Check Engine Light with No Fault Codes

[thompsdw]

I have a '04 RXP that I have been rebuilding for some time. Recently finished and took it out on the lake for the first time last weekend. Didn't get far before the check engine light came on and I think it beeped one time (not sure). Decided to put it back on the trailer. Did some research and decided to change both the front and back oil pressure switches. That is complete now. Also installed a temporary oil pressure gauge.

While I haven't been able to take it out and run it for a longer period of time, I did run it on a hose last night. The oil pressure was 90 psi and was falling below 80 when I shut down the engine. The check engine light did not come on at idle. I gently reved it up past 3,500 rpm - again - no check engine light. After I pulled the hose, I normally rev it a couple times to blow out the waterbox - and then the check engine light came on with NO codes stored.

My plan is to take it to the dock and let it idle on the trailer to see what the oil pressure comes down to after 5-10 minutes. I am really trying to be careful here - I spent too much time on this build to screw it up now.

Are there any concerns based on what I described above that I need to check before letting it run longer? Any ideas on check engine warning without codes that would be activated with elevated RPM?

 

[ski-d00]

It won't store the codes, you need to press set 5 times during the check engine light to get the code. As soon as you pull the key or shut it off, it usually will be lost unless you have BUDS to check the occurrances.

Usually you get an exhaust high temp warning when you run it without the hose, will only take a few seconds sometimes without the exhaust being cooled. This code will clear itself when it comes back down to normal temp.

Check engine light could be a lot of things, press set 5 times next time to get the code.

Where in Ohio are you? I've rebuilt lots of 4tecs and have BUDS and I can check it for free if you come to St. Marys.