cleaning engine bay

Discussion in 'Maintenance & Upkeep' started by reggiecab2000, Aug 5, 2012.

  1. pmf608

    pmf608 Epic Member 5+ Years 1000 Posts

    I just want to jump in here and caution anyone who uses a pressure washer to clean their engine - at least for those of us with the V8s anyway. I always assumed that as long as I kept the pressure away so that nothing was directly blasted, it wouldn't cause any problems. BUT, I rinsed my engine bay with a pressure washer on Thursday, and on Sunday I got a check engine light for a defective knock sensor. My research since then shows that apparently when you get that much water in there, it can sit below the intake manifold and corrode the knock sensors. A lot of the cases of bad knock sensors (P0332 code - only the rear knock sensor ever seems to get water damage) seem to happen a couple of days after the engine bay is washed. Sometimes it goes away, sometimes it doesn't. If my problem doesn't go away once its had a chance to dry, I'll have to replace both knock sensors and the wiring harness because I don't want to have to remove the intake again if the other one fails. The cost in that case would be about $200-$250 plus about 3 hours worth of labor... that adds up to about $500 or more total if you have a shop do it (at least in my area).

    Anyway, after all that, what I'm trying to say is just be sure to wash your engine bay carefully.
  2. reggiecab2000

    reggiecab2000 Epic Member 5+ Years 1000 Posts

    well it sounds alot like some guys should do a nice how to, or DO and DONT section on this topic LOL
    might benefit alot of people
  3. reggiecab2000

    reggiecab2000 Epic Member 5+ Years 1000 Posts

    okay so i just sprayed out my engine bay....
    i used skippys method, seems to have been good so far, started up and didnt die...
    however, ill use simple green and rags once i replace my fuel injectors to get down to the finer cleanliness...

    quick question... i know this aint the right thread but...
    ive had some misfiring problems for a few weeks, only on cold starts, and goes away once the engine is hot, but i noticed that after doing this engine wash and driving home then, to and from an autoparts store, it seems to have amplified the stumbling/misfiring. made it misfire while my engine was actually hot...
    so are fingers pointing more towards ignition caused misfiring now??? since being wet seems to have done this?
  4. Skippy

    Skippy Member 2 Years 100 Posts

    Two things. Not likely getting your engine wet would cause this. You'd have to actually break electrical connection at a fuel injector or spark plug. If you're concerned you might have done that, pull the electrical connections and smear some dielectric grease on them, and reconnect. If your misfiring is still there, you likely have a different problem (This is actually what I'm leaning toward anyway, since your engine was already misfiring...)

    When was the last time you changed plugs, and did you double check the gapping on them? Over time, the plugs' gaps will widen due to wear, takes a lot of voltage to cross that gap and a few misfires only amplify that due to fouling. I'd check plugs first, then check your fuel injectors. To determine if your injectors are firing, just hold a screwdriver against them (metal end on the injector) and the handle against your hear, you'll hear the tick tick tick from the pulsing if it's firing consistently.

    Beyond that, check your fuel pressure, and replace your fuel filter, if you've got one and haven't already done so.

  5. reggiecab2000

    reggiecab2000 Epic Member 5+ Years 1000 Posts

    yes, i did those some time back, i actually created a thread about it on here recently, i was just too lazy to pop it up real quick, but nothing ignition I know of, but i will be replacing my injectors whenever they get here :)
  6. zigger215

    zigger215 Member 2 Years 500 Posts

    Good way to test plugs and gaps, start truck, put foot on brake and gas (power brake). Apply small amount of load, if you have a plug issue, wire, plug, gap, you should here small popping and missing instead of a nice consistent groan.

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