Fiddle around with cars long enough and you’ll realize two things: first, anything beyond the simplest repairs will probably require some kind of specialized tool, and second, those tools can be prohibitively expensive. That doesn’t mean you’re out of luck, though, especially if you’ve got scrap galore and a DIY spirit, as this junk bin fuel injector test stand ably demonstrates.
[Desert Rat Racer]’s test rig is designed to support four injectors at once and to test them under conditions as close as possible to what they’ll experience when installed. To that end, [Rat] mounted a junk intake manifold to a stand made from scrap wood and metal found by the side of the road. A pickle jar serves as a reservoir for the test fluid — he wisely used mineral spirits as a safer substitute for gasoline — and a scrap electric fuel pump pressurizes a junk fuel rail, which distributes fuel to the injectors under test.
For testing, the injectors are wired up to an electric injector tester, which is one of the few off-the-shelf components in the build. The fuel pump and injectors are powered by the 12 volt rail of a scrapped PC power supply. Just being able to watch the spray pattern is often enough to find a faulty injector, but in case a more quantitative test is indicated, each injector is positioned over a cheap glass cylinder to catch the test fluid, and scraps of a tape measure are used to measure the depth of the collected fluid. No fancy — and expensive — graduated cylinders required.
While we truly respect the hackiness of [Desert Rat Racer]’s build, the concept of avoiding buying tactical tools is foreign to us. We understand the logic of not dropping a ton on a single-use tool, but where’s the fancy blow-molded plastic case?
I’ve built something very similar – TBH the injector driver can be a good old 555 in a variable pulsewidth configuration and a decent FET that can deal with the inductive kick, although Infineon do some nice devices designed for this (BTS142D family) that do all the clamping etc. for you.
Doesn’t work too well for peak and hold injectors but yeah, something as simple as a 555 is great for a lash up injector tester, that was my go to part for all sorts of automotive test rigs, injector testers, ignition coil testers, all sorts of actuators, flaps and valves…
Get a bit fancier when I started designing stuff for sale (I discovered a way to get my employer to buy me a PIC C compiler and PCB CAD software) but it really didn’t need to be much more complex.
Could always help your 555 trigger an LM1949 or similar…
For sure, but back when, the majority of injectors weren’t P&H types so although I did experiment with the LM1949 (and I was quite active on the DIY-EFI and EFI332 mailing list(s?)) I didn’t find it necessary for the fairly basic stuff we were selling.
Yes you can build your own tester with a 555 and a few other components.
https://hackaday.com/blog/?s=fuel+injector+tester
Add that to this build and it’s all DIY. :)
Thanks for sharing the video. I was interested in making one of those 555 controllers, but I was in a time crunch and also felt like It might exceed the cost of buying the $20 prebuilt. I do have plans to upgrade the controller though and will consider building one.
of course, but life as a whole is silly…
Get an ICE car and you don’t have to worry about range/charger anxiety. I have a 10 year old BMW Mini and it’s the most reliable car I’ve owned recently, I’ve driven it almost every weekend for the past 5 years and the range is still 100% of its original value.
If you enjoy only being able to drive 140 miles on a full charge before having to stop and recharge for >7 hours or more instead of over 350 before a 5 minute refuel then that’s OK but understand you’re paying more for the privilege.
People hanging onto their EVs with battery degradation are just silly.
I’d love to be in a position to be able to afford a new car. Until then though, secondhand ICE is the only realistic option.
*farts, leans over and sniffs it*
ThHhhAnnkkSsss
I do love the old trick of using a PC power supply as a 12v supply. Used to do that as kids when we are playing with car audio equipment.
The trick is to jumper the green wire in the mobo connector to any of the black ones. Voila, PSU thinks the “PC” is on and delivers power.
I’m old, my first PC PSU had a proper mains switch and didn’t need none of that fancy soft on/off stuff now get off my lawn
So much nicer than hunting down a battery.
The average passenger car age in the US is over 14 years old – most people aren’t holding on to ICE cars as a privilege, they are just what is affordable.
Also, reparability of older cars is much easier: not requiring dealer-only parts or dealer-only diagnostic scanners. It will be interesting to see what the aftermarket support for battery packs will be on old EVs.
I have learned a lot from silly hanging on to my old cars – namely reverse engineering control modules, sniffing packets/signals, and general mechanical repair things as well. 300k+ miles on my daily driver with myself doing all the maintenance including a junkyard motor swap.
That being said, if I was to buy a ‘new’ car I would probably go with a 5-year-old Bolt or similar vs an ICE car.
In general EVs should be far better for reliability, ICE engines are generally pretty easy to work on but they’re subjected to immense stresses all the time they’re running (and honestly I love me an ICE engine to tinker with) and EVs are just so much less stressed with far fewer wear components so themechanicals will last a lot longer.
But, electornics and battery failure is a killer, when one cell in a battery can break the entire thing and there are many cells in even a simple EV battery so we’re going to see lots of failures as the sheer volume of EVs on the roads ramps up.
With the increase in numbers and as the ‘fleet’ ages we will also see lots of dodgy battery repairs, ‘home mechanic’ fatalities and fires because people just don’t understand the dangers involved or take risks to save a few quid keeping their 10 year old beater EV on the road.
Interesting times ahead.
Virtually all cars less than 20 years old are designed by MBAs.
Once the loan is paid, the maintenance goes up to 105% of the typical loan payment.
Germans perfected it first, but they are ALL doing it.
Only exceptions are flat out disposable Chinese/Italian cars.
Tesla is no different.
Must suck to live in the rust belt.
While a simple 555 can work ok for most bench tests, most modern injectors are not driven by a simple 12V square wave at full power for the whole pulse. Some of them even use a 50V or greater power rail. This is particularly true with Higher pressure electronically controlled diesel systems, but is also found on other vehicles with high fuel pressure, especially direct injection. Most newer vehicles use both Intake injection and direct injection in tandem to increase combustion efficiency. These systems typically use active current regulation to avoid burning out the solenoids, essentially creating a two stage pulse, using the Higher voltage to kick open the valve very quickly, and then turning down the current for the remainder of the pulse using just enough to keep the valve open. This becomes necessary because of the extremely short cycle times of the injectors at higher engine speeds, and in some cases multiple injections per combustion cycle depending on the control strategy used by the ECM. Some of the tech in modern ICE engines is pretty amazing, and a lot of thought goes into their design.
Direct injection is pretty common in road cars built in the last 10 years, but still fairly rare in low end race cars – partially because the hardware and information to tune modified direct injection engines is still rare.
No.
Because ‘low end race car’ leagues have specific rules to prevent rich morons from just buying the win, like some lame ‘free to play’ video game.
For example:
Motor claim rules are common.
Anybody who finishes without being lapped can claim your motor for a few hundred $.
Typically you just counterclaim, swap motors and get less money.
You then take his motor apart and find out how he was cheating.
Then you do that cheat too, nobody rats.
After a few years, everybody is cheating (or they’re not really trying).
Except the newb, who gets lapped, so can’t claim.
Keeps costs way down.
Nobody takes fast Teslas to race tracks.
To take a plaid Tesla down a NHRA track you need to gut the interior, install a nine second cage.
Then a parachute.
Hence the twits street race them.
Sometimes Darwin smiles.
Lots of only DI cars out there now.
You can recognize them because of their yearly ‘remove intake and media blast valves’ service procedure.
Never buy one of these POS cars.
They won’t live past warranty expiration.
As intended.
I blame the Chinese market.
German cars there are just status symbols.
Hence the Germans have made their cars better status symbols (but much much worse cars).
It all depends, you could use seafoam or water or whatever to clean it yearly and only do rhe media blasting as needed.
Also Kia desperately wants to be Mercedes or VW. And they really are winning in the drop dead from sludge just out of warranty stakes.
In one car owners forum, a man built his own fuel injector test setup (similar to the one featured here), but he used fuel injector cleaner instead of gasoline.
Stoddard solvent is what the OEMs use.
https://walbrofuelpumps.com/images/gallery/GSL391-Flow-Chart.jpg
Thanks Uncle Ug!
I say this as a huge supporter of the move to electric vehicles – you are part of the reason people don’t want to switch. No one wants to be associated with this kind of pious evangelizing.
You walked into a discussion about steak sauce: “well you know if you just became a vegan you wouldn’t even need steak sauce”. Ugh. Give it a rest.
Ok, here’s a challenge for you if you don’t see a reason for hanging onto ICE cars: Find me a used battery EV that fits these requirements for sale in the US.
$10,000 or less
100 mile original range minimum.
At least 5 years of remaining battery life, preferably more.
Volume production, not something they only made 1000 and you can’t find parts
No, I don’t typically drive 100 miles in a day, more like 40. I’m derating the max range to account for the recommendation to charge to 80% and not go below 10%, plus leaving enough room for losing 20% of range to battery wear and 10% to adverse weather.
I’ve been driving my Tundra for 18 years and it has the same range as it did new. I did have a wheel bearing to replace once a couple of years ago. But, I guess I’m just silly.
Doesn’t the difference in viscosity between mineral spirits and gasoline affect the operation of the injectors?
I believe they’re very similar in viscosity. Also talked to a tech at Aeromotive and he said they use the mineral sprits to bench test their fuels pumps, and knew of others using it for injectors. Maybe if I need accurate flow numbers the viscosity might need revisited, but just testing for failures and consistency between injectors I felt like it worked great.
It affects the flow rate, but if you just want to confirm all four are roughly equal, it’s not a big deal.
Or, perhaps some people have a different value map than you.
I bet some LEDs as syncronized strobes would produce some great pattern visibility! Especially with some control as to the timing within the pulse.