Cascade Crew

Al Hasse

Ever since the headers went on, I have a problem with the car running very rich, random popping in the exhaust and loss of power on hills. The headers and exhaust system are tight with no leaks, O2 is a new heated type sensor. I can get the car to idle OK at about 650 (by the tach) without any noise from the exhaust, but as soon as a load is put on the car, it hesitates and then wants to rattle the valves out of the motor, especially uphill. New theory is either in fuel delivery or ignition. I think something went bad at the same time. I've been looking into the ignition stuff first mainly because the cap and rotor were shot. I replaced those and the ignition coil with one I had in the garage. It seems a little better, but all the symptoms are still there. The problem seems to get worse if I advance the timing any, so it's still at 0* base timing, and the computer likes to add about 15* at idle.

Sellmanb · Member Joined: 30 Nov 2004 Posts: 727 Location: Tigard, OR

Do you have a cat? Is it stock? Was it cheap? How old is it? Do you have a backpressure tester or a vacuum gauge?

If you have a vacuum gauge, put it at a good vacuum source, I would expect to see somewhere around 15-20 hg in of vacuum, steady at idle. If the gauge bounces at idle, then look towards something like a burned valve. If vacuum is low, then timing could be bad, or a plugged exhaust.

Now, you'll want to rev it to ~2000 RPM, the vacuum gauge will drop momentarily, but should steady out. You should expect to see some higher hg in from the gauge, if it drops in vacuum the more you rev, you definetly have an exhaust blockage, most likely cat or muffler.

Or you can just plug in a backpressure tester in the O2 bung, but a vacuum gauge reading can tell you alot more about how a car is running than a backpressure tester can.

Al Hasse · Posted: Sat Nov 10, 2007 6:32 pm Post subject:

Hey thanks for the ideas, but the entire exhaust system is new with no leaks. The only concern I had for the cat when I bought it was that it was 3" in and out, supposedly it's high flow, same with the muffler.

Where do I find a vacuum gauge or a backpressure tester? I don't expect any exhaust problems since the entire system is new.

This is the cap and rotor I took off today.

Xophertony · Posted: Sat Nov 10, 2007 6:34 pm Post subject:

another quick check to see if a cat is clogged is to remove your o2 (leaving a hole there) or to disconnect the cat and catback (open ypipe) and see if the problem lessens/goes away.

Al Hasse · Posted: Sat Nov 10, 2007 6:40 pm Post subject:

Cat is not clogged. It's brand new and was put on not only because it is 3" in and out, but to try to fix this problem after the headers were put on, but it has not.

Xophertony · Posted: Sat Nov 10, 2007 6:43 pm Post subject:

sorry, i started my post before i saw your post where you said that..

ninja'd.

Al Hasse · Posted: Sat Nov 10, 2007 6:48 pm Post subject:

Like I said already, I think something else failed at the same time I put the headers on. All the exhaust is new and checked for leaks. Now I suspect maybe fuel delivery or ignition or timing, or a combination of. Maybe a good computer tune can help???

Quasi-Traction · Posted: Sat Nov 10, 2007 6:51 pm Post subject:

hmm, the contacts on the cap looked less than stellar.....

are those fairly new parts?

I'm leaning towards over fueling, but that might just be because I've been dealing with a car lately that's been over fueling... Razz

Al Hasse · Posted: Sat Nov 10, 2007 6:56 pm Post subject:

I agree, no those are the ones I removed in favor of new parts today. Looking into an ignition control module tomorrow. The parts guy at West Bay/NAPA (NAPA was bought by West Bay in Kitsap County) informed me that the ignition control module can vary the timing by as much as 11* on it's own just from the inputs it gets. I'm also going to check the play on the dizzy while I'm at it.

LB985IROC · Posted: Sat Nov 10, 2007 6:58 pm Post subject:

Al Hasse · Posted: Sat Nov 10, 2007 6:59 pm Post subject:

aaron_sK · Posted: Sat Nov 10, 2007 7:33 pm Post subject:

Cause you might accidentaly pass emissions. Laughing

Al, does your timing jump around at all, or miss? When mine went out (still unsure if it was the module, or the pickup coil) I had a bad misfire, and the timing jumped around quite a bit.

Vacuum gauge you can get at Harbor Freight for under $20, or I have one you can borrow if you need it.

Al Hasse · Posted: Sat Nov 10, 2007 7:44 pm Post subject:

Timing is somewhat erratic with the EST wire connected. Withe the EST disconnected, it's solid 0*. When I dialed back the timing light after connecting the EST wire, what I was able to read was a best guess of 15*-20* added by the computer.

aaron_sK · Posted: Sat Nov 10, 2007 7:46 pm Post subject:

What chip do you have Al? My Hypertech will do exactly that.

Al Hasse · Posted: Sat Nov 10, 2007 7:49 pm Post subject:

Mine is a stocker. I have a 24 to 28 pin adapter socket soldered on the PCB for future upgrade.

Raiden · Member Joined: 10 Mar 2004 Posts: 193 Location: tacoma

Sounds like the mess I was having with my Z a few months ago.
Here's what I did to see if my cats were the problem or not. I loosened the header bolts and dropped the exhaust and inch or two away from the headers so there was a decent gap between the header and the Y pipe.

My Z was running really rich with 3 bad fuel injectors. All the sudden, My Z would not even idle for more that 30 seconds. I initially thought it was a computer problem due to some other gremlins. Then I did a leak down test, had my heads gone through. After all that, new injectors, it was still not running! When my car would idle, I would only get 5-8 inches of vacuumed. I then decided to drop my exhaust as mention above. I started it and I finally got a steady 15 inches of vacuumed. I ended up gutting my cats and welding them back in place. Now it purzzz with a bit more power too.

Twilightoptics · Posted: Sat Nov 10, 2007 9:40 pm Post subject:

Time to check plugs then start with a scan tool.

Sellmanb · Member Joined: 30 Nov 2004 Posts: 727 Location: Tigard, OR

When you put the headers on, did you install spark plug wires w/ 90* boots at the spark plug end? If not, the plug wires will be too fat and soak up too much heat, if not melt. The cap and rotor look wasted on the terminals, but judging by the color of the plastic, it doesnt look that old, maybe it's just the picture?

Check all primary ignition sources for proper resistances, if all check out, check all secondary ignition sources. If everything is good in the specs, then move on to fuel/ECM related issues.

Do you have access to a datalogger or some sort of equipment to show what your sensors are reading? I am curious as to what your O2 is reading.

edit: a vacuum gauge and backpressure gauge I have both seen at a few NAPA's, CarQuest, Schmucks, Baxters, etc... not all have them in stock, but all can order them.

Al Hasse · Posted: Sat Nov 10, 2007 11:25 pm Post subject:

Xophertony · Posted: Sun Nov 11, 2007 1:52 am Post subject:

AL, if you replace the Ignition Module, just replcae the whole dizzy. it's only a little bit more money, and then you have a new dizzy Cool