'85 Starts, won't run

[Quackling]

Hello all!

Brand new here! Thank you for having this site!

I have an '85 Crown Vic, which I need help with... It's been sitting for a while and I'm trying to get it going, smog it (Yeah, California), and sell it. It has that lovely CFI system... Fuel has been changed out, fuel filter has been changed out. Also the ignition switch replaced; it was flickering with a wiggle.

Trying to start it, it'll start but dies immediately. The only way to keep it running is to keep feathering the gas. As near as I can tell, the only time it actually puts fuel through the injectors is when the gas pedal is moving down (or the start circuit). Not holding it down, but actually moving down. Hence the feathering thing... It'll rev up pretty good, as ong as the gas it being feathered. If it was a carburetor, I'd say the accelerator pump is working but the jets clogged.

I suspect the Engine Control Module is bad, but don't want to drop $100 to test that. (The ECM controls the injectors, right?)

Anybody seen something like this?

Also, in case it makes a difference, it seems to be a late '84. To replace the cap and rotor the '85 doesn't fit. Have to get the ones for an '84.

Thanks!

Russ
Sacramento, CA

[Quackling]

Is it possible to have the computer module tested?

[pantera77]

I highly doubt it's a bad computer if it runs when reved up. How's the high idle set? Did you check it for codes? Unfortunately CFI cars can be very picky, hopefully Gadget or someone with more CFI knowledge then myself will chime in.

[gadget73]

make sure the high idle cam works. Its basically like a choke system, and relies on a cam on the passenger side to drop down and hold the throttle open a bit. Spray the linkages with carb cleaner to make sure they aren't gummed up. These usually require a pump of the pedal before starting to get the high idle cam to set so it will run. Its probably also not a bad idea to check the TPS to see if its working.

http://www.lincolnsonline.com/tech/00269.html

this is written for the multiport cars, but its the same sensor and test on the CFI cars. The TPS lives on the passenger side of the motor. Basically you're looking for dead spots. An analog meter works better for this if you have one.

[Quackling]

Thanks for the replies. I'll take a look tomorrow when I have some sunlight.
Pretty sure I do have an analog meter out there. I knew I kept it for something...

[Quackling]

Okay, here's the part where I start to feel dumb... I read the TechTip and it makes sense. Then I go look at the car and think, "That doesn't look like what I was after..." And then I think, "Wow. Nothing here looks like a TPS to me."
(I'm mechanically capable, really! I've changed out the clutch, slave cylinder and release bearing on my S-10. Just got done with tie-rod ends on my lancer. Countless simpler wrenching jobs. Then I look at this thing and just feel lost...)

So, here are a few photos:




And, to show just what it does, here's a Video:

The first two starts are without touching the throttle. After that, you can see the throttle moving, so you can see the effect it has.

Also, the high idle cam seems to be fine. Indeed it lives on the high cam; it literally hasn't been warmed up in two batteries, sad as that may be...

[Quackling]

The Check Engine light doesn't come on when it is running. So would there be a code? I don't have a code reader; what's the process to get the light to flash the code?

[marquisman]

That car does not have a check engine light like todays cars. Its not hooked up to the ECM. It what we call a "replace engine light". It tells you if you have low oil pressure or overheating. That's it.

[Quackling]

Gotcha.

Went out and bought a code reader. If it helps, it'll be worth it. And it'll work on my '87 too...

[Quackling]

Okay! This is progress!

Code reader gave me 23, verifying Gadget's guess as the TPS being at least one thing wrong. Also gave me a code 14...

Finally figured out what I was looking for and found the TPS. (Thought it would be bigger...)

Adjusted it to the specification, and tried to start it. Still didn't go, but it took longer to die. Tried a few times, then rechecked the TPS reading, only to find it had wandered... Did this twice. Does this indicate my TPS is bad?

I'm going to play with it a bit more, and report back later....

[Quackling]

Okay so every time I adjust the TPS then move the throttle over and back, the TPS reading has changed. That makes me think the sensor has failed, but I'm new to playing with these particular creatures.

[pantera77]

Then I look at this thing and just feel lost...

Welcome to CFI! At least it's not EECIII!

Okay so every time I adjust the TPS then move the throttle over and back, the TPS reading has changed. That makes me think the sensor has failed, but I'm new to playing with these particular creatures.

Certainly sounds like a possible bad TPS.

[miamibob]

Why not get a NEW TPS and give it a shot?? Not sure ROCKAUTO has OEM for this car and is it 302 or 351??

[sly]

IIRC, CFI was only ever available on the 302/255? The 351 used a carb.

If you can probe the sense wire on the TPS and sweep it with the car on/engine off using an analog meter... you can see if it's good or not. If the voltage when you reset it is only + or - 0.1V I wouldn't worry about it. If it's off my half a volt or more... then yeah... the stop point is probably worn slap out and the TPS needs to be replaced.

[gadget73]

302-only, and this specific type in 84 and 85 only. The 255 was a carb, maybe a 2150, the 351 was usually a 7200VV. The 3.8 also had CFI, but they put those in smaller vehicles. The TPS on the CFI cars is electrically the same as the SEFi cars. The only difference is the CFI one has a hole through it for a shaft. Some of the SEFI ones have a plug that you can knock out, or maybe you can drill out if you are extremely careful.

Some small amount of drift is normal, but it shouldn't change significantly. These aren't high precision devices. Less than 0.1v is probably fine, but I'd worry if it was much more than that.