WhiteOut Posted February 13, 2004 Report Posted February 13, 2004 Alright, since my car is temporarliy out of it from Monday's accident I thought I'd lend help to a friend with his 94' LQ1. Here's the thing. About a month or so ago his car just started running like crap. The catalytic converter was glowing red, and he had massive amounts detonation happening in the downtube/conveter area of the exhuast and the car had no power. We were looking at it earlier this week and the car had been running for 15-20 minutes plenty of time to warm up right? Well, I accidentally touched the front exhaust header with my hand and to my surprise I didn't get burned, in fact it was barely even warm. WTF? So we did spark, compression and injector tests on the front bank and everything looked good, spark was occuring fuel delivery was good according to the scanner, and compression was even at about 130psi across the cylinders. So that seemed odd. Even more odd is that the engine runs fine, no vibrations or anything else that would make you think cylinders aren't firing right, there's NO detonation at all in the front cylinders, not even from waste spark. We thought maybe the timing was off, but after removing the inspection cover the belt looked fine, with no idications of stress or cracking anywhere. So I'm stumped... So far we've replaced: 1. Catalytic Converter 2. Ignition Control Module and all 3 coils And it runs the same. Can timing get off that far from belt slip? I wouldn't think so, but I've been wrong before. The weird part is the problem just suddenly appeared. It drove fine and then he said the next time he started his car it ran like hell. What the hell is going on? Quote
joey b Posted February 13, 2004 Report Posted February 13, 2004 the cat is red, so there is gas. Try switching the wires on the coil pack for the other coils. Put the 1 on the 4 and the 5 on the 2 and 6 on the 3. Quote
brian89gp Posted February 13, 2004 Report Posted February 13, 2004 Since each coil fires 1 rear and 1 front cylinder I doubt its spark at all. Is the rear manifold hot or cold? The front bank not firing will cause the cat converter to glow red. Pull the front cam carrier cover and check if the cams are timed right. Only thing left is fuel, make sure the front injectors are firing. Quote
WhiteOut Posted February 13, 2004 Author Report Posted February 13, 2004 Its got nothing to do with the coils or ICM. Both the the ICM/coils I put in and the ones I took out are fine according to NAPA (who tested them for me). I think that its fairly unlikely that the timing is off given that the belt is intact. It seems to me that if it jumped timing the belt would be messed up and some valve train damage would have occured. Plus the fact that the problem suddenly cropped up seems to indicate that the problem is electrical in nature. I'm thinking it could be the Crank Sensor or the cam sensor. Problem is I have no idea where either of those is on this engine. Quote
WhiteOut Posted February 13, 2004 Author Report Posted February 13, 2004 Anyone know how to test a Crank or Cam sensor to see if its functioning? Quote
brian89gp Posted February 13, 2004 Report Posted February 13, 2004 If the 24x crank sensor goes out I believe it reverts to batch firing the injectors, if the 3x crank sensor goes out you loose spark completely. If you loose the cam sensor it reverts to batch fire. Is the rear manifold cold or hot? Is the SES light on? The fuel injectors are controlled independently, each with its own FET. It is possible but unlikely that just the front 3 FET's burnt out at exactly the same time. The thing is as far as electrical goes, there is no front and rear bank, just an engine. The cams are the only thing that are unique per bank. Pull the front cam carrier cover off and check. What do you mean by detonation? Detonation happens on the cylinders and you will feel it, the exhaust sound you hear is either a misfire or backfire. The engine is non interference, no damage unless it happens at 7k. Cam sensor is by the oil cap, 24x crank is under the crank pulley and damper, and the 3x crank is in the rear of the block. Quote
brian89gp Posted February 13, 2004 Report Posted February 13, 2004 Also, how are the spark plugs and wires? Quote
WhiteOut Posted February 14, 2004 Author Report Posted February 14, 2004 Thanks for the replys. We cleaned the cam sensor off and did a quick brush off of the plugs and it runs fine now. Odd. The plugs didn't look too bad, but the cam sensor had an oily type buildup on it, after cleaning with a rag it seems to work fine. Maybe the gunk that was on there was just enough to make it misread the magnetic field of the cam and cause the timing to be off. Who knows... That was the oddest problem ever. I don't think it helps that the plugs were Bosh's so I'll be recommending that he switch those out when he gets the time. Thanks for the help guys. Quote
brian89gp Posted February 14, 2004 Report Posted February 14, 2004 My bet is misfiring due to the plugs. Quote
WhiteOut Posted February 14, 2004 Author Report Posted February 14, 2004 Whats the deal with Bosh plugs anyways? They cost enough, so why don't they work in GM cars? Quote
brian89gp Posted February 14, 2004 Report Posted February 14, 2004 Waste spark ignition. One plug is always firing strap to electrode and the other is always electrode to strap. Bosch doesn't handle the reverse current flow through the plugs, they themselves even admit it. Quote
RedZMonte Posted February 14, 2004 Report Posted February 14, 2004 Whats the deal with Bosh plugs anyways? They cost enough, so why don't they work in GM cars? bosh plugs suck.. put in some oem resistor style a/c delco's or some rapid fire #8's. shane Quote
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