Off Roading Forums banner

Effects of HEI on Other Systems?

455 Views 1 Reply 1 Participant Last post by  TOM85CJ7
This question is for guys (and ladies) who have done the HEI mod. I have mine done and the engine is running great...however, I have a minor problem....the PCV solenoid is no longer working. As I am sure we all know, the solenoid between the PCV and carb energizes when the RPM drops below aobut 1200 RPM. When energized, it closes and helps the engine idle lower. With the HEI mod, mine does not engergize now leading me to believe that a signal from the Duraspark module was giving a signal to the computer to engergize it. Right now my idle is at least 900-1000 and I can't get it any lower.

In addition, the servo motor on the carb is also not working now....stays in the same position all the time. I suspect that its also related to the HEI mod.

If anyone has personal knowledge of these problems....please elighten me....

John......southern CA
84CJ7,3"lift,32"BFG,4.11's,ARB,Solid Axle's
1 - 2 of 2 Posts
When I reworked my vacuum hoses recently I noticed that I don't have a PCV solenoid on my Jeep. Is it reall necessary? What does it look like? If I need to I will replace it. My jeep is idling right around 1000 now that all the hoses are fixed and I haven't been able to find the source of the higher RPM's. Sorry I didn't answer your question, you could try bypassing the PCV solenoid to see if it makes a difference.


PS I am doing the HEI as soon as I solve my current Idle problem.

1985 CJ7 4.2L, T-176, Dana 300, 2.5" lift, 32"BFG MT, Durabak On-Board Air
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.