I've always been pretty sceptical of just stickin the nozzle under the hood and blastin everything, but it's really dirty under there. I read recently that with TPI motors you don't really have to worry about getting stuff wet (other than the air filter). Is this true? Should I cover anything up first? Thanks.

 

well you should always cover the alternator and battery, and try and get the coil and distrib. covered as best you can..then spray away...ive done it a couple of times and (knock on wood) nothing has happened...

im sure youll get some more in depth responses here..im awaiting them too

iroc2nv

 

Like he said, cover the distributor, alternator and battery. I also covered my intake since I had 'windows' cut in the airbox. Other than that, I blasted away and it looks sooo nice. Finish off with some of that silicone stuff for a really nice look.

 

Don't get the TPS wet or you'll be sorry.

 

i work with electronics all day long and I do a couple of things that people say you shouldnt do. I wash keyboards in a dishwasher (with no detergent) and let it air dry for a long while. When I wash under the hood I just cover up stuff like the tb (i got a crappy tbi setup and I might go to TPI soon). I disconnect the battery and move it out of the car. I spray anything that is covered with crap with engine degreaser and let it sit while I clean the battery. When I'm done cleaning the battery I check the fluid level in the battery and fill with distilled water as needed. I only added electrolite once (that was what I was taught to do). Then I go and spray everything down. YES i spray the alternator dissy and even the damn msd box. I just let it sun and air dry for a couple of hours (its +90* here in the southwestern desert, and very dry). Once I've determined that even the puddles that tend to form on the intake are dried out I hook the battery back up and move the car out of direct sun light. I've done this more than five times already with no problems. I just make sure that there is no residue left on electronic components that can conduct electricity. If your still scared that there is residue on electronic components spray those components down with an alcohol based substance that breaks down gunk and crap and make sure everything is completely dry before you hook the battery back up. I have more that 5 successful engine cleaning attempts under my belt already. BTW keyboards carry more that 7VDC current in them and have enough juice in em to kill a person with a poor heart. I've fixed laptop keyboards that have had beer, mixed drinks. coke, milk and other crap spilled on them like this. Save people money on keyboards that normally run between 100-200 dollars. Just my 2 cents though.

 

I just want to go on recored that disconnecting the battery to wash the engine is pretty extreme I've been powerwashing engines for years and nevr once worried about it, nor heard any horror stories from it either. But whatever floats your boat, lol.

As far as cleaning an engine, i just cover the dizzy, relays and TPS and blast away. If you had a MAF car you would want to protect that too.

Also keep in mind that hardcore degreaser and cleaner isn't a good idea on your O2 sensor in heavy amounts, or on plug wires either. A little won't hurt, just don't go nuts on those things...

 

I'm a little confused. Why shouldn't the throttle position sensor get wet? Now you've got me wondering, is this an electrical or mechanical device? I've hosed my engine down without problems and only covered the distributor and alternator.

 

The TPS is an electro-mechanical device that isn't sealed against water intrusion. If it gets wet you can throw it in the trash.

 

I guess I was lucky and didn't get it too wet. I'll cover it in the future.

 

I just want to go on the record that if there is no electrical current running through the entire wiring harness then it wont fry anything. As for washing the battery I learned a long time ago that the crap that builds up on the battery can and will induce electricity I've seen it with a multimeter i which it actually conducts electricity just like a conductive electrical paint will. As for the tps sensor I dont see why it would be crap if it got wet and was given adequate time to dry. just my 2 cents on that one. And Ed my post isnt meant as a challenge of your knowledge I just like to do very thorough jobs.

 

Because you can't be sure it is dry, it is hollow and traps water in it. I washed my engine and sprayed the whole thing down, left the hood open during a hot South Carolina summer for over 12 hours. When I fired up the car I had a badly surging idle (500-2500 RPMs) and it set a code for TPS within 10 minutes of running. I put in a new TPS and then cracked open the old one and got about 1/4 tsp of water out of it and this was a good 2 days after the washing.
I have known several other people that did the same thing washing their engines, got the TPS wet and it fried. Is seems odd that GM didn't have those sensors sealed better since they are in the engine bay and very close to coolant lines.

 

Just an idea here, but does anyone think it's possible to seal the TPS against water with a water repellant sealer like silicone glue?

 

I didnt have that problem due to the fact that I dont have a tpi setup. I just put a bag over the crappy TBI and whoala problem solved for me! BTW I'm not one of the TBI setup diehards anymore. Once I realized it was crap I just left it be.

 

No, it has a moving arm that rides on the throttle lever and will let water in there.

 

So, this is apparently limited to TBI setups! That's why I had no problems then, I have TPI. Learning more every day.

 

I had to replace a TPS because I believed water couldn't/wouldn't get in it. It started perfect, drove home, 4 hours later it wouldn't start. Hooked up scanner and readings were all over the place so. . . I don't spray it anymore. Everything else is fair game (with just straight water) when I'm in the cleaning mood though!

I've had anti-freeze get into the CTS a couple of time too before I quit using the cheap hoses from AZ and. . . replaced 2 oxygen sensors after having TPI intake leaks because they apparently became contaminated so I"d be careful what you spray on the O2 sensor like mentioned above.

 

actually I've never had that problem. i was just stating the fact that my tps sensor was covered each time due to the fact that I just covered the entire tbi up with a plastic bag.

 

Ok, I understand. I guess I jumped to the wrong conclusion.
Thanks for clearing this up.

 

np