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Cars > redraif’s Garage > Blog > 1984 Pontiac Fiero (Stormtrooper)


2005: Spark plug HELL!

By redraif

Filed under: 1984 Pontiac Fiero (Stormtrooper)

To stop confusing folks: This happened back in 2005 when we were first getting the car going. Since then the car is doing fine. The repair held and compression was restored

Ok we thought when we were doing the initial tune up that Joe, who leneded a hand with the once over on the fiero, swapped out he plugs. Though after looking at them he might not have. They look like they have more run time on them then 70 miles... and we sure did not install them in this condition...

Here is one that had no gap and its .025 partner.

The 3rd one had .040 gap (its not pictured)

Now here it the one that got beat up royally. What on earth could have caused this? The electrode is bent over and smushed sideways. The side of the plug is all knarled up... I hope the engine did not do this!

So they came out of the head like this:
Condition of plugs driver side to passenger side:
Smashed, no gap, .025, and lastly .040...

First thought was that this was the wrong plug and it was too long for this application....

Here is the number of the AC delco plug...verified to be correct from Advance Auto parts...

I even had them pull other plugs from other manufaturers to be sure there was not a part number mix up and this one is too long. Well all the other plugs are the same depth in the spark plug hole...

So believe it or not the car had been running with the plugs like this, not well, but it ran!

So I bought a new one... gapped them all to .060. Once installed the car finally purs instead up bucking and sputtering.

Well then the real fun began....

I heard a ticking and the car was not running right...

So we got to thinking maybe we need to further clean the air track on the car to be sure a carbon build up might not be the culprit for the sputtering under load. Plus the seafoam clean we planned to use could also point up to the exhaust leak. We had read that the 2.5s tended to crack the exhaust manifolds if water leaked on them when they were hot. So I was concerned was it that or had I blown a gasket???

So we started the car and ran the seafoam thru the Throttle body. Well I got smoke from an exhaust leak, but I was having trouble pin pointing it! So I looked closer and notice a plug wire was laying on the exhaust. It was all charred. I thought great the leak had toasted the wire. Well I got to looking further and saw the sparkplug was a mess as well. Thought great a big leak. Still was not pin pointing the leak. So I shut the car down & let it cool so I could check out the plug.

When I went to remove the plug it was horribly loose in the head. I thought WTF??? I know I tightened it down! Well when it came out I got my answer!

So over to the parts store I went, plug in hand. Well tom my parts guys was amazed. He is and older guy who has been working on cars as a hobby all his life. Well he took a look and said he had never seen this before. Well then a retired mechanic buddy came in and he also had not seen this before. So Tom figure what must have happened is the electrode in the spark plug got damaged somehow. (I'm thinking it was the one that the gap was closed on then we regapped) Well when it got damaged it started to spark out thru the side of the plug and ground on the head. Thus melting the plug....

My theory...This melting of the plug allowed for vapor to escape out beside the spark plug. This loosened it further in the head and allowed it to move arounf enought to damaged the threads, thus allowing even more vapor to escape.

So the plan was, get a new plug, obviously... Then compression test the car, to be sure the threads were not TOO damaged. So I did just that. A healthy cylinder tested around 120, this one... 50. Yep threads are bad! So it was off to Summit for a spark plug tap and heilicoil kit. Well I vasolined the tap per the guy at summit and tapped away! Then for further clean up I used a telescoping magnet to get any metal out of the cumbustion chamber. Next came instaling the heilicoil with high temp RTV per the instructions. SO I used Ultra Copper. Once installed I installed the plug per the directions and waited 24 hours for it to cure!

So then I fired up the car and poof, no exhaust leak! Go figure. Amazingly the plug wire was fine, but the boot was charred. Just to be sure I got all new ones that were swapped out.

The repair list to date

By redraif

Filed under: 1984 Pontiac Fiero (Stormtrooper)


Oil Change
New belts
New pcv
New Air filter
New Valve cover gasket
New used valve cover
New TB gasket
New vacuum lines (red silicone)

New battery (4)
New dist cap and rotor button
New wires
New plugs
New starter (2)
New coil
New grounds, cleaned all mounting points
New ignition switch
Fixed previous owners rewiring disaster of all power wires and cut A/C wires

Cooling system...
New coolant hoses (all)
New radiator cap
New thermostat cap
New thermostat
New temperature sensor (ECM)
New temperature gauge and pod to hold it (original broken even with electrical repairs made)
New water pump after it sprayed like a volcano out the weep hole
New coolant (obviously) LOL!
Rigged fan to run on ignition hot to bypass bad switch

New fuel filter
New fuel pump

Transmission (manual)
New clutch
New slave (2)
New master cylinder
New fluid
New used clutch arm and petal
New driver’s side axle

New EGR gasket
New O2 sensor
Cut off defective water logged stock catalytic converter & water logged stock muffler
Replaced with 2.8L (1.5inch) Firebird piping, 1.5inch cutout, and Flowmaster muffler

New front calipers
New pads (all)
New rear rotors
New stainless braided brake lines
New park brake cables and equalizer
New prop valve
New master cylinder
New fluid
Adjusted rear caliper's parking brake arms to make PB function properly (still INOP)

New shocks
New struts
New passenger side front lower ball joint
New passenger side cv axle inner boot

Body stuff
New used spoiler (original split and was full of water)
New used trunk carpet (original water soaked from leaky spoiler)
New used tail lights (original melted)
New used rear view and side mirror
New inner and outer dew wipes
Lubed and cleaned power window motors and switches
Replaced busted door lock inner rod connector
Drilled holes to help w/ sunroof leak per GM service bulletin
Replacing ribbed body side molding with smooth.
Patched holes in the floor and firewall

Replaced headliner fabric
Pepaired headliner board
Replaced and or cleaned all interior panels
Repaired radio console, center console, and internal framework

Getting the car running right (the never ending saga)

By redraif

Filed under: 1984 Pontiac Fiero (Stormtrooper)

When I first met the car it would not roll one bit. It was drug and pushed on a trailer by 3 guys, 2 girls, my Mom and I. The crappy calipers that GM used commonly seized when they sat for along time. The seized brakes meant all new flex brake lines at the calipers, along w/ new calipers and a fluid flush. So while I was at it, what the crap, throw on new shocks and struts.

Ok so it would roll, now for the clutch issue. A new clutch rod lead to a new slave cylinder and clutch petal. The clutch petals in this particular year liked to bend over time and eventually the car would not let the clutch disengage when the petal is depressed.

After a full tune up, oil change, and all new coolant hoses and fluid, it was time for the first start up... Well It was a no go. I had a bad starter too. For ease, the stock cat was cut off to get the starter out easier. Well the whole exhaust was FULL of water, so off it came too. When the new starter went in we discovered a landmine of red 10 gauge wire leading all over. There was wire wrapped around the suspension. I cleaned it up and removed 10 feet of access and we were in business, or so we thought. Seems someone did the big no-no. They must have taken all the plug wires off at once and then did not know what order to put them back. They were so off.

So once we go that sorted out... and after a few minutes of run time, we noticed the radiator fan would not kick on. After some investigating we noticed a odd looking rigged up switch on the fan. I was not about to try to figure that rigged up mess, so I just straight wired the fan and off we went.

So finally, its first voyage... to the muffler shop and alignment shop. Well it made it only a few miles to throw its new v-belt. Well once the alternator was tightened up the belt stayed. Then as we attempted to continue on it would not go into gear.

This time it was the clutch. We installed the new one in, but it was defective, so then we had to do it all over again. All seemed well, but then the master cylinder went out, followed by another new slave cylinder (Autozone crap).

So the car was engaging fine. We were finally done and then tried to start the car. Now the fuel pump is not priming. So now a new fuel pump, ugh! Drop the tank, new one in, but now there was no spark. Traced it out.... It needed a new coil.

Finally it ran, but wait...what's this, the water pump gushed coolant after 20 minutes of run time... Ok replaced it, then it needed 2 new coolant sensors to fix the fact that it idled at 2x the RPM it should. That and replacing the TPS and a few rotten vacuum lines.

Now it ran OK. I drove it a few weeks and boom... it went nuts. I was driving along and the check engine light came on and the car just started bucking and stalling with the CEL on. I got it pulled over at a gas station and tried to pull the code. The CEL light would then not come on at all. So I let the computer cool down. I had once heard that would work in some cases. The car limped home and I replaced the ECM. While I was in there I added a temperature gauge and fixed the rigged up wires and hole in the firewall.

I still needed to clean up the engine bay to be sure there were no oil leaks as the Dukes had a rep for having engine fires. Well the car got pressure washed to get most of the crap out. The firewall's heat shield padding had to be removed as it was oil soaked and torn up. Well I confirmed 2 leaks. The passenger side rear axle was bad and had to be replaced. I found grease due to the torn boot.

After the cleaning I found the valve cover was leaking horribly. I tried to use a gasket, but this was not going to do it. The cover leaked more. Research showed the 84 cover was meant to use RTV and had dimples in the cover. I got a new cover. Tamped out the dimples used RTV, and the flat long load spreaders off my Firebird's valve cover. It worked. I had to also replace the rubber grommets in the cover as well and no more oil leaks.

After driving around sounding like a deranged go cart, I finally got the exhaust sorted out. The final trick was to cut up the Firebird's old exhaust and piece it together for the Fiero. It actually worked great. The Flowmaster gave it a great deep sound for a 4 banger.

Finally a driver... only thing I still have to work out is the darn intermittent starting issue I have. I fixed the neutral safety switch as well as replaced the ignition switch. The starter went bad again and was replaced under its lifetime warranty. Whew! My best guess it that it leads back to the rewire job the previous owner did to the power wires. He eliminated the fusible links and straight wired everything. Like I said earlier the wires were wrapped all around the suspension and had to be sorted out.

So to start I replaced and cleaned up all the grounds. I think I will add a few more and check the ones up front. Then it on to replace the power wires and add back either fusible links or some type of fuse block in the engine bay. Now If I could just get the info on what the correct sizes are for what system and how to convert that into fuse sizes...

Cars > redraif’s Garage > Blog > 1984 Pontiac Fiero (Stormtrooper)

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