That headgasket will be a problem eventually. I see it/hear about it all the time. "Dump and go" quick fixes are more trouble than they're worth. Also, this issue may be the underlying cause affecting your fuel economy. Ive had them with next to no symptoms other than poor mpg, spikes/drops in temp, and an occasional skip or stall.
1992 YJ, 4.0 HO, 5-Speed (AX-15), 2.5" lift, 31" tires, Sony sound system, w/ pioneer sound-bar, copper-red paint, Loved it. Miss it. Sold.|1999 XJ. The "Cheep". 4.5" RC lift. 33" BFG MT. Train Horns. 2wd to 4x4 build. DD. Sold.|2003 WJ. 30" Michelin AT's. Curt roof rack. Train Horns. Stock. Soon to be lifted. DD.
Thoughts? If a fuel pump is going, would you see a higher pressure at the rail? The regulator is new. Mopar. I'm getting 58psi or so at the rail. Started it up this morning. Sat idle not doing anything for about 5 min and out of no where it died. Still had electrical components. Started right back up.
The other thing I noticed is that my scanner skipped tests when I started it back up. This I've only seen after a computer reset. Takes a few and then the tests will show. But, I didn't lose electric. Bad computer?
Anyone have any insite on the scan videos, fuel pressure question and the Evap?
So, the mechanic smoke tested and nothing. Scan tool shows that the Evap is showing 25% on the tool. Now, 25% of the time on? 25% open? I am not sure, I cannot find info on this, but he said from what he has seen, it should be between 0 and 11% max. So, he says the Evap is more than likely related to the issue. What we cannot find out is what triggers the PCM to tell the Evap Purge Solenoid to go on? Is there a valve at the canister that opens and tells the PCM to energize the solenoid? Could it be that the solenoid is going bad, not working as it should, so it stays on longer? Also, what effect on the gas mileage would the solenoid have? Could it be pushing air, but not gas vapor, but the PCM believes its gas vapor and doesnt adjust accordingly? Vice Versa. I've tried to read up on Evap systems, but I cannot figure this out.
From what I have been able to come up with...the Temp sensor comes into play, maybe the Cam postion sensor and the MAP sensor. I cannot throw parts at this thing, so if the weather is better tomorrow, I will see what I can test.
I know someone has mentioned the Temp sensor..Did you know there are two? One for the dash gauge and one for the PCM? Odd, isnt it?
I may have it. I checked the MAP sensor. I had read that it often goes and doesn't trip a code. I hadn't bothered with it because my live data was showing pressure changes as mentioned earlier in this thread...but, after doing some reading and seeing that it has such an impact on the system and also considering my over active purge solenoid, I sad hey why not. It's 5v key in as it should be, when started it stays at 5v. I let it idle for ten minutes, no change. It should drop in voltage down to 1.5-2v and no change at all. So I am really hoping this is the problem. It could screw up the o2 readings, the evap, pulse width and who knows what else.
So, while I had the resonator off I decided to do another tb cleaning. Why not. So, tomorrow I will try to get the part and put it in.
Cross your fingers!