94 dodge stealth just puts new plugs in and it has a lot of knocking in motor. it ran fine prior to changing plugs. why would this happen

130

Asked by Apr 27, 2013 at 09:20 PM about the 1994 Dodge Stealth 2 Dr R/T Hatchback

Question type: Maintenance & Repair

what would cause knocking after changing plugs?

46 Answers

104,275

Did you use the proper length plug? And did you use platinum plugs?

1 out of 1 people think this is helpful.
130

yes same length got plugs at orilleys platinum i believe yes

1 out of 1 people think this is helpful.
104,275

It's an interference engine. If threaded end of plug is not the same as stock plugs they may come in contact with top of piston. Also did you replace the wires? If so are you positive that they are installed in correct order?

1 out of 1 people think this is helpful.
104,275

Oh ok that's good. What else did you do other that the plugs?

1 out of 1 people think this is helpful.
130

nothing just changed plugs

1 out of 1 people think this is helpful.

could the computer have reset itself for the new load draw?...creating a slightly sooner spark?

1 out of 1 people think this is helpful.

if there is a way to reset the ECU, would seriously consider doing this, could be as simple as un-doing the negative for 30 seconds, then re-doing it first introducing a load without the negative connected to "cleanse" the system of parasitic galvonic currents- these things are goddamn sensitive, and battery corrosion can make them get weird~

130

its a 3.0 rt no turbo with dual overhead cam

1 out of 1 people think this is helpful.
104,275

Is knock on front or back head or both?

1 out of 1 people think this is helpful.
130

i could try that. couldnt hurt i imagine. its my sons car and i no electronics r a pain. i hate these cars with all the electronics.

1 out of 1 people think this is helpful.
130

both more so in front though

1 out of 1 people think this is helpful.

your knocking is/probably a vacuum hose what's cracked (replace with silicone) as it's cheapo mopar, saw 6 foot length of Gates, in attractive fleshy-tone or amazon or ebay have them, BMW, MINI and other european brands have switched off butyl-rubber, but it's hella cheap to mass-produce....higher idle, less power and coughs out easily all indicators of a vacuum leak, which could have happened while you brushed up against the lines...could check for a leak by waving an unlit propane torch over each line and see if the idle mellows out~

104,275

Did the plug wire boots snap in good and tight down thru the head?

1 out of 1 people think this is helpful.
130

thought about putting old plugs back in to see what it would do

1 out of 1 people think this is helpful.
130

yes seem to snap on fine

1 out of 1 people think this is helpful.
104,275

Torqued upper intake when re installed?

1 out of 1 people think this is helpful.

your ECU continually adjusts itself based on the readings from the 02 sensor, the pressures at the evaporative unit, TPS, MAF, EGR, MAP and another 02 at the cat---makes performance decisions based on this info~ get your diagnostic readings rather than willy-nilly switchin' stuff out--- oK??

130

i dont think its vacuum all hoses r in good shape. it ran fine prior to changing plugs but the old plugs where running rich and needed to be replaced over 100,000 on them

1 out of 1 people think this is helpful.
104,275

Judge might be on to something with the ecu. Disconnect battery for atleast ten minutes. This will reset everything.

1 out of 1 people think this is helpful.
130

yes tighted back down, but didnt over tighten if u no what i mean.

1 out of 1 people think this is helpful.
19,055

hope just carbon buildup till burned out clear ,otherwise piston pin or rod bearing knock not showing till firing as should .

1 out of 1 people think this is helpful.

SOHC=belt DOHC=chain for dodge this year~

104,275

Ok. Plugs running rich? Might be timing issue. When was timing belt last replaced?

1 out of 1 people think this is helpful.
130

ok thanks guys i will try what u both said.. see what happens

1 out of 1 people think this is helpful.

no way Jose, you got the tooths wrong?? nope....uh,uh~

19,055

tune-up thru intake will clean carbon !

1 out of 1 people think this is helpful.
130

i dont know when timing was last done.

1 out of 1 people think this is helpful.

my buddy DavidH25 (bless his heart) suggested once to disconnect the negative, put the A/C on, pump the brakes five times, reconnect~ silly, ain't it?....sometimes the magic works...

1 out of 1 people think this is helpful.
104,275

Also what fuel you running? Has to be 93 octane or more. 10:1 compression ratio. If running cheaper gas with new hot plugs could be predetinating the fuel prior to piston at top dead center. This would cause a knocking sound.

1 out of 1 people think this is helpful.

Think timing is the domain of the computer brain anymore...is like, don't mess with my decisions, now~

1 out of 1 people think this is helpful.
130

anyway i got my boy disconnecting the battery. will see if it resets

1 out of 1 people think this is helpful.
130

yes run premium fuel

1 out of 1 people think this is helpful.
104,275

The non turbos are 10:1 but the turbos ones are 8:1

130

im not a mechanic. im a parts changer if u no what i mean. not a big motor head, but do have common sense. ive changed plugs in all my cars and trucks for years and never had a problem. thats why i like the old cars easier to work on. dont have all this electronic crap on it lol

104,275

If Davidh25 said it then I believe it. Will have to try that magic.

130

i really appreciate all ur feedback..ty

DavidH25 is our number 2 GURU...think cancer's got his wife...he's out for a while...just have to pick up the pieces, man...you guys have got to step up, we've lost DavidH25, Gary's nailed himself into his own coffin, the other heavy hitters haven't answered the need for over a year...so hate to say it, you gotta step up dandyoun and 7jimmy7, what's the worst that can happen, your solution causes a fatal crash?

1 out of 1 people think this is helpful.
104,275

Hate to hear that. Our prayers are with him and his family.

Tom, and Tenspeed pretty much at the helm, guys like smoothpapa, Racer_X, mmooney, LouB, are fantastically knowledgable guys, and it's always a pleasure to hear their responses to problems~

104,275

You forgot to mention the honorable judge_roy.

1 out of 1 people think this is helpful.
19,055

he has a vast knowledge, and an artist also, soft scenery peacefully depicted

1 out of 1 people think this is helpful.
5,815

what did you set the gaps on the plugs at ? also just wanted to mention that all years and models stealth and 3000gts are belts and not chains

1 out of 1 people think this is helpful.
83,295

I would take out the new plugs, disable spark and fuel supply and crank over the engine and see if anything blows out of the plug holes.

1 out of 1 people think this is helpful.

these are for a new corvette~

92,205

I would be checking the firing order. It could be a pair of wires are on the wrong plugs. If the plugs were hitting the pistons, the center electrodes would be pushed up, the plug wouldn't fire and the engine wouldn't run.

1 out of 1 people think this is helpful.
2,255

I've done this more then once, check the wires, I've rushed, and put the wrong plug wires on the wrong spark plug. If thats the only thing you've done, that could be it!. and then check the gap of the plugs, there not gaped,right out of the box.Dodge Stealth 1994, Spark Plug by Motorcraft®, 1 Piece. Gap: .044. If you need to replace your worn-out spark plugs, Motorcraft is the way to go. Engineered specifically for your vehicle, their high melting point provides...

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

Stealth

Looking for a Used Stealth in your area?

CarGurus has 47 nationwide Stealth listings and the tools to find you a great deal.

ZIP:

Search Dodge Stealth Questions

UK Questions

Are you a UK consumer? CarGurus now has a discussion forum in the UK.

Dodge Stealth Experts

#1 Daniel Foster
Daniel Foster
Reputation 940
#2 dandyoun
dandyoun
Reputation 620
#3 TopShadeTree
TopShadeTree
Reputation 150
View All

Related Models For Sale

Used Mitsubishi 3000GT
86 listings starting at $3,995
Used Chevrolet Corvette
290 Great Deals out of 20,545 listings starting at $3,688
Used Nissan 300ZX
150 listings
Used Dodge Viper
445 listings starting at $24,995
Used Mitsubishi Eclipse
46 Great Deals out of 1,498 listings starting at $2,395
Used Chevrolet Camaro
444 Great Deals out of 40,684 listings starting at $3,500
Used Dodge Avenger
181 Great Deals out of 5,699 listings starting at $999
Used Volkswagen GTI
121 Great Deals out of 6,220 listings starting at $1,499
Used Mazda RX-7
50 listings
Used Ford F-150
3,079 Great Deals out of 208,275 listings starting at $1,200
Used Ford Mustang
575 Great Deals out of 42,796 listings starting at $1,699
Used Pontiac Firebird
17 Great Deals out of 776 listings starting at $2,495