As the title says, I've uncovered a few issues with the ol' gal as the temperatures in my area hit -45C (slightly warmer without the wind).

First, I think I've mentioned before that my right-hand petrol tank sprung a leak. I had managed to epoxy it (using a fuel-safe epoxy), but it didn't last. I finally broke down and bought a new Spectra tank. It'll be going in once the weather lightens up a bit. This also allowed me to figure out what's wrong with the drain on the left-side tank; it's a Spectra. At least I know that tank is new so I shouldn't expect more issues. So yeah, kind of a non-issue with the petrol.

Of greater concern is the fact that I go through a reservoir of brake fluid per week when it's cold. Particularly cold nights seem to take it from full to immediately empty overnight. From what I can see, the pistons on the rear calipers are leaking. Anything out of the ordinary on Jag clampers? Best to replace or can I just recondition? It's possible the booster is giving out as well. I have a significant "chuff" sound when I push the pedal. Is some air noise normal on a Jag?

The third problem is for the Lumper crowd. I have an L05 Chev 5.7L under the bonnet. This is a throttle-body injected model. I have, forever had idle issues; fluctuation, too high, too low, etc, but now when it's cold, it is the single most cold-blooded vehicle I've ever had the displeasure of dealing with. I know, I know, driving a Jag in the winter? Well, the car is far and away one of the most mild-mannered winter drivers I've ever owned. Superb traction, predictable oversteer in corners, my jungle cat has grown the feet of a lynx. So, the engine issue is more than a little frustrating. With fuel injection, I'd expect a rather smooth start, maybe a little stuttering, but what I get is crank for 3 seconds and no reaction. Cycle the key, crank for 3 seconds, 1 cylinder fires. Continue this process until about 5-6 cylinders are firing but it's still stumbling too badly to stay running. By this point, the battery has grown tired and needs charged. Only takes about 15 minutes to get enough charge back on the battery and she'll usually fire with one to two 3-second cranks. From there, it's stumble puff, cough, wheeze, bang, puff for about 3 to 5 minutes before it settles into high idle. Anyone have enough experience with the Rochester 200 TBI systems to have any ideas what I might be up against? The start issue only affects me when it's ludicrously cold, but I have a feeling the idle issues that persist may be related. I've had Rochester Quads with broken chokes that are less cold-blooded than this system. It's quite odd.

 

Well, the rear calipers began to seep aboput a year ago. First one, then the other. My loss of fluid was not as dramatic as yours. I believe that the pads were still being actuated, but, I had doubts. Brake failure is not a good thing. After decades of having critters with lousy brakes, i am touchy about the later ones that had good ones if in proper working order.

Tis a tussle to do th inboard rears. I was about to tackle it, but thought better of it. As i am a bit log in the tooth, I don't get up and down as well as I once did. And,as it is a tusslel i decided not to mess with overhauling the calipers. I found a great deal at Rockauto. No core exchange required. Well, the mobile mechnai that quoted me a decent price to do the job backed out. but, he did refer me to a shop that would do it for the same price. OK. sorta. I think they messed up the park brakes. But, the service brakes are fine. No more loss of fluid and measureably better stopping power. My rotors were decent, so not replaced.

The lumpers know TB injection. Not me.

Yes, you four barrels had acceleration pumps so cold strts minus choke is doable. FI relies on enriched in jection in one way or another.

Were it my car, I wopuld get the manual for the don or car and read up on the system. the manuals have excellent diagnostic charts. I have a factory manual for the 94 Cadillac Fleetewood btougham that donated it's power train to my 83 XJwuzza six.
A hundred bucks new, but worth it over and over. Might fid a used version for less at a specialty store or Ebay or even Amazon.

Carl

 

Its best to buy remanufactured calipers and install them. The job is quite difficult so its best to know you're going in with good calipers. Get new Ebrake shoes while you at it and a new set of rotors. You don't want to do this twice.


As for the TBI cold start issue. It seems like a vacuum leak or some unexpected air is making its way into the intake stream causing a lean condition and hard starting. Check your booster for leaks, just block off the hose and block off anyother path for air leaks while you're diagnosing the issue.


Make sure your MAP sensor and EGR valve are plumbed to the correct vacuum ports. Get the service manual for the vehicle your engine was transplanted from and compare it to what you have.


Check all the basics like ignition and look down the throttle and make sure all 4 of the TBI fuel injector pods are firing. Blip the throttle and additional fuel spray should be clearly visible. with bad tanks you may have fouled an injector.

 

Thanks all! I appreciate the advice.

I reckoned the calipers were worth buying new rather than rebuilding and honestly, the old car is worth the price. It's a daily driver, to be sure, but it's in pretty nice shape. I planned on doing the ebrake shoes and return springs while at the calipers; the rotors are actually in quite good shape.

I'm going to check for vac leaks again. I've done it before, but when we're talking about those kinds of temperatures, new problems can appear out of nowhere.

MAP and EGR are newly reinstalled as a part of trying to undo the disaster the PO had left the car in. I've checked the TBI injectors, watched under a strobe to check the spray pattern and they're as close to flawless as they can get. I have a water separator, pre-filter and high-volume fuel filter on the system to make sure no rust gets beyond the pump (if it makes it that far).

As far as the service manual, I'm still not 100% positive what the engine came out of. Every time I work on it, I notice something else a little odd (Walker main mufflers with 1 original BL rear silencer and 1 Walker, 1 BL fuel tank and 1 Spectra) so whether all numbers match on the engine is hard to say. I haven't taken the time to take the front accessories off to look at the engraving on the head.

 

Service exchange calipers normally don't include the handbrake calipers. I would suggest you rebuild these yourself, the parts are all available. The handbrake adjuster nuts and spring assembly will likely be well worn out by now. The calipers will also probably be seized on their pivot pins

SNG Barratt - The Ultimate Jaguar Parts Specialist