85 B2 low acceleration

[Mosier]

So I have poor acceleration, emissions facility wouldn't even test it because it couldn't get from 28-48 mph in thier time test. So here I am, testing sensors and doing my research. So upon looking around I found similar symptoms for bad tps sensor or knock sensor, I just test my tps sensor and its reading 4.25v and 1.25v (WOT and no throttle respectively). Adjusting the idle screw I can get it to bout 4.3v and 1v. According to my guide here it should be .6 and 4.5? http://rothfam.com/svo/reference/sensors.pdf

Is this tps adjustable other than the idle screw ie linear or rotary?

*85 B2 171 ci 2.8l v6 | Manual Trans
**Driving symptoms are: great in 1st gear, proficient in 2nd gear, and slow in 3rd 4th and 5th, can't get over 75 and barely get to 65 or 70. By the time I get off the onramp onto the highway I'm barely at 40 mph. Also has wierd idle symptoms, doesnt die or anything but it goes up and down constantly.
Also once or twice since I've had I've found something wierd, when doing high speeds at high rpm (4th gear 60-65) it will backfire out the tail, engine loses power, Emission light comes on then it comes back to normal and emissions light goes off.

 

[Mosier]

Sorry forgot to mention, plugs, wires, cap, rotor, coil, fuel pump, accelerator pump, map all new.

 

[bronco2fan]

If it's like mine was,2.8. Check if all the vacuum lines are in a wire loom. The ones coming from the passenger side. When I did my Duraspark converion those were melted and had holes in them. Could'nt tel because they were hidden in the covers. Hope that helps a little.

 

[PetesPonies]

With an EFI system, those TPS voltages are correct. You have a feedback carburetor, so I admit I'm not sure if the values are the same, but I would guess similar. Typically around 1V or slightly under is what you want at idle and about 4.5V is WOT. You also want no dead spots throughout, so check it while opening from idle to WOT and look for any wild changes along the way.

 

[Mosier]

alright cool, I kno if I have the idle screw where it was (1.25v) it was enough to where I could take off from a dead stop without having to give it alot of gas, so I'm thinking i might try unhooking the knock sensor as soon as my mother gets here to jump start me (don't leave your key on all day) and if that helps it I'll look for a knock sensor or a rebuild (hopefully no new heads)

Also, I'll try blowing smoke through the vacuums to look for a vacuum leak, I ran my finger down a few of em when fixing my egr problem and none were busted (except for the brittle pos ones I broke and fixed).

 

[Tedybear]

Put a vacuum gauge on it. I'm wondering if the cat's starting to get bunged up.....

S-

 

[Mosier]

Cat is also new, bought it 2 weeks ago, other one had holes in it

 

[Mosier]

okay so upon further testing of my tps, when at idle at 1v and I slowly increase throttle, it jumps from say 1.15v to like .6 or .7v. Is this a new tps?

 

[PetesPonies]

There is a little wiper movement in the TPS that changes the resistance as you move it. Sounds like you have a bad spot. Now if this was EFI, that would really screw everything up, but you have a carb. However, I'm sure the input to the computer is getting some mixed info and perhaps its pulling advance from the ignition? That would certainly mess with the power that an engine can make. Either way, if you are sure you are getting readings like you say from the TPS, it needs to be replaced.