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Thought I'd start a new thread to save time,.....
Currently, my 86, after warm up, has severe hesitation and sometimes back fires through the intake during a hard acceleration. After driving 5 or 6 miles, the engine progressively gets worse, then stops running and has to be pulled over and shut down for a awhile. After resting, it will start, but I'm usually very gentle with the foot feed until I get home.
Mostly using suggestions from this forum,
I've flushed the tanks, replaced the tank strainers, fuel pump, filters and pressure regulator. I have installed a large Fram filter prior to the pump (see pic).
I'm only getting 28-30 psi regulated pressure and 75 on a dead headed pump. Have not yet checked pressure during the times when it stalls out. I know regulated pressure should be 36 psi, but thought it should still run at lower speeds.
My thoughts now are that I've done all the right things, but not in the right order. I've installed a new pump (again) and will replace the intake filter element and recheck pressure prior to starting and driving it. If it stalls again, I will check pressure at that time also.
what you describe is a somewhat classic symptom of a bad CTS. the Sensor, not the Gauge, not the Temperature Sender, but the SENSOR.
let's see if Doug shows up and tells you how to bypass it or do a troubleshoot.
Just did some online research and now see what you mean regarding the CTA. Removed it and gave it the hot water sink test. The resistance started out about 1.8 k ohms and gradually reduced to about 700 ohms when the water reached 125 degrees. Checked the wiring to the ECU on terminals 13 and 17(Ground). Got a matched resistance after re-installation.
Sooooo,.. Unless you guys got any other ideas, it's back to the fuel issues.
Replaced the fuel pump and the pre-filter element. Started and idled about the same. Was able to bottom out the idle adjustment and get down to a rough 800 in PARK and a very rough 650 in DRIVE, but seems to run better. 10 mile, stop and go test drive was OK. Still a little flat on acceleration, but improved. I'm thinking I have a vacuum leak, but damned if I can find it.
The pump I removed did show signs of rust inside the inlet.
Should mention, the car only has 44k miles on it.
Gonna keep at it.
Thanks, Jim
Thought I'd start a new thread to save time,.....
Currently, [FONT="]my 86, after warm up, has severe hesitation and sometimes back fires through the intake during a hard acceleration. After driving 5 or 6 miles, the engine progressively gets worse, then stops running and has to be pulled over and shut down for a awhile. After resting, it will start, but I'm usually very gentle with the foot feed until I get home.
Replaced the fuel pump and the pre-filter element. Started and idled about the same. Was able to bottom out the idle adjustment and get down to a rough 800 in PARK and a very rough 650 in DRIVE, but seems to run better. 10 mile, stop and go test drive was OK. Still a little flat on acceleration, but improved.
So, to clarify, the severe conditions described in your first post have disappeared?
When you replaced the element in the pre-filter, how did it look? Clean? Dirty? So-so?
Did you ever re-check fuel pressure to see if you're up to the specified 36 psi? I'm not 100% sure that 30 psi would cause a problem....but it's clearly below spec.
I'm thinking I have a vacuum leak, but damned if I can find it.
Maybe, but I'm not convinced quite yet that your fuel problems are over
The pump I removed did show signs of rust inside the inlet.
The pump you had already replaced (how long ago?) showed some rust? Not good.
So, to clarify, the severe conditions described in your first post have disappeared?
After 10 miles of around town driving only. I've learned to not be optimistic.
When you replaced the element in the pre-filter, how did it look? Clean? Dirty? So-so?
Rusty fuel with a little residue. Bought several extra elements. Wished I would have installed this filter prior to replacing pump.
Did you ever re-check fuel pressure to see if you're up to the specified 36 psi? I'm not 100% sure that 30 psi would cause a problem....but it's clearly below spec.
Pressure is strange now. Gauge in mounted 6 inches prior to the fuel rail. It bounces up to 36psi when cranking or engine acceleration but settles at 30 to 32psi after starting. Starts very quickly now. Fuel line between rail and gauge is clearly a low pressure hose and seems to balloon. Gonna change it today.
Maybe, but I'm not convinced quite yet that your fuel problems are over
I'm thinking the new tank strainers are catching allot of the residual rusty stuff still in the tanks but changing from one to another makes no difference, so ?
The pump you had already replaced (how long ago?) showed some rust? Not good.
Concur. Thanks Doug.
Cheers
DD
I have yet to figure out the forum quote system.
Thanks, Jim
Replaced the the low pressure hose from gauge to fuel rail with high pressure line. Put the trans in drive and when I turned the key to start, pressure went straight to 38+psi. In Park, started and dropped to 30-32psi.
Drove it approximately 10 miles and ran OK. Still flat during acceleration and pop through the intake sometimes depending on the trans gear I'm in.
Any thoughts?
Thanks, Jim
A back-fire through the inlet manifold is a symptom of fuelling problems, especially when wanting to accelerate ad said in the article below.
This article takes you through the Bosch L-Jetronic EFI system as fitted to the Jaguar XJ6 Series 3 and also some late Series 2s. It was made under licence by Lucas in the UK as fitted to Jaguars.
I'm nearly positive you simply have dirty/rusty tanks.
A good pal of mine went thru a similar scenario with his Series III a number of year ago. Cleaned tanks as best as possible without removing them simply with a garden hose. Added pre-filters, one from each tank to the changeover valve.
First pair of filter clogged after 2-3 days; replaced. Second pair clogged after 7-10 days, replaced. Third pair, about a month. Fourth pair, several months. Fifth replacement, clear sailing for years.
He probably spent $125 on filters but, for him, it worked out OK. Dropping the tanks for proper cleaning is no small task; he was happy to avoid it
A back-fire through the inlet manifold is a symptom of fuelling problems, especially when wanting to accelerate ad said in the article below.
This article takes you through the Bosch L-Jetronic EFI system as fitted to the Jaguar XJ6 Series 3 and also some late Series 2s. It was made under licence by Lucas in the UK as fitted to Jaguars.
I'm nearly positive you simply have dirty/rusty tanks.
A good pal of mine went thru a similar scenario with his Series III a number of year ago. Cleaned tanks as best as possible without removing them simply with a garden hose. Added pre-filters, one from each tank to the changeover valve.
First pair of filter clogged after 2-3 days; replaced. Second pair clogged after 7-10 days, replaced. Third pair, about a month. Fourth pair, several months. Fifth replacement, clear sailing for years.
He probably spent $125 on filters but, for him, it worked out OK. Dropping the tanks for proper cleaning is no small task; he was happy to avoid it
Cheers
DD
I used a water based flush on my tanks and got out allot of rust. Apparently not good enough. My new tank strainers may be getting plugged if I didn't get all the rust or have developed more in the 2 years since I flushed.
Will continue to drive around town and change pre-filter elements as needed for whatever gets by the strainers. If opportunity presents, I'll flush the tanks again. Easier to do on a hoist.
Will report progress.
Thanks for all, Jim
04-09-2017, 04:17 PM
Series 3, 4.2 Fuel issues (I think) cont.
