Help SR Red Top issue!!!!!

[72nismo]

So my buddy has an SR and this is whats happening. His running JWT ECU , Z32 Maf and 720 injectors.

When its cold and you start the motor dies, but when you disconnect the MAF, she start up and stays running. No Ecu fault except for the MAF because it's disconnected. But when the motor is warm, you connect the MAF. Motor runs ok... So his thinking his fule pump might be the problem. But If the fuel pump is the problem why does she stay running with the MAF disconnected?

Any thoughts on what it can be fellas?

Also he put all stock ECU, Maf , Injectors and still same problem.

[Darren]

try cleaning the maf, and / or checking the voltage to make sure it's working correctly....

Also... check your timing, had a similar problem, and once we figured out my timing was retarded by a tooth on the chain, it worked properly...

[Edwin562]

i had similar issue . found out my MAF was faulty... so i upgraded to z32 and ran fine.

[Kingtal0n]

Hello everyone! I wish to add some insight to this discussion.

There are several different maf sensors and several maf related issues that I want to address.

Over the years working with these sr20 engines, I have seen some strange things. Sometimes two exact same maf sensors will act differently on an engine. For instance I have tested KA24E maf sensors on S13 sr20det engines and found that 3x of the same identical mafs all give different air/fuel ratios under wide open throttle and part throttle!

As to the S14 maf sensors, usually when you have selected the correct MAF for that engine it will idle and rev clean and drive right (no surprise there)
As far as I know they make two or three different maf sensors, corresponding to the different year ECUS available: (red WC, black WC, black NA)
the red WC is the oldest S14 ecu available that I am aware of for the sr20, and corresponds to the 1995 zenki model iirc.
That black WC was the transition the S14 made during the 1996-1997, not sure of the exact year.
The black NA ecu was the 1998 version, the final S14 ecu that I am aware of.

While all of the housings for these maf sensors are identical, the hot-wire voltage output configurations are apparently different, since installing the wrong maf results in an un drivable vehicle as some have found out.
-A tip that I have for you is to clean the hot-wire with a proper solvent to ensure that your problem is not related to a buildup of dirt or oil.


The next thing I wish to address is simply that a boost leak or any kind of leak in the intake plumbing after the maf sensor will also result in "bad maf" performance. The maf sensor reads incoming air as it should enter the engine- and anything that affects that exact quantity, such as a leak (out OR in) will change the air/fuel ratio and therefore the tune/performance.
So my final suggestion is to ensure a leak free plumbing by performing a boost leak check, the parts can be made to do this from home depot for a few dollars.

[SlideOrDie831]

try cleaning the maf, and / or checking the voltage to make sure it's working correctly....

Also... check your timing, had a similar problem, and once we figured out my timing was retarded by a tooth on the chain, it worked properly...

friend has the same problem with an S14 SR. his timing was retarded a tooth also.

[mhubble91]

Jesus christ man, why in god's name would you need 720cc injectors!?!

The stock injectors are good until nearly 13-15psi if i remember correctly... at 15psi 430cc injectors were sufficient. I have a mathematical formula that will tell you the necessary injector size needed, per psi, volumetric efficiency and RPM. I'm telling you now though that those injectors are far too massive. They would sustain around 26psi!!! lol!

[Pinggg]

Jesus christ man, why in god's name would you need 720cc injectors!?!

The stock injectors are good until nearly 13-15psi if i remember correctly... at 15psi 430cc injectors were sufficient. I have a mathematical formula that will tell you the necessary injector size needed, per psi, volumetric efficiency and RPM. I'm telling you now though that those injectors are far too massive. They would sustain around 26psi!!! lol!

thinks that's a lot i'm on 1000cc injector on E85 and i barely make it to 200 miles full tank lol