Plenum off, injector cleaning next
Plenum off, injector cleaning next
I got the plenum off (for the first time) in around 5 hours, working carefully, closing off & IDing most hoses so I know how they go back. No scrapes, no cuts, no damage even to old hoses. I was expecting a really grunged up TB & plenum at 160K & no record of a cleaning, but it just has a thin brown layer. 1) Should I remove the lower runners to clean this thin deposit ? I'm worried about all the grit down there falling into the heads if I do. 2) Will new gaskets be needed between lower runners & heads ? While I'm in there, I thought I'd remove the injectors, ohm test, and take them to a shop for cleaning, or do it myself with pressurized solvent. 3) What is the best cleaner to use off the car that will be safe for the injector coil insulation ? The manual say not to apply battery voltage directly to the injectors, but how else are they going to open for cleaning. I assume a quick pulse to the injectors will be safe, but not continuous 13.8. 4) Do they receive full battery voltage in normal operation ? I could borrow an O-scope & check, but things are already apart. 5) Are new O rings & lube needed to re-install injectors ? Thanks for your help & ideas.
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Q451990
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- Car: 1990 Q45 - 118K, 2022 Toyota 4 Runner, 2004 Frontier M/T - 108K, 2012 Xterra (Mom's), 2023 Rogue (Inlaws)
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Re: Plenum off, injector cleaning next
I got the plenum off (for the first time) in around 5 hours, working carefully, closing off & IDing most hoses so I know how they go back. No scrapes, no cuts, no damage even to old hoses.
I think that alone qualifies you for ASE Certified Master Tech! I'd still replace all of those PCV and cooling hoses! Check knock sensors and harness at the same time. Once you get that plenum back on you won't want to take it off again!
1) Should I remove the lower runners to clean this thin deposit? 2) Will new gaskets be needed between lower runners & heads ?
I wouldn't. Those gaskets are expensive and you'd need to replace them. The runners can be cleaned with throttle body cleaner and a bottle brush. Just make sure to soak up as much solvent as possible. I think they're metal with a coating similar to the EGR valve gasket.
While I'm in there, I thought I'd remove the injectors, ohm test, and take them to a shop for cleaning, or do it myself with pressurized solvent.
Just be careful removing them from the rail. It's easy to crack the tips! I'd lean toward a pressurized rail flush after re-assembly. You can ohm test them while they're in the rail. Unless something is really out of spec then you need to decide if you want to replace it or just move it to the 1 or 2 spot for plenum-less removal later.
3) What is the best cleaner to use off the car that will be safe for the injector coil insulation ? The manual say not to apply battery voltage directly to the injectors, but how else are they going to open for cleaning. I assume a quick pulse to the injectors will be safe, but not continuous 13.8.
4) Do they receive full battery voltage in normal operation ? I could borrow an O-scope & check, but things are already apart.
Not sure - another reason I like using the pressurized rail flush.
5) Are new O rings & lube needed to re-install injectors ? Thanks for your help & ideas.
Yes. New gaskets are needed. Lubricate them with di-electric grease or vasoline to keep them from getting pinched! A bad lower o-ring can cause flooding and hydrolocking - upper will cause a fuel leak in the engine compartment.
Good luck!
Heath
I think that alone qualifies you for ASE Certified Master Tech! I'd still replace all of those PCV and cooling hoses! Check knock sensors and harness at the same time. Once you get that plenum back on you won't want to take it off again!
1) Should I remove the lower runners to clean this thin deposit? 2) Will new gaskets be needed between lower runners & heads ?
I wouldn't. Those gaskets are expensive and you'd need to replace them. The runners can be cleaned with throttle body cleaner and a bottle brush. Just make sure to soak up as much solvent as possible. I think they're metal with a coating similar to the EGR valve gasket.
While I'm in there, I thought I'd remove the injectors, ohm test, and take them to a shop for cleaning, or do it myself with pressurized solvent.
Just be careful removing them from the rail. It's easy to crack the tips! I'd lean toward a pressurized rail flush after re-assembly. You can ohm test them while they're in the rail. Unless something is really out of spec then you need to decide if you want to replace it or just move it to the 1 or 2 spot for plenum-less removal later.
3) What is the best cleaner to use off the car that will be safe for the injector coil insulation ? The manual say not to apply battery voltage directly to the injectors, but how else are they going to open for cleaning. I assume a quick pulse to the injectors will be safe, but not continuous 13.8.
4) Do they receive full battery voltage in normal operation ? I could borrow an O-scope & check, but things are already apart.
Not sure - another reason I like using the pressurized rail flush.
5) Are new O rings & lube needed to re-install injectors ? Thanks for your help & ideas.
Yes. New gaskets are needed. Lubricate them with di-electric grease or vasoline to keep them from getting pinched! A bad lower o-ring can cause flooding and hydrolocking - upper will cause a fuel leak in the engine compartment.
Good luck!
Heath
The injectors see 12V during normal operation, but only for a small fraction of a second at a time. Under pressure, I know other cars allow you to apply voltage for a few seconds at most. I'd feel comfortable just "tapping" leads together to open them and see their spray patterns. Haven't done it yet, but I do have a spare fuel pump and a spare fuel rail waiting to be hooked up for this.