Ok. I will try to make this as short and explanetory as possible. I have an 87 Fiero GT 2.8. I've replaced the plugs, wires, hei module, cap, rotor, vaccum lines,TPS, AIC, throttle body, ECM, prom, and a bunch of other stupid things along the way. Ok when I got the car it would run extremely rich, hesitate, and not idle. I replaced everything above and it halped nothing. Today I just received my Hypertech stage II performance chip and installed it. NOTHING, it still runs like hell. I'm not getting any codes at all. if I make it to the road and get the car above 3000 RPM it runs great, it still runs really rich though. IF and when I can get it to idle if you step on the gas it sputters and dies. then I have to hold it to the floor just to get it started. Please guys I need some more help. I have almost every automotive tool/tester known to man and this car fools them all.

ALSO I saw today that when I hold the car at about 3000RPM the tach seems to jump around a little (like 2-300 RPM).Thanks in advance to all

[This message has been edited by GT-O-YA (edited 02-20-2004).]

have you set the timing? If so, what did you set it to? And did you ground the diagnostic terminal while you set the timing?

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Three questions: 1- Did you replace your O2 sensor? 2- Is your timing set properly? 3- How good are your grounds?

WOW you guys are quick. I'm fairly sure the timing is set right. I did ground the terminal, and I set the timing at 0 degrees (as per manual. but I'm not completely sure where the timing marks are though. Yes I did replace the 02 sensor when I first got it but it could be plugged by now from all the carbon And third I'm fairly sure the grounds are ok but not 100 percent.

quote Originally posted by GT-O-YA: WOW you guys are quick. I'm fairly sure the timing is set right. I did ground the terminal, and I set the timing at 0 degrees (as per manual. but I'm not completely sure where the timing marks are though. Yes I did replace the 02 sensor when I first got it but it could be plugged by now from all the carbon And third I'm fairly sure the grounds are ok but not 100 percent.

wow...0 degrees? Factory setting is 10 degress BTDC. I'd look at the timing. If you're not really sure where the marks are, then you likely have it incorrect

Dave

Leaky injectors?

Well the shop manual I have doesn't give me a reference as to where the timing mark is. I just happen to find one. It also says that on my year car it should be 0 degrees. Can anyone give me a reference as to where the timing mark is?

Yeah, the timing should be at 10*. If you look at the pointer down by the crank pully with a flashlight you can see the numbers on it, and that will tell you which notch is 10*. You might have to wipe the dirt off it first. If you have a scanner that shows you all your sensor readings check your Coolant Temp sensor. If it reads -40*F, check your connectors to it and it's circuit. A bad coolant temp sensor can make a car run rich and like crap also.

Wow......you're running rich as hell........duh! Could be so many things in the fuel system. Assuming you don't have.....or are able to buy or borrow a fuel pressure gauge, I'll give you some things to check. However, if you can beg, borrow steal....lol a fuel pressure tester, we can prob solve this problem quite easily.

If you have no scan tool, I would replace the coolant temp sensor and unplug the cold start switch. It would be most helpful to know if the cold start injector was working properly......on only until the car gets warmed up. You could do it, but it's a bit of work to remove the cold start injector. The reason to do this is to prove that it is not still leaking fuel after the car warms up. That's why you unplugged the cold start switch.

Anyway, if you, replace the coolant temp sensor, there is very little chance that you will have 2 bad ones in a row. This assures that the ecm really knows what the engine temp is. If it thinks it's 4degrees f , then it's gonna shoot the fuel to the engine......prob twice the normal amount at 60 degrees f.

Anyway, spend some time and get a feel for it and check some other stuff on it. You'll get an idea of how the system works and about a 85% success rate.........LOL

Phil

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87 FIERO GT 2.8 5spd

GM auto tech for 27 years. Specializing in electrical and computer problems. Now on workers comp. and it looks like I will be unable to return to work as a tech.

When reading through this I would of said a bad injector or two but then reading what you said about the timing it began to sound like you are over your head and wasting a lot of money. I would suggest taking it to a shop.

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What the others said. Timing should be around 10 degrees advanced.

Have you checked your fuel pressure? It should be around 40 lbs at idle. If it's way higher, your fuel pressure regulator could be defective, or the vacuum line could be unplugged or blocked.

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Raydar
88 3.4 coupe.

Coming soon...
88 Formula, presently under the knife.

[This message has been edited by Raydar (edited 02-20-2004).]

Ok thanks for the eadvice guys. I did replace the coolant temp sensor. But I was told there are 2 of them? I can't find them anywhere in my manual. I found the one next to the coil and replaced that one but no change. Also where is this cold start switch located? can anyone give me a breakdown?

calm down, woo saa... woo saa... (bad boys II)
make damn sure your timing is set right and that your injectors arent just stuck open. have you checked for a physical restriciton in the intake?. just go aout and change the timing 1 or 2 degrees at a time until you think its running right. just my .02

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'86 Fiero GT

www.KylesFiero.tk
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In my Duke, the temp sensor that feeds the ECM is located a few inches down from the cap in the coolant pipe (thermostat housing), plugged into it.

I believe that in a 2.8L the sensor is further down, in line with the same pipe but plugged to the engine itself, not the pipe/housing like in mine. Also, it is likely that the wires are colored black and yellow.

Beno

The sensor next to the coil is the one that runs your temp gauge and light.
The one that the ECM uses is in the end of the intake manifold, kind of below where the thermostat housing bolts to the manifold.
The cold start switch is also on the manifold. It's the one closest to the right side decklid hinge. There are two sensors in that general area. The one with the plastic connector is the fan switch. The one with the metal spring clip is the cold start switch.

The ECM coolant sensor is located above the waterpump, directly below the EGR solinoid. GM has an updated part# and it's only about $5.00 from the dealer. I would set the timing first.

Also check to see that the cap that goes over the idle speed screw is in place (top of TB). If its missing, then someones been screwing around with it.

Other ideas? clogged cat, leaky cold start or injectors??

Did you look at the spark plugs? If all of them are black then the temp sensor, pressure regulator and cold start injector are all suspects. If only a few plugs look bad it's probably faulty injectors.

I would say look no further then the timing if it is set to 0*. As mentioned above quite often, your timing should be set to 10*. I don't believe the manuals (excluding the helms) even tells you what degree the timing should be set at. The manuals say's "Check the cars VECI LABEL for degree setting". If you check the VECI Label you will see it should be set at 10*!

Short of that i'm with Ski.........."take it to a garage".....if they tell you there is nothing wrong tell them to drive it....if they still say nothing is wrong take it someplace better!

[This message has been edited by camon (edited 02-20-2004).]

quote Originally posted by GT-O-YA: I have taken it to a shop and they all told me to get F***KED! One shop looked at it and told me there was nothing wrong (that was the GM dealership)

WTF!

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The End of an Era...The Thingy is finally absent from my Siggy.

Thanks guys, Sorry about getting pissed off but I've taken it to every shop within 40 miles and none will work on it. I'm heading down to my shop today, I'm going to replace the coolant temp sensor, check the cold start injector, and set the timing at 10 deegree BTDC Thanks again.

This is what the timing marks look like FYI.

have you change the fuel system....try a new filter....it wouldnt hurt
if you have low fuel pressure the ecm could be getting the signal to richin up the mix
and cause all kind of problems. it doesnt hurt to do the basic tune-up stuff.

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I have a 93 Grand Am with 3300 - It had ONE really leaky injector. I had to floor it and crank and crank till it finally started, then lotsa black smoke. It would barely idle - still black smoke and lotsa unburned gas smell. Rev it up and it got somewhat better, but back to idle, and back to barely runs. No codes, but I didnt run it more than I had to. I didnt think one leaky injector could make it run this bad, but it did! It was easy to pull the injectors on the 3300, but not so on a Fiero. Do a plug check and maybe you will see a really wet one or two. Based on all the stuff you have already replaced, I will betcha a dollar to a donut this is your problem!

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Tim
Red 88 Formula Auto 2.8 100K+ Miles - Hypertech - No Cat - No EGR

Murphys Law - "Nothing is as easy as it looks, Everything takes longer than you expect, And if anything can go wrong - it will, At the worst possible moment!"

10* - I replaced my distributer 6 months ago, and my shops computer says 10* (and mines retarded for nitrous 2*).

Hello - I think Spark1 one hit the nail on the head, I hope you paid attention.
Not leaky injectors but DIRTY FUEL INJECTORS. How many miles are your car ? and you always burn high quality American gas. At about 102k original miles on my car, it would die when warm, and if it didn't die the RPM's would jump all over the place.

Drive your car tell almost empty, put some injector cleaner and run ONE bottle through your system. things will improve.
You can always pull your injectors and do the glass bottle test first if you wish.

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FIEROS ARE JUST STREET LEGAL RACING GO KARTS - IT'S ALL GOOD

THANKS TO ALL!!! Well turns out that all it was was a wrong tempature sensor. damit some of those parts guys are complete idiots. Thanks to everyone for the help. ALSO the timing is O BTDC on my car as per veic

quote Originally posted by GT-O-YA: THANKS TO ALL!!! Well turns out that all it was was a wrong tempature sensor. damit some of those parts guys are complete idiots. Thanks to everyone for the help. ALSO the timing is O BTDC on my car as per veic

I was looking through the posts looking to see if anyone mentioned a coolant sensor then I saw your post..... glad ya got it.

[This message has been edited by 84Bill (edited 02-21-2004).]

Just for the record, I have built numerous J-body engines and have had no problem, I'm not trying to sound like a dick but when people come on here and tell you your over your head and take it to a mechanic, (after going to school for 4 years to get ASE certified) you tend to get a little mad. Also sorry I didn't include all the info on the car, I did completely rebuild/replace almost everything in the top end. (injectors, TB, TPS etc. etc.) just one wrong sensor made all the world of difference. Heres a link to my car that I completely rebuilt about 4 months ago. Take a look at the engine. http://www.v6z24.com/registry/importkiller/

I'll bet you 2 Dollars to a Pretzel its either a fuel pressure problem along with timing.
Or it could be 6 of one or one half dozen of the other.

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quote Originally posted by Raydar: The sensor next to the coil is the one that runs your temp gauge and light. The one that the ECM uses is in the end of the intake manifold, kind of below where the thermostat housing bolts to the manifold. The cold start switch is also on the manifold. It's the one closest to the right side decklid hinge. There are two sensors in that general area. The one with the plastic connector is the fan switch. The one with the metal spring clip is the cold start switch.

Oh, poop...lol
I just went and looked at mine because I have been running somewhat rich since I got mine on the road... ONLY getting around 120miles a tank..
One of the sensor's you mentioned above is not even plugged in and I dont have anything from the harness for it..
These 2 sensors are next to each other, ones toward the front of the Fiero and the other is next to it toward the rear... Which is which..?? The one towards the front is the one that I have plugged in. Please tell me this is my problem...

Original post deleted not "value added".

[This message has been edited by DanielKJenkins (edited 02-22-2004).]

GT-O-YA...Glad you got it!
Thanks for letting us know what it was.

quote Originally posted by NotAFieroAnyLonger: These 2 sensors are next to each other, ones toward the front of the Fiero and the other is next to it toward the rear... Which is which..?? The one towards the front is the one that I have plugged in. Please tell me this is my problem...

The one toward the front of the car is the thermal/timer switch for the CS injector. The one just to the rear of it is for the radiator fan. (Does your fan work?!)
The temp sensor for the ECM is the one that sticks straight out of the manifold, above the water pump.

There is one other that may cause the problem... The intake air temp sensor is in the air filter canister. If it's reading incorrectly, it could cause the ECM to think the air is colder than it is, and feeding more fuel.

Also, are you running a stock thermostat?

[This message has been edited by Raydar (edited 02-22-2004).]

One of my 86se was in the shop and the mechnic set the timing at 10 degrees because that was what the sticker showed under the deck lid. I drove it out of the shop and it kept stalling.

I took it back and he set the timing to 14 degrees and it runs great.

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85 GT 4sp black
86 SE auto black
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quote Originally posted by GT-O-YA: THANKS TO ALL!!! Well turns out that all it was was a wrong tempature sensor. damit some of those parts guys are complete idiots. Thanks to everyone for the help. ALSO the timing is O BTDC on my car as per veic

I have never heard of a fiero's timing being adjusted at "0*". I thought they are all 10*?????????????

Glad to hear you got it fixed!!!!!!!!!!!

Well as Quite a few of us know the best way to time a car is to road time it. But most people have lost the touch and the knowledge on how to do it.

I actually timed my GT by ear. Shortly after, I bought a timing light and checked it out. It turned out I had it set @ 12 degrees, which I left as is. Car works like a dream!

quote Originally posted by blazin': I actually timed my GT by ear. Shortly after, I bought a timing light and checked it out. It turned out I had it set @ 12 degrees, which I left as is. Car works like a dream!

Blazin, how did you road time your car? did you do it with the connector grounded, or just advancing the timing while test driving?

quote Originally posted by GT-O-YA: THANKS TO ALL!!! Well turns out that all it was was a wrong tempature sensor. damit some of those parts guys are complete idiots. Thanks to everyone for the help. ALSO the timing is O BTDC on my car as per veic

If you think it runs good at 0*, set it to 10*, or even 12*-14* if you want to run Premium Fuel....

You'll be AMAZED at the difference. You MAY need to retard it for emission's testing if you have that in your state.... No matter what the sticker says, trust the good people on the forum. It should be at least 10* BTDC

Rob

quote Originally posted by Raydar: GT-O-YA...Glad you got it! Thanks for letting us know what it was. The one toward the front of the car is the thermal/timer switch for the CS injector. The one just to the rear of it is for the radiator fan. (Does your fan work?!) The temp sensor for the ECM is the one that sticks straight out of the manifold, above the water pump. There is one other that may cause the problem... The intake air temp sensor is in the air filter canister. If it's reading incorrectly, it could cause the ECM to think the air is colder than it is, and feeding more fuel. Also, are you running a stock thermostat?

No my fan does'nt work... ahha.. Now I know why...lol
I have the air temp sensor in the stock location but, within the last 2 week's though I did add a vent to it DIRECTLY from the front edge opening.. I CAN tell a difference at over 70-75mph. It seem's to have more top end now.
Is that why I am running rich from the extra airflow at higher speed's..??

I am running a 185* Stat. I have a fan switch (which was there when I bought the car.) I just watch the temp and switch it on for a few minutes if needed!