Swap is complete. but car runs like ... wow

[Burnsey]

so i did a single to dual swap ... and ... well my car kinda runs like ... crap. ...granted my radiator is leaking a bit (new one is on the way) and I need to plug the bolt thing in the downpipe (getting it welded shut) .... it seems to have ABSOLUTELY no power? ... and just doesn't sounds very good, or rough. It doesn't accelerate very well AT ALL and seems to get really rough and kinda almost "cough" in higher RPMS. I can't tell exactly what RPM range, do to my cluster not working but I'd get 3-5k? ... anyways any input anyone has is much appreciated, thanks.
Modified by Burnsey at 3:41 PM 3/27/2006

[Florida240sx]

Spark Plugs/ 02 sensor / bad fuel/ Vaccum lines should only be an issue at idle once your moving they shouldn't matter.... so check your plugs, fuel filter, and whether or not your gas has gone bad or is it still good??? Could also be the MAFS sensor going bad. Also have you checked timing???

[Burnsey]

spark plugs are brand new and gapped properly, timing is fine, vaccum lines are correct and sealed, o2 sensor seemed fine (but i will go ahead and replace it i guess just to make sure), fuel should be fine. ... hmm I guess it could possibly fall down to the MAFS which came with the DOHC. Can the SOHC MAFS be compatible with the DOHC?

[OldmanPurdy]

No the SOHC mafs is not compatable with a DOHC motor, and from what you said that could be your problem. First thing I would try is wiggling the connector to see if its just a bad connection, second thing would be to actualy clean the mafs itself. be sure to use an intake safe cleaner the mafs is very sensitive, if that dosent work get a multimeter/omh meter and make sure the mafs is reading properly. you can search to find the correct procedure for that, good luck!

[Burnsey]

okay, got the new MAF on and it revs correctly, but still ... lacks a LOT of power... any ideas?

[deviousKA]

I think there is a technical medical term for this, no-satisfaction-without-the-single-cam-action or something along those lines, I could be wrong.

Im joking, check your ecu codes.

[Burnsey]

apparently, or so i was told, that the swap elminates my ability to get ECU codes

[emperor_lunchbox]

did you swap ECU's?

[deviousKA]

All of the nissan ecus have the diagnostic built in.

If your ecu is a 91-94, this is what you need to do.

Unbolt ecu from kickpanel and lay it on the floor. Locate the diagnostic turn knob that is on the side opposite the harness connector. This knob may be covered in tape if has never been used.

Currently the knob should be turned fully counterclockwise. Take a screw driver and turn the knob full clockwise for 2-3 seconds. Turn it back full counterclockwise and the ecu will begin to flash your code on the LED that is in the ecu (there is a little window to see it on the side). Long blinks = 10's , short blinks = 1's.

So if you have 1 long blink and then say, 3 short blinks, it would be code 13, and so on.

You need to do this with the key on but the engine off, preferrably after you have run the car for a while without disconnecting the battery so that the ecu has a chance to pick anything up.

If you get a code "55" (5 long, 5 short blinks) that means that there is no codes, aka "all good". If you get a different code (or a few), look it up either in some sort of nissan manual or online, the lists are all over.

Start there, and also, check your base timing with timing light.

and btw, sohc maf can be compatible with dohc, any nissan maf and many ford hitachi mafs can be used on nissan ecus, but not directly plug and play. That is a whole different topic though so I will leave it at that.

[deviousKA]

And just to clarify, checking the codes on a single cam ka24e ecu is just a little bit different than what is mentioned above.

All steps are the same except instead of turning knob to full clockwise for 2-3 seconds and turning back, you turn it full clockwise and wait for the light to blink 3 times, and then turn it back.

And the ecu has 2 led lights, one for the "10's" and one for the "1's", except the stanza which is a morph between the two (single led, built in 5 mode diagnostic).

If that didnt confuse anyone enough.

[DjPantsSpecR]

Everyone always overlooks dead injectors

check the resistence of the injectors. it should be like 12 ohms across the terminals. a zero or higher spec will indicate a malfunction.

on two seperate occasions in two seperate cars after swapping in KAs, they would spontaneously kill injectors. Before they were removed they worked fine... idles like crap, sounds like a lawn tractor, has no power.

[Burnsey]

yea swapped out the old engine, transmission, wiring harness, ECU, and tach .... then replaced everything with DOHC stuff

[KATwo40]

I looked at this car today and here's the deal.

Timing is sitting at 5* ATDC haha! No wonder there's no power. You can idle and rev the car to the moon. Take off down the road, WOT, won't go over about 3k rpm.

Anyhow, here's the big problem. Went through the FSM procedure for timing adjustment. When I get to the point at which you unplug the TPS, start the car, adjust idle down to ~800rpm, it won't do it. Idle screw is all the way in, car still idles at around 1200rpm.

Any ideas why this thing won't choke down? Checked for vac. leaks and such, still no luck. Maybe the IAC is bad?

Oh, btw, no codes on the ECU.

Thanks in advance. Lemme know any idears ya'll have.

[DjPantsSpecR]

is the throttle closing all the way?

I control my idle by plugging that idle valve and then letting in a certain amount of air by tightening the throttle cable. Its possible you have accidently done this, or you can try doing this.

I still think its a vacuum leak somewhere, but there are longshots.

i did some work on one of my 240s and when i started the car the idle was up to 3500 rpm. The tiniest piece of silicone from a gasket i made for plugging the resonator box had gotten stuck in the throttle body. You could hardly see the piece at all, but it causes the idle to jump to 3500 rpm. The only thing i'm saying with this, is that a very small amount of too much tension there or a carbon deposit on the throttle body can cause a serious idle hike, or a lesser one.

so you can try cleaning that too... but you need to find wherever this vac leak is coming from. I would try plugging the big hose going to the IACV from your intake and see if it makes any difference, that should tell you if its getting past the IACV somewhere, so you dont try to replace something that might be straight. But if its not, then you could also clean that. I did something that i wouldnt recommend, but it worked nicely. With the car off i sprayed a few sprays of throttle body cleaner into the large hose coming off the intake going to the IACV. Then run the car for a min, or a half, a repeat maybe two more times.

just some stuff to try...

[Burnsey]

just checked the TB and it does close all the way.
Modified by Burnsey at 3:40 PM 3/27/2006

[boon240]

when you swapped from sohc to dohc, does it pass visuals at smog station?

[KATwo40]

We don't have state inspections here.