the only place smoke came out was the air cleaner box.


Then it is not testing for much, other than for holes that are bigger than your throttle body. There is no way that thing pressurized the intake enough to check for vaccuum leaks. I guess it could check for passive leaks and really badly cracked hoses or unhooked hoses, but definately not going to tell you if the IMG is cracked.

OK, I searched a bit on these machines. a) You should have blocked off the throttle body or air filter. b) It may not be a very high pressure. 1-2psi max. Again, I am not sure that is enough. 3) These things seem like your average shop scam. One article talked about using the smoke machine on every vehicle and then trying to upsell the customer on what they find. Is it mechanically correct? Yes. Is it diagnostically correct? Debatable. Is it fishing for business? Yes? Ok, I'm off my soap box on that one.

I would get out the carb cleaner or propane on this one. I think Rubo's suggestions are good, but remember, we got a lot of history with bad IMGs on Isuzus. There are better ways to diagnose the problem than that smoke machine.

Good Luck,
Michael

Currently searching but does any one happen to have a like to how to test for a leak with propane or starter fluid? I just feel like I'll blow myself up if I try to just figure it out.

I just feel like I'll blow myself up if I try to just figure it out.

Actually, it is the other way around. If you DON'T figure it out, you blow up. But, if you do figure it out, you will not. <img src="/forums/images/graemlins/smile.gif" alt="" />

Using carb cleaner or starting fluid, spray around the mating surfaces where the IMG is, with the vehicle running. If the idle changes, you have found the leak. Same procedure with propane. Using a propane torch, unlit, wave it around the same area. You could attach a hose to the end of the torch if you wanted something a bit more "directable" when trying to reach a specific area.

I bet they don't teach ya that in school, eh? <img src="/forums/images/graemlins/smile.gif" alt="" />

Good Luck,
Michael

They probably think it is to dangerous for a bunch of kids to be spraying flammable liquids and gases so close to the ignition. But they did tell us that propane is better to use because manufactures are starting to make less/non flammable carb cleaners and such, but I guess starter fluid is good to cuz it's supposed to burn.

Thanks

Ok this is odd and has me confused. I just tried checking the IMG with propane, had a new tank of propane and the nozzle with a hose on the end and ran it around the gasket, unlit, with the engine running but the idle never changed. So to see what would happen if there was a leak I unplugged that vacuum line the shift actuators, felt it had vacuum and put the end of the propane tank nozzle over the hole and the idle didn't changed. So with the propane on a known vacuum leak the idle still didn't change, the idle only changed for a second when I unplugged the vacuum line but went right back to normal. So I don't know but propane had no effect on my idle.

did you open the propane valve?

yes............

Just tried some starter fluid too. Sprayed it around the IMG and the idle didn't change, but you can't quite spray there inner sides of the IMG in a valley so if there is a leak that's were it must be. To see what starter fluid would do I sprayed it down that same vacuum line I mentioned last and that did change the idle.