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newbie here once again-'95 cougar v8; at 3/4 throttle seem to get good acceleration and transmission shifting. when I floor it, it noses over, no acceleration and won't kick down. linkages seem to be hooked up correctly. could this be related to egr malfunction and/or clogged passages to intake? had a '93 linc tc that almost wouldn't accelerate at all due to egr problems. haven't checked the tps yet, but it seems to work thru most of its travel. any and all ideas out there welcome.:frown2:
 

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Potentially a TPS issue - mainly because the TPS is what controls shifting behavior; shift points are set by throttle position vs. vehicle speed (or RPM when at WOT). If the PCM isn't getting the signal that you're at WOT, the shifts will be premature.

Probe the voltage at the sensor. It should be less than 1V at idle, at more than 4.5V at WOT. http://www.tccoa.com/articles/engine/tps.html
 

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newbie here once again-'95 cougar v8; at 3/4 throttle seem to get good acceleration and transmission shifting. when I floor it, it noses over, no acceleration and won't kick down. linkages seem to be hooked up correctly. could this be related to egr malfunction and/or clogged passages to intake? had a '93 linc tc that almost wouldn't accelerate at all due to egr problems. haven't checked the tps yet, but it seems to work thru most of its travel. any and all ideas out there welcome.:frown2:
wide open throttle sends the ecm into the default fuel/timing map.
3/4 throttle the ecm is in adaptive learning so the car will self adjust fuel and timing.

go back to the basics check for fuel restrictions (filter)
have a look at the plugs, check what makes the engine happy.
 

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Agreed, get motocraft. I put in two new ones in my 5.0 and they weren't anywhere near the correct voltage at key on engine off....
 

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Discussion Starter #6
Potentially a TPS issue - mainly because the TPS is what controls shifting behavior; shift points are set by throttle position vs. vehicle speed (or RPM when at WOT). If the PCM isn't getting the signal that you're at WOT, the shifts will be premature.

Probe the voltage at the sensor. It should be less than 1V at idle, at more than 4.5V at WOT. TCCoA Tech Articles
tps seems to be working ok according to voltages- about 1 volt at idle and 4.9 volts at WOT. used an analog voltmeter to maybe detect 'flat spots' thru the voltages-saw none. car had been sitting awhile, and is a little loose in the bottom end (slight rattle above 4.5k rpm). it'll be an ongoing project for a while; most of my other stuff runs well enough not to fool with.
 

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new motorcraft tps did not solve the issue of no WOT. about 3.5k rpm is about tops for this engine. any more application of accelerator and engine noses over. beginning to think some restriction of exhaust system may be present, for lack of better ideas. have a fuel filter on the way, and will see about disconnecting exhaust tubing from manifolds to check flow. very difficult to remove screws from tps; steel to aluminum adhesion I assume. could this engine be timed wrong? very smooth idle.
 

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That was my next suggestion/suspicion (clogged cats) if TPS testing proved unfruitful. You can more easily (potentially) test the exhaust by removing the O2 sensors if completely removing it from the manifolds is too difficult. Getting at the right O2 sensor can be a bit of a chore though.
 

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Discussion Starter #10
meanwhile, back at the ranch, after a 20 minute cruise down the road and parked on the carport, held at WOT (about 3750 rpm is all I could get) for about a minute, I notice an orange glow on the exhaust from front to back. how about some input on this? thank you.
 

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...I notice an orange glow on the exhaust from front to back. ...
Without looking, you have a 94 or 95. :)

You have an injector hanging open; The glow is too much fuel burning in the pipe.

There probably IS no cat on that side, lol.

If there is one, it will have issues.


Start with a solenoid light... Ah, **** that.

Disconnect the injectors one by one on that side, and see which one makes no difference at all.
Three on that side will make for a rough idle when you unplug them, one will barely make a difference.

Put a test light into the plug; it will be on, not flashing.

This is a common problem with those years.

You will need a new EEC.
 

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Discussion Starter #12
BOTH sides were glowing. does this mean an injector is hanging on both banks? I have only noticed this after I held the accelerator down for about a minute and the engine was only running about 3750 rpm.
 

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I would test all the injectors with a "noid light".

I bought a set years ago; Advanced will loan a set, iirc.



Of course, holding the throttle open for a full minute, with it running very rich, would do the same thing.

I missed this part:
"held at WOT (about 3750 rpm is all I could get) for about a minute,"

I wouldn't do that; it won't help.



Cats will definitely need replacing; I'd recommend the "Rebar treatment" until you find out why it's dumping fuel.

No need to replace them and kill new ones.
 

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Discussion Starter #14
first I would like to thank you for your kind responses. the car has a smooth idle and runs well as long as you don't push the accelerator beyond about 3/4. after that it pops and sputters and you lose speed if you are moving. holding the accelerator to the floor for a minute was an attempt to either "make it or break it", if you will. there was a horrible smell associated with this also; not the hydrogen sulfide smell, either. I think I will take you advice on the "rebar treatment" this weekend and report back. once again, thanks.:smile2:
 

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Yeah, definitely sounds like it's running rich along with whatever else is going on (glowing exhaust usually means exhaust restriction). Although these cars are notorious for running rich at WOT with the factory program.

I would think a hung injector would smooth out a bit at high TP, and cause a rough idle.
 

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Discussion Starter #16
well, removed the exhaust sys back of the resonator-no difference. then removed entire exhaust from manifolds back and still no difference. makes me think throttle position sensor again. maybe a new set of plugs, too. sure runs and pulls good and shifts good at part throttle, but at WOT, sputters and misses. gonna keep at it, though.
 

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Dirty MAF sensor?
 
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