Fuel Injectors and a audience inspired article from Scotty Kilmer's videos

Scotty Kilmer said he has a tool to see fuel trim per fuel injector. That's incredible and I think my ECU has maxed out adjustment if they still can't run even. Or the ECU is just not sensitive enough to get the fuel injector's timing any closer to being right.

I'm on my 3rd change of fuel injectors. This only covers a fraction of the times I had to pull the system a part because fuel leaks kept developing above the fuel injectors. With how my fuel injectors sit on my engine this gives an amazing opportunity for them to sit in fuel. I don't think they're designed to do that because they failed right and left until I got better at setting them up without leaks. Part of the posts that my fuel rail secure to are plastic and damaged so I think they were the cause of most of my frustration. It's easy to get the fuel rail to tight with this setup on my 1999 Chevy Prizm - same as a Toyota Corolla.

I developed an interesting problem towards, hopefully the end, of this project that has had me under my hood for hours at a time repeatedly for days and going into weeks.

At this point, I can do the job of changing them out or a certain faulty one out in 10-30 minutes. The 30 part was added just in case of pride, but I've really gotten much faster.

When the remanufacturer wanted me to switch fuel injector 1 and 2 I found myself to be very upset. Sure, I had misfires at every startup on cylinder no. 1 and sometimes I had a P0300 as well, but this was less of a misfire to do no flow, and more likely just incorrect flow.

When I switched 1 and 2 the problem would have disappeared without my laser thermometer.

Let me explain.

Cylinders 2 and 3 fire one after another just like 1 and 4 fire one after the other. Basically, switching two injectors got rid of a misfire as each cylinder firing order set has a lean and rich injector. The O2 sensor sees the pulse on exhaust of each group of time of cylinders next to each other in firing order and everything looks on target. Virtually no fuel trim, except at idle, but I'm sure that's a separate issue.

I believed that my original set of fuel injectors were actually much more efficient because the leaking fuel injector actually caused the rest of the engine to run lean.

When they sent me a set of fuel injectors that ran perfectly even all the laser temps were the same per cylinder and fuel mileage was down from 43 to 35....or way worse if you include that over some days all but one failed on the first set, but that's a bigger more frustrating story....

So, with how long winded I am, I only could ask Scotty Kilmer one tiny bit of all this on the live event, but what I'm going to do before I install yet a 3rd set of injectors is widen the spark plug gap on the two cylinders that are getting more fuel.

You see, I learned from my ACE studying today that the spark line can indicate a problem in a cylinder. The shorter the spark line, the shorter the secondary resistance should be, however, when spark is normal, it can also be a way to detect a greater fuel to air mixtures.

More fuel equals less resistance to spark. So, I'm thinking of checking if I can change my richer cylinders 3 and 4 to .046 spark plug gap instead of .044. This would raise resistance, get a longer burning of the richer fuel, and I'd LOVE to see the car's miles per gallon results on that!

All I could fit in to ask Scotty Kilmer on the live event today on YouTube was if I should keep plugging on with my current ones, I mean, I have better MPG because the O2 is seeing stoichemetric...yet it's due to a bit of a trick ;) lol. He guessed right away what I didn't have space to say that they were remanufactured and that they'll never be perfect unless I want to buy new ones...

To check out my question from this mornings live event check here: Scotty Kilmer Live Event He does this about weekly, except that his older son had a wedding so this was the first event in a few weeks.

....this is very tempting as my system is pretty stable and I have another miles per gallon experiment to run. :) If you want to check out the conversation that lead to the making of this article go to Scotty Kilmer's video on Gasoline and Your Car

12/21 update:
I've been running the 3rd set of warrantied injectors for about a week now. I was able to put my spark plug gap back to stock 0.044 inches. The trick with increasing the spark plug gap where I had hotter cylinders due to more fuel did help. I almost got the temperatures even. The engine wasn't actually running even of course, but it was a lot better. So that's a trick that can help you get through a leaking injector...though in my case that fuel injector was less leaking and more just over spraying...I think ;).

10/11/2015
A year later, and now I'm making videos. See some knowledge I talk about here presented in video format!

by AutoBravado

Decarbonziing Your Engine with Water with Ericthecarguy

I was like a child again after I did this to my 1999 Chevy Prizm with all the jumping up and down I did as I told my neighbor, and then my wife, and then the internet. I had just taken care of my fuel injectors - at least one was very leaky, but that cylinder was still 5-7 degrees hotter than the other cylinders. For a bit I was thinking and growling, did I spend too little? I actually diagnosed that the fuel injector was bad, right? Of course I did!

I watched a bunch of YouTube videos about different engine clean up chemicals while I considered removing my engine's cylinder head. I read a lot of MSDS on those cleaners and found which ones did more cleaning by their ingredients. (Note: Ericthecarguy's review on Gumout Regane? Had more PEA or what actually does the cleaning, about 2-3 times as much as The Scotty Kilmer review on Gumout Multi-System fuel cleaner...though that also protects you from Ethanol. It turns out that some cleaners have quite approximate values for the cleaner with a range of percentage.)

I digress. I tried a spray water bottle. Knowing how I fried my MAF not waiting to run it for long enough after cleaning it with MAF cleaner, I didn't want to spray the water in pre-maf.

I also didn't want a CEL over my MAF not being involved. So I finally opted to use a tube that takes blow by gases to my intake right before the throttle. (For more about MAF go to Schrodingers Box MAF diagnosis reaction blog)

For 10-15 minutes I sprayed water in there (engine was already warmed up to a normal operating temperature), when the engine started to struggle a little, I kept the RPM up a bit until it cleared.

When I was done, the temperature on all the cylinders were the same! No more super carbon on one from the leaky injector!

Sure it wasn't a dyno, but I used my Torque App - which calculates everything accurately if you have give it the right values (weight of the car plus me for example). I went from 109 to 114 wheel horse power!

The engine was so SMOOTH. I checked my oil after this, it was due, for my car at 5,500 miles, but I had to change it 500 miles early because of all the crap I knocked out of the engine. So I recommend doing this before an oil change because of the filth and because there was probably some water in the oil after this.

My water bottle was filled just above the 21 oz. fill line and afterward I couldn't even tell how much water I had used because it looked like it was in about the same spot.

After the test drive, I rechecked the cylinder temperatures (or as close as I could get to them on my metal intake*) and all the cylinders were still the same temperature.

My car didn't complain about any knock that I know of, but that cylinder was hot enough that it may have been getting ignition a little early so my timing was retarded, or possibly I just stopped that cylinder from putting out extra power over the other cylinders.

Final consequence: I could hear my engine wasn't quite even in spark. I rechecked the gap on my iridium spark plugs and steamy water had changed their gap. This may not always happen, it only threw one spark plug gap off.

I've made my own video now too!



Check out my latest article about fuel injector cleaners and another YouTube channel that's really putting it to the test! Does Techron Concentrate Plus really work? Or another upgrade entirely that really smoothed out my engine: grounding wire upgrades.

*my metal intake has air in between each tube so I didn't feel the need to take off my exhaust shield and check engine temperatures there

by AutoBravado

Beating the P0420/P0430 Catalytic Converter below efficiency

If you have trouble understanding this article, better understand the role of Upstream O2 Senors first.

Try cleaning first, but find the cause to prevent it again!

If the catalytic converter is dirty I can see how cleaning it would work. Try a gallon of lacquer thinner in a 10 to 12 gallon tank. P0420 comes with just 5% below correct efficiency threshold. If it was broken, it definitely would not work. (Melted or broken up.) Also, remember, if your catalytic converter went bad, be sure to look for any leaking fuel injectors, check timing and spark, as these problems make catalytic converters go bad. (To test fuel injectors requires some advanced equipment.)

My point about trying to clean a catalytic converter, is that it just has some carbon build up on it keeping combustion gasses from getting the catalyzing metals, then cleaning it off will work. If enough of these metals are eroded away off of the ceramic honey comb, no amount of cleaning will make it work. If the catalytic converter doesn't have to be cut out of the car, then it may be practical to unbolt it and leave it in a thick concentration of dawn detergent over night, rinse it off, reinstall it and it may work again. This is a more aggressive and more effective way, but if your car is really old, my guess is that it just needs replacing.

Back to the analysis, has it really gone bad?

On a live data scan you can see the stoichiometric up and down from lean to rich on traditional O2 sensors. Seeing that on bank 1 sensor 1 or bank 2 sensor 1 - O2 sensors that are prior to the catalytic converter you're fine. If you see that same, or nearly the same wave form on sensor 2 for bank 1 or 2, then you should have a bad catalytic converter (saying this to cover V6/V8 cars with two engine banks, just apply the information to to a 4 cylinder or inline 4, (L4) engine without the bank 2 information. The sensor 2's on bank 1 or 2 are after the catalytic converter. Bank 1 catalytic converter below efficiency is a P0420, and a P0430 is a the same problem on bank 2.

I had an exhaust leak prior to my cat (a nickname for catalytic converters). When I replaced my cat I was lucky that I did indeed need it.The new cat almost stopped the wave form on the sensors behind the cat. You see, as outside air burps into your exhaust via the venturi effect (move gases down a pipe at high speeds will pull outside air in through a hole) it'll cool the exhaust gasses, and make your catalytic converter cooler for a moment, and burn less of the unburnt combustion gasses. A human can see the difference but the car figures exhaust leaks as a bad cat.The rear O2 sensors should be pretty steady. They can stay steady rich or lean and you've beat the P0420 and/or P0430.

They can go from lean to rich at times. My car's cat lives super lean, by my O2 sensors estimation. If I'm accelerating for a while onto the freeway or the exhaust isn't warmed up yet, then that sensor will go rich. Some rear O2 sensors will see rich all of the time. That's how usual catalytic converters/rear O2 sensor relationships are.

by AutoBravado

Related content:
Catalytic Converter and Horse Power, Why More HP?

Catalytic Converter and Horse Power. Why more HP? Part 2

Back to reduced back pressure
(Click here for Catalytic Converter and Horse Power part 1)

For a while, I thought less back pressure was the key to my additional power. I think there are a couple more factor's. My 1999 Chevrolet Prizm, same as the 1999-2002 Toyota Corolla, or 8th generation Corolla, has an ECU that may just be determined to not be a polluter. A bigger Catalytic converter decreased my emissions tremendously, still 400 cell by the way, I didn't go for high flow (often only 100 to 200 cells and in many cars that guarantees P0420, catalytic efficiency is too low for emissions requirements). If the car can run richer at WOT (wide open throttle) then maybe it'll just go ahead and burn richer if it still will keep the environment clean. So, that's my second theory for why so much extra HP. Note: this car is more famous for having a too sensitive ECU for that second O2 sensor, so I would not recommend a high flow catalytic converter. If all my theories in this article are true, you may not get more power. And if you do, it'll probably only be at high RPM's and if you're like most of us with an automatic, you'll only see start to see that power above legal speed on the freeway. Reducing back pressure reduces low to mid range torque, which my engine is doing most of the time.

My 1999 Chevrolet Prizm actually has the 2000 engine upgrade the the VVT-I, and an upgraded wiring harness and ECU to match. WHP on these cars tends to be about 109 (versus factory reported 125 at the flywheel). That's what I'm getting now. Since the catalytic converter I've completed replaced the shocks and struts in the back. Since I'm not using a dyno, lost acceleration on the road will lower my HP numbers. The "real" HP that everyone wants from a dyno, may be more accurate, but it can't account for a bad suspension (or as much). In fact, I think a dyno compensates for a bad suspension.

Back to catalytic converters and a 3rd factor for the "extra" or restored HP?

My old catalytic converter didn't appear to have any function. Watching on a live scanner the front and rear O2 sensors reported nearly identical electric values. Sometimes I could spot that the rear O2 sensor would say what the first one said on a slightly delayed basis. I could easily see sunshine through the converter so it wasn't terribly clogged or melted, but I think the wholes were corroded enough to look smaller. (See my new Upstream O2 sensor article about diagnostics and understanding.)

Both the stock catalytic converter and the new one I bought reported 400 cells, and since I had a bigger one that my have accounted for the additional appearance of space.

My next exhaust upgrade will be a 4-2-1 tuned exhaust. A 4-1 will help more in the higher RPM's while a 4-2-1 will get more power in the lower to mid RPM range, which is good seeing as how most of the HP numbers reported happened when the car was between 3,000 and 4,400 RPM's. The car likes to shift too soon around 3,300 even at WOT so until about 80 MPH at WOT, you won't get the 5,500 RPM's needed to see the 109 HP.

Weapon Dragon R short ram intake had me up to 41 miles per gallon. This had me back down to 28-31, which is still better than stock. With a lot of practice on how I drove using the Torque App, I got back to 41 miles per gallon, and even when I spend time doing these HP tests, I don't manage to get lower than 41 miles per gallon most of the time. Occasionally, I get 38 miles per gallon during a performance test. That's simply incredible. Used to be that if I sped up quickly a lot less in a gas tank I'd be losing 3-6 miles per gallon, and that's over the whole life the of the gas tank. I still got 41 miles per gallon over the whole gas tank during these tests, just sometimes I got 38 during the test.

by AutoBravado

Try my other catalytic converter by Eastern article.
Try my video on YouTube. My video shows the catalytic converter in action so you can get a practical example of live sensor data.

Note: The

Catalytic Converter and Horse Power. Why more HP? Part 1

When I replaced my catalytic converter it had to be cut out. The new one has to be welded back in. Facing all that work, I didn't even consider cleaning it as seen on Ericthecarguy's channel in this video catalytic converter cleaning. I've seen a lot of Honda's on Ericthecarguy's show and one Honda on an AutoZone show easier to remove catalytic converters with flanges. Theoretically, You can just bolt the new one one. Catalytic converters last too long and exhaust rusts, so "easy" is not how it usually still turns out. How kind of Honda to help make this possible. (Forgive me if I forget that maybe Eric had to add the bolt in flange to make that true?)

Anyway. I bought my catalytic converter (often called a cat) from Auto Parts Warehouse. First and only product I've bought from them, being fans of AutoZone and O'Reilly. I got it for $98. The reason I bought it here was because when I talked to O'Reilly's or AutoZone they wouldn't look at their database without my car in it. So, all they would see is stock cats. Only Auto Parts Warehouse out of 5 stores would work with me to look at cats by their diameter of pipe. I bought an Eastern Cat made for GM cars, which were designed to resist coolant and oil better than other cats since these leaks burned up so many cats on GM cars. It was legal in all but CA and I think NY. Catalytic converters don't have to always be expensive. If you live in CA or NY this article really doesn't apply to you (be sure to check your local laws). Since I thought I had a 2.5" catback upgrade I went with a 2.5" catalytic converter. I wanted a little more power. I went from 59 to 90.1 wHP. Not a little more!

It turns that my catback upgrade of 2.25" exhaust measures 2.5" on the outside, whoops. So, that was also a lot of extra work, but I wouldn't have done it any other way as this reduced back pressure further. Since catalytic converters are the biggest bottleneck on the exhaust getting out of the tailpipe, I figured bigger was better. I had to use pipe conversions from the catalytic converter to the down stream pipe. Plus, the 2.5" OD catalytic converter needed a 2.5" pipe into it, before the pipe converter would work. The converter and the catalytic converter were both 2.5" OD, meaning it fit over 2.5" and was more like 2.75". ID means it'd fit in rather than over. If ID and OD aren't mentioned it SHOULD be actual 2.5", not the case for the catalytic converter.

The worst part of the conversion was going from the 2.5" OD pipe of the catalytic converter to the 1.75" stock down pipe. They don't make a conversion pipe do that all at once. Took 2 conversion pipes and hours of cold steel work with a pipe expander that broke on a 2" pipe to get big enough to fit over rather than under the 1.75" down pipe. (The pipes I bought were 1/8" thick which adds to 1/4" of size for how it fits, but the stock pipe's were much thicker, maybe .375" thick.)

Back to back pressure on part 2 of Catalytic Converters and Horse Power.

by AutoBravado

Discussing Tire Pressure or PSI

In my 2004 Nissan Frontier I run 40 PSI and I can't remember what they recommend, but it's definitely less. I ran 44 PSI for a few months and I noticed that I was stiff enough that I was wearing my tires faster and dropped back down to 40 and I was happy with what happened after another few months where I barely noticed wear.

When I have a big load I go up to 50 PSI. My tires are rated at 55 PSI, but this is based on the logic that a heavier load means the contact pad on the bottom of the tire was bigger. I didn't want a blow out. I followed the advice of a local grandpa who's tried everything when it comes to tire pressure changes and looking at my tires and feeling how they were cooler with more PSI when the truck had a heavy load all matched up with what he said.

On my 1999 Chevrolet Prizm they recommend, if memory serves 32 psi. I ran 40 to 44 for a long time following the same grandpa's advice (not my grandpa, just saying he's played with this for a long time). I put up with this for a few sets of tires wearing out at 1/2 what the tire manufacturer recommended. I decided to try 36 psi and my tires still wore just as fast. I went to 32 psi and finally my tires were lasting a lot longer. They only look half worn and I've driven as far wearing out the other tires. (same brand)

You see the problem on my 1999 Chevrolet Prizm is that it has no cam adjustment. So running my tires softer like the manufacturer recommends under my circumstance is preventing the inside of the tire wearing.

Recently I posted this opinion about how tire pressure effects a car's miles per gallon (edited):

Air pressure? Just do what the manufacturer recommends and you'll have better mileage and long tire life. That's putting it simple. Let's go complicated. Putting extra air in stiffens up your tires, reduces rubber movement in the tires and you'd think it's raise your mpg. What actually happens: your tire real height (after the weight flattens the bottom of your tire) goes up and your car will go "fewer miles". You see the taller your tires the farther you actually go, but your miles goes up slower from the car's perspective or on the odometer. This will appear to reduce your gas mileage. I ran the math on my mpg going up and down with this experiment. It was equal to how many apparent miles I was driving from taller and shorter tires.

Long story short apparent mpg changes from these up to an inch changes in tire radius didn't change my actual real mpg at all. It just appeared to be changing.

I used to run my tires with higher psi - and chose tires that could handle it. All I got was tires that wore faster because they were more sensitive to alignment never being perfect no matter how much you get alignments and a lower apparent mpg...the worse consequence is that over-filled tires increases stopping distance and if you accelerate quickly you have less traction. Just keep it simple and do what the manufacturer recommends unless you have custom wheels - you'll have to rethink it at that point.

Back to something new:

When I tried the putting more or less air in a car it was on a 7,000+ mile car trip. I was in a 1996 Saab 900 SE. I ran the math on how far the Saab was going according to it's odometer. I ran a ratio off of that and how tall my tires were at a "recommended" tire pressure versus stiffer pressures I was into at the time. So as I changed the tire height I knew that the actual circumference of the tire was changing. I ran the circumferential changes as a ratio against how far the car was going more or less distance against the car miles per gallon. Equal to how much better my car appeared to be doing on it's miles per gallon was the ratio of how less much less distance the car went due to the tires being shorter. Exactly equal. So I believe that, at least based on this one experiment, it's a myth on how much your tire pressure really effects mileage. I even messed the car up for one of the drive tires having more or less PSI by 6 PSI than the other and it still wouldn't effect the car's miles per gallon (of course when you include the ratio of how much farther or shorter the car is ACTUALLY travelling).

Note: When I say exactly equal I should say that the amount of change was 4-6 decimal places in or using 6-8 significant digits since the mpg was in double digits like 36 miles per gallon. That car has active readouts so I didn't have to fill up at every PSI change to get the numerical changes. I ran these experiments for about 1/2 the trip. The ratio of change kept being consistent up hill, down hill, across relatively flat terrain and over mountains.

by AutoBravado

Struts, Shocks, and the Steadiness of your Car or Truck and Wheel Bearings

Okay, so about a year ago, my car was bouncing down the road. A small flat spot had developed on my tires from an emergency braking moment and that spot kept growing. It damaged my probably already aging struts and a few months later my car was bouncing with every bump in the road. Turning on the highway slowed my car down really fast. There was so much bounce in the car, that I couldn't even coast down highway roads in neutral...I'm talking about going down hill folks.

It was bad, my car miles per gallon was of course was down to 23-27 miles per gallon. Having been double that in my best moments, I certainly tried not to think about that to prevent self-torture.

So, it was time to use the other 2 Monroe struts I'd bought 7 years ago. I had bought all 4 on a buy 3 get 1 free with rebate and it took that long for them to go bad on my front suspension, lol. Once installed the difference was positively amazing. My car got an immediate 30 miles per gallon. A long way to go back from once I came, but it was a start.

Trying to coast down hill in neutral still didn't speed up my car for my miles per gallon, but at least I could maintain speed. My wheel  bearings were still cutting into my car's miles per gallon for sure. I wanted 2 replaced and they only thought 1 needed replacing. Yes, I'll go back and get this fixed. They're an honorable shop. It's just that the Auto Technician didn't see the point without it being totally shot. They were about to close, so I didn't want to argue the point. Wheel Bearings, roughed up just a little will really hurt you. Months later it clicked. I tried greasing the old wheel bearing, but it was too late. It's like my neighbor said once they're making a little noise it's too late. (Regreasing was better on the short run, I didn't get for sure a car miles per gallon boost, but my my numbers didn't dip as much.)

Nearly 5 years later the
springs had to be replaced
too. Notice the extra coil
in the new one?

Fixing just the axle and 1 wheel bearing got me 40 car miles per gallon on a long trip (the 30 car
miles per gallon was city driving), but still I was getting like 33 or 34 car miles per gallon on the freeway before.

By the way, critical note to all. NEVER just replace an axle. They go bad because motor mounts are bad (at least check the motor mounts). $1,000 dollars later, (shop kept guaranteeing the first $400 of work for the axle which kept breaking, but they had to drop the transmission to replace the transmission mount (you can call it a motor mount, does the same thing)), the axle stopped breaking.

See Weapon R Dragon Intake Review for what I did next. :)
See what I did before: Weapon R Dragon Intake Review

2 years later I'm replacing the front and rear motor mounts, one or both of which was replaced above. The both look up as motor mounts for my engine, but the both attach to the transmission. I'm sourcing the top passenger side motor mount and that one only looks up if I use the word transmission mount. Funny right? Well, I'm replacing that and the other passenger motor mount next. You see the motor mounts are good enough, but the engine isn't as solid now with my 2 new ones as it was before at the time of this article, so it's time to finish replacing them all.

Here's part 2 embeded and as a link parts 2 and 3 (part 3 will be further edited for it's official release):

Motor Mounts Front & Back Installation Part 2 and 3 for your convenience 

by AutoBravado