1990 f150 runs better while running code test
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1990 f150 runs better while running code test
Ok so heres whats goin on my truck a 1990 f150 300-6 5 speed truck stumbles an hesitates badly it starts easy idles really nicely but when your driving and push on the gas a lil bit it acts like its starving for fuel i cant drive over 50 mph cause if i push the gas to go faster it just stumbles and makes the whole truck vibrAte so i decided to do the self test and pull codes i hooked my wire up and pulled the codes from check engine light flashes and i decided to see how it would run in self test mode so i started it the check engine light flashes 3 times and the engine idles up a lil high but the throttle is nice and snappy revs smooth an no stumble or hesitation and alot more power but when i unplug the wire i hear a whoosh sound and it idles back down and starts running like crap again i assume when its in self test mode whatever the problem is is bypassed till i undo the wire again i just replaced the tps the aic valve is working and i did the egr delete im lost any ideas??
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I ran the code test and got a few codes i got egr not opening witch of course i knew cause i deleted it lol i also got a right side lean o2 sensor code i got a tps voltage low code witch i just replaced tps an i got a coil code this may sound stupid and i feel like a fool cause iv been a mechanic for about 15 years but how do you test fuel pressure and vaccum guess iv just never had to do it lol
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I checked em all seem to be fine i blocked off the air idle controller and it cleared up and ran good for a few min then started running like crap again there is play in the aic valves when there all the way closed i can move em up and down side to side etc in the holes is the supposed to be slopin them??? Or is that normal?? It just semms to me when the engine is past idle the aic valves are leaking causing it to run lean maybe?? And act like its starving for fuel i pulled a couple spark plugs and they were light brown/tannish color so the air fuel ratio is correct thats whats kinda throwing me off if it was lean they would be white but maybe its cause its not lean sll the time just when aic valves are supposed to be closed or maybe its not working correctly and the engine is starving for air i dont know i just have a hunch thats the problem it is working i just think its leaking around the valves in the aic
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oh you did get codes.
1 idle air control only cycles at idle (very rapidly) Often they get clogged and won't seat correctly. I usually clean em once then replace the second time. They are spring loaded shut, and the solenoid pulls it open. shouldn't be really sloppy
2. o2 sensor code prolly time to change it. If its a three wire heated one check the heat circuit.
3. Fuel pressure test is done with a fuel pressure gauge attached to the press test port on your fuel rail. I use the cheapy harbor freight $20 kit works fine.
Looking for 40 psi or so when the key is turned on. And that it doesnt bleed down fast after pump cycles off. That would show a bad fuel pressure regulator.
4. Manifold vacuum test is accomplished by attaching a vacuum gauge to the vacuum tree (easiest spot) and monitoring for low or fluctuating vacuum at idle and acceleration.
If you are seeing codes i'd cure those first. Most likely cause of your drive ability issues. This gen really doesnt set a lot of codes and if you do get them its best to cure them.
Did you install the egr delete kit? It tells the computer its closed and wont set the check engine light. though it does store perm closed code on mine.
1 idle air control only cycles at idle (very rapidly) Often they get clogged and won't seat correctly. I usually clean em once then replace the second time. They are spring loaded shut, and the solenoid pulls it open. shouldn't be really sloppy
2. o2 sensor code prolly time to change it. If its a three wire heated one check the heat circuit.
3. Fuel pressure test is done with a fuel pressure gauge attached to the press test port on your fuel rail. I use the cheapy harbor freight $20 kit works fine.
Looking for 40 psi or so when the key is turned on. And that it doesnt bleed down fast after pump cycles off. That would show a bad fuel pressure regulator.
4. Manifold vacuum test is accomplished by attaching a vacuum gauge to the vacuum tree (easiest spot) and monitoring for low or fluctuating vacuum at idle and acceleration.
If you are seeing codes i'd cure those first. Most likely cause of your drive ability issues. This gen really doesnt set a lot of codes and if you do get them its best to cure them.
Did you install the egr delete kit? It tells the computer its closed and wont set the check engine light. though it does store perm closed code on mine.
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