jeepxj99

I have a 99 XJ Sport with 4.0 i6. Been with me since '06 with 72K miles and now has 174K. For the past several years I have periodically had a CEL come on for Small and Large Evap leaks. When it first occurred, I took it into a dealership and they replaced the EVAP cannister. The light stayed off for about 90 days, then came back on. Since then, it will come of for few days, periodically, then go off. The odd thing is that when the weather turns cold here in NC, the light doesn't come back on until the summer.

Does anyone have any advise so that I don't have to spend a load of money getting this thing tested? I paid the 400 bucks for the Evap canister replacement, which did no good. I've done extensive research into the matter, but most information online doesn't seem to have helped me so far. Today I traced the lines in the EVAP system looking for cracks in lines and connectors all the way back to the canister near the gas tank. All look great. I checked the connections (electrical and vacuum) on the purge valve which looked fine. The only rubber connection i could find that looked worn and cracked came from the evap system to intake manifold (just below the MAP sensor). I will replace that, but any other ideas? I don't want to just go replacing all the parts as that gets expensive.

ShowMe Cherokee

How does the seal look on your gas cap? Oddly, that is one of the most common causes of that problem. I have chased EVAP leaks in both my Ram and my wife's Town & Country. They are a total PITA.

Best of luck finding your leak.

djb383

Yep, we had a Evap CEL on our Pontiac Vibe (Toyota Matrix).....new gas cap shut the light off.

jeepxj99

I took a look at the gas cap and there were two splits in the O ring on it. I have ordered a factory mopar replacement cap from Chrysler which should be here tomorrow.

Does anyone know if the Leak Detection Pump filter needs to be changed (Cylinder on top of LDP)? has anyone ever changed one? The part description says they can cause CEL to show if clogged up.

ShowMe Cherokee

The LDP is generally pretty easy to change. Just an electrical connector and a couple hoses with a mounting bracket.

The pumps don't fail very often, and if the code says it is leaking rather than no signal or something, then it is either a hose or the gas cap or the canister itself (which I think you just replaced).

G

jeepxj99

After a slight delay at the dealership, a brand new Mopar gas cap is installed. Reset the CEL and now we wait to see if it comes back...