Engine Troubles

[Dirtydave]

KA24DE

Its a new swap, never ran this motor. Fires up and runs great with MAF disconnected. When MAF is plugged in will die/ or try to die, have to pump the throttle to keep it going. Once it reaches 2500 rpm or so revs normal. I have tried 2 other known good MAF's with the same result. I have checked the usual suspects, vacuum leaks, Dirty/bad IACV. No vacuum leaks to be found, removed and cleaned IACV. Gonna try a coolant temp sensor tommorow. But don't think that will resolve the problem. I have used the SEARCH, but only to find similiar threads with no resolve. Anyone got some info?

[redsx13]

i would try running new maf wires

[Dirtydave]

From MAF to where? ECU? If so I am not sure how to do that without hacking my harness.

[redsx13]

From MAF to where? ECU? If so I am not sure how to do that without hacking my harness.

ya, maf to ecu. you dont need to hack your harness, just tap into it at the back of your ecu plug. done it multiple times.

[Dirtydave]

Ok, can try that then, is there somewhere I can get a pinout or do you know which pins to tap into?

[redsx13]

Ok, can try that then, is there somewhere I can get a pinout or do you know which pins to tap into?

I can tell you how to run the wires without one.

there are 3 wires coming out of your MAF one will be white, one will be black but the last one varies, it should be something like black with white stripe. anyway, your white is signal your black is ground and your last wire is power.

1.The power wire (black/white stripe)-this taps into the black/white stripe wire on the back of your ecu plug, there is probably two black/white stripe wires coming out of the back of your ecu, it doesn't matter which one you splice into(be careful when you run this wire, unplug the battery, black/white stripe is the main ecu power wire, if you short it you will fry your computer).or since this wire is a simple 12v, you can just run it to your battery

2.The ground wire (black)- simply run this to your chassis (it doesn't normally run to the chassis but it will work)

3.signal wire (white)- looking at the back of the ecu plug there will be around 6 or so white wires, one of them it the correct wire, you can use an ohm meter/ multi meter to find it.

its really simple, if you still need help let me know and i can walk you through it

[Dirtydave]

Ok, will try that today, and post results. I did find a ECU Pinout.

http://i131.photobucket.com/albums/p287/Dirtydave75/ecu.gif

http://i131.photobucket.com/albums/p287/Dirtydave75/ecu2.gif

[Dirtydave]

i would try running new maf wires

Tried this today, no luck. It ran just the same, stuttering and bogging down when maf is plugged in. I guess it's safe to say its not a wiring problem. I also replaced my coolant temp sensor, it checked out ok with the multimeter but replaced anyway.

[redsx13]

Did you check your ecu for codes??

[whytrickme]

di you try running a different ecu? I had similar problems, changed the ecu out and never had the problem again....

[ms!3]

just for shits, whats the distance from your maf to the tb? nvm if its a stock intake. lol

[Dirtydave]

Haven't checked codes yet

I have tried two other ecu's

Its a cheapo Ebay short ram, about the same length as stock, and all extra vacuums ports are plugged.

[Dirtydave]

I'm gonna read up on the code process. Scanned over it before, and seems a little confusing, sure I can figure it out though. This is a 90 model with dohc, so will only be able to pull codes at the ecu.

[redsx13]

Haven't checked codes yet

I have tried two other ecu's

Its a cheapo Ebay short ram, about the same length as stock, and all extra vacuums ports are plugged.

what!? that's the first thing you ever want to do, even before coming here.

Its really really easy to check for codes....

1.Turn your key to run but don't start the car, looking one of the sides of the ecu you will see a red light, it should be on.

2.next to the light you will see a small screw, turn that screw all the way to the right, wait 2 seconds and then turn it all the way back to the left

3.the light should start to blink, these are the codes. all codes consist of two digits, the first digit is represented by long slow blinks of the light, the second is represented by quick short blinks.

4.codes can easily be found online, a code "55" means no codes, all good

5. when your done, turn the screw back to the right, wait two seconds, and then turn it back to the left. you should see a steady red light again.

[Dirtydave]

Pulled codes today 13, 34

13- coolant temp circuit
34-detonation circuit, so knock sensor i guess

[Dirtydave]

Seem like it has to be a vacuum leak, like it is getting unmetered air and stalling.

[alzahakar]

Get a can of carb cleaner and spray it around the engine bay while it's running. If it starts running funny, you have a vacuum leak. Then you just start spraying smaller areas until you locate the leak. GL

[Dirtydave]

Found the vacuum leak, was at the injector o-rings that sit on on the upper manifold. Installed on o-rings lubed and reseated injectors, motor now starts and idles fine. But still has a slight miss, and when accelerating cannot stomp on the throttle, if I do it will bog down or start bucking. I know the alternator needs replacing as yesterday my 1 month old Never Start went dead on me. A quick of check of the battery while car was running shows 12.84 vdc, telling me alt. is not charging. My tach has problems too, it is jumpy and sometimes get stuck, could this be related to alternator?

[alzahakar]

Check the timing. As far as the tach goes, you will probably need the DOHC cluster out of a 91+ S13 as the single cam tach takes a different signal.

[Dirtydave]

Fixed it! (I think)
Since one of the codes the ecu was throwing was maf sensor, I replaced it with an E60 Maf from a 96 Maxima. The car now runs pretty well. I guess when I was replacing the maf with know good ones, it shows no effect, because of injector vacum leak. The tach is from a dohc, actually this is my second cluster to do this. I think I am going to recheck the dash harness wires that are spliced at the ecu. Or could this be timng?
Thanks for everyones help.