Does anyone know a way to test the evap system for leaks? I don't have a smoke machine. I did a visual on the lines going to and from the charcoal box and didn't see much - it was kind of dirty It barely failed (.4 is max and I got a .42) so it is a small leak. So how can I find this?

 

How about some truck info;make, model, year, engine. Evap system issues can range from deteriorating hoses to solenoid seals leaking.

 

its an 89 BroRunner 22RE. I'm thinking of spraying soapy water on all the lines and then somehow (?) pressurizing the system

 

Fuel cap seal??

 

You can not fail the evap test for a bad gas cap. The gas cap has nothing to do with this test. You either have a leak from the canister to the tank or the filler neck or the sending unit is leaking. Other that tell you what could be leaking, the only way to figure it out is test it. Some people fill the tank to the very top early in the morning and crimp off all the lines and wait for the temperature to rise. The gas will expand and start leaking out of the leaky spot. Or figure out a way to pressurize the system with a bicycle pump to approx 3 psi. Any more and the gas cap will vent. DO NOT USE A COMPRESSOR! Very low pressure.

 

When the evap test is done a adapter is screwed into where the fuel cap goes and connected by hose to the evap machine. Then the line that runs from the tank to the canister is pinched closed. On the 22re it will be done under the hood. Then the tech enters the last 4 digits of the vin number and hits test. When it fails the machine will ask if any leaks are found with the pliers or fuel cap adapter. If none are found the truck is failed,if the tech finds any leaks with the pliers or a loose adapter the problem is corrected and the test is rerun. Since yours has a .42 leak then there was no leaks with the pliers or adapter so the problem must be between where the gas cap is to where the hose was pinched with the pliers on the canister. It cant be the gas cap since that was not part of this test. You could have loose clamps on the filler neck or on other hoses or the seal on the fuel pump assembly. Start checking all hoses and clamps that you can find. I smog'em all the time.

 

Thank you for the info! I will try doing those tests on Wednesday (only day I have time to) if I can't figure anything. You work at a shop in Antelope? I work at a parts store in Sacramento

Thank you, this is great info too! It should be help isolate where to look. I can actually see where the tech crimped the hose to do the test. What's a common spot these trucks develop leaks at?

 

I'm the owner. We do not do repairs. I can retest the truck for you when you fix it and can give you advice online but thats it.

 

I can't speak from personal experience, but I've heard that trucks in the rust-belt sometimes get leaks on the plumbing on the top of the tank. Road-crap sits up there and eats through everything.

If you work in Antelope, our sunny California weather should protect you. Did your truck spend a lot of time in the mountains?

If that is your problem, just looking at the top-of-tank plumbing should confirm the location of the leak. Unfortunately, so far as I know you have to drop the tank to see it, which is not an easy task.

Good luck!

 

Alright so here's the update, boys. I unplugged one of the rubber hoses off the top of the tank and plugged in a bicycle pump to it and heard air escaping from the middle of the truck, here was the leak... one of the hard lines :eek: Not sure what happened to it
Pic:




Solution? JB Weld of course!

 

I would say thats a problem. Good job finding it. kind of good job fixing it. If it doesn't pass cut it out with a die grinder and put a piece of fuel line on there with clamps.

 

cheap fix but i would prefer to do it the proper way

 

That's probably the best option and I will do that if the JB ever breaks. I took it in today and it passed with a .03 on the machine. I noticed there was a TINY little part that the JB didn't fill in before going over, but it passed fine so I'm happy.

Cheers!