**Qaking and FestivaBiker** engine stumble!?!?!

[rotinaj13]

yep I fallowed the steps on it, and came up with a few more for my curiosity.. ;-) the gas cap doesn't his on mine but I didn't drive much b4 adding gas. The head intake and FI wasn't tampered with. It has every thing the 93 had that was attached to the head. It has all of the ignition components. It has the 88 alt. , radiator , water pump block ext. 93 fuel pump, 88 fuel lines. new fuel filter new air filter new screen on the fuel pump. wires were farely new. I checked them on morning when it was still dark and raining out so they got wet and I reved it to 3500 and let it idle and so forth didn't see and spark gapping. The plugs are new. added FI cleaner to gas I have half a tank (88 gas tank). The timming is 10 deg ( properly checked this time) idle is dead on now. It just has that annoying hesitation. Some times it is worse then others... I dunno. I am going to check the o2 sensor tomm and see if it is working, and see how my engine is running I will look for a lean condition.... that should tell me if there is a gasket leaking air into the plenum... And I still haven't gotten a code.... I am running out of ideas..... I think it might have been built on indian bariel ground... lol CURSED CAR!!!!! :evil:

[FB71]

I see a problem with your fuel readings. The pressure should not drop more than 1psi in 5 minutes. You have a bad check valve in the pump, but that shouldn't cause your hesitation. Did you check the tracking resistance of the tp and vaf? Trouble with either of those will cause you concern, and not throw a code.

[rotinaj13]

no I haven't... I will tommorow though. tp = thorottle position sensor? I'll post the results tomm. The check valve that is what lets it fall to fast when I turned the key off right? That would probably be the reason it takes a little bit to start up after it sits right? Thanks for the help FB!!! and thank you Qaking! well I hope I find the problem tomm.

[qaking]

Jim, I was thinking TPS as the next thing to check have AJ check - haynes page 4-12 has test procedure. page 6-10 for O2 and 6-11 for airflow sensor. Hang in there AJ, you'll figure it out :wink:

[rotinaj13]

TY much! I'll post some results tomm.! and we will see if it is still cursed LOL. thanks

[rotinaj13]

I think I might have found it..... I broke off from testing to post this... If you look in the book for the MAF It shows a pinout B+ gnd vaf gnd ref another gnd and something else. The b+ is getting 5 volt but the gnd beside it dsoesn't appear to work. It doesn't ground.... Could that b it???

[rotinaj13]

ok ford and haynes has a funny sense of humor. The pin out in the book is wrong if u check the schematic against the wire colors... However I did find a big concern.... I am not getting any voltage to the TP I did it with the key on and back probed. I turned it off disconected the conection and turned the key on. I tried with it running nothing.... and it seems the pin out in the book is wrong for it as well It list a yellow a yellow/black and a black well the yellows are from the ecu and black is ground the wire locations don't match the pin out... I see what my problem is now I bought a haynes manual insted of a ford manual :roll:

[rotinaj13]

go figure it works like most things I get agrivated and walk away then come back out of curiosity and it works. the top pin and ground are showing 5 volts. The bottom pin and grnd show nothing at idle, but when U have the thorottle wide it shows a little over 12 volts... ohh duh this is for the TPS

[rotinaj13]

is there a good way to adjust the TPS the way in the haynes manual sux. you think you have it right and it still doesn't have any voltage when at idle. and that is with a different TPS that I know works..

[FB71]

dude, you should NEVER have 12v on any wire to the tps. the black wire is ground. use a dvom and verify there is less than 0.02 ohms of resistance. if the resistance looks high, clean ground 102, near the coolant temp sensor on the block. with the key on, engine off, backprobe the other two terminals. with the accelerator released, the yel/blk wire should show 0 volts. with the pedal pressed, it should show 5v (my EVTM says 12, but I believe it is wrong). Then check the yellow wire. pedal released should show 5v, and WOT should show 0v. the tps on these cars is nothing more than two switches, one closed at idle, one closed at WOT.

another test would be to go key on, engine off, unplug the tps, and check voltage at both yellow and yel/blk. they should both show 5v (possibly 12v on yel/blk).

[rotinaj13]

Jim,
every thing checks out with what you said. At the end of your post the voltage was 12 volts. The VAF checks out good. I sprayed carb cleaner around the gaskets and vac. line to check for a leak no leak. Milkey white under fill oil cap. Hesitated so bad today that it cut out coasting in second when I lightly pushed the gas if i let off or pushed harder it came back to life. Am I just going blind or is there no egr valve on them? I looked all over and didn't find anything that resembled an egr valve... If there is can you please give me some directions to where it is. I rechecked my vac. after replacing the pcv cause it was covered with the milkey white crap. My vac was now at 16, and every now and again it would stumble on idle and drop low on the guage and flectuate through a wide range, then return to 16. Thanks for the continuing great advice guys! You 2 really are a life saver!

[FB71]

milky white/ brown stuff in oil fill and pcv = blown head gasket

better check that, my friend......

that means, remove the head......

[rotinaj13]

I think it is from when I changed the head. I didn't get all of it out of the head and tilted it when I pulled it off and it all went into the number one cyl... So I am going to oil flush it. I know this head gasket didn't blow i think it was because i didn't change the oil yet.... but i will compression test none the less.

[rotinaj13]

I think I know what the problem is... It seems to be in all gears when I shift at low rpm so i am thinking it is the return line off of the fuel preasure regulator... The 88 had a smaller line than the 93 did, so i think I am going to use a length of rubber line and use it instead of the steal line to check and see if my assumption is correct. I'll post results. Let me know what you think. Cause I will probably wait till another day to do it. It is raining pretty good here and I can't get it into the garage... My Gf's car is in now.. GRRRR I hate when every thing breaks at once!

[BloodFang]

OK, i have been having similar problems with my 93 festiva, its a manual also.
I replaced the plugs wires, fuel filter, air filter, and gave it an oil change, also a new distributor cap. But when i start up it runs super rough, and sometimes stalls, it runs fine in gears but not when idling, it idles to slow, i had someone look at the timing and they said it was set to the max, so I'm alittle confused and frustrated, i was told it might be the mass airflow sensor, but am not too sure about that one, i just took it to the mechanic and he is gonna look at it( a friend of mine thank god!) so i will post my results after i get it fixed.