Fuel Boggin

[SHO_Time]

hey whats up guys, a local guy in town suggested i vist the forums here because i recently just purchased a 90 MTX SHO, now mind you i did not get this car in the best shape, things already replaced are the entire rear break system, including valves and lines, e-brake, fuel pump, plugs, wires, trany flush, throttle body cleaning, new alternator w/ belt. just so you know what i've replaced/done already.


Now when i first got her, i noticed se was a bit sluggish for a sho, having driven them before, having owned it awhile its gettign even worse, its to the point you can smell the fuel wasting out the exhaust, not to mention only getting about 10mpg( at 2.41 a gal that hurts) i've not worked on these alot and not entirely sure how the extra runners work, but if there anythign like the ones on the older cobras, when they open they allow more air and fuel right? and just playing with the car at idle i've noticed them moving while only lightly playign with the pedal, even below 3500. so any tips suggestions? things i start checking? i have't had a chance to pull any codes from it yet, just moved and kinda short on tools. Also reading a few more articles on here dunno if this helps but just like a few others i notice, the tach does't work at times and does other, and oddly the car seem to run better when the tach Does't work, then when it does.( don't ask me i did't design it)


found me a nice lil code reader for obd1 fords only $30 not bad, and here's what i get

koeo

66 - maf
14 -engine rpm sensor circuit?
19 -eec failure

koer
26-maf
13- rpm idle out of range
52 psps out of range

 

[Redline]

Well, for the MAF code I would try cleaning your MAF with some electrical cleaner. Oil and dirt can build up on the little sensor wires and cause driveability issues, especially if you have a K&N air filter.

I'm not sure about the others. Looks like your off to a good start with the maintenance. Are you sure the plug wires are in the correct order? Most of the manuals list them in the wrong order.

 

[SHO_Time]

the plugs have to go back, stupid autolite professional my ass, they don't even sit right, they fall out,lol have to take them back and get some motorcrafts. as far as the maf goes i went ahead and ordered a new one, because the one on it, is't even the correct one, i checked the part numbers, its from a xr7 cougar ..... and looks like i've got some spark plug well gaskets to replace to, found oil on the plugs and wire ends, another thing to add to the list.and yeah i had to msg someone on the board to get the correct firing order, even the shop i got it back from had them in the wrong order :cry: so got that right, still bogging way down, gonna wait till i get the correct maf before i do anything else, especially with the new midwestsho y pipe on the way, since fps needed a 25 pre order :cry:

 

[SHO_Time]

well maf is replaced,still runs like a granny, the odd thing is when i run a koeo test, after the idle test the car seems to run the way it should, not sure if that helps any

 

[shoR]

sounds to me like a fuel pump circuit problem, maybe not the fuel pump gone bad but this wires inbetween may have a fault, i have a 91 mtx, boggs the same way you discribed your car, and when i pulled the codes after the engine test it ran better, i noticed on my car the fuel pump sometimes doesnt circulate like it supposed to on start up when the key goes to "on", i have tryed everything from 73mm mafs to new timing belt but it still boggs, just gotta find that fuel pump circuit fault, could be CPS too, seems like they make your tach go a little wierd somtimes.

 

[SHO_Time]

well after a 20 dgree walk home, i have finally decided to just send it to ford and let them figure it out, fortunately the manager i talked to even owns one, which is always a plus.so will keep ya posted, maybe can give ya a direction to even look in

 

[SHO_Time]

A Week and a few hundred later, ford figures it out, she had jumped exactly 1 tooth in timing, between that, the new plugs and wires, and the y pipe installed came out to about 1k, not bad from a dealership

 

[Redskull]

If the PO. put a new MAF in there, theres always a chance there is an LPM plugged into the computer...worth a look at least.