Fuel Injector Cleaning Advice

[re_guderian]

What the consensus on cleaning fuel injectors on a rig with 205K miles? On-vehicle machine? Take 'em out and have them bench cleaned? Or say, "200+ K miles, just suck it up and buy new ones..." (gulp, x8)? I'm still battling intermittent stumble/misfire and some less-than-the-usually-abysmal-MPG around town. Injectors are about the only thing I haven't looked at. Recommendations? 2000 100-series, btw...

 

[LandCruiserPhil]

I'm still battling intermittent stumble/misfire....

How were you able to rule out a coil pack?
Have you had it put on a diagnostic scope by a professional?

 

[re_guderian]

I'm still battling intermittent stumble/misfire....

How were you able to rule out a coil pack?
Have you had it put on a diagnostic scope by a professional?

I've had 3 coil packs fail and been replaced since I've had the truck (2009). In addition to those, I bought two more new ones, and rotated them through the remaining cylinders, with no improvement. Have 8 new spark plugs as of last year (I think old ones were original, so they were due). Have not had it on a scope. What information would that give? injector timings? Fuel trims? It stubbornly won't throw any codes. It does it more often in D with the foot on the brake and AC on, but will do it in N, P, and R, with and without AC on. Annoying more than anything. O2 sensors have been replaced. New fuel filter. Difficult to tell if it happens at higher RPM's while driving, as it is a quick stumble. Sometimes will happen 3-4 times in succession. Engine never dies. I've been troubleshooting this off and on for two years/25K miles... MPG's on a trip to SLC last weekend were "OK", ~15 on the way up with a tail wind, and about 12.5 on the way back with hellacious head-wind. Around town I'm down to 10-11, from around 13ish. Some of that may be the 's driving style. She really enjoys driving the 100...

 

[murf]

I suggest pulling them and having them professionally cleaned, resealed, and balanced.

I have a injector guy I can suggest that several other mudders have used and have been very happy with.

He is very reasonable

 

[re_guderian]

I suggest pulling them and having them professionally cleaned, resealed, and balanced.

I have a injector guy I can suggest that several other mudders have used and have been very happy with.

He is very reasonable

Suggest away... "happy with", "reasonable", and CSC-referred are good!

 

[Michael Hanson]

I second the prof. Cleaning, if they can't be cleaned, they should let you know. Mike

 

[LandCruiserPhil]

Have not had it on a scope. What information would that give? injector timings? Fuel trims? It stubbornly won't throw any codes. .

No codes more reason to throw in towel IMO.

I have seen guys throw lot$ of money and part$ at a problem that a trained eye can detect by understanding the huge amount of information today's car computers can provide.

Maybe throwing more money by cleaning the injector will do the trick but what is the next step if it doesnt?

 

[re_guderian]

...
Maybe throwing more money by cleaning the injector will do the trick but what is the next step if it doesnt?

keep driving it??

 

[LandCruiserPhil]

keep driving it??

Its only .10/mile

 

[murf]

I have seen guys throw lot$ of money and part$ at a problem that a trained eye can detect by understanding the huge amount of information today's car computers can provide.
Maybe throwing more money by cleaning the injector will do the trick but what is the next step if it doesnt?

Sound advise, I have seen this countless times.

 

[LongDuck]

Had similar symptoms on another car of ours recently and after the usual plugs, oil change, A/C charge check etc, it turned out to be the Coil On Plug units which were misfiring but not frequently enough to throw a code. Would stumble lightly at any engine RPM or throttle position, it got better at higher RPMs as the engine inertia would mask the stumble. An intermittent problem like this makes it hard to diagnose, but I'd focus on coils if you already did the rest.

Injectors are a possibility of course, but I'd expect a badly leaking or spraying injector to exhibit rough idle and stumbling ALL the time instead of intermittent. Why not throw a can of Seafoam in the tank on your next fillip and see if that improves things? Many injector shops use a 50/50 mix of Seafoam and gasoline to clean injectors on the bench from people I've talked to, and for $10 a can, I've spent more for less...

 

[inkpot]

What the consensus on cleaning fuel injectors on a rig with 205K miles? On-vehicle machine? Take 'em out and have them bench cleaned? Or say, "200+ K miles, just suck it up and buy new ones..." (gulp, x8)? I'm still battling intermittent stumble/misfire and some less-than-the-usually-abysmal-MPG around town. Injectors are about the only thing I haven't looked at. Recommendations? 2000 100-series, btw...

If it has never been done, the the injector cleaning may be due as a matter of baselinling, even if it does not improve the symptoms you mentioned. But it MIGHT. There is a place in south Tempe that does 1 day service on them for about $100 a set. When you walk in the door you can tell they know the injector business. We have run several sets thru them over the last year or two. 100% satisifed. You could PM Kevin (ToolsRUs) to get the name. John

 

[Wile E Coyote]

Just throwing this out there:
I've not used them, but I've read that OBDII scanners that capture real-time data are great for finding trouble that doesn't cause a DTC to be stored or triggering the CEL.
The one's that plug in and display data on your smart phone via Bluetooth seem to be equally useful but less expensive than the traditional built-in display and cabled variety.

 

[re_guderian]

Just throwing this out there:
I've not used them, but I've read that OBDII scanners that capture real-time data are great for finding trouble that doesn't cause a DTC to be stored or triggering the CEL.
The one's that plug in and display data on your smart phone via Bluetooth seem to be equally useful but less expensive than the traditional built-in display and cabled variety.

I've got one if those, and used it for a few years now. I think what Phil and Eric were referring to is more complex, an oscilloscope that can read the voltage timing and duration of individual coils and/or injectors, (or anything), and sample on a very rapid basis. Not a built in function of an ECU/OBD-II. But the Bluetooth/smartphone OBD-II thing rocks for what it DOES do...

 

[re_guderian]

No codes more reason to throw in towel IMO.

I have seen guys throw lot$ of money and part$ at a problem that a trained eye can detect by understanding the huge amount of information today's car computers can provide.

Maybe throwing more money by cleaning the injector will do the trick but what is the next step if it doesnt?

Sound advise, I have seen this countless times.

Well, thank goodness for sound advice from CSC'ers with more experience that I have!

I never took the injectors out, but right after I posted this in early July I took the rig to my local mechanic in Chandler, since the family was out of town and I didn't have a way to get down to CBT. Sure enough, he says, "we hooked it up and it showed cylinder 4 misfire right away!". New coil pack, new plug, it's all good, right? NOT. By the time I got home, it had exhibited the same behavior again.

Family back in town, life settled to a dull roar, and I finally get it in to Eric at CBT last week. They find several spark plugs loose, causing the problem. Not sure what diagnostic wizardry they used, but for the last week now, not a single, solitary stutter. Awesome!

BTW, I'll admit I was the last one to touch the plugs. All OEM, all torqued to spec. I never re-checked them later though, as I've never had that problem with plugs before. I DID use the copper anti-seize that came with them in the box, though. Should they go in dry?

Thanks for the sound advice and the good service at CBT!