No power, rough idle

[Roy]

98 SL1, 165,000km
I have rough idle down around 500-750RPM (it usually idles just over 1000RPM). Very little power. When I floor it in neutral the RPM gauge goes to 4200 and pulses. Looking under the hood at lunch time and the PCV hose was cracked/split and flattened. I replaced the hose but that seemed to make it worse. I remember talk on here of cleaning the PCV vavle but the Haynes manual I have only says what it does, no mention of cleaning. My question is, what should I clean it with? compressed air, gasoline, methyl hydrate...? Or should I just get a new one? Does this sound like a dirty or defective PCV valve or should I continue to look for other causes? Any advice or suggestion will be greatly appreciated.

Roy

 

[Doug Miller]

98 SL1, 165,000km
I have rough idle down around 500-750RPM (it usually idles just over 1000RPM). Very little power. When I floor it in neutral the RPM gauge goes to 4200 and pulses. Looking under the hood at lunch time and the PCV hose was cracked/split and flattened. I replaced the hose but that seemed to make it worse. I remember talk on here of cleaning the PCV vavle but the Haynes manual I have only says what it does, no mention of cleaning. My question is, what should I clean it with? compressed air, gasoline, methyl hydrate...? Or should I just get a new one?

Just get a new one -- it's only about five bucks, if that much. Hardly worth trying to clean out...

Does this sound like a dirty or defective PCV valve or should I continue to look for other causes?

My guess is an ignition problem of some sort. Check the plugs; I'll bet they're not all firing. And *that* could be due to a bad plug, a bad plug wire, or a failed electronic ignition module.

Another thing to check: make sure the exhaust system isn't plugged. A stopped-up catalytic converter can cause similar symptoms.

 

[Roy]

Thanks, after doing a little more searching I found there wasn't anybody suggesting cleaning although here in Canada it's more like $15 for the part (still very affordable). If that doesn't do it I guess it's time to start pulling wires and plugs. I really hope it isn't the cat, it was replaced 3 years ago and I really don't want to buy a new one yet.

 

[Doug Miller]

Thanks, after doing a little more searching I found there wasn't anybody suggesting cleaning although here in Canada it's more like $15 for the part (still very affordable).

Wow. That's kinda high. You buying that at the Saturn dealer? The going price at auto parts stores around here (Indianapolis) is about US$3.50-4.00, which is still under CDN$5. Have you tried WalMart or Canadian Tire?

If that doesn't do it I guess it's time to start
pulling wires and plugs.

Most auto parts stores can test the ignition module for you, too, and the test is usually free.

I really hope it isn't the cat, it was replaced 3 years ago and I really don't want to buy a new one yet.

If the cat is only 3 years old, it's not likely to be causing trouble.

 

[Roy]

I was going by prices from web sites and forums, it was actually $5.94 plus tax from the dealer. That was cheaper than the other parts stores which were around $7-8 but none of them had one in stock, not sure why they bother to give you a price if they don't have one. As for free testing, we don't have Autozone here (I keep seeing people refer to them for free testing) and it is very hard to get anybody to do anything to a car for less than $40 (even to check codes). After I try the new plug wires I may see if the Saturn dealer will test it for me after I've spent $100+ on parts there. I replaced the PCV valve and hose. I put in new spark plugs (figured they were due anyway and inexpensive). The plugs helped a little by getting rid of the rough idle but it still has the miss and a little hesitation when I give it some gas. I guess next is plug wires ($70, I priced them while I was at the dealer).

Not sure what to do if the new wires don't do it but I guess I'll keep following the ignition system unless somebody has a better idea.

 

[Doug Miller]

I replaced the PCV valve and hose. I put in new spark plugs (figured they were due anyway and inexpensive). The plugs helped a little by getting rid of the rough idle but it still has the miss and a little hesitation when I give it some gas. I guess next is plug wires ($70, I priced them while I was at the dealer).

Seventy dollars??? Damn. I realize that's Canadian dollars, not US, but your dollar is a lot stronger against ours now than it was just a few years ago. Right now, CDN$70 is about US$62 -- and that's a *hell* of a high price for spark plug wires. Especially for a 4-cylinder engine.

For comparison, I just bought a set for my Suburban at a local auto parts store last weekend -- and that's a V-8 engine, twice as many wires -- for US$25 (= CDN$28 and change).

 

[Roy]

$70 was the dealer price. I got a set today at Canadian Tire for $30+tax. About the same as you paid for your 8 wires. They didn't help any so I guess I'm either getting a new distributor or going to get the codes read, whichever is cheaper. One of the terminals on the dist was white with corrosion and the last one had a big pile of rust setting on it when I took the wire off. Been a log time since I've dealt with an ignition system but I've never seen rust on a distributor before. The terminal wasn't rusted, it just wiped off so the rust must have come from inside the wire end.

 

[BläBlä]

$70 was the dealer price. I got a set today at Canadian Tire for $30+tax. About the same as you paid for your 8 wires. They didn't help any so I guess I'm either getting a new distributor or going to get the codes read, whichever is cheaper. One of the terminals on the dist was white with corrosion and the last one had a big pile of rust setting on it when I took the wire off. Been a log time since I've dealt with an ignition system but I've never seen rust on a distributor before. The terminal wasn't rusted, it just wiped off so the rust must have come from inside the wire end.
]

Roy it sounds to me you went way to long without servicing your ignition system! The rust is from your spark plug wires connector. You have no "distributor", what you are looking at is a coil pack. Two coils each with two coil "towers". This system is known as a waste spark system.

FYI a new set of wires doesnt mean a darn thing if you do not use an OHM meter to check the resistance of the wires. It seems no less than 50% of the wire sets I buy have at least one wire that is either out of spec or completely dead! A bad wire can make your car run like crap and WILL eventually kill your coils.

The resistance of the wires on a S-series Saturn should be no greater than 12,000 OHMS (12k ohms). If you tug or bend your wires you can damage them so if in doubt check the resistance again. Buy some Silicon Greese (if none comes with the wire set) and apply it to the insides of the spark plug boots. This will prevent future corrosion and keep the boots from sticking. Wires should always be replaced at the same time as plugs or sooner if they are in poor shape.

There are only 2 types of spark plugs I recommend. AC DELCO and Autolite both in "double platinum". Some say NGK but I have never ran across double platinum NGK's here. The double platinum plugs should last 80k miles. Non platinum plugs last 30k tops. (do NOT buy Bosch plugs at all) Also buy Anti Seize compound and apply a small dab to the spark plug threads and keep it away from the electrodes.

Other advice
Clean your coil towers before attatching the new wires.

Before removing your old spark plugs make sure there is no debris that will fall into the combustion chamber.

If you find oil on your spark plug boots and in your spark plug wells (DOHC engine) you will need a new cam cover gasket set.

See if your old wires have nicks or chafing. You can use "wire looms" to help prevent the new plug wires from chafing in those same places.

The order of your engine from front to rear is
1234
The order of your coil towers from front to rear is
4123
Just match the numbers.

Inspect your old plugs
http://www.gnttype.org/techarea/engine/plugs.html

 

[BläBlä]

of cleaning the PCV vavle but the Haynes manual I have only says what it does, no mention of cleaning. My question is, what should I clean it with? compressed air, gasoline, methyl hydrate...? Or should I just get a new one?

Brake clean. Only replace it with the OEM if you do.

I really hope it isn't the cat, it was replaced 3 years ago and I really don't want to buy a new one yet.

The cat failure is a symptom of a greater problem. Was the problem ever corrected? Failure to keep the car tuned up is one way of taking out a cat. It could of also been an "Upsale".

 

[Roy]

Brake clean. Only replace it with the OEM if you do.

It was only $6 for a new one so I replaced it. Had to be from Saturn as no one else in town sold them.

The cat failure is a symptom of a greater problem. Was the problem ever corrected? Failure to keep the car tuned up is one way of taking out a cat. It could of also been an "Upsale".

Cat was replaced under warranty so it wasn't an "upsale." Not sure why it failed but the dealer didn't seem too concerned and I'm sure they were looking as only the emission system was still under warranty.

 

[Bob Shuman]

The key point in Bla's advice (lots of good stuff, but didn't want this to get lost since it is very important) here is to clean the corrosion off the ignition tower. This is most likely what is causing your rough idle. Also make sure all grounds cables are clean and tight as well.

Good luck.

Bob

 

[Roy]

Got the miss fixed. It was the ignition coil. Found what was probably the cause of the failure or at least contributed to it. Somebody worked on it before I bought it and snapped off the bottom bolt on the passenger side. IT is in there fairly tight using just the upper bolt but does anybody know of an easy way to get the broken bolt out so I can get a new bolt in to secure it properly.

 

[NapalmHeart]

broken screw extractor?

Got the miss fixed. It was the ignition coil. Found what was probably the cause of the failure or at least contributed to it. Somebody worked on it before I bought it and snapped off the bottom bolt on the passenger side. IT is in there fairly tight using just the upper bolt but does anybody know of an easy way to get the broken bolt out so I can get a new bolt in to secure it properly.

 

[Roy]

Kind of a tight spot to get into with any kind of power tools. I was just hoping somebody had taken one out and knew a trick.