ok tgo here is another mystery for you guys: I have a 89 rs with bone stock 305tbi 170hp (maybe) under the hood. it has a 700r4 from out of a 88 firebird ( if i remember correctly) now its been about 5mo since i have really driven the car and longer than that since i've really gotten into it. It has a full tank of premium gas a full tune up (wires, plugs, dist.cap, rotor, fuel filter, fuel pump, tempo control sensor, air filter, an the fan is wired to run with the key on and it stays below 200 degrees no matter how much i run it here in NC on 50-70 degree ddays.

now the problem is that I was driving today and the car got to about 70 when all of a sudden it felt like someone had a rope tied to it and yanked HARD backwards. it felt like it was trying to die and then it instantly came back to life the whole incident diddn't take a second. it did this several times in a 6 mile stretch on the interstate. Never when taking foot off the pedal only while accelerating. And only while going btween 45-70mph. Some ppl would call it "bucking" i ddon't what to call it but it disturbed me. when i come off the gas it would slow down but it would run normal but if i got on the gas even remotely hard it would buck. maybe this will help:

rrrrrrrrrrrrrrrrrrrdrrrrrrrrrrdrrdrrrrrrrrrrrrdrrrrrrrrrrrrdrrrrrrrrrdrrrrdrrrrr.

that is what it was doing. please help if you can. as far as i could see there was no smoke. the car did not shut off. i think it runs a little rich but i dont think its major. please help. oooh adn i ddont know anything about tuning the chip/computer. someone please help. tomorrow I will try the fuel filter again although i don't think that is the problem. thank you all.

 

Could be a bad injector(s) or an ignition problem. Ohm all of your injectors first,check for codes too. Does this only happen when the engine is warm?

 

First check I would do would be the TPS.
Also, I'd be running 87 octane in it, and not running the fan full time.

 

yes only when the engine is warm and how do i ohm the injectors and when?

 

ok will do a search for how to test the tps. why 87 instead of 93 octane? and will get a new fan switch from advance auto that was the reason for the fan straight wire.

 

Your compression isn't high enough to use premium fuel. It will actually make better pwr with 87. You probably have bad gas and or need a tune up.

 

87 burns faster,thus providing more power. 93 is only beneficial if you have raised the timing and/or are experiencing knocking.

 

http://www.youtube.com/watch?v=_g8PdrT0MCU

 

thanx for the video ill have to check out YTube for checking the tps also and get these checks done probably tomorrow.

 

another question from a rookie would the "lock up" from the tranny cause anything like this? i'm not having any probs from my tranny but if this is the beginning of one I want to nip it in the bud as quick as possible.

 

alright i took a crash course in reading multimeters and this is what i came up with. Injectors: on a 305tbi unit both injectors with the meter set on 10ohms they read 1.3-1.5 ohms give or take.
the tps: I put the meter on dc volts and set it to 10. then i stuck the red prong in the sensor's blue wire and stuck the black prong directly to the battery ground and best that i can tell i got .3v+- and then operated the throttle with my hand to WOT and got all the way up to 4.25+- so what does this tell any of you. please help!!!!!!

I drove it to work and it was doing the same thing again the same way SES came on but went back off when i got to mcdonald's. any ideas?

 

No, set the meter on 2k ohms. Your injectors should come out to like 0.015 or so.

 

that is incorrect. Octane is the ability to resist detonation

Heck, go to the Ford web site and look at the new 5.0 and check the HP rating for premium vs regular. They come right out and show about 20HP more when using premium

 

Its probably either your distributor or your throttle body

 

Yeah, if your timing is set for it or the car can adjust itself for it. Our cars don't. You have to raise the timing.

 

87 burns faster. 93 burns slower.

 

Right. And how does it do that?

By burning slower.

Can you say, "Knock sensors"?

 

You should get a smooth sweep from 0.50 volts to 4 - 5 volts (however high it goes) when you slowly open the throttle with your hand. Your problem is at part throttle, so you want to pay particular attention when you have the throttle open around 20%.

Also watch your fuel pressure as you drive to see what it does when you are having this problem.

 

the claim was lower octane makes more power in an engine. Octane is the ability to resist detonation

knock sensors compensate for lower octane by ........................retarding timing which reduces power (well, the knock sensor doesn't actually do that)

please pay note to the claim by the poster which was what i addressed

 

also remember,more timing does not always mean more power either.

 

the knock sensor aids in lowering timing,but the timing ends up getting lowered by too much.this is for safety reasons.

 

the idea is to run the lowest octane u can without knocks.

 

got some more info: your right about the setting on the meter but everything was about where it should be. now, I drove it home and it threw a code. code no.13 oxygen sensor but there's no way that the o2 can cause this much havoc can it? what about tranny modulator? or tcc lock solenoid? I dont know im just asking.

something else my car when started cold revs 3500 rpm after warming up it slowly drops to 1200-1500 rpm and goes to about 1100 in gear sometimes it goes to 800rpm the plate over the idle screw has been removed and i'm going to check the timing with a timing light. please help me I hope this info helps us all make a diagnosis.

 

http://www.ehow.com/facts_4815064_co...en-sensor.html

http://www.iroczone.com/2009/10/1982...maro-firebird/

i ddon't know how to adjust the tps on 305t tbi

 

it really sounds like a fuel issue,but do you feel the tcc lock? code 13 is a bad o2 signal,but it wouldnt cause those types of drivability problems,just poor mileage.

 

Didn't you just say that you checked the TPS and it tested good?
You also seem to keep getting side-tracked about transmission worries.

Your ECM controls TCC lock-up based on inputs from the TCC, MAP, and VSS.
Stick to troubleshooting your engine.
Datalogging while driving would show you exactly what the ECM is doing when the problem occurs. It would save a lot of speculation.

 

yes the tps seems to be in good shape and i don't feel the tcc lock as a matter of fact (it FEELS) like when the tcc should be locking is when the car cuts back. its so bad that when the problem happens its like someone jabbed the brake. but only for a second. i don't know what the problem is but believe me i appreciate all of everybodies input. I hope its not the ecm.

keep giving me things to check FOR FREE and i will keep all of you posted. thank you!!!!!! what is datalogging?

 

If you're seriously suspecting the transmission, then why don't you do some testing to confirm or rule out the trans.
Have you tried bringing the car up to speed while holding the trans in a lower gear like 2nd or 3rd ?

The converter locking or unlocking should not physically be able to cause the symptom you describe. A gear in the transmission binding could, but I would expect a LOT more calamity if that were in fact happening. The trans binding would try to lock your rear tires, and you would likely hear bad noises during this process.
You need to make sure your trans isn't having any problems with shifting or with TV line pressure. When your symptom occurs is the trans trying to down-shift? Your RPM would shoot up if that were happening.
What is your RPM doing? Is the check engine light flashing?
Does the symptom go away as soon as you back off of the pedal?
Does it get worse with more gas pedal once it happens?

A DMM can be as cheap as $5 at Harbor Freight. You can run longer wires to your TPS so you can monitor your TPS signal from the driver-seat.

 

the rpm when this is happening is dropping by maybe 20 or something and as soon as I let off the pedal and at times w/o lettting off the pedal the car immediately comes right back. the rpm jumps around b/c i push a little harder on the pedal about 1/2 way to the floor to try to make it go.

when doing this the speeds up and slows down irratically until i come off of it and get back around 60mph i'm driving it this morning when i get to work i can tell you better how it acted. thanx, oh wheels stay rolling ffreely and ses light came on but the only code was the o2. yes gets worse when u get on gas after 60mph

 

guess what fellas: my fp just quit. here's what happened i made it to work and I jumpered my aldl a and b with a paper clip it gave code 13 again all of a sudden the SES light went out and when i tried to start the car i didn't hear the fp relay prime i jumpered 12v to it ( the green wire) and the relay still kix but the fp won't run. so i straight wired the battery to the orange wire and still nothing (i did that just in case the power wasn't getting TO the relay)

let me check the fuse! I checked the fuses inj1&2 and fp and they were fine could this have been the problem. the fp has been changed or at least that is what the shop said although lets be honest if he had did something wrong it would not have lasted a year with all the driving that i have done. so HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

HA!!!!!!!!!!!!! not the FP just the relay or the wiring I straight wired the orange wire one more time and patted the gas twice and voila purring like a kitten. as soon as i disconnected the power it died this weekend i'm going to try another relay and drive it down i95 and i40 again to see if i still have the other problem.

but at least no $700 FP repair bill. How do i tighten up loose and exposed wire connector that attaches to the relay?

 

Got the problem!!!!!!!!! its the wiring the idiots that had the car before somehow screwed the wiring to teh FP up and now I can't get fire to the connector unless i straight wire it. I thought it was the relay itself when in reality I dont think the relay was getting 12v in at all now I have to find out where/how it either blew a fuse or got a broken wire connection uuuuugghghhhghghhh!!!!!!!!!!!!

if you don't know alot about wiring electrical problems will kill you!!!!!!!!! warning to all thirdgeners DON'T HACK THE WIRING please ask someone like I will have to do if you don't know?

since the FP was working at one time ( i don't think it was only working off of the oil pressure switch circuit) I have to assume that it is probably the fusible links and then move on to the more difficult task of trying to trace the wires under this low a$$ car.

one last "?" is there a way to straight wire the circuit to the key and will it still prime like it is supposed to. someone also put an on off switch in the dash of the car i flipped it and it still didn't put 12v to the orange wire I don't know what to do

 

You know you wont hear the fuel pump everytime you turn the key either. You have to turn the key off and wait a little while and then turn to the on position again and you may hear it energize.

 

according to austinthirdgen I would have to go to the ecm and tie into where c16 is or somethin and run the new power all the way to the relay is this right?

edit: just got your response so what i did was reconnected where the orange wire is broken (just under the relay) and then turned on the key and used a volt meter and got ground with the black prong and the orange wire with the red and
nothing. Am i doing it wrong? when i straight wired it from the battery i got 12v when i carefully plugged it into the relay and started the car it ran as soon as i disconnected the battery it died. retested the orange wire and no power.

 

sounds to me that your timing chain jumped... thats happened to my other car before, drove it that way for about 6 months until it finally popped. it would do it wonce in a blue moon.. worth a shot to change it out

 

update!!! played a hunch actually i was like i can't afford to pay nobody to charge an arm and a leg to find this and the good lord gave me an idea. I stopped checking the power coming in on theorange wire and started tracing the green wire coming from the inside of the car and what do you know power 12v now what must have happened was the PO lost power to his FP so instead of finding out how/why he just wired up a manual switch. I know SIMPLE but understand that for the most part I like for things to work OEM style and wouldn't have done such a thing so i flip the switch back to on and it worked the wire under the hood is old and frayed it must not have been getting good contact and made it seem like a bad relay and FP. I believe that this is probably the reason for the power loss at high speeds that i was experiencing. Does the strain on the wiring increase as the demand for fuel increases? or not on this part of the wiring?

I think the wire from the switch was barely making contact! EVERYBODY THANX FOR YOUR HELP!!!! ESP. YOU NINETYIONE. I'll let you know tomorrow if securing these wires CORRECTLY solved the power loss issue happening above 60mph!!!!!!!!

 

I know this is a lot of entries by me but I got it running!!!!!!!!!!!! thx to all of you when in doubt check the simplest thin first I will be securing the wires properly tomorrow and maybe this will help the power loss issue.

edit: got it and didn't have to move the car. It shut off just completely shut down. before doing anything i checked the voltage at the junction where the wires connect (both sides of the orange and the one coming from the inside switch) I was getting voltage about 3v. Well you know that the FP was designed to run on 12v so I tightened the connection and the voltage went to 12v and I fired it back up. I trully believe that this is what was happening on the hiway so I will definitely be securing all of the wires tomorrow and taking for a test drive (my favorite part)

 

still doing the same thing!!!!!!!!!!!!!!! I'll take it to the shop and if it's too far gone (expensive) this car and all of the other thirdgen parts go bye bye. anybody looking for a car runs darn good just not perfect for about $1200. lots of other parts with it!

 

I'd respond to that, but it's too far off topic.