1988 Lincoln Town Car

[VicCrownVic]

Lol, you did say needle.
I'll keep any eye open for one at the JY. By the time I find one you might already have found one yourself, but we do tend to have decent box picking around here.

[nfldfordltd]

Does your car have the digital cluster or analog? (sorry if this has been answered already, ctrl+f failed me if you already mentioned it)

I believe I read somewhere on the Internet (so it must be true) that the digital cluster uses a sending unit with a different resistance range compared to the analog. If what I read is correct, the fuel sending unit for a TC with digital cluster will use the same resistance range as 90+ panthers.

For Analog clusters on 89 and down panthers:
Low fuel = high resistance = 60-86 ohms
Full fuel = low resistance = 8-12 ohms.

For all clusters on 90+ panthers:
Empty = 15 ohms
Full = 160 ohms

If anyone is able to find a stock TC sending unit they may need to know if it is for the digital cluster or not.

Analog cluster it is. I sort of said that in the original post but not as clear as I could have been lol.
I didn't check the sender for resistance, but something's definitely wonky when it hunts around so much and has a flat spot with no resistance causing it to read over-full and stay like it until it's almost empty.

[VicCrownVic]

Does your car have the digital cluster or analog? (sorry if this has been answered already, ctrl+f failed me if you already mentioned it)

I believe I read somewhere on the Internet (so it must be true) that the digital cluster uses a sending unit with a different resistance range compared to the analog. If what I read is correct, the fuel sending unit for a TC with digital cluster will use the same resistance range as 90+ panthers.

For Analog clusters on 89 and down panthers:
Low fuel = high resistance = 60-86 ohms
Full fuel = low resistance = 8-12 ohms.

For all clusters on 90+ panthers:
Empty = 15 ohms
Full = 160 ohms

If anyone is able to find a stock TC sending unit they may need to know if it is for the digital cluster or not.

[nfldfordltd]

LTB a Fuel Gauge Sending Unit

Hey mangs, my fuel gauge is not very helpful these days.
It always used to go way up past full and stay there for a long time, probably until it was between 3/4 and 1/2 full, then drop fairly quickly after that. I was used to it as it was like it the whole time I owned the car.
Since I replaced the fuel tank back in May or June, the needle stays way up past full (vertical) until the tank is almost empty, then hunts around for a little while before settling down on empty. I can roughly guess how much petrol I have based on kilometers driven since the fill up, but the car isn't consistent enough on fuel to totally trust that.
Does anyone here have a fuel gauge sending unit they are willing to part with? I have been searching high and low for one and it seems to be made from unobtainium. Dealers are telling me it's an obsolete part. I did find one on a website but the price was a bit rich for my blood, like over $200 plus taxes and shipping.
Keep in mind, this car is an '88 with the fuel gauge sender separate from the fuel pump and is located in the front of the fuel tank. If I had my time back, I would have ordered a tank with pump/sending unit in one from a later model car and installed that instead of the two different units.
Even if you don't have one in your possession, if you find one at a JY and could be so kind as to pluck it out for me and send it, I'll pay for it and the shipping so long as it's not a ridiculous price.
Thanks in advance mangs.

[87gtVIC]

nice. That is something I seen eons ago at the yards and always forget to look for them again when I go. I am gonna write it down this time.

[nfldfordltd]

1992 Signature Series armrests

Liking the storage compartments and concealed cup holders already!

[gadget73]

it wouldn't have been drawing air, it would have been spraying fuel out around the loose hose. That would definitely make it have low pressure.

[nfldfordltd]

So I got it all up and running properly again.
Turns out the Chinese fuel pump was fell apart inside the tank. The hose was just barely onto the steel line where it goes through the pump hanger. So loose in fact, it flicked off while I was pulling the pump from the tank. It had to be drawing air as well as fuel, which acted like a split hose. The rubber boot and fuel pump itself was really loose on the bottom of the hanger as well.
I put the old pump back in for the time being until I can get a new good quality pump as the old one is still a CH low on pressure, like about 30 psi at idle, up to about 33 psi when the gas is goosed. Still runs a lot better than it did though.
Thank Christ that's over.

[nfldfordltd]

I disconnected the return line and it was dry as a bone. I tried both pumping gas into a can and plugging it to observe higher pressure, the pressure still never rose above 20 psi.
I'm going to get 2 more 5 gallon cans and drain the tank using the continuous pumping method you described and drop the tank to have a look at the pump. May even try my original pump to see if it helps.
So much for this weekend...lol

[gadget73]

ok then, thats definitely tells the story.

The only way I could think of to test if its the FPR is to disconnect the return line and plug it to see if the pressure comes up, or feed the return into a container of some sort. If its dumping lots of gas out the return line, then the FPR is not working properly. If you're not getting fuel return, then it has to be pump side.

If it was a restriction in the line, you can power the fuel pump without the engine running and the pressure will slowly come up. In the self-test connector, ground the fuel pump relay trigger wire and turn on the key. The pump will run steady, and with no demand from the engine the pressure will come up if its a clog in the line. Personally, I find this highly unlikely.



I'm going with fuel pump since it doesn't retain pressure. Could be the line in the tank is split too, but it seems to me there is something wrong back in the fire juice can.

[nfldfordltd]

Fuel pressure test is done (three times for good measure).
I have 17 lbs at idle and with throttle. No retention of pressure after it's shut down.
Flow seems good, I'm getting about 250 mL (or 1 cup) of fuel at the front end of the inline filter when I run the pump for 10 seconds. Pressure looks like an average water tap running (corroborates the 17 psi at the rail)
There is no external leakage anywhere from the tank to the injectors.
Only places left to look are:
1. Fuel pump (I don't trust made in China crap)
2. Fuel Pressure Regulator (I did unhook and plug the vacuum line to it, never made any difference)
3. Fuel line between the filter and rails (internal obstruction)
Please school me if I'm missing something...

[nfldfordltd]

I read up on the balance test after and learned a lot about what it does. I understand it a lot better now than I did.
My dad sent me a spare TFI that I should have today so I'll try changing that to see if it causes any change in the way it runs. Honestly, it feels a lot like the plug wires are wrong, but they really shouldn't be as they weren't removed since a year ago. There is no difference in symptoms with respect to the temperature of the engine. It's the same broad flat spot regardless if it's hot or cold. Bad PIP should produce a code, no?
In any event, it's a case of hurry up and wait for stuff to arrive so I can diagnose the problem. I have lots of spare parts and tools here, just not what I need as per usual...haha
Oh well, Life in the North.

[gadget73]

it doesn't really know which isn't working. If both injector and spark are working, the cylinder works. If either are not working, then it doesn't work. You're sort of on your own to figure out which it is, or if its a low/no compression thing.


4.1v seems right. It runs off a 5v reference voltage, and the sensors typically do not hit the full 5v.


Just another thought, but wonky spark stuff can do this too. Bad TFI or pickup can have some really non-specific running symptoms though generally they tend to get worse as the engine warms up.

[nfldfordltd]

I'll try that cylinder balance test tomorrow before I do anything else with it. I assume that will tell if injectors are working on certain cylinders as opposed to spark?
Main thing I see is the need to get a good fuel pressure test done. Hopefully that tester kit arrives tomorrow (right now I think the airline has it lost...ugh) so I'll be able to see if the pig is getting enough gas or not.
4.1V of juice at the TPS @ WOT is enough to run it properly you think?
Hope it doesn't rain tomorrow

[gadget73]

if you had unplugged the MAP, that'll be why it has 22 as a stored code.
Same with the TPS. This could have been an issue any time between the last time the codes were cleared (or the battery was dead) and today.
33 probably means there is a vacuum problem on the EGR valve. If it doesn't open, it won't cause you running problems. It might fail emissions inspection but thats a different issue.
29 would be why your cruise doesn't work, if it doesn't work. Also not real important. The car does not need this to idle clean.

44/94, smog crap, ignore this
33, see above
74, also BFD


THe blinky thing at the beginning I wouldn't worry about. If it was running on 4, you'd know it.
None of those codes would make me suspect anything in particular. Might be worth trying a cylinder balance test. Once the engine running codes are pulled, goose the throttle. The idle should pick up and you'll hear it get a little rough. It will shut cylinders down one at a time to see which one is working and blink the cylinder number(s) that aren't doing what they should be.