up one and briefly because of the RTV for the valve cover gasket, but it appeared to "catch" more promptly even though it sat for four-five hours cold.