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91 Seville Running Horrible...

2327 Views 21 Replies 8 Participants Last post by  Unforgiven33
91 Seville with 4.9

Lately it has been getting poor gas mileage and the exhaust smelt rich and the smell was coming into the car. So had it diagnosed and changed out the front O2 Sensor, ECT Sensor, Thermostat, Spark Plugs and Distributor Cap. Still ran rich and got poor gas mileage. Now it has begun to run extremely poorly. It barely gets to 20 mph and it doesnt even have the power to get up a hill and it gets about 4 miles per gallon. So it's been taken to a few shops to try to figure it out and none of them know.

Then today it was taken to another shop and when they went to pull it into the shop, it wouldnt start. Turned out both the injector fuses had blown. So now its home and no shop in the area can tell me whats wrong with it. Since the injector fuses blew, I am starting to suspect them. No check engine lights. It did backfire once, so this thing must be running SUPPPPER rich.

Basically, anyone have any ideas? I am mechanically inclined. Next things on my list to do are to test fuel pressure, then pull the rails off and see if any of the injectors are leaking by when the fuel system is primed, and then to do a spray pattern test on them. Am I headed in the right direction?

Also, with regards to the distributor, I did trace all spark plug wires to the right spot in the right firing order. My question is that one the distributor cap, right side there is a 3 wire plug that plugs up into the cap and then a little white plug with a single red wire going into it that plugs next to the 3 wire plug, but there is then a spot open next to the white plug that it looks like a wire should go into, but i can't find any stray wires that go there. Is that spot supposed to be open next to the white plug or am I just not finding the wire?
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I did check to FPR by pulling the tube off while idling. No leakage. How are you checking the converter? I'm assuming you mean catalytic converter. And yes I understand how to check injectors.
havent done it yet. its got to wait til this weekend.
basically to test injectors. first hook fuel pressure gauge to port, turn key to ON and look at fuel pressure see if it drops off. turn key off, pull rail off with injectors still attached, turn key to ON. see if any gas is dripping out end of injectors. then stick each injector into a catch ( prolly going to use old jars), crank vehicle to see what the spray patterns look like. repeat for other side. when complete test resistance of each injector.
So got to work on the car today...

Due to crappy running I just went ahead and did full investigation on injectors. Got the rails all pulled out with the injectors still attached.

Fuel Pressure Gauge 45-46 psi and no leak by on any of the injectors. That's a plus, so we go ahead and crank the engine and watch them all. All of the injectors spray well, EXCEPT number 1 isn't spraying at all. I swap the injector from 1 to 3 and sure enough now 3 isnt spraying and 1 is. So bingo found a bad injector, so went ahead and did resistance on them all.

Front Bank
#1 - 1.0 Ohms, #3 - 2.1 Ohms, #5 - 2.0 Ohms, #7 - 7.2 Ohms

Back Bank
#2 - 12.4 Ohms, #4 - 9.8 Ohms, #6 - 12.1 Ohms, #8 - 12.2 Ohms

So basically thinking replace the front 4? What's everyone else think?
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Ya we can do 4 right now. So we'll see what that does. 5 would be pushing it on money.
Awesome info, Ill look into it. Can we get a link with an example of these lincoln town car injectors? What years? And do the wire plugs match up? Are the O Ring sizes the same? Are these a direct drop in? Basically what years would be acceptable?


Im thinking of actually getting this set of 8, after looking into that.
So just to update everyone, this problem was solved when i put the new injectors in. Runs like a champ now.

Some of the old injectors are still good, are they worth anything maybe on this forum?
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