Hi, I think my TPS is missadjusted since when I unplugg it I don't have the hiss after acceleration. I have the normal hiss, but it kinda hisses weird after I let off the gas. Check the pics out. Can I adjust this screw. P.S. I know its only held by one screw.

See how far it is from the TBI, can this be adjusted a bit.

Should it sit flush with the TBI???

Let me know.

Thanks.

From searching and reading I am thinking that my TPS is non adjustable. however, what is that screw, and it seems like I have to rotate it to get the TPS it self right.

Can someone give me some pointer of how to do this right.


Never liked messing with sensors, and if I don't find the problem I will swap to carb. This sensor bull is pissing me off.

that is how its soposed to look and no that isnt the screw for adusting. the two bolts that hold the tps to the tb is were the adjustment would be. the holes in the tps would be slots if it was adjustible.

Use a multimeter and adjust the TPS to .54 volts.

I used this article to help me on the adjustment.

http://www.iroczone.com/techarttpsadj.html

So, I'd just unscrew mine and move it around a bit till I get the voltage. How than can I put in both of the screws on there and still hold that voltage. It seems like the TPS can only go in one way on my TBI. I don't think I can move it.

Could someone show me on my picture how to move my TPS to adjust it???

Thanks.

What you are showing in your picture is not what you need to adjust. Look at the pictures in the link I posted. It's much clearer what you need to do. Just loosen the two torx bolts like in the link pictures and move the TPS up or down slightly until the multimeter reads .54. Then tighten it down.

The volts might move around as you tighten it so you may have to play with it a bit.

I'm pretty sure the hissing your hearing is the IAC doing it's thing. Other than the hissing what is it doing wrong?

The IAC is brand new, and it sounds like the IAC, but I am sure that my TPS is misadjusted.

How can i fix my IAC if its doing that???

I mean, I have more off the throttle problems and some idling problems. Not steady, and really bogging off the line, or if I get off the throttle and get on it again.
I replaced CTS, IAC, TPS and I'll see what happens once I adjust the TPS.

Should I tighten IAC even more???

Where is the screw to adjust minimal air???


Have new distributor, new wires, new pluggs, new coil, set the timing to 1advaced.

I have a hiss after I accelerate. More like, press gas... let off... hiss..back to normal. It normally has to hiss when I give it gas, and not afterwards. Something is out of adjustment.
I am not sure where the IAC screw is, otherwise I'd adjust that too. But the throttle response I am sure can be contributed to the TPS.

I'll let you know what happens when I adjust it.

You do know that the reason your TPS isn't adjustable like the TPI tps is because the ECM automatically adjusts itself?

I think you have another problme thats causing your IAC to be open further than normal, which is causing your louder than normal hiss. The fact that your having idling problems also renforces this.

If you have a digital camera, turn the MACRO on, which is the picture of that little flower on most digital cameras.

That way close up pictures will turn out clearer.

Just thought I would help you out because my vision isn't perfect and I can't really see the pictures too well.

Sorry man. I am a film guy and I can set that camera up really good, but I am just lazy.
I went adjusting my idle air screw and it did not do much. ALl I found out was that my blades were sticking. Also, I went adjusting the TPS which at inital reading was at 0.67 V, which was to high. However, I can not adjust it, and I realize that its sitting to high at idle.
I think thats where my hiss is coming from.

I don't know how to adjust TPS since I can not move it up or down at all. I tried moving the screw in the picture and nothing happened. So, i am not sure how to move that spring back a little so i can get the TPS at .57 instead of .67. Let me know if there is the way.

THe only thing I've noticed is that with TPS unplugged my car does not hiss what so ever.

Later on after 30 mins. of thinkering my voltage on the TPS went to like 2.56 and even over 3.4. I was not sure why it was doing this... Grounding maybe??? I will play with it more tommorow, but if you guys have any suggestions please help.

Thanks sooooo much for your help so far.

i have to tbi firebirds both of the tps voltage is .64 or close to it. when you unpluge the tps it run better the hiss goes away? have you tried unplugging the map? i noticed on my car when i unplugged either it would run better. this is because the computer dumps more fuel in. and again we are back to a fuel problem you might want to get a fuel pressure guage or have a shop do it just to be sure.

I am thinking that its the fuel problem, but the hiss did not seem like a fuel problem.

It could be, cuz when ever I bog down my Air/Fuel gague goes very lean, off the charts... So, I know that TPS unplugged works a lot better, and what am going to do is plugg some vac hoses to see if they might have something to do with it.

Otherwise, I will be putting a new pump in on the 30th of this month.

I am gonna do the vac lines right now, and comeback with the results.

Thanks TBI5.7
Thanks to all of you.

Checked every vacum hose and no leak. I know I am pulling vacum cuz when I take them out the engine will either go up a bit in the idle or stumble a bit.
So, i went to adjust my IAC, and guess what!
My throttle blades are sticking. The car idled at about 600 650 with the IAC unplugged and extended all the way. It hissed quite a bit too. So my idle screw will go back, but my blades and linkeage is not. My cables have enough play for the linkeage to go down thus making the idle around 450, this leads me to belive that my blades are either sticking, or there is something else other than vacum thats keeping my idle hissing like that.

I checked my cone from the injectors, which are new, and they are perfect. I have good fuel pressure since I can go past 1/2 throttle and actually run rich.

So, I just might need a new TBI.

Ok, after few minutes of thinking I've got few questions.


1. Can the adjustment screw for air on the TBI actually move if the protective cap is still there??? I mean can it actually mess up enough to get a crappy idle.
2. If the blades were sticking, would that mean that my screw for air might be to far back???

3. What else could make me have a higher idle, if its not a vacum leak, the timing is dead on and I have a brand new ignition put in.

4. Could poor fuel preassure cause the IAC to open further to compensate?/? If so, would I still have a good cone spray???


Thanks.

hmmm how HIGH is your idle ?

I have to run my car for hmm two minutes before my idle drops down

I warmed it up past operating temperature and it was idling about 700-800. It drops under 500 when I shift, and thats when the hissing starts. If the intake was leaking, would that cause a hiss from the TBI??? I sprayed carb cleaner throughout the intake but nothing happened.
If I unplugg the TPS there is no hiss. If I unplugg the IAC there is still hiss.

My blades seem to stick to the tbi if I take the idle air screw in lower, and my linkeage does not move back anymore.

Idle sounds about right .. .typical would be around 750 .. sometimes up to 800 .. often a bit lower.. like 650-700

Throw a towel over the TBI ... and see if it still hisses *lol* I did.. and discovered it was simply the TBI sucking in air

Oh dude, belive me I know that TBI sucks air. Its like the first thing you learn with an open element.

I guess what am saying is that its hissing waaaay more than usuall, and when it happens my car works like crap.

The hiss comes after acceleration and not during which should be the case.

Its a strange hiss through the TBI as if its sticking or something is making it suck air after the gas gets in.

I am really stoked to what the problem is, and I migh be replacing the throttle body. I went through every single damn test for vacum, intake, TBI gasket to the intake. Its just puzzling why it would suck afterwards. So, my last thing would be to put in the old stock chip in and go from there.

The hissing does go away if the TPS is unplugged, which leads me to belive that whatever is sending the signal to the TPS is either faulty or is making it stay open longer. Which in that case makes me wonder what sends the signal to the ECM that makes the TPS stay open longer after acceleration.

Maybe even EGR.... damn,... here we go again.

The IAC is opening up to compensate for the low idle, which is causing the hissing noise your hearing. The IAC is opening because something else is causing the motor to bog down, the hissing isn't the problem, something fuel related is. You said your AFR guage goes way lean when it bogs, right? That makes me think that your pump is giving out causing your idle to go low, so your IAC opens to compensate, of course with more air going through the IAC you get the hissing sound. When you unhook the TPS the ecm probably just locks the IAC at a set postion, probably closed enough to keep it from hissing.

Find out whats causing your to go lean, a vacume leak WILL NOT cause your to go lean, the MAP sensor will see the drop in manifold pressure and compensate with more fuel.....if it has the fuel to give the motor. A vacume leak on a speed density system is no different than opening the throttle.

I've got 10$ that says it's the pump.

BBMonteSS, I am pretty sure that the pump needs to be replaced. However, how can I run rich past 1/3 throttle. I thought pumps give out and not just "ache".
I idle sometimes borderline rich, and sometimes my idle will go from rich to lean, and off the charts, than come back up and the car would feel the same.
After I accelerate it hisses a bit. Its like the hissing and the gas are not in sync. Would IAC be in play after I let of the gas pedal???
I checked every fuse, and I have a new fuel pump relay and I can hear the pump priming when I first go to start the car. However I do turn for about 15secs before the motor turns on! Could that be telling me something.
Maybe the relay is out??? I can hear a relay trip when I first start the car though??


Oh by the way, when I tried to release the perassure of the lines I did what chilton told me. I took the fuse out, I let the air out of the tank, and when i crancked the engine it never died. How's that. IT ran horribly but it never ran out of fuel????

Oh, sometimes, if the car wants to, runs perfect without a single problem!???
Could that still be the pump or maybe something electrical???



What would you guys check if the electrical stuff is to be checked???

I replaced the distributor,
I've got MSD blaster coil
New cap and rotor
New wires and pluggs.
Timing 0 base. (I am putting it to about 6 advanced though, it starts a lot better advanced).

What else should I check??

Note, my 8 plugg I did not change and it has about 8K miles on it.

When you lift off the throttle, the throttle follower routine is in effect. This opens the IAC and keeps your rpms from dropping too fast. Try it at idle, you'll notice your rpms hang for a second before returning to idle.

Pumps do "ache" most people have some form of drivability problem before they let loose. It's also easy to confuse a lean smell with a rich smell. Most people don't realize that being way lean will also cause a smell. It smells differently than rich. Kinda acrid and funky, while rich smells alot like gasoline. Also your ecm may be trying to compensate for the lean condition and when the fuel pressue comes back be way rich. The best way to diagnose something like this is to datalog and see what the sensors are telling you. If you only hear the hiss when the IAC counts are high, then you know thats what is making the hiss. You can save alot of time by seeing what the ECM sees.

Alright u got me convinced. Fuel pump is going in soon. I'll let you all know if it was the pump or not.

Hey I noticed when I drove it today that my idle got crappier once I turn my lights on and my heat. The RPM's droped maybe 200-300RPM;s down.

Hmm... I know some of this is normal, but how normal??

It could be something electrical causing your problems, or it could be that your idle is so crappy that just the extra load of your alternator is draging your idle down. I don't suggest aimless parts replacement. Proper diagnostics via a fuel pressure guage and or datalogging is going to keep you from replacing a bunch of stuff you don't need to.

Time to invest in a ALDL cable .

Its almost snow time in Denver, so I tried fixing it before, and it seems like I'd be doing some work in the snow.

Thank g0d that I have a coverd parking spot.

When I do the ALDL data logging I should probably drive it right??

Thanks a lot for your help.

I'll let you all know what the problem was.

Dony know if its been mentioned yet but the ecm self calibrates the TPS on its own. As long as its not too low or high your fine.

Would a bad pump have symptoms such as crappy off throttle response. Working fine right after start up, and over 1/3 throttle?
I'll post some scans once I get the cable.
By the way, Dimented, do you know how I can build a cable for cheap. I am not good with schematics, maybe some pics or sumtin.
THanks a lot.

The cable shouldnt cost more then $10, assuming radioshack still stocks the parts. Seems all they have now are cell phones and other electronics for the typical brain-dead consumer

Its not much more then some wire, a transister, some resisters, and a serial connector. All it does is invert the signal from the ALDL so the laptop can read it in properly. Just follow the schematics for the single transister cable and you should be good. Just make a not to look at the package that the transister comes in and make sure you hook up the right pins. C=collecor, E=emitter, B=base. You should be able to compare the schematic picture of the transister on its package with the schematic for the cable to determine what pins to hook up. Would take a pic but I no longer have an ALDL cable. Sold it several years ago to another member here at TGO.

The other thing to be mindful of is that in the schematic he gives the pins for both a 9 pin and a 25 pin serial port. You see a 2/9 and a 5/9. The 2 and the 5 are the pin #'s. The /9 is what connector it is. You want to follow only the ones with the /9 after them. The /25 are the pin #'s for the 25 pin connector, which no one really uses anymore.

Heres teh schematic.

Thanks, i'll see what I can do. I know how to wire stuff, but transistors are somewhat beyond me.
Do you by any chance have a parts list. If not I'll just take the schematics to Radio Shack and see what I can comeup with.

At least I got the sauterer (spelling)

Grand discovery today.

For the heck of it I checked my relay and my oil preassure sender. First of all I noticed that with the key in the on position, but the car not started my pressure will go to about 30 than drop down and fluctuate. This was kinda interesting to me so I went around inspecting wires. Most of them were in the protective plastic, so i followed them and I moved them around a bit. Than I played with the wires that go to the feul pump relay connector. They were all stripped about half inch before the connector and some of the connections were pulled back. So I pushed them all back in and my car performed a lot better. Once in a while will it bog, but most of the time it felt like it was before. So, I am thinking that I migh have to re-wire both of the connections and maybe even replace my oil pressure sender. I bought a new one but have no wrench to take it out. DOes anyone know how to take it out???
I am thinking that this might be parts of my problem since my car performed like a champ and the ilde was good too. It only once went up a bit and immidiatelly droped down to where its supposed to be. I know that it must be a wiring problem/sensor problem now.
What would you suggest.
Should I just go buy another connector to the fuel pump and wire it in???
How can I change that sensor, any pictures of the tool???

Thanks.

Anyone???

My wires for my fuel pump relay are the same way. Must be the angle the wires come in at. A new connector is probably available from autopartsgiant.com. They have alot of replacement pigtails available from A/C Delco and others.

As for the sender, a wrench is all you need if you have the standard one along the rear of the engine. It just screws into an angled brass fitting. Theres a square nut portion on the bottom of the sensor. IIRC, its something like 1/2".

Mines by the bottom by the filter. It is over 1" big. I know cuz my biggest wrench 3/4 wont even come close to fitting it. It is just at an akward angle and I have headers. SO its even more of a pita.
Do you if there might be a socket for it???

Yes, there's a socket for the sending unit. I had to buy one because it is over 1" like you said. It fits perfect in there and is deep enough so it won't hit the large plastic part of hte sender.

I got mine from Pep Boys, its marked late model oil sending unit socket or something to that effect. Looks just like a deep socket.

I will try to get that from my local pep boys.

Now my starts are longer than usuall. I am not sure I am hearing the pump prime. I advanced the timing to 4 degrees.

The most important problem I am seeing is when the key is turned on without starting the car, the needle jumps up and down from 30 to 10 and up.
Once the car runs the pressure is fine.