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Help on 1989 Lincoln Towncar

I have a 1989 Lincoln Towncar with a 5.0L V-8 EFI w/140k miles and have a problem with missing/shuddering. It started with a few months ago with a small shudder at idle that occured every 10 to 20 seconds, particularily when the engine was cold. The shuddering became more frequent and more pronounced after a while. Now the engine speed goes up and down and shudders at idle and shudders frequently during normal driving. During acceleration the shuddering is less noticeable. Also I notice the exhaust has a strong distinct smell of shoe polish? Is this indicative of anything? Another strange symptom, when I shut the hood the engine seems to rev up a few hundred rpm for a couple of seconds. Odd eh?

Here's what I've done so far:

  1. I replaced worn/corroded battery cables but that was not the problem.

  1. I replaced a alternator and that took car of the flickering headlights etc but that did not cure the problem.

  2. I replaced the fuel filter and that did help high end acceleration but not the shudder.

  1. I replaced the belt tensioner pulley because it was squeaking but did help the shudder.

  2. Dist cap and rotor are less than 2 years old and belden premium spark plug wires are about 4 years old, so i didn't mess with them.

I looked in my shop manual but unfortunately most of the info concerning driveability/emmissions is located in another manual called Engine "Diagnosis/Emmissions".

Some things I am thinking about doing are:

  1. Getting a fuel pressure gauge and checking the pressure. There is a bicycle type valve located in the fuel supply to the injector manifold. Is this where I check it? What is a typical pressure?

  1. My plugs are bosch platinum that are about 2.5 years old with maybe 25k on them. Maybe I should inspect or replace them?

  2. Connecting up the timing light and possibly looking for intermittent spark on each plug wire.

  1. Take it to the dealer and get soaked for major bucks.

Any thoughts or suggestions would be much appreciated.

Thanks, Bob

Reply to
Robert L. Wells
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.... I would start by getting the codes stored in the ECM

Reply to
Spark

Robert, The first thing to do when troubleshooting a computer-controlled, fuel-injected engine is to run self diagnostics and check for stored codes. The only tool that you need for an '89 is a paper clip. Here is a good link which will explain how:

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Reply to
IK

Sure does sound like them though. I would be looking at the ignition system first, plugs wires, base timing.

Reply to
Thomas Moats

Agreed, my guess is plug or wire.........how many miles on them (not years)?

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Reply to
Scott

Thanks for your replies Scott and Thomas. Plugs about 25K and wires are actually Bosch premium set with about 40K on them.

I got a Equus Innova 3145 and did the Key On Engine Off test and got a code

34 (continous memory code) which is insufficient EGR flow / EVP voltage high / PFE sensor voltage high or out of spec. I then did the Key On Engine Running test and got no error codes. I then popped the gas 1/4 of the way down to initiate the Cylinder Balance Test but received a code 77 which is "Operator error during Dynamic Response Test / Wide Open Throttle not sensed". I redid the test again with same result and then tried again giving the gas a quick shot to the floor. Still error 77. I don't know if my 89 Town Car has Sequential Electronic Fuel Injection so if it doesn't this may be why it does not go into this test (I'll research that). Any suggestions?

Thanks, Bob

Reply to
Robert L. Wells

Thanks for your inputs Spark and IK.

I got a Equus Innova 3145 and did the Key On Engine Off test and got a code

34 (continous memory code) which is insufficient EGR flow / EVP voltage high / PFE sensor voltage high or out of spec. I then did the Key On Engine Running test and got no error codes. I then popped the gas 1/4 of the way down to initiate the Cylinder Balance Test but received a code 77 which is "Operator error during Dynamic Response Test / Wide Open Throttle not sensed". I redid the test again with same result and then tried again giving the gas a quick shot to the floor. Still error 77. I don't know if my 89 Town Car has Sequential Electronic Fuel Injection so if it doesn't this may be why it does not go into this test (I'll research that). I am going to drive it around some more and check for more continous memory codes(I think they get wiped out when i disconnected the battery to replace alternator. Right?) Any suggestions?

Thanks, Bob

acceleration

Reply to
Robert L. Wells

Yes you are supposed to floor it for the TPS and knock, ect. The plugs are due for sure. You better start there. The EGR sensor is a common problem, do you have a book to diagnose it? If its the one I thinking of, black sensor on top of the egr with 3 little screws in it (i think), I remember a fix for those was to remove the sensor and grind about an 1/8 of an inch off the metal tip and reinstall. Or you can space it up with some small washers to test it first...If that does the trick, then grind it or replace it. The sensor was VERY close to being out of range when new. The EGR code will cause a rough idle and don't ask me why. Its a mystery to me and the guys I worked with. Even if the egr is closed all the way still will. It just does. Anyway, put plugs in it, check out that EGR sensor and go from there. Always do a key on engine off test first, fix those problems then move to the KOER test. You really should get a book for it if you dont have one. Hell try pep-boys, $15 your in. Ford ECM diagnosis is by the book baby ! If your not broke a set of wires wont hurt either, otherwise I understand.

suggestions?

Reply to
Scott

Yes it is SEFE, you must wait till all codes have displayed, remember the codes will be displayed twice, then WOT. You will be able to run the test three times. Each time you run the test, the processor will "look harder" at each cylinder. Even though it does this is no guarantee it will pick a miss. The cylinder generally has to be pretty much dead.

Reply to
Thomas Moats

Thanks for the help Scott, I took a ten mile jaunt this morning and then ran the KOEO test and it gave me a code 31. This coupled with the code 34 I read on it last night seems to point to the EGR or the EVP. When you talk about the tip on the egr sensor is that whats called the EVP(Exhaust valve position)? I guess the EVP sort of checks the EGR valve position to make sure that its moving like its supposed to? Well, I guess I would have to actuate the egr vacuum to test the little bugger, and see if it moves. At 75 bucks for a Niehoff egr I want to be somewhat sure before i replace it. The shop manual also talks about cleaning some orifice that might become blocked so i will look further into that. I'll check out pep boys, Autozone and Checker for ECM books. Is the ford factory manual "Engine and Emmission Diagnosis" about the best? I'll get into the plugs and possibly wires although shuddering seems to be pretty pronounced when it does it and otherwise it seems to idle fairly smoothly.

Thanks again fort your help,

Bob

Reply to
Robert L. Wells

The miss you discribe is most likely not the evp/egr although it should be fixed. It really sounds like a plug and/or wire. Yes on the Ford book, but expensive. You are correct about the evp/egr. EVP is the valve position and that is what the sensor does, tells the ECM if the valve is open/closed and how much. After you do the PLUGS/WIRES try the spacer trick on the EVP I told you about. If that seems to fix it (get no EVP codes) then you can grind about an 1/8" off the tip of the sensor. GL

Reply to
Scott

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