Could it really be the CPK AGAIN?!?!?!

Lake_Bueller

Well-known member
Aug 11, 2004
1,961
27
52
Green Bay, WI
I had a professional import shop do an engine swap about 2 years ago. While they had the engine out, I had them swap the crank position sensor as a precautionary measure. 9 months later the sensor failed. They replaced on their dime. Now I'm having "crank/no start" issues from cold. Could it really be the damn CPK again? And if so, what can be done to eliminate this from being a yearly ordeal?
 

discostew

Well-known member
Sep 14, 2010
5,156
141
Northern Illinois
Just stick to the basics and diagnose the truck like you had never replaced the crank sensor. Check for spark. If you have spark your crank sensor is ok. If you have spark and it won't start then spray some carb cleaner in the throttle and see if it runs. If it runs on carb cleaner then you have a fuel issue. WD40 burns too.
 
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mlnnc

Well-known member
Mar 23, 2008
207
9
Charlotte
More typically a failed CKPS allows the truck to start when cold but the engine shuts off and won't restart when warmed up.

Like discostew said, diagnose without regard to the fact the crank sensor was replaced.
 
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Swedjen2

Well-known member
Sep 12, 2018
325
48
California
... I had them swap the crank position sensor as a precautionary measure. 9 months later the sensor failed. They replaced on their dime. Now I'm having "crank/no start" issues from cold. ...
You mean it cranks but doesn't start? Got one of them OBD2 readers? Not some cheap pile. but a decent one.
No D2 owner should be without (at least) one.
O.K., I've got a cheap one, @$20.00, that can at least clear codes.
 

jymmiejamz

Well-known member
Dec 5, 2004
5,638
125
32
Los Angeles, Ca
The next most likely thing is the fuse box under the steering column. I did a post on NAS-ROW on how to diagnose this. Basically the ignition coils are losing power when cranking. There is a connector near the expansion tank that is accessible to check there. IIRC, it will still have power until the circuit is actually loaded like when cranking and then it drops to 0V.
 

Howski

Well-known member
Oct 19, 2009
1,048
35
Greenville, S.C.
More typically a failed CKPS allows the truck to start when cold but the engine shuts off and won't restart when warmed up.
I had the experience of the truck shutting down at 75 mph in the left lane of I-285 in Atlanta. Fun times... Mine would crank (and run fine) after sitting for 20 or so minutes but die again few miles later
 

SGaynor

Banned
Dec 6, 2006
7,135
157
49
Bristol, TN
Just as a point of reference:

I had one fail after about 2-3 years.

But that was because coolant was dripping on it from the coolant leak I had from the back of the engine (external head gasket leak).
 

JUKE179r

Well-known member
Sep 14, 2016
425
32
Suffolk, UK
I had the experience of the truck shutting down at 75 mph in the left lane of I-285 in Atlanta. Fun times... Mine would crank (and run fine) after sitting for 20 or so minutes but die again few miles later
Same here but my Disco 2 died on I75 heading into Smyrna. I had to pour water onto the Cpk to get it off of the freeway and then got it towed. That sucked