CIS Guru's.........HELP!!!

Gumba11 · 08-04-2005, 02:41 PM

Hey all,

The weather here in Portland is pretty hot right now. About 95 degrees in the shade. I have been driving my car in the evenings to avoid unneeded oil temp. but I did drive it to work the last couple of days and when driving in the heat I noticed a small problem.

I am getting a small backfire through the intake once in a while upon takeoff from a light after being stopped for the duration of a light. It doesnt happen all the time but when it does the car will sometimes even die.

Is this a typical CIS issue or could something be starting to break? I dont want to overspend trying to solve this as my time with this euro CIS setup is limited. I am going to an Electromotive Tec3 set up in the spring.

Any thoughts or suggestions would be great.

Thanks in advance..............................C

sammyg2 · 08-04-2005, 05:02 PM

Vacuum leak is my guess. Do you have a pop off valve? If so check it to make sure it is seated and not leaking. If you don't have a pop off valve check everything including the air box for a vacuum leak.

azasadny · azasadny's Garage

Yep, sounds like a vacuum leak!

HarryD · 08-04-2005, 07:49 PM

Hi Chris,

I am not a guru, but if this is your car:

Then I would bring it back to the builder and have him take a look. For what you paid, some service after the sale is not a bad thing to expect.

Gumba11 · 08-04-2005, 09:14 PM

That is my car, the problem is Im the builder and Ive had it for 6 years. No PO to contact and the engine I had built was only built and I installed it. I am planning on checking for vacuum leaks with a smoke machine at my shop tomorrow. From there I will look into adjustments as needed.

Thanks for the help everyone..........................C

HarryD · 08-04-2005, 10:22 PM

Chris,

Nice ride. Good luck. Looking at the CIS trouble shooting chart, vacuum leak, a stuck plunger, or incorrect fuel pressures may be your problem. Still, if you still have the relationship, a chat with Gordon may shed some light on where to look.

Paulporsche · 07:25 AM

I don't know which engine and CIS you have, but simply richening the mixture a little may do it. It could also be a control pressure (WUR) problem. Do you have points? Also, your timing may be a little too advanced.