Z45 engine running problems

[zmech]

Hello all. I usually post on Z31performance.com but I am having a problem with a VH45 engine. I have put a 1995 VH45 into the Z31 chassis. It will start up but it runs very rough and smells horrid. I am not getting smoke from the tailpipe like running rich.

This engine came from a running Q45 with TCM. I have deleted all the TCM stuff and used a non-tcm throttle body but still using the tcm harness and ecu. Will that cause my problems?

[BLACKonBLACK98]

have you ohm tested the injectors? pretty common issue and will cause the symptoms you described.

[Q45tech]

Without secondary throttle [secondary TPS] without secondary TCS motor the TCS and TCS ecu is not receiving signals that throw codes and cause weird things.

USE a standard ecu and use a standard ecu harness to start trouble shooting.

I would suggest NICO engine section VH45/VK45 where there are dozens of swap posters.

[maxnix]

Presume TCM = TCS?

Check MAF connection then MAF board solder joints for outboard components. Did you observe this engine running before the transplant? If not, you must rehabilitate it, especially if it is a pre 1994 due to the chain guides.

Ethanol does kill injectors, so that is another factor.

[elwesso]

I would suspect an injector or MAF issue...

did you mess with the injectors when you swapped the engine?

[zmech]

The engine from 1995 Q. IT was running very nicely and passed smog without an issue. I swapped maf and ecu with another and still same problem. Did not ohm the injectors, will try that tonight. This engine sat on a stand for about 9 months so maybe that it a problem.Did not take off anything from the top at all. not even the spider.

[maxnix]

Did you let it sit with ethanol fuel?

Might want to visit http://www.jerrytucker.net if you test everything and it is still bad.

[Q45tech]

People who have never done a cross car VH engine swap will confuse you into thinking our problems are your problems.

[zmech]

My thanks to all for the posts. Problem solved. It was the fuel injectors that were clogged up. I went and got a Nissan fuel injector service kit and ran a can of cleaner through. Cleared it right up.

Thanks!

[maxnix]

I hope a new OEM fuel filter was installed somewhere in this process!

[jltibbs]

Probably not.

[zmech]

Probably not. <IMG NAME="icon" SRC="http://images.nicoclub.com/forums/image ... lleyes.gif" BORDER="0">

You guys obviously do not know me. I am meticulous. Fuel filter... typical of forum members to thing others are dumber than they are...

[zmech]

So I got it running but could not get the idle to smooth out. Started doing everything as posted all over the place on the internet. Followed the FSM troubleshooting methods. Came up with two bad knock sensors. Fixed that and still the idle was oscillating. Seemed to be worst with the radiator fans running. Back to troubleshooting. Here is what I found...

These mafs are HIGHLY sensitive. I was running the maf open at the screen end (no filter or anything). I could very lightly blow air into the direction of the maf and make the engine stumble. Remove the maf and it idled smoothly. So looks like I will need to make some piping soon to get this thing running right.

BTW: anyone come up with a bypass for the transmission signal to the ECU to make it stop kicking codes for the transmission not being there???

[Q45tech]

The MAF assembly alone has a restriction of 7" water column at redline so removing the screens will only add to inaccuracy and not help flow more than 3" which is 3/27.7 =0.108 psi or 0.7% x 320 HP or ~~ 2HP at BEST!

The screens are there to straighten the air flow and improve accuracy.

[zmech]

The MAF assembly alone has a restriction of 7" water column at redline so removing the screens will only add to inaccuracy and not help flow more than 3" which is 3/27.7 =0.108 psi or 0.7% x 320 HP or ~~ 2HP at BEST!

The screens are there to straighten the air flow and improve accuracy.

Umm, maybe you should read my post again. I did not state anyplace about taking out the screen. That meant I was open at that end, ie: no air box or filter of any type.

But hey, that was a great dissertation on the function of the maf and screen... Were you a nuke in the Navy?

BTW: Flowmeters on most Nissans are a type of hot wire (resistor) anemometer that is placed inside a known diameter tube thus giving the engineers a way to measure airflow. The screen does not straighten the air. Tubes in front of the anemometer straighten the airflow and that screen is just there to catch anything large comming it's way. It actually will create turbulance because behind each strand in the screen is a tiny vortex. Granted, it may not make too much difference in this application. There is actually a flowmeter that uses the measurement of vortices. If interested, feel free to look up the Von Karman theory of vortices.
Modified by zmech at 12:43 PM 5/15/2009

[qship96]

Why would any sane person run a Q with no air filter?????

[zmech]

Because it is sitting my garage and I have no place to put an airfilter at this time.


Modified by zmech at 1:33 PM 5/15/2009

[maxnix]

No radiator might be a problem also!

Did you completely rehabilitate the intake and fuel system also? Including EGR and IAC valves and cleaninig the TB and plenum and lower runners?