Kappa Performance Forum

Kappa Specific => 2.0L Ecotec Engines => Topic started by: XplosivePlushToy on May 21, 2018, 03:58:26 PM

Title: Full rebuild, p087 fuel rail pressure low
Post by: XplosivePlushToy on May 21, 2018, 03:58:26 PM
Bit of a tech question here:

So after a top to bottom rebuild, my GXP is running again. However, she is sick. The main concern for me right now is the p087 low fuel rail pressure code. HPT is showing 0.0 rail pressure, but the car is running. Reduced engine power error and all that. No misfires, knock or extreme timing compensation in the log.

I installed Opel injectors, the ZZP stage 2 cam with lobe, and an LT1 fuel pump. Another oddity that might be related: the fuel tank was completely dry after sitting for 2.5 years, though the computer is reading >80% full. Could the low rail pressure be due to a faulty in-tank pump, damaged by the byproducts of separation and evaporation of the fuel? I do have an AEM E85 320lph pump going in tomorrow, as soon as my lock ring tool arrives.

If anyone is curious (or feeling super generous) I do have the log file available to email while Im at work.
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: LatinVenom on May 21, 2018, 04:52:44 PM
I would think the tank pump is probably shot, and a replacement is in order. I believe you said the LT1 fuel pump delivers more pressure than the OEM on our GXP's, so unless that pump is also not performing the issue has to be the in tank pump.
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: XplosivePlushToy on May 21, 2018, 06:10:27 PM
Im changing the tank pump as soon as my lock ring wrench arrives tomorrow so we'll see.

Do you know the part number for the fuel rail pressure sensor?
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: LatinVenom on May 22, 2018, 04:40:57 PM
No I do not. You maybe able to get an answer from GHOST at the BB, since he had his changed.
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: XplosivePlushToy on May 22, 2018, 11:55:09 PM
Well AEM pump went in. No change. The new sensor will be here tomorrow. I had forgotten that I reused the one from the original fuel rail, so hopefully thats the case.
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: DeepBlueGXP on May 25, 2018, 06:54:48 AM
clean HPFP connector?
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: XplosivePlushToy on May 27, 2018, 12:22:15 PM
Found the likely culprit. The cam roller for the hpfp doesnt fit in the heads. It was so stuck I had to remove the valve cover to extract it.

Does anyone know if the LDK used a different roller from the LNF?
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: KappaTarbo on June 05, 2018, 09:42:57 AM
I'm not sure if they are the same or not but I am using the stock roller from my LNF in the LDK long block I have in the car right now. 10,000 miles so far with no issue.
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: XplosivePlushToy on June 06, 2018, 06:09:15 PM
The cam cap alignment pins were slightly bent from the factory. It caused an imperceptible rotation that prevented roller movement. I straightened it out, bolted up the LT1 pump, and pulled 2900psi of rail pressure!

New ecm and battery goes in tomorrow and all should be well. 500+hp to come!
Title: Re: Full rebuild, p087 fuel rail pressure low
Post by: Johnny_gxp on June 12, 2018, 11:08:40 AM
Found the likely culprit. The cam roller for the hpfp doesnt fit in the heads. It was so stuck I had to remove the valve cover to extract it.

Does anyone know if the LDK used a different roller from the LNF?

The LDK has a tiny tiny tiny more aggressive cam than the LNF to run the brake vacuum pump attached to the rear of the camshaft. I had to fight that pump getting it to fit between my block and firewall actually :lol:. Hope that helps!

OH! I didn't see you fixed the issue. Best of luck with the build!