88 BII keeps giving 77 code

[3406pack]

Hello everyone. Long time lurker finally posting and I have a problem. My 88 BII with 2.9, 5spd, and 3.45 gears keeps throwing the 77 code and nothing else. KOEO comes back clean as a whistle with nothing stored. What got me to check the codes was it was sluggish up to about 2500rpms and then it would take off like it had 2stroke powerband. After the first code pull I came here and searched and found the ziptie on the throttle cable trick. I found I had .5in of slack and fixed it.Pulled codes again and same thing. So I take it by my local shop and they no longer have their OBD1 reader so after a test drive I was told to advance the timing some. I used their fuel pressure gauge and it read 38psi @ idle and 32psi @ 3000rpm so fuel pressure is good since I had changed the fuel filter and cleaned the canister. So I get it home and adv. the timing ( remembered to take out the spout and I find its still on 10deg b4 TDC.) I take it to 12 deg b4 TDC and it helps alot with the power loss But I run the codes and I get the same thing only now with idle out of range low. Ok back to square one. Put the timing back and back to same only code 77. I backprobe the TPS and get consistant voltage increase from .285 volts to 4.80 volt with no large gaps when rotated slow. Ran my scanner again and still code 77. Then I had a thought Unplug the computer and see if theres continuity between the plugs. Might have a broken wire somewhere ya know. Well I do and I find that there is good continuity between the TPS and ECM plug. Should I just say to hell withit,adjust the timing back to 12 and drive the piss out of it or is this something that could have some adverse effects down the road such as sucky fuel mileage. It wasnt that great b4 @ only 18.5 mpg on the country commute to work and back. What has been done to it so far is a good tune up, plugs, wires, dist. cap and rotor. I have changed the fuel filter and used 2 cans of seafoam. I put about 1200 miles on it since I got it from my parents and they didnt drive it much. They did drive it enuff to crack the heads about 15 yrs ago and had the motor replaced. Dont know how many miles it had but it kicked gas on fuel mileage for being as aerodynamic as a throwed brick. I apologize for this being so long but more info is better than not enuff. I thank you in advance for any help with this issue.

 

[Mike828]

Did you even look up code 77?

77 System did not receive "goose" test - see TESTS

Which I believe means you didn't do the test right.
My 2.9 doesn't do much below about 2200 rpm, so I would set the timing back to 10 and drive the piss out of it.

Just my 2 cents......

 

[3406pack]

Yeah I looked it up thats why I did so much testing on the TPS.

 

[3406pack]

Anyone Here?

 

[TexCaliBII]

Hello,
Have you looked at the induction side of things? Made sure the filter is not clogged, there is not a bunch of stuff in the bottom of the air box? Might also look into cleaning the throttle out but beware cleaning it too well as those wire sensors are very sensitive to damage. Also might try a new TPS just in case as they aren't too expensive. When you advanced the timing did it still have the same "dead" spot as before? The 88 motor I have in my 87 runs best at 12 degress. Hope you have success.

 

[3406pack]

I just put in a new filter from NAPA and the box looked very clean. When I adv the timing to 12deg it was still there but not as prominent. I bumped it to 15 and it really opened it up. I know its been said to not go past 12 but I was thinking there might be a little slop in the timing chain and gear mesh of the distributor. Thats when it started giving the idle too low code. Cant remember now think it was code 03 maybe. My front 2 injectors are hitting hard, sounds like a lifter tap but I dont think it is because with a stethascope the center and rear two are just clicking but the front are tapping. I dont hear it in the valvecovers. On my code scanner which is an Innova, When I get to the goose test it says to "quickly depress accelerator to the floor and release". As soon as it comes up thats what I do. Still gives the same code. Ive tried doing it slow, fast, Ive even had it on the cowel and jumped out and throttled it open with my hand in case something in the pedal assy is stopping it.I think Im going to get a new tps and try it. If yall think of something Im missing let me know, In the meantime Im gone to the parts house. Thanks for the advice.

 

[TexCaliBII]

It's possible to have malfunctioning injectors that are preventing the engine revving enough for the test. Had a similar issue on a Mercury Villager I had, also found with a stethoscope. Might try running injector cleaner for a couple tanks and see if that helps. In my case it was new injectors.

 

[Mike828]

Your TPS voltages look a little wacky.....Have you tried backprobing the TPS and using the set screw to set it at .09v with the throttle closed?

http://fordfuelinjection.com/?p=30

 

[3406pack]

Ok I just installed my new TPS and still getting code 77. I backprobed the throttle again and I got .811v @ idle and 4.39v @ WOT. When I ran my code puller I made sure to hold it WOT till it hit 4.somthing volts. It still giving the code 77 and Im at my wits end because everything is adding up but Im not getting anywhere.I mean does it have to be EXACTLY 4.8v before it reads WOT. Thats the only shortcomings it has. Idle is within spec so Im lost. How can it run if its not getting a signal from the TPS? Any ideas?

 

[3406pack]

hell with it Ill time it 15deg adv and drive it

 

[3406pack]

22.2 mpg now w/ ign adv to 15deg and runs great. was 18mpg and ran sucky.

 

[Mike828]

You using premium gas?

 

[3406pack]

nope its not detonating or anything.5th gear up 5 percent grade @ 2200rpms and it pulls it like a champ.

 

[holyford86]

On my code scanner which is an Innova, When I get to the goose test it says to "quickly depress accelerator to the floor and release".

I had the same problem with my innova scanner, It tells you to perform the "goose" test at the wrong time. I kept getting the same code you did, and pulled my hair out trying to figure it out. I used the Snap On MODIS at work, it told me top perform the "goose" test at the right time and I had no codes after.

 

[bfiakas]

Do you still have the stock TB on it, I put a 86 TB ( 58mm bore) with a new TBS and it gave about 30% more power.