2000 S10 misfire/stall

Kevin Owner/Technician British Columbia Posted   Latest  
Resolved
Driveability
2000 Chevrolet S10 4.3L (W L35) 4-spd (4L60-E)
P0338 — Crankshaft Position Sensor "A" Circuit High

4.3L auto. Died while driving. Code P0338 Crankshaft Sensor circuit high frequency. Being covered in oily goo I cleaned and inspected the harness and replaced the sensor. Symptoms haven't changed but no more code. Cam retard is at -13° at idle. Seems to run ok in open loop but starts to misfire shortly after going into closed loop. Gonna check valve and distributor timing tomorrow. Any ideas?

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Frank Manager
Tennessee
Frank
 

Worn out dist drive gear. stretched jumped timing chain.

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Joel Mechanic
California
Joel
 

You may want to check for carbon tracking in the cap, condition of plugs and wires, also check fuel pressure and injector balances. May want to also scope cam and crank signal at the pcm

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Glenn Owner/Technician
Texas
Glenn
 

Hello Kevin, First question to ask yourself is if the cam sensor code is the fault or a result from the stall while driving. Oil does not conduct voltage. This is a 2000 model. How many miles? According to All Data, this model has an inline fuel filter mounted on the driver side inner frame rail. I would change that first. Next perform a pressure test. This engine requires 60-66 PSI to run…

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Scottie Owner/Technician
North Carolina
Scottie
 

Distributor shaft worn. Aftermarket from parts store works well.

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Jesse Engineer
Missouri
Jesse
 

-13* is too far off even at idle. It's supposed to be +/- 2* @ 1500 rpm. Anything below 1500 rpm and it's not accurate. Distributor gears are a common wear item on these. The bushings also wear out on these, especially the top one. Pull the cap, Try moving the rotor front to rear and then left to right. It should be nice and tight in all directions. Twist the rotor and see if you can feel any…

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Tom Owner/Technician
Tennessee
Tom
 

-13* degrees is about the amount of offset that it takes for the distributor to be out of phase enough for spark to start jumping to the wrong tower under certain advance conditions. The 4.3 distributor hold down is not adjustable for phasing/adjusting cam offset like the V-8 one is. However, I have fixed at least a dozen of them by removing the hold down and grinding the hole elongated in the…

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Geoff Diagnostician
Hawaii
Geoff
   

A car that immediately goes to crap in CLOSED Loop, screams O2 sensor problem. It's tough on a car that wont stay running, but try to verify that front and rear O2 both respond correctly to extra air and extra fuel.

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Jeff Owner/Technician
Idaho
Jeff
 

On these the timing is set by the computer based on crankshaft position. The cam offset is set by the distributor, turning the distributor will not effect ignition timing. The cam timing is used for injector timing. If the distributor is too far off as in the -13 DEG you have the spark could possibly jump to the next terminal on the distributor there by causing spark on the wrong distributor cap…

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Jesse Engineer
Missouri
Jesse
 

He mention it was cam retard that was at -13*, not the timing. Timing is controlled by the computer but crank sensor and cam sensor have to be able to sync up. At -13*, it's to far out to be able to do so correctly. Turning the distributor is the only way. A V8 hold down clamp is the easiest way to do that via salvage yard or parts store. Or grind existing one to allow some rotation. It doesnt…

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Jeff Owner/Technician
Idaho
Jeff
 

Exactly, the cam sensor is mis-timed and the only way to change it to adjust the distributor.

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Gregory Owner/Technician
Dominican Republic
Gregory
 

Do a fuel leak down test; these engines are known for lousy fuel pressure valves that leak. Could be your issue?

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Jeffrey Technician
Indiana
Jeffrey
 

-12 degrees rock solid should be ok. Graphing CMP should show fluctuations on test drive with worn parts. Is cylinders 3 & 4 misfiring? The great late Harvey Chan had a discussion on IATN about this if you can search it. Different CMP retards for V8 and V6, acceptable degrees are different due to spacing of terminals in cap. Of course, this is an opinion based on memory, I'm older lol

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Jesse Engineer
Missouri
Jesse
 

-12 cam retard is too far out. Cam and crank sensors can't sync together. Kind of like trying to run with a track shoe on one foot and a construction boot on the other.

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Jeffrey Technician
Indiana
Jeffrey
 

That analogy to me seems more like a P1345 ;)

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Glenn Owner/Technician
Texas
Glenn
 

Hi Kevin, I replied earlier, but it has been a few years since I have dealt with these on a regular basis. Lots of good replies so far. As I recall the these had a tiny “8” and a “6” on the cap mount ring area of the distributor. The rotor had to be clocked correctly when the distributor is installed to ensure injector timing and spark event were “in time”. When these first came out years ago…

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Stephen Technician
Tennessee
Stephen
 

I would determine the root cause (eg; ign?, fuel?) of the misfires, considered with the conditions under which the misfires occur to determine a logical path of tests to isolate the failed component. Since the misfires occur with going to closed loop, an electrical event(vs mechanical), don’t have the characteristics associated with valve timing( what is the vacuum on the engine?) and…

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Jesse Engineer
Missouri
Jesse
   

Cam timing is not necessarily “fixed”. In open loop, the computer runs on preset conditions not fully controlled by all sensors. MAF and coolant temp are the main sensors monitored in open loop. Cam angle and timing are preset. Once it hits closed loop, usually 160-180*, then it switches over to reading all sensors. Cam angle, O2, ect. If it's running fine in open loop then runs poorly in…

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Stephen Technician
Tennessee
Stephen
 

Can you elaborate on how the cam timing isn’t fixed? I’m OK with picking the low hanging fruit but if lemons are the low hangers and you want cherries there is no use in picking the lemons, yet. The cam retard is for control of injection time. Emissions may suffer but spraying the fuel at little different time won’t cause a misfire. Central port Vortecs sprayed all injectors at the same…

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Tom Owner/Technician
Tennessee
Tom
   

Just to be clearer, cam retard affects at least TWO things that I know of. One, CKP/CMP correlation. If it gets far enough out, it sets a P1345 code. But it ALSO affects distributor phasing. The relationship between where the rotor tip is at in relation to the plug wire terminals inside the cap. As the ignition goes from base timing to full advance, that relationship changes. At base timing, the…

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Jeffrey Technician
Indiana
Jeffrey
 

Hey Tom, the spec is different for the V6. If read the flow chart for P1345 it gives the allowable range and shouldn't fluctuate +/- 2 degrees from this range. I have seen -13 degrees with no problems on 4.3 s. We only look when there's a problem. In no way am I saying this is or isn't his issue. There was not enough data provided. Be nice to see the CMP graphed on test drive. If we had an…

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Drew Mobile Technician
Pennsylvania
Drew
 

We are going back a number of years, but if I remember correctly the cam retard at idle is not a legit number, take it up over 1200rpm (may have been 2k) and see what it is. If still high, make sure distributor is properly installed.

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Boyd Technical Support Specialist
Georgia
Boyd
 

If it runs good in open loop that means it can run. If a valve train issue was there it would run bad in open or closed loop. This condition usually means an incorrect or out of range input is in play. Pay close attention the O2 sensor inputs and trim activity. When it goes to closed loop and runs bad use your scan tool to force open loop. If it cleans up on fixed strategy deal with that…

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Kevin Owner/Technician
British Columbia
Kevin Resolution
 

Hi all, thanks for all your help. Looked under intake plenum for fuel leakage from regulator and found none. Closely inspect distributor cap and rotor. Found a burn through on the rotor. Replaced rotor and problem solved. Thanks again.

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Thanks