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i am doing a mtx to atx swap swapped the engine with the tranny. i took the pcm and everything out of the manaual and put it in my car. i started it for the first time today and it started back firing . when you give it gas the rpms hold high for abit after the throttle is released. i lined the timing up arrow to arrow does it have to be turned back one tooth on the cam or something ?

drummer7878 wrote:i am doing a mtx to atx swap swapped the engine with the tranny. i took the pcm and everything out of the manaual and put it in my car. i started it for the first time today and it started back firing . when you give it gas the rpms hold high for abit after the throttle is released. i lined the timing up arrow to arrow does it have to be turned back one tooth on the cam or something ?

did you put your plug wires on backwards?? i bet you did

no thanks im not a complete idiot im asking what degree the camshaft has to be in relation to the crank shaft. not asking for someones stupid comments. thanks tho

XxWhiteNeonxX wrote:
did you put your plug wires on backwards?? i bet you did

The timing should be good, as you swapped the entire engine, assuming it ran fine beforehand.


Obviously it wasn't NGC in a non NGC, vice versa, or the PCM wouldn't have plug and played.

Edit: The guy was trying to help you, not be a smart ass. It is a simple mistake. Like getting the coil and CPS sensor connector switched. It has happened to more ppl than they care to admit.


Maybe lighten up your attitude, so you will get some further assistance to your problems...

no i changed the head due to bent valves to a stock 04 head.

Arrow to arrow as in the cam mark is facing down, and the crank mark is up, or the crank to the arrow on the oil pump.

Being a little more specific will also help us help you.

When the crank to oil pump arrows are dead on, the cam mark should be straight up 90º from the valve cover mounting surface.

yes the marks are both lined up perfect just went and double checked. is there and other reason it could be back firing. is the cam shafts differant between the 01 and 04 ?

drummer7878 wrote:yes the marks are both lined up perfect just went and double checked. is there and other reason it could be back firing. is the cam shafts differant between the 01 and 04 ?

cams are the same.

Your acting like im making a " smart remark" when really im trying to help you. Trust me, i bet im right, ive done it before and im not a noob to neons, its a simple mistake.

the wires are differant lengths to the spark plugs. sorry bout that thou just alittle frustrated with this thing . just wanna figure out whats wrong with it, im thinking because i changed the cam shaft magnet that its flipped upside down or something. i made sure i put it on right or could this be a bad cam or crank sensor?

drummer7878 wrote:the wires are differant lengths to the spark plugs. sorry bout that thou just alittle frustrated with this thing . just wanna figure out whats wrong with it, im thinking because i changed the cam shaft magnet that its flipped upside down or something. i made sure i put it on right or could this be a bad cam or crank sensor?

cam sensor going bad shouldnt cause it. i dont believe a crank sensor would either. As stated, if your timing is right, either your injector wires are switched around backwards, or possibly the plug wires.

Double check, for the hell of it, plug wires, back passenger on coil goes to far passenger tube, front passenger on coil goes in the next tube, and same on the other side.

Not trying to come off as an asshole, but its very easily done.

ya i double checked the computer or what it sounds like is making a buzzing noise when the key is turned to run poistion. im thinking it runs like garbage because the magnet but this shouldnt cause the computer noise. considering the camshaft could be in any position when the engine is turned off. not sure if this means i need my computer flashed, i remeber when we did the head and head asket on my girlfriends car. the computer was making the same noise then we brought it to a mechanic. before i became one and he said it had something to do with the camshaft? dont no what he did but got it back fixed and i no her computer was flashed at one point of the process.

drummer7878 wrote:no thanks im not a complete idiot im asking what degree the camshaft has to be in relation to the crank shaft. not asking for someones stupid comments. thanks tho

that was a little uncalled for, he was trying to help you..

Johny wrote:

drummer7878 wrote:no thanks im not a complete idiot im asking what degree the camshaft has to be in relation to the crank shaft. not asking for someones stupid comments. thanks tho

that was a little uncalled for, he was trying to help you..

Meh, I think we covered that already.

The cam magnet can only go on one way, unless the pins are broken.

The injectors being switched might make it run bad at idle, but due to the lack of time, it should run ok at higher rpm. It would be tough to get the connectors switched anyways, as the leads are a bit short.

What year is your car? the magnets changed from '02 to '03, I can only assume you either swapped magnets because of that, or the "new" head did not come with. Not sure how it would run with the wrong magnet.

Are you sure it is the PCM making noise, or the IAC? The IAC can sing you a nice song at times. Perfectly normal. The PCM on my 1gn also makes noises, but it runs fine. I wouldn't worry too much about that.

Check the o rings on your IM, if one of those is damaged, it can cause issues. The vacuum leak will cause it to suck the air in before the fuel, so it will not necessarily get enough fuel to that cylinder.

ya my battery was dead so i was boosting it and noticed the noise is only present at the first turn of the key. after that it it does not make the sound. it does run fine at high rpm only rough on the idle i will check tomorrow but . i think i may be missing a vacuum hose. the cam shaft magnet is in the right way i took the one off the head i replaced that was on the car. possibly thinking the cam sensor could be bad i found it laying around the garage.

A missing vacuum hose will only make it idle higher, not rough. Unless it is a large hose like the brake booster line, but then it would be an obvious leak. And the rpm's would be going up and down sort of violently.

i checked it over the side vacuum line on the valve cover was still disconnected on the intake. i am pretty sure it is the Iac making the buzzing noise when i started it today it stopped and the radio and dome light didnt come on. and the odometer was blinking fuse. is there usually a reason why the Iac stops working ? or do they die after awhile i didnt not change any of the wiring inside the car during the swap. it is running better and revs nice now but the idle is abit lumpy , it is throwing a cam sensor code so i am thinking its just the sensor on its way out.

drummer7878 wrote:is the cam shafts differant between the 01 and 04 ?

They aren't, but the cam magnet is different. Install your old magnet and see what happens.

He swapped the magnet from the old head.

Check your dome light, it may have burn't out. Or a fuse, since the radio no longer works. There are fuses under hood and in car. Under hood does go to some in cabin things.

A liitle less run on sentences would make it easier to read too. Just sayin'

Ah, I see it now. Yeah, the run-on sentences make your posts pretty hard to read.

Danteneon wrote:Ah, I see it now. Yeah, the run-on sentences make your posts pretty hard to read.

Come on man run-on sentences are the way of the 21st century how else are we the ADD generation supposed to get out thoughts in anything that resembles a coherent thought pattern drawing from all the knowledge gained time and time again.

Ow