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-99 sts stalls/rough idle


jorgenw

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It is possible to force the start but hard to keep idling. Seems to run on only a few cylinders.

This problem turned up suddenly during overtaking, with 4000 rpms.


Error code P0101, P0102

Seems to be something that triggers the error code for the MAF but can not make it to safety mode by pulling the cable to the MAF.


Where do we start looking?
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P0101 Mass Air Flow (MAF) Sensor Performance
P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency

It looks like something may have come through the air cleaner and hosed the MAF. It could be just water, shorting or cooling the resistance wires. I would start by looking into the throttle body with a flashlight and see if the wires are OK and not fouled with water or a dust bunny, or broken. If so, clean it out or replace it with a used one as appropriate and you are done.

You might put in a new AC/Delco air cleaner element while you are under the hood. Be sure and take the air box out and sit on it to get the clamps closed so that it seals well. The box is hard to close up completely and most mechanics just leave it loose, and that can eventually cause problems like yours.

I've also heard of yahoos pulling the air cleaner element completely, thinking that it was a trick performance enhancement. One, in particular, hydrolocked his LS2 when he ran through a deep puddle with his truck a couple of years ago. It's still parked.

EDIT: Are the P0101 and P0102 the only codes?

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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The 102 just showed up ones. Its just the 101 code all the time. We cleared the codes many times and unhooked the battery and so on to just get fresh codes. Its not my car, but I have -99 deville engine in my -97 sts, so we tried my MAF unit on his car with no changes and even the cam sensor seem to be ok.

We have resently changed the head gasket on the inner head and re-threaded the head bolts. Is there any possibility that the timing chain can have jumped a kogg suddenly? The car worked just fine for a week. We drove it like 300 miles without any problems. And now this.....

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I've never heard of a Northstar jumping timing. That kind of thing usually means engine destruction unless the valve reliefs in the pistons will prevent contact, which I suppose is possible because the Northstar does use four valve reliefs in each piston, but if it happend much at all we should have seen cases of it on Caddyinfo in the last ten years or so and I don't recall any. Kevin? Ranger?

I checked the 1997 FSM pages 6-301 through 6-305 and these codes are thrown when there is a big air leak between the MAF and the intake manifold.

If it happened suddenly at about 4000 RPM under load, I would suspect something caused by vibration, like an air gap from loose bolts somewhere on the throttle body, or a hose coming off, or perhaps an EGR line coming off.

The 1997 FSM says that a distorted or missing intake air duct can cause P0101. Things to check for P0101 include the MAF Sensor seal, the throttle body spacer, the intake manifold itself, the EGR valve/plate/tubes, the PCV system (!), and the power brake vacuum line.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Anything is possible but I think that you would have a very noisy and rough-running engine if a tensioner was not right. It wouldn't be OK and then suddenly jump timing. How long was the engine running before the problem started?

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Next weekend we are gonna pull the intake manifold and inspect gaskets and the knock sensor. How do one check the sensor? Just ohm meter? The wiring is harder to check during cranking, maybe? Maybe can crank a little just for a reading. Im gonna check the cam sensor again for resistance.

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The knock sensor and the knock module in the PCM go together. If there is a problem there you will likely get a code. The knock sensor codes for OBD II in my list are:

P0324 Knock Sensor (KS) Module Performance
P0325 PCM Knock Sensor Circuit
P0326 Knock Sensor Circuit Excessive Spark Retard
P0327 Knock Sensor Circuit Low Voltage
P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
P0329 Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor)
P0330 Knock Sensor (KS) Circuit Bank 2
P0331 Knock Sensor 2 Circuit Range/Performance (Bank 2)
P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
P0333 Knock Sensor 2 Circuit High Input (Bank 2)
P0334 Knock Sensor 2 Circuit Intermittent (Bank 2)

My 1997 FSM has special pages for P0325, P0326, and P0327(pp 6-434 through 6-440) but not the others. The schematics in these sections show just one knock sensor. The Knock Sensor Replacement section on page 6-762 says that it threads into the block in the valley between the banks, where the starter lives. The knock sensor and the knock sensor module in the PCM come as a matched/calibrated set and you can't mix-and-match and expect them to work well or at all.

In the schematics the knock sensor is shown as a piezoelectric crystal, like some phonograph cartridges or microphones. The schematic shows a resistor across the crystal internal to the sensor but I don't think that an ohmmeter is a good way to test it. A very sensitive voltmeter might show a jump in the needle if you have it out and tap it gently with your fingernail or a coin.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Forget about pulling the intake and messing with the knock sensor... The codes you have point to an issue with the MAF - start the troubleshooting there.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Are you saying there is no compression on cylinders 1-3-5-7? Not sure how the chain would have jumped unless the tensioner lever was not released after it was installed. Maybe pull the front cover or the cam cover and rotate the crankshaft by hand to see if the chain is moving.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Yes thats exactly what i mean. I dont know exactly how the tensioner works. I didnt install it personally. But can the valves have cleared the pistons if the chain jumped 1 kog? Or do we might need new valves here? I have a spare engine from a -97 sts, maybe i can take the head and just bolt it on to this engine?

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The tensioners are activated by oil pressure. In order to install them, the release lever needs to be depressed, the plunger pad compressed and the release lever locked. Once the tensioner is in place, the release lever is "released" and the tensioner pad is forced against the chain. Oil pressure sets the final position.

If the chain breaks, you will have bent valves. Not sure if it only would jump one tooth - it would need to be pulled apart to knoe for sure. You can remove the front cover and the cam covers with the engine in the car and verify all the timing marks are aligned. You may need to rotate the crankshaft up to 7 turns to get the marks aligned.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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  • 3 months later...

The tensioner is NOT activated by oilpreasure !!!!

The lockingmechanism was not activated so the timingchain jump !!!

All valves are bended !!!

Havent got time to fix it yet but i hope i will soon !!!!

I miss my caddy !!!!

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I would try just re-aligning the timing and adjusting the tensioner before I pulled the head. If it did just jump one cog, you may not have bent valves. If the valves did hit the pistons, you may also need pistons. But if they didn't, you just have a two-day job instead of an engine-out overhaul.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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The tensioner is NOT activated by oilpreasure !!!!

The lockingmechanism was not activated so the timingchain jump !!!

All valves are bended !!!

Havent got time to fix it yet but i hope i will soon !!!!

I miss my caddy !!!!

Uh, yes the tensioners are activated by oil pressure... Once extended, the detent teeth of the tensioner keeps them from retracting. If you removed them you would see the oil passages. The oil pressure allows them to extend to the proper tension to keep the chain tight.

If you have bent valves, there was something wrong with the intial static timing that allowed the valves to contact the pistons. Are all valves bent or just on 1-3-5-7?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Perhaps what he meant by "not activated by oil pressure" would be more accurately translated to English as "not activated". What we do need is more detail. Why do you believe that all the valves are bent?

Vi behöver mer detaljerad information.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I'm guessing he meant the initial tension was spring tension and that's what didn't happen. Probably didn't realize oil took over after that, I sure didn't.

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Ok guys !!!

When i was change headgasket i was take the tensioner out , and yes it was full of oil but i dont see any oilpassages ?? Because i also thought it was tensined by oilpressure, Then it shouldnt be jumping while im driving .. So i guess the Environment it stay in make it full of oil ... ok ..

And when i put head back and mount and aligne the chain ,, I FORGOT TO MAKE SURE THE LOCKING PIN WAS ACTIVATED !!!

And trust me , the valves are bended !!!

Correct me if im wrong , thank you

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If you did not release the lever on the tensioner after aligning the timing marks, that could result in the chain jumping teeth and valves interfering with the pistons.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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  • 3 weeks later...

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