Well, im Suffering Loss of power During accleration, warm Or cold. My Fuel pressure gauge upstream of the Carb idicates steady pressure, So I have ruled out the Pump/filter ect.

It feels as tho The motor is starving For Fuel Occasionally Upon acceleration, At Low RPM, under load or in Park. Filter is New, So Im not entirely Sure what it Could be, Anyone have any Ideas ?

a Friend Mentioned something about the Mixture solenoid, but Im not entirely sure what that is :0

Im also gettting Idiot lights but havent gotten around to decodeing what # it is, can anyone tell me how to do this ? Im new to comp controlled cars.
The car drives Fine at speed, and Idles without problem, its only under accleration at low RPm that it Falls On its face, then suddenyl picks up and Acclerates just fine

Appreciate any Help I can get.


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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

It could be the M/C solenoid. That is the thing with the 2 wires going to it just about where the gas line goes into the carb. The 3-wire plug is to the throttle position switch (TPS).

It could also be some gunk stuck in one of the idle ports. Give it a shot of carb cleaner and see if that helps.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock... all the suspension stuff... 9-bolt posi disk is in... K&N filter... 93 octane...

-=ICON Motorsports=-

 

Okay, I unplugged the Thing above the Fuel Inlet, and it Fixed it, But My secondaries dont seem to be openiong and My gas milage appears to Suck


What the Hell Did I unplug? I thought that was the anti desiling solenoid.



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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

That thing you unplugged was the mixture control solenoid or MC solenoid. It needs to remain plugged for the computer to adjust the richness/leaness of the mixture.

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1983 T/A LG4 w/T-tops
Rebuilt/Modified E Q-jet
Custom Dual Ram-Air
Self painted cherry red w/ restored black/grey interior
Welded Comp Eng SFC
Tokico Struts/Shocks
Hotchkis LCAs and Panhard Bar
Energy Suspension bushings all around

 

Allright, Well, Apprantly this is Malfunctioning in Some manner, Is it replaceable ? I assume it must be, who where and how Much ?


Also, Could this Be Messing Up as merely a symptom of something else, IE something else Reading screwed so the Mixture was being adjusted improperly.

And would that In any way cause the Secondary's to not Open, or is that Just Me leaning out at WOT Cause the mixture is staying at 14.7:1 as opposed to the 16:1 or whatever its supposed to hit at WOT ?



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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

Okay, Update.

I pulled the TCS, and the car seemed to Run pretty well, But My gas milage went to ****.
Also, At WoT the car lacked Huevos, but This makes sense.

I didnt get a Code with it Pulled

With the TCS in, I got occasional Codes At idle, same bogging blah blah

I Put the TCS back in and pulled the MC solenoid, The Car ran the same as with the TCS out, but This time I get a Code all the time.
I dont know about the gas milage yet, But it stands to reason It would be just as bad.

What Does the TCS control on these cars? Seems to me that THAT is the root Of My problems.

How Do I go about replacing it ?

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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

er TPS, not TCS

To many Acronyms.

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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

I've gone through FIVE TPSs! It's a potetiometer that uses a sliding contact that results in a varying resistance. The ECM sees the resistance and assumes throttle position. The ECM uses the TPS, along with some other sensors, to determine fuel mixture, timing, TCC lockup, and EGR. A defective TPS really makes the car suck!

In order to replace the TPS, you'll have to take the air horn off of your Q-Jet. There are 13 Torx heads screws; don't forget the two screws under the choke plate!!!!!! You'll also need to remove the vacuum diaphragm thingy for the secondaries on the choke housing side. When all that crap is off, remove the air horn straight up! There's a buttload of little airbleed tubes and stuff. The TPS is on the forward left corner. Pull it out and put your new TPS in.

Put a new gasket on and use a flat tongue depressor or something like that to hold the TPS down while you put the airhorn back on. Hopefully, the voltages from the center terminal will still be correct.

Pull out your ECM fuse for about a minute to reset the ECM. Put it back in and fire it up! That should solve your TPS problem!

 

OK, you are all screwed up here, you need to take a step back and start over again.
First, clear your computer of all codes. Also, plug everything back in that you may have unhooked. Now drive it around until the SES light comes on again so that you can find out what your real problems.
Now on to a reality check...your loss of power is most likely not related to anything wrong with your computer. In fact, so far the only thing that it could possibly be is a stuck TPS, but even that shouldn't cause a significant loss of performance. The reason i say this is simple. CCCS is as dumb as a rock, and therefore, either works or it doesn't. Enrichment (WOT) mode is the default, so even in the event that several sensors are bad you'll still run fine at WOT, the worst things you'll have to deal with are bad gas mileage and an SES light. If it's any worse, it'll run really bad. Of course, if this is the case, resetting the computer and getting codes out of it will tell you what is wrong in seconds.
I think you need to look at your mechanicals first. Are all your tune-up parts fresh. Vacuum leaks? Timing set OK?

how to check the codes in the computer.
-Get yourself a paperclip.
-Straighten it out
-Stick it in the top right 2 terminals of the ALDL connector.
-turn the key on
-watch the SES light. You will see 1 flash pause 2 flashes, pause, then it will repeat 2 more times. That is code 12 and is normal. It will then flash any other stored codes 3 times as well. When it starts flashing code 12 again you have gone through all the does.
...ed

 

Jrr, have we even verified a bad TPS yet? I'm just curious as to why you would tell him how to change it without even telling him how to check it first. And even better, hoping that it is set correctly after dropping it in, again without checking, which chances are very high it won't be (i have never seen a new TPS even close to being right without adjusting.)
...ed

 

Thanks ed, Ill Check the ECU tomarrow after class.

yeah, My Mechanicals are all Fine.

hopefully I can get this squared away with Your Help.



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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

It was a knee-jerk reply to Bort62's fourth post. Having suffered through five TPSs and seeing the results of what happens when they go bad, his symptoms sounded similar to mine. Normally, I try to include what I did to verify a bad TPS using a common ohmmeter, BUT...I was writing that reply while at work and I heard the boss walking down the hall and I had to click the Submit Reply button and shrink the screen down FAST...y'know how that goes!

 

Normally i'd agree with you, TPS's are the most common problem you can find on these cars when you are looking at a bad gas mileage / poor idle / stumble type situation. I've never seen one cause a real loss in power though. I suppose if it got stuck in the middle / bottom of it's range it might cause some loss of power, but even that seems unlikely, AFAIK the timing curve is more dictated by RPM and VAC sensor input. And enrichment mode would be sure to be had with a low VAC signal too.
I didn't mean to sound harsh, i just didn't want to see him ripping his airhorn off when no real diagnostics had been done yet.
...ed

 

Well, The Car stopped throwing Codes magiacally, The problem Sorta went away for about a week, and Now It Got progressivly worse Untill I had to unplug The TPS today To be able to Drive

Still havent Checked the computer cause Im a Lazy *** , but the car stopepd codeing anyhow, Just runs bad now.

I will Check it tomarrow To see what it has in Memory tho



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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )