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Where exactly is the CPS sensor on the 1990 Chevy Lumina 3.1 Vin T engine?


bobotech

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this sounds like a dumb question but I can't find it. The Chiltons manual sucks, it tells you to remove it but doesn't give specific locations to where it is. Since my friend's car is a 1990, I don't think it has the 3x /24x sensor that the book does mention for the Vin M/N (or something like that ) models.

 

Where exactly is this stinking thing?

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right below the DP on the back of the engine in line with the crank in the middle of the block. If it had a manual trans you could remove it in 10 seconds. But an auto is tougher I've heard. I just replaced mine when I had my engine out. :showoff:

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Here's a picture showing where the cps is on the rear of the block.

 

image1-3.jpg

 

To remove them, I usually slave the engine forward by removing the dogbone mounts(should be a post about slaving the engine foward in the faq section) and reach behind the engine from the top. Another alternative that gives you room to get back there is removing the alternator. If you remove it with it still attached to it's aluminum mounting bracket & set it aside, you open up a plenty of space to get behind the engine. Either method is pretty quick to do. If need more information about alt removal, let me know. Be sure to disconnect the negative battery cable before alt removal if you do go that route.

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What a pain in the arse to find that stupid thing. None of the pictures I found showed it until the above posting. And what does DP mean? I did finally find the thing though, it was beneath the header pipe/exhaust manifold.

 

HOWEVER I have a new problem. We cannot remove it. We took the bolt out and we can spin the sensor in its hole but we can't get it out at all. I tried using a small screwdriver and it is starting to break up to the point where I don't know how we will be able to grab ahold of it.

 

What do we do now? Is there a trick to getting the damned thing out?

Edited by bobotech
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DP = Down Pipe

 

 

ah, the famous crumbling CPS. It's caused many a heartache. I'll let others who have had to deal w/ it jump in here. I've read plenty of posts about it, but don't remember exactly how others got it out.

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Ugh, I tried searching on CPS in the search forum tool and it comes up with zero results. I can't find any old posts related to this topic. Is the search function not functioning when searching for stuff like "CPS"?

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I was gonna share my couple experiences, but this write-up pretty much covers the same:

 

http://www.w-body.com/showthread.php/16057-crankshaft-position-sensor-tutorial

 

Thanks for that info. That was exactly what I need. I didn't think to use a red hot drywall screw jammed into it to pull it out. Plus I'm going to have them start soaking the sensor with some chemical, do you think WD40 would be adequate or should we go for something like PB Blaster or carb cleaner?

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Well its out! Thank god. The owner used my auto-adjusting channel lock pliers and just got a good grip on the remaining chunk that was still on it and pulled and it popped out.

 

What a relief. Now to put it back together and hope that the problem is finally gone for good.

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Put some grease around the shaft of the CPS before you put it back in. IF it has to come put again, this will hopefully keep it from seizing in there.

^This. Either some anti-sieze or die-electric grease would be the best to use.

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