| Lt1 engine trouble......got me baffled! Any info/advice/thoughts | |
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+3toomanytoyz mega Ironfistdog 7 posters |
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Ironfistdog
Posts : 2141 Join date : 2011-01-11 Age : 42 Location : Warren, MA
| Subject: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 5:30 pm | |
| Ok so I've been trying to tackle this problem myself (and with the input of 2 others) since I got this car. it's a 96 lt1 140k miles. Original everything I'm sure. Still had death-cool in it.
I drove it home from the lot and the wife said she saw black smoke from the drivers tail pipe. I chocked it up to it had been sitting a while. Well I got a few codes on the obd2 reader and they were po131 and one for the MAF sensor. I posted here an for advice it was for a leaky exhaust gasket. Changed it and saw no broken studs in the head. All bolts accounted for. The code went away as I swapped a new o2 sensor on that side (drivers pre cat) cleared code and drive it for a day and a half,
Then I decided to spray down the engine and clean up the oil slick in the front of the block, right after that the car ran like crap. Skipping and still spitting black smoke. Po131 came back along with a po300 random misfire.
I decided to start looking around and did research on misfires. Been through almost everything -swapped opti for a low mile reliable working opti -swapped water pump incase of weeping -did plugs and wires properly gapped and routed away from exhaust -swapped injectors and fuel rails -just did intake manifold gasket
I'm getting the po131 constant now, and intermittent po300 po301 po303 po307 Seem like I'm getting misfires from onl the drivers side, and because it have black smoke from that pipe from the start I assume there is something going on specific to that side. So I'm thinking no on: -fuel pump failing -fuel filter -coil -icm and harness -iac -tps -coolant temp sensor -or absolute pressure valve.
Could this be: Clogged cat? Burned valves? Bad piston rings? Crank positioning sensor Any other good ideas????
Car runs and drives now, but Idles rough at cold and gets progressively worse as it heats up. At traffic lights it's misses sometimes so back it feels like im getting rear ended. And sometimes the car lurches forward to the point. Gotta put it in N, it has a shutter and stumble at around 65 mph while accelorating also. It's leaving soot only from the drivers pipe in the driveway and at all the stop signs I stop at, no other codes just po131 and po300. With an occasional drivers o2 post cat (po136 or something). Ses blinks at hard accelerations up hill, and on highway as I slow down and it starts to misfire. I'm at my wits end with this and I really want the car to make it to the round up. I run 89 and 93 octane, the egr is working, and I still have the old crappy plugs and wires on the passenger side. No misses over there just on the drivers. I have not done a leak down or compression check yet, hoping for any ideas before I do that. I have the low mile motor from the caprice that will get swapped in if this is piston rings. H-E-L-P ...---... | |
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mega
Posts : 907 Join date : 2011-03-01 Age : 43 Location : Hyannis, ma
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 6:06 pm | |
| I had sorta the same problem with my car when I got it. Mine was fuel filter. How's the voltage on the tps? | |
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toomanytoyz Club President
Posts : 6876 Join date : 2009-01-20 Age : 47 Location : East Hampstead, NH USA
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 6:12 pm | |
| Well, if you're getting misfires all over the place and it got worse when you sprayed the front of the motor, I'd swap the coil and maybe the icm for a known good. Also check the grounds there, they tend to break. | |
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Ironfistdog
Posts : 2141 Join date : 2011-01-11 Age : 42 Location : Warren, MA
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 6:24 pm | |
| I didn't check it yet. Would assume the tps and fuel filter would affect both sides of the engine. I'm thinking more specific to the drivers side. Head's, valves, cam (although it would be one in a million to weardown just DS lobes), exhaust manifold crack, clogged cat, piston rings that side. Etc. | |
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Ironfistdog
Posts : 2141 Join date : 2011-01-11 Age : 42 Location : Warren, MA
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 6:29 pm | |
| Bill, but would a coil only cause misfires in 1 3 5 and 7??? I also forgot to mention it got worse after spraying it because I knocked the no 5 spark plug wire loose. But when I change them it continued to run rough. Tail pipe is Pure black drivers side only. it runs good at wot before getting to about 65. The only other thing I did was add some of that guaranteed to pass emissions stuff. But ghat was 3 tanks of gas ago. Could the timing be off? Would that only affect drivers bank of cylinders? | |
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Cadet57
Posts : 4481 Join date : 2010-03-14 Age : 36 Location : Chicopee, MA
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 8:16 pm | |
| My wagon issue is apparently contagious. Sorry Indigo. | |
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sdstick
Posts : 4292 Join date : 2009-03-20 Location : Revere, MA
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 9:14 pm | |
| Not to insult you but the firing order was correct right? Pull 1 drivers side wire at a time & see if each affect the idle Did you disconnect the battery & let it reset itself? Are both tailpipes passing the same volume of air? Did you pull that valve cover to take a look? If that lean burn (exhaust gasket) went on for a long time, the cat might have been affected IDK.
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Tomz9C1
Posts : 1498 Join date : 2009-01-21 Age : 61 Location : Rumford, Maine
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 9:41 pm | |
| - sdstick wrote:
- Not to insult you but the firing order was correct right?
Pull 1 drivers side wire at a time & see if each affect the idle Did you disconnect the battery & let it reset itself? Are both tailpipes passing the same volume of air? Did you pull that valve cover to take a look? If that lean burn (exhaust gasket) went on for a long time, the cat might have been affected IDK.
Agreed, get a friend & check the firing order again. | |
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Ironfistdog
Posts : 2141 Join date : 2011-01-11 Age : 42 Location : Warren, MA
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Tue Sep 27, 2011 10:33 pm | |
| No insult taken. Mistakes can happen. I will check again just to be sure. I did stuff them all through the bracket for the air pump so it's possible, but I've seen cars with wrong plug wires and it's not pretty. I will also disconnect the battery and try that. The original opti had corrosion in one terminal #5 or #3 I believe and also #5 and #7's wires were burnt up. So it's probably been running lean for a long time. I was thinking the same thing about the cat being clogged up. Because it only misfires real bad sometimes other times it's just a small rumble. As if the exhaust is only being trapped part of the time. The tailpipes seem to have even flow but I'm not looking at them when I'm in the car. There is an exhaust leak somewhere but it's way way after the o2's so I don't see much harm from that.... Like down towards the over axle pipe. I had the valve covers off to paint them and it looked clean and nothing out of the ordinary but I wasn't really looking for anything at the time either, I had a severe oil leak from behind the block, turns out the back intake gasket rtv was completely gone, and it looked like it had been changed because some goon only torqued the intake bolts finger tight, so I was assuming it was gonna run good when i was done. I had a 96 with the l99 that had a clogged cat, and you couldn't drive it past 30mph and it squealed through the check valves. But that was an extreme case. It is higher mileage..... How can your test for a clogged cat? Thank you everyone for your input, I really appreciate it. | |
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MASShole9C1
Posts : 4294 Join date : 2009-12-16
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Wed Sep 28, 2011 12:27 am | |
| I like the "Lac of faith". Genius :cheers:Let me know if you need those cat(s). | |
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Guest Guest
| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts Wed Sep 28, 2011 5:40 am | |
| Make sure to check the wires that power the coil. They seem to fail near the connector. |
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| Subject: Re: Lt1 engine trouble......got me baffled! Any info/advice/thoughts | |
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| Lt1 engine trouble......got me baffled! Any info/advice/thoughts | |
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