I Have a Lincoln with a 302 With Throttle body injection and about 150K
miles. The motor Still feels strong So I am not sure about internal Engine
problems such as low compression or so on. The symptoms have been coming on
for some time. They started with on deceleration the car would die as it
slowed between 25 to 10 miles and hour. If the car was driven very gingerly
it seemed to be able to upshift into first gear fast enough to raise the
idle and keep the car running but if it was slowed quickly to turn a corner,
it would not upshift fast enough and the car would stall. I was thinking at
first it was a vacuum problem or a EGR problem. Then a new symptom came and
that was it would only idle if it was cold. as long as the High Idle cam was
on the highest step, the car would run. Now it will only run if you hold the
throttle up with your foot and as soon as you release the gas pedal, the car
dies immeadiatly. as if it is an electrical problem. The car will fire after
two or three cranks every time. I have taken it to one mechanic and was told
that they could not get a signal from the OBDIII system and give up just
before charging my 100.00 and telling me nothing in return. Anybody out
there have any ideas on these old systems that might be of help please?
Thanks for your time for listening
As you said, you have a CFI(Central Fuel Injection) system and I don't
believe that the throttle body has a high idle cam like a carburetor.
Most fuel injection systems use an ISC (Idle Speed Control) which is a
computer controlled valve which bypasses air around the throttle plates
for idle speed control. I would suspect that device and try cleaning its
internal passages before anything else is tried.
With 150K miles, also check for play in the timing chain as severe
stretch there could cause excessively retarded valve timing.
In 1983 Ford used a form of computer engine control they called EEC III
which had a first generation diagnostic system predating OBDII (On Board
Anthony & Denise Akers wrote:
This is a very easy system. It is OBD1 not three. The "mechanic" most likely
does not know how to access codes if it has any.
First things first, the electronics only give it fuel and ignition timing
advance, so making sure the engine mechanically sound is the first step. I
would first check to see if the cam and crank are properly timed, i.e. the
timing chain. Check fuel pressure, needs to be 40 psi. too high you can have the
same symptoms you describe. An open EGR valve can also cause the symptoms. This
engine has a cooler under the EGR valve, it was known to be a trap for carbon.
When the carbon build up gets large enough it would break up and wedge the EGR
pintle valve open. The fix for this is easy and cheap. Take off the EGR valve,
and cooler, clean out the carbon. When you reassemble it back together put a
piece of aluminum screen over the ports, the screen traps the carbon preventing
it from holding open the EGR valve.
I had an 83 Tbird with a 302 and throttle body with the exact symptoms you
are reporting. Since the drive train in the two vehicles is the same for
most purposes, I expect the fix will be the same as well.
I see that many people are pointing you to the EGR valve and it's possible
that it is contributing to the problem, but I replaced/cleaned mine about
4 time without really fixing the problem. It just got somewhat better for
a little while.
In the end, what I found was a modulator valve (could be a differnent
name) on the transmission was bad. I'm not sure now (it's been about 10
years since I owned the car) whether the problem was that it wouldn't let
the torque converter unlock at slow speeds or if it wouldn't let the trans
shift into first at slow speeds. In any event the result was the same
symptoms you describe and the fix was about $25 instead of $200+ (at the
time) to replace the EGR valve.
On Fri, 30 Apr 2004 21:34:01 -0500, Anthony & Denise Akers wrote:
Unless your bird has a C5 transmision there is no modulator valve.
The C5's converter clutch is centrifugal, no other control. So if it was not
unlocking you replace the converter. The AOD does not have a locking converter.
I dont know what fixed your car, but it was not transmission, at least what you
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.