Georgia Fiero Club Forum
All Things Fiero => Tech Tips, Tech Questions => Topic started by: The Art Doctor on December 07, 2020, 05:26:49 pm
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OK time I started a thread to fix the issues that are starting to creep up with regular use and bonehead operation.
#1 current high idle issues: seems stuck between 1800 and 2000 which makes driving no fun.
Since pulling the distributor I have been having very high idle issues. I pulled the intake rubber snorkel tube today to to block off the idle port and check for vacuum leaks. Well something is up. Before when I had a high swinging idle issue I covered the small idle port the car would die. Now it drops way down to 500rpm and keeps running. I sprayed ether and used propane all over looking for a vacuum leak with the idle port close off and no dice. Listened all over too and cannot hear a leak. I next covered the whole throttle body opening and it dies. The extra air must be getting in around the throttle plate because it is not getting air from anywhere else I can find. I am not getting throttle to reset properly? The factory plug over the adjustment screw is in place.
#1a I was not getting a check engine light but tried to see if there were any codes. Well I was not even getting the 12 code so I tore apart the dash to find no bulb. Put in the bulb from the seat belt light and get the normal 12 and a 21 for throttle position sensor. The light does not stay on all the time but the code is there. Could this be part of the idle issue? It has had a buck and stumble around 3000 rpm just off and picking back up the throttle. I have a spare from Charlie to try but have been afraid to change as the screws seem stuck. I only tried removing with a screwdriver like handle tool and I could not budge them. If I use a wrench to get leverage and break them off what is the recourse? Drill and tap? lightly nervous about messing this up.
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While reading your first paragraph describing the problem and steps taken, I was already formulating that it might be the throttle position sensor. It could be that the stop on the sensor has been bent, holding the throttle slightly more open. You can bend the tang back slightly.
Should you snap the screws in the throttle position sensor, I have several intakes with throttle bodies still attached and I know I have at least 1 throttle body alone. Something you can do before trying to remove the screws is to place a drift or punch against the heads and give them four or five good bumps. You could also spray them with a shot of keyboard cleaner. Turn the can upside down so it sprays liquid. Do this 3 or 4 times letting them defrost before the next shot, bump them with the drift and then try to loosen them. That should shrink the screws and the bump should free them. Of course, put some never seize on them when reinstalling.
An impact screwdriver is also very useful in this situation. https://www.harborfreight.com/search?q=manual%20impact%20screwdriver
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Another potential issue is carbon deposits. Deposits build up around the IAC hole, but can also block the throttle plate. I wonder what would happen, if you blocked off the IAC tube, rather than the IAC hole.
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Cracked EGR tube....... may have been bumped pulling distributor
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Somehow, I thought that had already been checked.
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The wife told me to put on my big boy pants and just get out there and turn the screws and if they break just deal with it. Ill try the tricks above and hope for the best, tomorrow, when its not dark, hey is that a cat over there.....
The EGR tube is a Fiero Store braded hose type, not so easy to crack as a stock type. https://www.fierostore.com/Product/Detail.aspx?s=67019
Yes, it could still be the culprit but I did give it a heavy dose of combustible gas and it had no effect on idle RPM. Can it be removed and blocked off without having to disassemble anything else? Enough room to turn the two bolts out without having to mess with the manifold itself?
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Yes, some have done it, but it's a tight space to work underneath the manifold. You would need blocking plates for both ends. There are also some reports of burning pistons when the EGR system is deleted.
Try bending the stop tang on the TPS before delving into the alternatives.
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Has the intake ever been removed? Did Alan remove it when the plug blew out? Or has the EGR tube ever been removed? Has the throttle body ever been removed?
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The intake end is very tight. I think you could block just the intake end, temporarily.
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I know the intake was removed to replace injectors just before I got it. No idea if the TB has been messed with, but the bolts don't look boogered up.
I don't recall bumping the TPS arm but it certainly is part of some issue as its throwing the code.
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Code 21 indicates a high voltage. Does anyone know if the voltage increases as the throttle is opened? If it does, that may be a good sign the stop tang position has changed.
Voltage to the tps should be 5 volts. You can test the voltage feed by probing the feed wire with positive lead on a meter and grounding the negative lead to the frame, not the engine. Ignition should be in the ON position.
I found this on testing for high voltage on a TPS.
I’m not sure why you are getting such a high voltage, but you are making one mistake when checking TPS voltage. The ECM sends a 5 volt reference voltage to the TPS which passes through a variable resistor of the sensing circuit. This of course is connected to your throttle pedal. When the 5 volts passes through the resistor of the TPS, the voltage will vary based on the position of the throttle plate. This is how the ECM knows what you are doing with the gas pedal.
You can test a TPS in two ways, You can simply test the resistance with an Ohm meter or you can test the voltage change that occurs in the reference circuit. The mistake you are making is connecting the multimeter to the negative battery post. You need to connect one end to the 5 volt reference sent to the TPS from the ECM and the other lead to the center wire coming out out of the TPS. This is what they mean by inline. While doing this, with the key on, move the throttle plate and the voltage should change smoothly. It is the smooth change in voltage or resistance we are looking for. If it glitches, jumps or just doesn’t change, you need a new TPS.
To add, a TPS won’t make a car not start. You need to check the fuel pressure, check for spark and injector pulse.
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TPS was it. Yippie it worked. I use an impact driver to loosen both and was successful on getting the top bolt out whole. The bottom one loosened and made around two full turns before the bit finally stripped out the rusted female t25 end. With it now loose I could slowly grab the head swing the TPS around and with vicegrips slowly worked it the rest of the way out resetting each 1/4 turn. These must have been factory bolts as they had blue thread locker on them and the TPS had the factory paper label.
Idle when right down, actually better than before. Fairly stable between 950 and 1025. I guess it was fully unrelated to the distributor but funny that it decided to let go at just that moment. I have only taken if for a short ride but it was running super.
I switched the ICM back to the new one this morning to see if it would help with the stumble which came back with the old unit. This was prior to the TPS switch out. I didn't notice a stumble this morning but it is irregular. Drive time will tell.
Now the code is still there, I checked. Is it worth it to resent the ECU again or just leave it be as its working?
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Disconnect the ecm power near the battery anytime you replace a sensor thats read by the ecm. That way if it comes back you'll know for sure that you have an issue.
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Glad it's getting sorted.
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Next issue. The factory installed belt squeal remedy. Should I go with the Rodney Dickman fixed idler pulley and longer belt or Dodgerunner's spring active belt tensioner? Rodney's looks easier to install so I'm leaning that way. Any opinions?
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I personally think the auto tensioner was a god send in the auto industry but that's just my professional opinion. and i hate adjusting belts.
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The spring tensioner will be more user-friendly in the future when you must replace driven components or the belt itself.
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I have dodgerunners kit and it was easy to fit, though I was already doing stuff in that vicinity which may have made it easier. There are destructions in his thread on PFF. I think he sent me a copy of destructions when purchased if you need em.
I haven't seen Sir Rodney's kit but I am sure it will be up to the normal excellent RD standards.
What a lovely dilemma/choice to have
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I installed Dodgerunner’s kit over the summer and love it. Not too hard to do. Figured I would upgrade the alternator while in there. I had a lot more trouble getting the old alternator out than installing the kit. Thought about Rodney’s but went with Dodgerunner.
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Rodney sells great stuff. That having been stated, the tensioner pulley is the way to go.
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There is an article on the idler and tensioner in the July 2019 newsletter.
If you do the install, an install article would be nice.
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The dodge runner kit was easy to install and is a complete solution to the problem.
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My 86 has somebodys kit on it, but it would constantly squeal anytime someone spit on the road. Replacing the splash shields fixed it
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If it was spring loaded it was Dodgerunners. Otherwise it was Rodney's.
My 86 had Rodney's pulley on the old engine and it was removed when its first new engine was installed after I bought it, due to squealing.
Not knocking Rodney's products. I prefer them. It's just that 1 piece didn't work for me.
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The tensioner pulley is awesome.
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Looks like it will be Dodgerunners. I'm pretty much over hearing the squeal every time I start it. Certainly its much worse with some rain. The neighbors probably agree its time to fix it.
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Can't wait to hear your results.
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Did you install the tensioner pulley?
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I have it but have not installed it yet. Transaction with dodgerunner was smooth. He had just sold his last two. So it took a bit to make it and paint it. It still smelled like wet paint when it arrived. Took about three weeks total between first contact and parts arrival. I told him I was in no hurry. Still not on a hurry to install as it has been a bit chilly or raining but weather is getting better.
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Got it installed today. It was real nice outside. On pennocks several folks said they did it in an hour but it took me three, which included driving to a friends to find an 18mm socket. Each of my three metric sets skip 18mm. Apparently only GM and Mercedes use an 18mm. I was told none of the Japanese cars do so its not a common size. I tried to follow the directions but wound up taking it off and putting it on in a different order. There is a small secondary support arm that was much easier to put on first. I then got the big bracket back on, aligned and tightened it all up. Adding the tensioner is a one bolt deal but it takes two people to put the belt on. There is a lot of force in that tensioner and moving it takes both hands leaving none to fish the belt around. Good thing I have a helpful and interested spouse.
Squeal is gone.
Next is dew wipes. I have a pair of outers I was given with the car.
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Glad the squeal is gone. How long was the handle on the wrench you used to allow the belt to slip on?
Gonna write an article for the tensioner install?
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Larry, I have a loaner dew wipe tool if you need it.
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I used a 9/16 wrench on the tensioner it is only around 9" long. There was a tab on the tensioner backside that the open end could slide over and grab onto. I have a lot of tools but never just the specific one for the job. A length of pipe might have helped but there is not much room to work. I just muscled it over and Michelle slipped the belt on. This would be near impossible by the side of the road and definitely a no go for a single person on a hot engine with limited tools.
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I just muscled it over and Michelle slipped the belt on. This would be near impossible by the side of the road and definitely a no go for a single person on a hot engine with limited tools.
See, easier for married people ;)
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That tensioner doesn't have the square hole for a breaker bar?
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No square hole. A real long open end wrench is your best bet. There is a lot of spring force there, pinched a finger or two trying for a while to get it done myself.
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About a month or so back I lost a lower front caliper bolt. Quite a ride as the caliper swung up, shaved out a shallow ribbon of aluminum inside the rim before it finally wedged in the rim locking up the right front doing about 30mph just down the street from the house. I threw it back together with a new bolt, and drove on up to Carlisle, but I certainly tweaked at least one thing. Been having some issues during breaking and a repeating squeaking noise with some clicking all coming from the right front as witnessed by a friend sticking his head out and listening while costing down hill. I took it apart again today and can see/feel the rotor is warped. Bearings/hub and ball joints/tie rod all are tight and good. Rotors, 4 options, are between $13 and $22 on Rockauto, neither Advance or NAPA has any in stock locally. I need to pick out pads, they offer the usual variety Ceramic, Metallic and Semi-Metallic which do I pick?
Second issue, If I bent the caliper too there are none available. RockAuto, Napa and Advance all only list a reman left front for 88's. Same on eBay; only reman lefts no rights (even used) Should I get a extra left front for the shelf before they are no longer available? There was a listing for Dorman rears on ebay??? do those fit a Pontiac 6000 as well as it was listed for both? I thought rears were unobtanium.
Third issue, though unlikely, if I bent the rim too anybody got an extra 88 Formula/GT front in black they are willing to part with? Might be a good excuse to go 17"......
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I have right and left front calipers on my 88 parts car, and i also have 88 gt/formula front rims.
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Wasn't there also a front rim among those I brought for the parts barn?
Larry, didn't you say you replaced the missing slider pin with a bolt? Was it a brake slider pin for the 88 or was it just a bolt?
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Last time I looked (a couple of weeks ago) calipersonline.com has rebuilt calipers for 88s. They only do the rears on an exchange basis, since cores are made of unobtainium.
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Charlie, I used an appropriately sized bolt. It is the same one TFS sells. I just got it at my local ACE . https://www.fierostore.com/Product/Detail.aspx?s=56725%20%20%20%20%201988
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Every time I remove a caliper, I reinstall the bolts with blue Loctite or similar.
I've heard enough stories about 88 caliper bolts going AWOL.
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https://www.ebay.com/itm/154453251383?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200818142055%26meid%3Daa43377be88a401694330ffb35bd82aa%26pid%3D101113%26rk%3D3%26rkt%3D12%26sd%3D184894625544%26itm%3D154453251383%26pmt%3D0%26noa%3D1%26pg%3D2563228%26algv%3DDefaultOrganic%26brand%3DCardone+Industries&_trksid=p2563228.c101113.m2108
They have both sides listed in separate sales, +$50 core. Calipers online makes you send yours in first then if they can be rebuilt only then will send you out a rebuilt pair.
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I looked it up, apparently this happens a lot to 88's, because they upped the torque spec from 45 to 85 for 88 only. This is only in the factory 88 manual so folks used to 84-87 under tighten them. ALL 4 calipers were at only 45ish, obviously tight now!
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Last time I looked (a couple of weeks ago) calipersonline.com has rebuilt calipers for 88s. They only do the rears on an exchange basis, since cores are made of unobtainium.
Mine came from calipersonline. Since then, there have been some changes, supply issues, etc.