Cold Start Issue

[Ray-Az]

I've been searching to find this answer, yet I couldn't find anything that actually helped.

Basically my Rb20 drives like crap 'till it warms up, I've been trying to find more info on this "cold start valve" but no avail. I have no idea what im looking for, nor do I even know what the problem is even if I were to find it.

The car has to get around 50c degrees before it starts to run correctly. If the temp is anywhere before that, you step on the gas any little bit, it'll basically idle out. So to give you an idea of how to drive it, I have to keep the rpms at around 3k rpm just to start in first gear, then as soon as I get above 3k rpm itll run kinda normal in any gear (except I hate the idea of running my car that hard when its still cold.)

Edited March 26, 2008 by Ray-Az

[Ray-Az]

Bump?

[Cubes]

Engine (ecu) temp sensor.

[Ray-Az]

  Cubes said:

Engine (ecu) temp sensor.

And if that were the case, what would the cure be?

[blind_elk]

The cold start valve is the little torpedo-shaped unit directly under the throttle body (in the "U-turn" of the manifold).

When cold, the "gate" is open, you should be able to see through it. It closes the gate by applying 12V to a bi-metal strip.

The ECU temp sensor usually causes problems because, when it poops itself, it tells the ECU that the engine is still cold, and you run extremely rich.

[steven22]

Sorry if this is a hijack, but does anyone know how much one of these temp sensors is to replace for an RB26?

[steven22]

I just ordered a water temp sensor of Bursons, $12. I will see how it goes and give an update tomorrow night.

[Jmaac]

Wont be water temp sensor. If it was to effect it that much, the temp on the dash would be off the scale at normal op. temp

[blind_elk]

  Jmaac said:

Wont be water temp sensor. If it was to effect it that much, the temp on the dash would be off the scale at normal op. temp

???????

There are 2 sensors - 1 for the ECU (2-pin connector), one for the gauge (single-pin connector).

[Cubes]

  Jmaac said:

Wont be water temp sensor. If it was to effect it that much, the temp on the dash would be off the scale at normal op. temp

There's 2 temp sensors. The dash and the ecu. If the ecu one is buggered it won't show on the dash.

[snappy_]

I also had the same problem, when i first got the car, everything was running fine, i could drive normally when the car was cold, as soon as i put in a remapped eprom, on cold starts, if i was to accelerate it feels like its bogging down. Now i switch it back to stock ecu, runs fine again.

[steven22]

I cleaned both the sensors with some wd40. Appears to have worked. Drove it this morning, and was was cold in Melbourne this morning and it drove fine. I will still replace the sensor though as Bursons had to order it so I feel bad for them. Its only $12.

[Ray-Az]

I like in Arizona, United states.

Happen to know the part number to that temp sensor? Or what it can be cross referenced with?

Awesome replies, just need a day to check all this stuff out... Not to mention a dreaded battery draw.

Again this Rb is in a 91 240sx coupe.

[steven22]

Hey I installed the new temp sensor. I took the car for a spin around the block with a fairly cold motor and by the time I got the car in the driveway again the temp guage was on the 'H'. I got out of the car, opened the bonnet and everything was sill cold. WTF?

[Ray-Az]

  steven22 said:

Hey I installed the new temp sensor. I took the car for a spin around the block with a fairly cold motor and by the time I got the car in the driveway again the temp guage was on the 'H'. I got out of the car, opened the bonnet and everything was sill cold. WTF?

Sounds like the wrong temp sensor - different resistance will show different temp on your gauge.

[steven22]

Hey I got the Nissan water temp sensor, fixed both the cold satrt problem and the guage problem.