Rob95CS Posted October 21, 2003 Report Share Posted October 21, 2003 I have a '95 Cutlass, 3100 SFI. Here's the problem I've developed over the weekend: While cruising at a steady speed, the engine shudders and makes the whole body of the car shake slightly. Accelerating, it's fine. Sitting idle in gear, it almost seems like it's going to stall, but it never does. It also seems a little hesitant when first getting on the gas from a stop. When sitting idle in park, it still shudders slightly. Also, every once in a while you can hear a faint puttering sound coming from the muffler when standing toward the back of the car. This ALL developed on Saturday. What could it be? I'm thinking there's a spark plug misfiring, but the plugs and wires were all replaced not more than 5 or 6 weeks ago w/ AC Delco Platinum plugs and Bosche wires. I'll still try reseating the wires and checking the plugs for the hell of it. But is there anything else that could be causing this? Quote Link to comment Share on other sites More sharing options...
MaroonRegal Posted October 21, 2003 Report Share Posted October 21, 2003 Shit, man...My Cougar used to do that. I really wish I remembered what was causing the problem....Maybe a sensor? sorry man. Someone else will know. Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted October 21, 2003 Report Share Posted October 21, 2003 Sounds like classic faulty EGR Valve symptoms... Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 21, 2003 Author Report Share Posted October 21, 2003 Please tell me that's easy to fix! Addition to the story: So I checked all the plugs and wires, they're all beautiful. This time at idle, I noticed I can visibly see the engine pulsing within the engine bay. It was shaking quite a bit actually... it looked as if there was a blockage somewhere and it was struggling to run. So I took it out and punched it to the floor. I hit the limiter at 115 (according to the speedometer) in no time. I just don't understand why it only does it at idle and cruise when the RPMs are steady. So... how do I diagnose this EGR Valve problem, and is it safe to drive with it doing this until I get it fixed?? Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted October 21, 2003 Report Share Posted October 21, 2003 Well, your EGR Valve is digital. The GM Part # for it is: 17091147. They also list a "Solenoid Valve" which is Part #: 1997201. Here's a lot more info: PURPOSE The digital Exhaust Gas Recirculation (EGR) valve is designed to accurately supply EGR to an engine, independent of intake manifold vacuum. The valve controls EGR flow from the exhaust to the intake manifold through three orifices which increment in size to produce seven combinations. When a solenoid is energized, the armature, with attached shaft and swivel pintle is lifted, opening the orifice. The flow accuracy is dependent on metering orifice size only, which results in improved control. OPERATION The swivel pintle feature insures good sealing of exhaust gas, reducing the need of critical assembly alignment. In addition, the effects of EGR leakage on idle quality are reduced because the shaft and seals are exposed to exhaust pressure instead of manifold vacuum. The shafts are sealed from the exhaust chamber by floating seals held in place by the seal spring. These springs also hold the upper seals that seal the armature cavity in the solenoids. The solenoid coils are fastened together to maximize reliability and to seal the coils from the environment. The coils use a common power terminal with individual ground terminals. The digital EGR valve is opened by the Powertrain Control Module (PCM) Quad-Driver (QDR) , grounding each respective solenoid circuit. This quad-driver activates the solenoid, raises the pintle, and allows exhaust gas flow into the intake manifold. The exhaust gas then moves with the air / fuel mixture into the combustion chamber. If too much exhaust gas enters, combustion will not occur. For this reason, very little exhaust gas is allowed to pass through the valve, with virtually none at idle. The EGR valve is usually open under the following conditions: Warm engine operation. Above idle speed. Here's a link that tells you all about how to diagnose them: http://www.wellsmfgcorp.com/counterpoints/Counterpoint3_4.pdf Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 21, 2003 Author Report Share Posted October 21, 2003 Ok, thanks! I'll test it when I find the time. If it's bad, there's a scrap yard nearby with a half-dozen W-Body 3100s I'm sure I could get one from. Anyway, back to the second question I asked... Am I going to damage anything by driving it like this? Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted October 21, 2003 Report Share Posted October 21, 2003 In one word: "NO":) Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted October 22, 2003 Report Share Posted October 22, 2003 youll need one from a 94 or 95 3100 Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 22, 2003 Author Report Share Posted October 22, 2003 This is probably a stupid question, but does it have to be a 94-95 W-body 3100, or just any 94-95 3100? Edit: I searched ebay for that part # (17091147) and came up w/ several results. One guy is selling multiples for $35.00 each, which would also give me PayPal's buyer protection against faulty products. Sound like a good deal? I'm lazy and don't feel like perusing the junkyards this week. Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted October 23, 2003 Report Share Posted October 23, 2003 I done some checking and anythig before 95 will work with that # Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 26, 2003 Author Report Share Posted October 26, 2003 Ok, not meaning to sound ignorant here, but this is the first fuel injected engine I've ever had to work on and I have no Chilton manual handy. Where is the EGR valve located? Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted October 26, 2003 Report Share Posted October 26, 2003 its right next to the throtle body in the rear Quote Link to comment Share on other sites More sharing options...
PaPaPooh Posted October 26, 2003 Report Share Posted October 26, 2003 big round thing probally 3" round has a black center Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 26, 2003 Author Report Share Posted October 26, 2003 wow... I feel stupid. Thanks for the help! Will let you know how it turns out once I have the new one put in. Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 26, 2003 Author Report Share Posted October 26, 2003 I replaced the EGR Valve today, taking extra care to make sure the gasket was sealed properly. Fired it up, and it STILL stumbles and surges. What else could it be? Maybe this EGR Valve is bad too? TPS? O2 Sensor? Clogged Cat. Converter? Would any of these do this too? It's getting colder by the day, and the colder it gets, the worse it shudders on a cold start. Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 28, 2003 Author Report Share Posted October 28, 2003 Anyone? Quote Link to comment Share on other sites More sharing options...
Redfox340 Posted October 28, 2003 Report Share Posted October 28, 2003 Anyone? Can you be more specific? When and were does it surge? During idle? Cetain RPM's? What have you replaced over the last year? Any Service Engine Light(s)? Trouble codes? Have you complete an extensive tune-up (plugs / wires / clean throttle body) lately? The more you can give the better; we can't dignosis your can through computer monitors. - Erik Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 29, 2003 Author Report Share Posted October 29, 2003 I apologize if I sounded like I was nagging. Plugs and wires were replaced about a month ago, as well as throttle body cleaning. I checked all the plugs when it first started acting up, and all were fine. Now, when starting the car after sitting and getting cold, the engine would shake quite noticeably within the engine bay, shaking the whole cab of the car. So I replaced the EGR Valve and gasket with no change in behavior. The colder it is outside, the more violently the engine will shake. As the car warms up while idling, it will get less and less noticeable as the temp gauge raises. Once it hits about 120*, the vibration is hardly felt, and at 180* it's ALMOST gone (it's still there, but barely noticeable). Now, until the temp gets up to about 140-150, it will also be really hesitant (and again, shaking) when accelerating. Once the car is warmed up, almost everything is fine in stop and go driving. When stopped at a light, the vibration is felt once again and it will hesitate again when first getting on the gas from the stop, but then resumes normal behavior. When accelerating or decelerating at normal operating temperature, all is fine once again. But once a steady speed is reached and the RPMs are held constant, the shaking starts once again. Like I said, I replaced the EGR Valve with a used one and the behavior didn't change. I tried testing it using the battery method described in that newsletter that was linked to earlier in this post, but I couldn't get any of the solenoids to energize and just ended up throwing some sparks (and soldering my testing wire to the solenoid) I must've done it wrong. Can anyone explain that better so I can properly test my EGR Valve? Oh, and the SES light never illuminates, and as for trouble codes, don't have access to a scanner. Quote Link to comment Share on other sites More sharing options...
Slade901 Posted October 29, 2003 Report Share Posted October 29, 2003 I'm leaning towards a failing cat. Take out the O2 sensor and start the car and see if the engine shakes or not. If the engine does not shake if the O2 sensor is removed, then you have a failing cat. Replace it with free flowing cat. Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 29, 2003 Author Report Share Posted October 29, 2003 Again, I'm still a newbie w/ fuel injected engines.... where's the O2 sensor located? Quote Link to comment Share on other sites More sharing options...
Slade901 Posted October 29, 2003 Report Share Posted October 29, 2003 Again, I'm still a newbie w/ fuel injected engines.... where's the O2 sensor located? It's located right behind the engine. The O2 sensor is usually located at the exhaust manifold close to where the catalytic converter connects. Some use an open end wrench to remove the O2 sensor. I'd recommend to buy an O2 sensor socket instead for easier removal. This 02 sensor socket looks like a deep socket with a slot on the side (designed keep the connector wire out of the way when you are removing the O2 sensor. Of course you need a rachet and long extension bar. Quote Link to comment Share on other sites More sharing options...
Rob95CS Posted October 30, 2003 Author Report Share Posted October 30, 2003 I'm definitely going to have to buy an O2 Sensor socket... I just tried to remove that thing with an open end wrench for a solid half an hour and I cannot even get it to budge. Will post back tomorrow. Failing Cat. makes sense though, b/c my exhaust REEKS! Also, I found out if you rev the engine up in park, it'll stop shaking after 1500 RPM. Quote Link to comment Share on other sites More sharing options...
Rossp Posted January 19, 2004 Report Share Posted January 19, 2004 I am wondering, before all of this happened did you replace the battery in your car? I am experiencing similar problems in my 94 and I just had the battery replaced a week ago, I am thinking it might be related. Let me know Quote Link to comment Share on other sites More sharing options...
Bizzo Posted January 23, 2004 Report Share Posted January 23, 2004 I used to have a 95 Corsica with the 3100 and one day it started shuddering at certain speeds with the pedal in a certain place. Turned out to be the TPS and ended up costing like $40. After that it ran sweet. Quote Link to comment Share on other sites More sharing options...
gwims2 Posted May 11, 2004 Report Share Posted May 11, 2004 I have the exact same symptoms that Rob was having with his '95 Cutlass. I have a '94 Cutlass convertible with 142k miles. About 6 months ago I started having the same symptoms. I replaced the egr valve but still was unable to cure the problem. I will try to pull the O2 sensor and see if I can tell a difference. I was unsure where to go next with this problem, but I figured it was either an injector gone bad, or an air intake sensor or exhaust related. I have another problem now as well, my AC compressor stopped running. As far as I can tell, it is not getting any juice. I have full freon, so I am thinking the electronic climate control box is bad. I checked all the fuses I could find and they are all ok. I will keep post my reply once I pull the 02 sensor. Greg Quote Link to comment Share on other sites More sharing options...
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