Hot rail / fuel issue

[Phram1]

My EMS does not have the software for fuel temp like the stock ecu so when I turn the engine off for say 15 minutes, the rail / fuel gets hot. Then starts require 3-4 minutes of idle before the rail / fuel is flushed and the fuel returns to a normal temp.

So, has anyone have a solution to this issue?

[AZ-ZBum]

What car? What motor? Turbo or not?

[Phram1]

88 300zx. VG30ET

[z31na2t]

I don't have a FTS or the FPR solenoid. Never have an issue. I think your problem is elsewhere. You should have warm start enrichment tables of some sort, you need to work on your tune - as theres more to it than just the base maps.

[Phram1]

The warm temp fuel values reference the water temp and air temp. These parameters are correct. If I change either of these values then the engine will run very rich once the cool fuel has flushed the rail. Hmmm what am I missing?

[camarokid]

the 280zx turbos had a fan to keep the injectors cool so maybe you can get one of those 'eletric superchargers' off ebay and rig it so it blows on your fuel rail. or you can try a heat wrap on your turbo.

[Phram1]

I don't have a FTS or the FPR solenoid. Never have an issue. I think your problem is elsewhere. You should have warm start enrichment tables of some sort, you need to work on your tune - as theres more to it than just the base maps.

Just to verify, are you running a stand alone EMS rather than your stock ECU? Also, note that the issue does not keep the engine from starting. Its only that my AFR are very lean until the fuel rail cools off from new fuel from the tank.

[z31na2t]

The warm temp fuel values reference the water temp and air temp. These parameters are correct. If I change either of these values then the engine will run very rich once the cool fuel has flushed the rail. Hmmm what am I missing?

Warm-start enrichment goes away after a short period of time, and the system should revert back to base maps, after idle tables, etc. You don't fix this issue with changing the base map. There are enrichment tables for different periods that modify the base map depending on the condition. These are where you need to look. What EMS are you running?

I am running a stock ECU with Nistune, but the only sensors I have are MAF, CAS, TPS and CHTS.

[Phram1]

The warm temp fuel values reference the water temp and air temp. These parameters are correct. If I change either of these values then the engine will run very rich once the cool fuel has flushed the rail. Hmmm what am I missing?

Warm-start enrichment goes away after a short period of time, and the system should revert back to base maps, after idle tables, etc. You don't fix this issue with changing the base map. There are enrichment tables for different periods that modify the base map depending on the condition. These are where you need to look. What EMS are you running?

I am running a stock ECU with Nistune, but the only sensors I have are MAF, CAS, TPS and CHTS.

Would I be correct in saying that you are running the stock fuel pressure regulator and have removed the FTP from it? I have limited experience with Nistune but it appears there are parameters that exceed the EMS I am running.

I am running an SDS EM4 which has limitations. I can only adjust the start temp values - air temp values - engine temp values. As I had mention in the begining of this thread, it is only a nuisance for about 3-4 minutes.

I am looking at upgrading my EMS to a Vipec i44. I expect that it has the range and parameters to alleviate this issue. Your thoughts?

[evildky]

I'm running megasquirt on a stock fpr and a stock fuel rail, no problems, you need to figure out why your fuel is getting so hot, you have a clogged or kinked return line?

[Phram1]

I'm running megasquirt on a stock fpr and a stock fuel rail, no problems, you need to figure out why your fuel is getting so hot, you have a clogged or kinked return line?

I will investigate the return line for issues.

Since you are running a megasquirt, this would mean that that your stock ECU does not interface with the megasquirt and therefore the fuel temperature sensor that screws into the fpr is not activated, correct?

[evildky]

I have no factory ecu or harness. the fuel temp sensor is still screwed into the fpr but nothing is connected to it.

[Phram1]

Thanks for the confirmation on the fts.

I will check into the blockages in the return line in the next day or so. I will let you know if it is.

If it is not blocked in any way, then I will know One solution would be to move to a better EMS. As mentioned in a another post about an interest in the Vipec i44.

thanks for your help.