Rough running problem...

[gniknave]

Frustrating, and weird. I drove the piss out of my Q for about an hour today. When I returned home, it was running very rough in drive and reverse, noticably rough at idle also. I've had this problem twice before and it was the EGR connector the first time, the MAF connector the 2nd time.

Here's a few notes to break down what I'm experiencing and what I tried.

*After driving hard, rough idle. Violent rough in a slow reverse, very rough in a slow drive (10-30mph), steadily rough at idle.

*Wiggled MAF, EGR, and CAS connectors.

*When I wiggled CAS connector, engine studdered and shut off. I restarted and wiggled it again (at the wire portion, not the actual connecting part) and it stalled again. Could this be why my car stalls when I come to an immediate stop? (see below for this problem)

*With the car running I unplugged the EGR connector and nothing happened. No drop or increase in idle, nothing. Shouldn't something happen?

*Before coming home I filled up on Chevron w/ Techron (91 octane) for the second day in a row.

*Fuel Pump, Fuel Filter, MAF, all new. Throttle body cleaned last month. Spark plugs 6 months old (NGK platinum).

Also STILL having stalling problem. I replaced the MAF and though the acceleration is much better, it still stalls. In fact the car stalls to all hell if it isn't at operating temperature. I'm suspecting the FPCU for this problem but I'm not quite sure. I'm now also suspecting the CAS because of the moving (hardly touching) of the wires I did and the car failing because of it.

I can deal with the stalling for now, but a rough idle brings the words "chain guides chain guides chain guides" to my mind 100 times per minute. I don't think that's the problem though and I'm getting them done on the 24th of this month (praying they can hold up til then).

For the idling problem it seems like it's a nonfunctioning EGR to me because it feels just like it did before when the EGR stopped working...after I drove the piss out of it. I listened to the exhaust and it seemed to go "putt putt putt" along with the rough idling engine. No check engine light..well other than for my right o2 sensor because the valve cover is leaking oil on it...I'll replace the sensor when I get the valve covers resealed. I also have/had a knock sensor code but I've had that for a while, I doubt that suddenly my car would run THIS rough.

I did a search and found this thread:http://www.nicoclub.com/zerothread?id=65022 after checking Q45.org for rough idle fixes. Though some of this seemed to give some hints, I'm looking to see what responses I'll get for my issue(s).

BTW, after I played with the CAS connector, I drove around and did a few fast accelerations to quick slowdowns and the first 5 times it didn't stall...it didn't even studder, the 6th time...well you know...

[elwesso]

Id suspect the CAS connection...

I would clean the connectors... Then see what happens.....

[DAEDALUS]

The EGR is mostly a "cruise" device to improve mileage and decrease emissions. It would have a negative impact on idle quality, but at 70 mph you'll not likely notice. If your car was overheating you might see it at idle though.I can't see how the chain guides would cause a rough idle...just a sudden death or a no-start.

[DAEDALUS]

Is it an intermittent miss perhaps?

[gniknave]

Is it an intermittent miss perhaps?

Seems like it COULD be missing because Lord knows how old my injectors are, but it sure as heck isn't intermittent.

Wes, I wiggles the wires that lead to the CAS connector and that's what caused the car to shut off. The wires feel hard and I can even see one of them splitting a bit. You think this would cause the car to run rough like it is?

[elwesso]

Its possible... The CAS is one of the most important sensors to the system...

Id still try and take off the connector, clean it out and then go from there.. A lot of times just removing it and putting it back on will help!

[gniknave]

Drove the car to work today. Noticed a power loss, and lots of bucking in the acceleration. It takes way more effort to get to 4000 RPM on a quick acceleration. It also took more effort to maintain a consistent speed when going up a slight hill. Usually I can just hold my position on the throttle and I maintain a steady speed. But today I had to press harder to maintain the speed. MAN I'm FRUSTRATED! Just 3 weeks from getting the guides done and this s**t happens!

I get this serious "put put put put put" sound from my exhaust as if something is clogged or something...now fuel smell from exhaust. Damn, I'm thinking an injector problem. Just when I sent Jesda my spares....

I just had our master tech look at the car a sec ago. He saw the CAS and noticed the wires were open and exposed. He says this is dangerous. I noticed a little better idle when he SLIGHTLY moved the wires, but when he moved them too much, STALL. He's saying that it doesn't always cause a loss in power because most of the time the CAS is simply the difference between the car starting or not. He said the CAS part itself is something in 13 years of servicing these cars he's only replaced twice. He suspects injectors or coils could be my problem, but he's suggesting to coat the exposed CAS wires with silicone and let it dry before checking for the next problem.

Any other suggestions? I'm hoping the above paragraph can lead to a success story and help anyone else having the same problem. I'll keep you guys and gals updated.

[Jesda]

Drop me an email with your address and I'll send four injectors your way.

Did you ohm them?

[DAEDALUS]

A fuel smell suggests an injector leak or possibly a bad coil. If one or more ohms bad then suspect more than 1 problem. A quick vacuum test would probably reveal a hanging valve, and a rail leak-down test would confirm an injector leak.

[gniknave]

Question...when ohming the injectors. I'm assuming car should be on and radio off???

[911/Q45]

Everything off.

[DAEDALUS]

No power, open circuit anytime you're measuring resistance.

[gniknave]

My understanding is that 10-14 ohms is normal...My results

#1. 15.3#2. 13.8#3. 13.5#4. 13.5#5. 13#6. 16#7. 15#8. 13.5

Only 1, 6, and 7 seem questionable, and they're pretty close to borderline. I did the silicone treatment to the wires from the CAS like the tech told me to. Once I got everything back together, the car was taking a while to start. I then moved the connector signifigantly and it returned to an immediate start. BUT, still the rough idle!

The car is running obviously rich and going putt putt putt, and you can hear ticking similar to an injector problem, but according to the measurements the injectors aren't that bad. Man I'm stumped! HELP!!!

[elwesso]

Make sure EVERYTHING is off.....

When I did my injectors today, I had approx 1 ohm difference when just the door was closed and when it was open...

This is important... Id go ahead and measure no 1 injector right on it since its easy to get to...

[DAEDALUS]

Why would an open door affect the reading at the injector harness?

Evan, is your DVOM quality? I'd guess all reading were 2 ohms high. I still recommend a vacuum test and rail leak-down check.

[gniknave]

DVOM? If you're talking about the tester, it was our master techs Snap On tester. Sorry, I'm still learning all the abreviations but thank you for using them so I can ask what they mean

Another no mechanical experience question:

How would I go about doing a vacuum test and a rail leak-down check?

Wes, the door was closed and key was off.

What are some issues that follow a bad or inop transistor unit? I'm asking this question because looking back at some old notes, it was a loose power transistor connector that caused this problem at one time and not the EGR connector. I think this correction makes a little more sense.

[DAEDALUS]

LOL Actually I'm not certain what it stands for, but I think DVOM is Digital Volt Ohm Meter. Still kind of surprised by the readings. Tight group, but all off. Usually most are 12-13 and any that are off are off by a lot.

Borrow the tech's vacuum gauge or vacuum pump with a hose and a tapered fitting. You measure vacuum at any of the ports past the throttle body, so the brake booster hose is one place. Measure the vacuum at the port (make sure the fitting is snug and sealed well) and watch the needle. It should read about 18" of mercury and be very stable. If you have a hanging valve the needle will show a jiggle from the imbalanced cylinder vacuum. If vacuum is less than 16 in HG you probably have a problem. You could also do a compression test, but this is a 5 minute test vs 5 hours taking the plugs out and cranking the engine repeatedly. For the rail leakdown test you'll need a fuel pressure gauge, a fuel hose T and a couple fuel hose clamps. Tee in to the line between the filter and the rail. Turn the key to "ON" to get the pump running and to pressurize the rail. The gauge should read about 34psi. Quickly clamp off the fuel return line, and the line between the filter and the Tee. Then just wait. If the injectors aren't leaking and if the clamps are on tight, the system should hold pressure for a good long while. Record the pressure readings at 0, 5, 10 and 15 minutes after setting the clamps.

[elwesso]

Why would an open door affect the reading at the injector harness?

Evan, is your DVOM quality? I'd guess all reading were 2 ohms high. I still recommend a vacuum test and rail leak-down check.

Because with the lights on it draws a little more current... Since you have to put the positive terminal of the VOM on the positive terminal of the battery.... All i konw is that it changed my ohm readings by 1 ohm across the board.....

Its kinda weird when theyre like 1 ohm out of spec.. generally that means theyre still going but on their way out.....

[DAEDALUS]

Like I've said, you can't have any current in (potential across) the circuit you're measuring. That's the point of disconnecting the harness--to isolate the injector circuit. The meter sends a tiny current of its own through the circuit. It figures out the resistance by the amount it reads back.

[gniknave]

I hear some serious ticking that from my experience points directly to an injector problem on most cars. I decided to reohm my injectors. I used a cheap tester this time but spend lots of time doing it to get consistent results. I've done it 3 times in the past hour. This is what I've come up with:

1. 14.82. 13.43. 13.64. 13.65. 13.46. 16.67. 18.58. 13.5

[DAEDALUS]

Humor me and try reading the #1 and #2 injectors directly. You'll have to remove the little metal clip on each connector, then just pull the connectors off. When you put them back on, put the clip on the connector first, then just slide the connector overe the injector. The clip will lock in place.

[gniknave]

It's hailing, thundering, and lightning here where I'm at. I'm going to call it quits for the day. I'll test #1 & #2 directly tomorrow. Question; Is there a way to ohm the coils? If so, how and what is the average range?

[oxs1]

You have the exact same problem as me. 188k miles 91 q 45. I need a solution as well.

[DAEDALUS]

Yes, the coils may be ohmed, but the resistance test may or may not reveal a problem. Often when the coils go out the insulation between the wires breaks down, but the wires themselves are just fine, so they ohm OK. Only during the high-voltage spark is the problem evident, when the engine begins missing. The individual component inspection pages, in the back of the EF-EC section show how to do an ohm test on the coils.If you're going so far as to remove the coils, you may as well remove the plugs too. They can probably narrow down the problematic cylinder.

[gniknave]

I've decided to take it to work with me Monday and let the pro's do their diagnostic. I don't mind doing regular maintenance things myself, but when it comes to diagnostics I like to leave it to the pros. I'll make sure to post the results for everybodys benefit. And THANK YOU DAEDALUS!!! You've been a BIG help so far!

oxs1, Have you looked at Q45.org under Tech Help, Resolving Rough idle? http://www.q45.org/roughidle.html MAF seems to be a pretty common contributor, though it isn't my problem this time. Do you have any pics of your car? You have a pretty interesting mod list..

[gniknave]

Problem solved. Though I'm leaning towards parting out the car, I've at least bought myself some time.

Solution was a loose connection on the right ignition module aka transistor unit. Thanks guys for your input! I owe you a few!!!