# [SOLVED] '98 vortec 5.7 stalls when stopping



## Nattydrd (Jan 15, 2011)

I have a 1998 chevy vortec 5.7L with 4L60E trans. The motor is a newly installed crate motor. All new: fuel pump, fuel line, spider injectors, oil cooler, oil lines, and trans flushed with filter change.

Now the problem: starts up fine, but when warmed up and I come to a stop or even slow to turn a corner the oil pressure drops and engine dies.
It starts right back up and drives fine until the next stop. There are no engine codes. 

An oil pressure problem is my first idea. Oil pressure at start-up is:40-45psi. When warmed up it drops to:20-25psi. I double checked with two different senders but I don't have a machanical one. I think this is low and I don't know what would cause low pressure in a new engine.

Anyone have any ideas?


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## octaneman (May 13, 2009)

*Re: '98 vortec 5.7 stalls when stopping*

Hi Nattydrd


Is the the engine overheating ?


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## Nattydrd (Jan 15, 2011)

*Re: '98 vortec 5.7 stalls when stopping*

Not over heating. 195-200 deg.


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## octaneman (May 13, 2009)

*Re: '98 vortec 5.7 stalls when stopping*

Its strange that a new engine off the box would stall out it has all the signs of a bad crank sensor. As for the oil pressure problem at idle the minimum should be around 20-to-25 psi range, then gradually increase as you accelerate. At highway speeds it's expected to be as high as 45 psi or higher because the pump is spinning faster. Although I do have my doubts of a bad oil pump on a brand new engine, but there is that possibility of the pick-up screen being poorly positioned in the assembly process. The one way to be certain is to hook up a oil pressure gage and compare the readings on the engine spec sheet.


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## Raylo (Feb 12, 2006)

*Re: '98 vortec 5.7 stalls when stopping*

No idea if this is your issue but I had exactly the same symptoms on a 1987 Camaro 350 motor. No codes, ran fine otherwise.... That ended up being one of the few times I ever had to take a car to the dealer. They told me that the problem was in the distributor where the little magnet that interacted with the pick up coil was losing its magnetism and dropped the signal at low RPMs... or so they said. They replaced it and all was fine. Cheap repair, too. That was the old GM HEI distributor IIRC so not likely what you have. But perhaps the issue is similar on the cam or crank sensors losing their signal at low RPMs? Just a thought...


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## Nattydrd (Jan 15, 2011)

*Re: '98 vortec 5.7 stalls when stopping*

The spec sheet shows oil pressure at 58min-65max, ten min run time, water/oil temp at 142/140. My oil press. gauge shows very little differance from idle to highway speed. I have pulled the pan and double checked the pickup screen clearance to the bottom of the pan: 3/8". I guess I need to get a machanical gauge and check again.
As for the distributor: all new Performance Distributor cap, rotor,and Livewires with old Screamin' Demon Coil, Dyna Module.
BTW how do I check the crank sensor to see if it need replacing?


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## octaneman (May 13, 2009)

*Re: '98 vortec 5.7 stalls when stopping*

Disconnect the the crank sensor plug and set your DVOM to ohms scale. Connect the probes to the crank sensor the readings should be between 200 to 500 ohms. Re-set your meter to the A/C scale with probes still connected and have an assistant crank the engine. The readings should be between .2 to 2v A/C if either readings fail replace the sensor. 



post back your findings.


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## Nattydrd (Jan 15, 2011)

*Re: '98 vortec 5.7 stalls when stopping*

The crankshaft position sensor has three pins to connect to. I checked the sensor every way I could. No readings anywhere on any setting or scale. But isn't this just a hall effect sensor, just an on/off switch to a magnet?


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## octaneman (May 13, 2009)

*Re: '98 vortec 5.7 stalls when stopping*

What chevy model is it ? If you can take the number off the sensor would be most helpful.


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## Nattydrd (Jan 15, 2011)

*Re: '98 vortec 5.7 stalls when stopping*

Motor out of a Chevy pickup K1500. Sensor #DR6200


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## octaneman (May 13, 2009)

*Re: '98 vortec 5.7 stalls when stopping*

In my catalog there are 2 types, 1 has a metal bracket the other does not. Which one is yours ?


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## Nattydrd (Jan 15, 2011)

*Re: '98 vortec 5.7 stalls when stopping*

The one with the metal bracket


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## octaneman (May 13, 2009)

*Re: '98 vortec 5.7 stalls when stopping*

Ok, The pin outs are as follows: Looking at it with the notch on top the center pin is ground , the left is signal , the right is battery (12v). Take your DVOM and set it to a high scale if your meter does not have auto-ranging. Connect the probes to the signal pin and battery pin, you should get a reading somewhere in the vicinity from 750-to-1.25K ohms. If you get no reading at all then the sensor is gone. 


Set your meter on A/C volts connect your meter to signal pin and ground pin, have an assistant crank the engine, if you get no reading the sensor has to be replaced. 

If just one of the 2 tests fails replace the sensor. 

After re-analyzing your posts I'm convinced the crank sensor needs to be replaced. The reason is that your engine re-starts after it cools down. On your model the crank sensor also affects ignition spark which is also pointing to it.


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## Nattydrd (Jan 15, 2011)

*Re: '98 vortec 5.7 stalls when stopping*

Well that seems to work. Changed out the crank sensor, went for a test drive and no more stalling. I never would have guessed that. Thanks Octaneman.


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## octaneman (May 13, 2009)

*Re: '98 vortec 5.7 stalls when stopping*

Good job ! :4-clap:


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## Boruskarloff (Jul 15, 2013)

I had this exact same issue on a buddies truck, but my experience was a bit different. Truck runs great until stopping.

I rebuilt the whole thing new short block, heads redone, clean the poppets while I had it apart.

Had intermittent miss as light loads, did a little twist of the dizzy and solved that issue. Sent the truck on its way. 

Now two and a half years later he has this dies at stopping issue.
So I do the usual tune up with no difference. So I check for resistance between the signal and power pins and got nothing. 

With that test I purchased a new ckp sensor put it in and the. The truck wouldn't even start. Puzzled I checked the resistance on the new part to find it was within spec. So why the **** won't this thing start. At this point I checked for spark and there was absolutely nothing like the crank sensor was bad. So I probed the signal wire while turning the motor over by hand. Which should produce a signal 5 volt when the tooth passes over the sensor (see article: http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/how-to-test-the-crank-sensor-2 ) I got no signal.

The no signal with new sensor was puzzling as well as frustrating. To get the thing to start I cleaned up the oil on the old sensor put it back in ( open "no resistance" btw signal and power) and the struck started right up. So I said well I'm gonna take it for a little ride. 

Surprised to see that this test drive the truck didn't die once and ran like a champ. So I kept driving, I stop almost 30 times and the truck never missed a beat. I drove it back to my buddy and once again it rAn without a hiccup.

Any ideas on *** is going on? 

Truck has: new plugs, cap rotor, coil....also had icm and dizzy replaced at time of rebuild about three years 30,000 miles ago


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