Can an intake manifold leak without responding to the usual tests? I used starting fluid sprayed around and on all the usual areas and the engine bay; cannot make it surge. Normally I'd just say 'not leaking' and move on. Am I overlooking something?

Lovely car, with only 36k miles. The former owner put only about 1000 miles in the last 3 years (at least). It barely idles and is hard to start. I'm wondering about the issues related to non-use.

Car has a myriad of codes and I am sorting through them. I've already identified very plugged cats and have rodded out the catalysts--I will replace cats once everything works well again (no emissions testing in HI). The coils and plugs have been replaced; I will replace fuel filter and will test fuel pressure once my tester arrives.
Crank sensor: replaced.

For the sake of entertainment, here are the codes for yesterday Random misfire, and plugs #1,3,5, and 6. P1313 and p1316--Catalyst damage, and excess emissions (expected due to removal of catalyst. Random other codes, probably due to the need for a new battery.

Wry, teasing, or even sarcastic comments are always welcome
marc

 

Why do you think you have a leak?

The car probably cannot reliably diagnose anything much other than the things you know given the situation re cats etc. The back pressure is wrong, etc.

You may be able to read fuel pressure via OBD (can on most cars).

 

Ah, I forgot to mention my good friend and good mechanic seemed fairly certain. However, I had not yet tested it. Perhaps I was looking beyond the mark.
At any rate, I have much to do to narrow these issues down. Perhaps I can discover something of use to others in my shoes!

 

I don't think you will experience a surge from a smaller size intake leak. The better method is to monitor STFT on both banks while spraying around the intake and PCV plumbing. You'll see a big negative spike when you close up the leak. Or alternately, get the engine smoke tested for intake leaks.

What makes you think intake leak? What are your fuel trims?

 

Hard to really tell without an OBDII tester which may well tell you fuel pressure info. Although in your case I think the air/fuel mixture is more what needs to be looked at. Usually you would get a "lean" reading with a leak (it could also come from a vacuum leak) and not just a misfire. Replace the bad battery ASAP because you will not get her to run well without good, steady voltage. These cars are very sensitive to battery issues. Check for cracking rubber on a car that has sat for a long time along with bad wires and connection/grounds. Moving parts around manually will usually make a leak worse and you may even hear the leak with a stethoscope. From what I have read on the forum a lot of misfire conditions can be related to the MAF sensor being dirty. Sitting for a long period can certainly gum up things unless the fuel was treated. Also it is unusual for the cats to go bad unless there was a major contributing factor. Especially with so few miles. I do not believe that gutting the cats would cause it to have the kind of problems you describe but they would throw codes for sure. Your injectors may need cleaned. If you can you may need to obtain the SDD program so you can really see what is going on. Good luck.

 

Update: Head gasket leak.
I finally did a full compression test on the engine. Apparently there is a combustion leak into the coolant on the #2 cylinder. No leak into oil.

All cylinders show 185 lbs holding pressure after 30+ seconds. That's at WOT, holding down the gas pedal during cranking. All, that is, except Cylinder #2. It shows a consistent 90 lbs.

I've been hoping for any other solution than a head gasket replacement, but no luck.

I'll be spending more hours researching this, but it looks inevitable. I've done many head gasket jobs, but this may be too much even for me.

Sad, especially for such a low-mile car.
marc

 

That's bad luck and only 38k!

Any idea how that happened?

It can be done but for $$$$$$$

BTW how did you rod out the cats?

 

The cats were easy to rod out, with a drill and an old 12" long drill bit. Much easier than I had expected.

As for the damage, this is my take: Owner spends $75k on his new Jag in 2004.
Drives it like a grandpa, babies it, and never drives more than a few miles at a time. The cats never heat up sufficiently to burn off the emissions, and eventually become clogged. Owner's family member starts driving it and doesn't notice that it starts heating up. They hire a neighbor kid to fix it. He doesn't have a clue. Eventually the backup becomes like a giant banana in the tailpipe.

That's when I buy it, and now it's becoming a millstone about my neck...

 

If the car has suffered a serious overheating episode that is what has caused the HGF. It seems to be a weakness with all all-aluminium engines.

Why did you buy the car ? I would have thought it normal to carry out a road test at which point all the faults would surely have displayed themselves. The blocked catalysts are a puzzle, as these are usually arranged to "light-up" within a couple of miles. It does sound as though the person who sold you that car was economical with the truth. Likely no lies, but maybe you were bedazzled with that low mileage and didn't ask enough questions, or maybe the price was "right".

A HGF is a big deal, but not toooo big; why not do the repair ?

PS: hope I haven't upset you, if I have, I apologise. Most of us have bought a "bad buy" at some time.

 

I suspected the head gasket, but with the very plugged cats, it couldn't be driven for more than a half block. I went into it with eyes wide open, as it only cost me $1800. I enjoy going to auto auctions and making silk purses out of sow's ears too .

Normally I would just do some homework and do the head gasket, but reality intervened. I developed a sudden hernia within days of buying the car, and the surgery means I can't do much of anything for many months ahead.

Time to take up needlepoint?