Scott205 Posted September 18, 2012 Report Share Posted September 18, 2012 Ok here is the deal. I have a 92 Oldsmobile Cutlass Supreme with a 97 3.4L LQ1 crate motor in it. Put the new motor in about 6 years ago and 50k on it. I was driving last monday, and it hesitated a couple of times as I accelerated across a road and then about 5 seconds later died. I couldn't get it restarted, it seemed like it was spinning the motor but no signs of life. While waiting for the tow truck, I managed to get it started after swapping out the ICM & coil packs (I have an extra, it used to be a problem in this car), checking all the fuses, swaping the relays between the fans and ECM etc. Seemed to me like it just decided to start after 30 or 40 minutes. Drove it back to work, then drove it home that night. I took the ICM and coils to autozone, and they declared the icm bad, and the coils good. And I thought good, that is that. Tuesday was meet the teacher night, and after driving to work, and then about 15 minutes over to a Wendy's before the MT night. When I went to leave at 8:30.. no go.. Cranked wierd like it was trying to fire, but sometimes more like a mis-fire. Swapped ICM and Coils.. nothing but spinning. Called my wife and she drove me home, and dropped me off early the next day and I played with it... put the ICM and coils that were on it back.. just cranked. Checked to see if there was fuel, sprayed it all over. Checked the fuses and the wires at the ICM.. looked good. Then once again it started. Went in cleaned up, taught all day, drove it to a shop near my house. They looked at it Wed, Thurs, Fri and supposedly called me late friday to say that they thought it was something in the wiring harness causing a mis-fire, but they also said that from camshaft sensor should be hooked up. The 92 has 1, the 96-97 two becuase it is OBDII. I still have the original computer, so I don't use that sensor. So I go late Saturday morning over there, my wife drops me off and I go out to the car and it won't start. Supposedly it hadn't started since I dropped it. Work on it for about 2 hours, checked the wires on the ICM (can't really see much of the one from the CKP), checked the wires out of the computer and fuse area. Later I bought a new Volt meter (my old one was malfunctioning), saw the right power to the ICM, signal from the CKP, but also did an ohm test on the CKP and it read 984, and was supposed to be between 300-900. Charged the car battery, becuase it didn't want to spin well... after about 10 or 12 cranks it fired off and stalled, a couple more times and it ran... threw the tools in the car and van and drove it home. Sunday I tried to replace the CKP, and just don't have a long enough 10mm to get in there with my big hand. My pastor suggested his mechanic so I drove it over this morning (Mon). 3 times while driving it sputtered: turning right and accelerating medium light, from a stop light in 1st gear, and getting ready to accelerate from a turn onto the feeder onto the freeway (which was a right but the turn was completed). It would hesitiate like there was 0 power then catch. Mechanic replaced the CKP, started and ran great. Then on another test drive this afternoon, the mechanic drove down to the local gas station/convience store, and it wouldn't restart, sounded like it was mis-firing when it tried to start. What can this be? Camshaft position sensor? Thinking the cam is in one place when it is another? Shorted wires? if so why does it run well sometimes and then completely not start, and no blown fuses? Ideas? Thanks for your help Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 18, 2012 Report Share Posted September 18, 2012 I'm a little confused...'97 engine, '92 body...did you convert the car to OBDII? I ask, because I was certain '92's had no need of a camshaft sensor, so I'm assuming you updated the car to use that sensor? Quote Link to comment Share on other sites More sharing options...
skitchin Posted September 18, 2012 Report Share Posted September 18, 2012 I'd think that if it were something related to the swap, the problem would have presented itself a while ago. I don't have a clue what it could be - sounds electrical/sensor related though. A co-worker had problems with their daughters car, apparently a squirrel or sromething had chewed up the wire harness. Did all sorts of similarly screwy things. I'd just be very delicate with it doing the misfiring thing. Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 18, 2012 Report Share Posted September 18, 2012 That's not quite what I was getting to...on a '94-up, there are 3 timing sensors...crank sensor in the block, 24x sensor at the harmonic balancer, and the cam sensor... Do you have access to a scantool? Bet you'll find no stored codes. I'm betting you have lost either the wiring integrity to either the 24x or crank sensor, or the sensor itself is bad. I'd think that if it were something related to the swap, the problem would have presented itself a while ago. I don't have a clue what it could be - sounds electrical/sensor related though. A co-worker had problems with their daughters car, apparently a squirrel or sromething had chewed up the wire harness. Did all sorts of similarly screwy things. I'd just be very delicate with it doing the misfiring thing. Quote Link to comment Share on other sites More sharing options...
Scott205 Posted September 18, 2012 Author Report Share Posted September 18, 2012 (edited) Oops, i guess I was thinking there was 1 on OBDI and two on OBDII.. .but I bet the only one is the one on the front of the engine that isn't hooked up to anything Edited September 18, 2012 by Scott205 Quote Link to comment Share on other sites More sharing options...
Scott205 Posted September 18, 2012 Author Report Share Posted September 18, 2012 Does OBD1 have a 24x sensor? If so, can a 24x sensor cause a no-start? I read an article that says it can't, just make it run bad. But a wiring short especially to the CKP I still think is a strong possibility. Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 18, 2012 Report Share Posted September 18, 2012 I agree....most likely culprit is the crank sensor on the back of the engine, on the firewall side, or associated wiring. 24X sensor shouldn't prevent the car from starting. In your case, not sure what exactly the cam sensor would be attached to, since '92's didn't utilize them. Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 18, 2012 Report Share Posted September 18, 2012 After thinking about this a bit... The 3.1 AND the LQ1 have 24X crank sensors all years. Here's about the best way to explain the sensors...someone correct me if I get any of this wrong. The "main" crank sensor is the one on the block, on the firewall side of the engine, in the back. This sensor provides "base" crank position information that is sent to the ICM, and is responsible for ensuring a trigger is sent to the ICM for spark. This one MUST function, or there's no spark. The 24X crank sensor lives behind the harmonic balancer. The signal from this sensor is sent to the ECM, and is essentially used to "fine tune" ignition timing by providing more accurate positioning information to the ECM. If this sensor isn't functioning properly, the car should start, but will not run very well. The camshaft sensor is used on '94-up LQ1's, and is used to determine when the injectors fire. Earlier LQ1's used a "batch" fire system for the injectors, '94-up used sequential injection. If your car, a '92 wasn't updated with a different engine wiring harness/ECM when the newer engine was installed, this sensor isn't used at all, as the '92 wiring harness/ECM has no provision for the camshaft sensor.. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted September 19, 2012 Report Share Posted September 19, 2012 Let's see, you've already replaced the ICM and crank sensor, cam sensors likely not used because you're using a 92 ECM, correct? Only other thing I could think of other than wiring, would be the ECM. I have had a bad ECM cause intermittent stalling once, and the replacement caused the car to drive weird so I had to replace the replacement. So they can definitely go bad, I keep a spare just in case. Quote Link to comment Share on other sites More sharing options...
Scott205 Posted September 22, 2012 Author Report Share Posted September 22, 2012 OK, guys has to be the wiring (assuming that is the new CXP in there) The wire had frayed a bit at the top near the ICM, ran fine for 3 days, then Friday it started acting up again, cutting out a few times, then coming home it cut the engine off completely about 10 times. Only once did I have to get out and jiggle the wires. Does anyone know if they sell the CXP sensor to ICM wiring harness? it seems to be completely seperate from the main harness. I was hoping there was still one on my 92, but after thinking about it, I had already converted the 92 to the ICM being on top instead of the front of the engine and used that harness in the move. I noticed that AZ had some odd pigtails, but don't know if they would have these two. Quote Link to comment Share on other sites More sharing options...
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