Lost power after tune-up

[ScottnAshley]

Ok i did a complete tune up, plugs, wires, rotor, cap, fuel filter, air filter, and oxygen sensor. After i did the tune up i lost all my power i can stomp it and press it alittle and i get the same power. In higher rpms i dont get as much power niether. I think they gapped the plugs at 0.044 is that to big or small of a gap? The ones that were in there was at 0.048 - 0.050. The wires are AutoZone house wires, Plugs are AC delco, Air filter is STP, Fuel filter is from AutoZone, same as rotor, cap and oxygen sensor. What could be wrong?

[niznos]

.044 is too big. Go .039 to .043 max according to my manual. When spark gap is too big, it has an effect of retarding the timing.

Also make sure they didn't set the spark timing too far off.

If they disconnected the ECU when they did this, or if it was too far out of tune to begin with, your overall performance may suffer for a short time as the ECU has to relearn by varying the outputs for a while to see what the engine does. This should clear up within a week or so if this car is driven daily.

[nlzmo400r]

i used bosch platinum +4s and htey're pregapped at .o41 which is just right according to my FSM

[180fan]

bosch +4 platinums don't really work well on the 240sx from personal experience, and they don't work well on z31's from a friend's experience. Stick with the NGK possibly v-grooves and call it a day.

[ScottnAshley]

Well guess what. I read your throttle response thing niznos and mine was so off it wasnt funny. the top bolt away from throttle body was screwed all the way as far as it could away from the throttle body. the throttle cable was so loose i could put it almost aroudn my whole fingure. So i read your directions and tightened it as good as possible and my hp is back and it can move when pressing it down all the way lol. Thanks.

[niznos]

Glad to help. you should still regap your plugs though.

[PhaneSoul]

lol, yea ima get around to tightening the cables soon too.... although ive revved mine from there before and dont think itll be a problem for me

[ScottnAshley]

ok wait after i fixed it i did get better but after driving tonight i was wrong its still all bogged down. aftwer runnign seafoam do you think it clogged up my cat i cant think of what else could fo gone wrong?

[niznos]

You need to regap your plugs to .039 or .040.

Seafoam shouldn't plug up your catalytic converter, and should have no ill effects if used correctly.

Have you tried to read the ECU codes yet?

[ScottnAshley]

First off it says the ecu is at the passenger quarter panel in the engine bay? If so i dont see it. But at the junk yard i believe i seen it its in the passenger kick panel? Which is it? And when i check it i just count the beeps? then look in the manual and see what it is? Because it feels like i have a ton of bricks in my trunk and i get no power till like 4,000 rpms. When i first got it i could spin my rear wheels no problem. But now i cant even get it to burn out. Tomarrow im going to a friends house and ill use his socket and get those plugs out and regap them. Oh, and teh pluggs i took out of it was gapped at .050 and i got tons of power of them. Why is that?

[niznos]

I think you should double check all the work you did during the tune up, make sure everything is put back in the right place. Like spark plug wires fully on the right plug, easy stuff like that first.

The ECU is in the passenger side kick panel. There are only like 3 fasteners that hold that panel on. Once it's off, you'll have to take the two bolts off that hold the ECU onto the car and turn the ECU so you can see the back of it WITHOUT disconnecting the harness to it. You may have to cut the ziptie off that holds the trunk of wires at the bottom of the ECU to get it to turn.

Your spark timing may be off. If the old plug was gapped too wide, and the timing was too far advanced, those two things may have a cancelling effect on eachother and run like it's fine. Now that your gap is closer to normal, the timing is off from the new and correct setting. Make sure the gap is right and check/ adjust your spark timing.

Not sure on your DOHC, but my SOHC showed two different distributors at the parts store (a Mitsubishi and a Hitachi I think). The two different caps and rotors were very similar, so make sure the parts they sold you were correct.

[ScottnAshley]

How do i adjust the spark timing. Im a total noob on this engine. I had a ford. When you say something new please explain how to me if you can i mean. So ill regap, check computer for codes, and check teh tune up and make sure its all correct, and then if still wrong correct the spark timing.

[Dattebayo]

You also could have a bad or weak ignition coil. that would seem fine when you start it up, but wear out when you drive a little.

or maybe you forgot to put the gism on the metal connections in the wire, i.e. the metal plug connectors or the ones that go into the distributor.

[niznos]

Well, I would do this: 1. Regap plugs, 2. Make sure cap and rotor are infact the correct ones for your engine because the wrong ones may actually fit, but not work right, 3. Double check all items on your tune-up, including everything near what you serviced incase you knocked something else loose, 4. Check and adjust timing, 5. If all is checked and adjusted okay, do the ECU thing.

You will need a timing light to adjust the timing. It should be set to 20 (+ or - 2) degrees before top dead center. It may be easier to just have a shop do this since you would have to invest in a $40 timing light. It should not be expensive if that's all you would have them do.

[ScottnAshley]

Reading around people say reset your ecu should i do this after a tune up? If so this may be my problem heh. By teh way my bud has a timign light except you told me what it should be on ill ask him to check it for me tomarrow and well go over teh stuff you said hes gonna help me out. He owned a 300zx twin turbo and he said he can help me out a bit. So wish me luck tomarrow and i will update tomarrow right after we do the work on it and check everythign out. Thanks Scott

[ScottnAshley]

wait i forgot to ask this whats gism on teh wire connectors on the wire and teh distributor. The metal prongs on teh wire that connect to the distributer? lol if so their on there but tomarrow im double checking. Im so confused ehhh

[BoyWonder]

wait i forgot to ask this whats gism on teh wire connectors on the wire and teh distributor. The metal prongs on teh wire that connect to the distributer? lol if so their on there but tomarrow im double checking. Im so confused ehhh

What? You're not the only confused one now

[niznos]

You do not have to reset the ECU, unless the operating conditions have changed so much that the ECU sees the massive change and thus assumes it must be false readings. A simple tune up should not require this, unless it was really far out of tune prior to the changes.

Scott, you have got to stop drinking when posting. I have no idea what that last question(s) was/ were.

[ScottnAshley]

me neither and i was sober. jeez i must of been confused as hell and i was tired heh. Of course my bud had to work and couldnt help out today. The car seems like its running alittle better today. Maybe the gap being at .050 since who knows when made teh comp way off? Who knows i think im gonna run out there and do the ecu codes my self ill post if i need help.

[ScottnAshley]

i get no codes, I decided to try my cone filter again and i reset my ecu. I dont understand when i stomp it the engine feels like it pushes back at me and then it feels like i gained a ton of weight on it. Its not a problem with the engine( works perfect with air box) Does it take a couple days for the ecu and engine to get use to the new air flow?

[Dattebayo]

well check the spark between your ignition coil and distributor, then check the spark between you distibutor and spark pugs. look for a large powerful blue spark. If your spark is small and whitish, you might need new ignition coil (like i said) geez.

the gism is a small packet of goo that comes with any decent kit that you are supposed to spread on the metal contacts on the inside of the spark plug wires, both ends.

[ScottnAshley]

their blue and i know because i got electricuted ehh fun.

[ScottnAshley]

^^ ADD^^ blue when at idle but you said it could get weak when driving itsself.

[Dattebayo]

the spark should maintain almost same quality no matter what state of stress the engine is in: wide, light blue, "snapping" spark.

you can get the distributor coil for cheap so try and replace it, huh? the only other choices you got are more expensive. If the one you have is cracked or weakened, it can effect you over-all get up and go after the warm up. remember it is just a giant capacitor.

[ScottnAshley]

Niznos come online tonight.. i gapped the spark plugs at .039. checked everythign else in teh tune up its all right. But still with teh cone filter its bogging liek hell i gave up and put the box back on again until i have money to figure out whats up with it.