Guest butlersZ Posted August 30, 2004 Share Posted August 30, 2004 Hey Guys, Sorry this is a non-Z related question hopefully someone can help me. Ok, I have a '90 Olds with the 3.8 V-6 FI, pretty much the same engine that ScottieGNZ has in his Z. Anyway, The #6 cylinder is dead. I replaced the fuel injectors,plugs,wires, and still the #6 cylinder is dead. I pulled the plug and it is black as black can be so it is rich. Did compression test and I get 90-98 psi across the board, which is borderline to me. So the #6 cylinder has spark and has fuel but is running rich. Oh and when the car is placed in drive or reverse it stalls 90% of the time, I have to rev the engine just so it won't stall, and once I get going it doesn't stall but wants to because it's only running on five cylinders. I ran the error code tester by it and i get code 44 which means"O2 sensor-lean exhuast indicated". So given all that information can anyone tell me what might be wrong or what to check next? The only other thing I can come up with is a blown head gasket. Sorry for posting this here, but I'd rather ask here before having to take it to a shop and pay $150 just for a diagnosis. Scottie GNZ, have any feedback on this, perhaps you have the same engine and have had similiar problems??? Quote Link to comment Share on other sites More sharing options...
datsunlover Posted August 30, 2004 Share Posted August 30, 2004 You are SURE the #6 plug is getting GOOD spark? That car uses coil packs for the ignition right? (little package of coils, one for each plug, mounted on the firewall or somewhere close in there..maybe on the engine..) I've seen a few of these cars (pretty comon actually.. olds 88, buick lesabre, pontiac.. bonnevile? its all the same) with simmilar problems and it turned out that the coil pack, or one coil.. was dead, causing a weak/no spark issue. Would be a simple swap in to find out.. As for the O2 code.. my guess is that because #6 isn't firing, it sences too MUCH fuel, and causes the ecu to back off on the injectors.. causing it to go lean. I might be way off on that though.. Also, as far as I know, if the compresion in within 8psi across the board, its fine...(I think 10 is acceptable) a bit low maybe, but its more important that all the cylinders are even so I wouldn't be woried too much about that.. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Guest mtbrider586 Posted December 2, 2004 Share Posted December 2, 2004 well . 80-90 psi compression is very low. a good engine will be in the 160s this uses a waste spark dis ignition with paired coils. mounted on the module located on the side of the motor facing the radator. If one coil is bad you will missfire in two cylinders. are you sure about your compression readings. Is that the only missfiring cylinder? Install a fuel pressure gauge and shut off the engine and see if it will hold pressure. If it drops fast. you probley have a fuel injector that is stuck open on number 6 Fred ASE master tech Quote Link to comment Share on other sites More sharing options...
Guest Magnum Rockwilder Posted December 2, 2004 Share Posted December 2, 2004 Try changing the O2. Maybe it's a bad O2 that's incorrently reading lean and overrichening the A/F ratio. Aside from that, replace the engine. They're $150 and plentiful. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 2, 2004 Share Posted December 2, 2004 Good advice so far. Here is what I would do for starters: - Check the connector to the O2 to make sure it is not disconnected. - Replace the O2. I believe that engine uses the same 1-wire O2 as the '87 and I pay ~$26 new at Autozone with a lifetime warranty! - You can also check the coilpack with a meter. Set the meter to 20K Ohms and check the resistance between the terminals of a coil and it should be between 11-13. Not uncommon to see one completely dead. - Before you restart the engine you must reset the ECM. It sounds like whatever the problem has caused the ECM to go into limp home mode. This will also clear the 44 code. Simplest way is to disconnect the battery and wait 10 seconds. If the problem persists, DO NOT run the engine if it idles bad and black smoke is pouring out the tailpipes. That is limp home mode and you will eventually wash down the cylinder walls. MOF, that will have an impact on the compression reading. If you did this a lot, I would suggest fresh oil and a filter as cheap insurance. Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted December 2, 2004 Share Posted December 2, 2004 I had 3/4 cylinders and still had a poor idle, but didn't stall, but your comp might be over compensating, your compression is too low I think, it's a sign of either blown head, jumped timing belt or stuck valves? but on all cylinders my money is on the timing belt, if you blew a head it probably wouldn't blow both heads at the same time. Check the belt, and check the valve timing. Quote Link to comment Share on other sites More sharing options...
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