1995 Ford Ranger Engine misfires

Tiny
BARRRY
  • MEMBER
  • 1995 FORD RANGER
  • 4 CYL
  • 2WD
  • MANUAL
  • 99,999 MILES
After replacing head after severe overheating, head was cracked in three cylinders, the engines misfires.
Checked compression, low but even. Cam, crank, and oil pump in index.
Retrieved codes of PO 300 Random Misfires, PO 340 Camshaft Position Sensor Circuit, PO 351,352 Ign Coils A & B.
Cam and crank sensors have resistence of.346 K ohms or thereabouts.
Cam circuit has one wire that goes to ground. The crank cirduit does not. I assume that both sensors work the same.
I do not know how to check out PCM.
I never saw the truck run normally before replacing the head.
I don't have ready access to scanner.
Any help directing me in right direction will be appreciated.
Barry.
Any help will be appreciated.
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Friday, November 20th, 2009 AT 12:26 AM

9 Replies

Tiny
RACEFAN966
  • EXPERT
Ok how did the spark plugs look? Have you checked the spark plug wires? If not ohm them. What was the compression?
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Friday, November 20th, 2009 AT 10:14 AM
Tiny
BARRRY
  • MEMBER
I replaced the spark plug wires. One plug had insulator blown out. All the others had gaps of over 100/1000, yes almost 1/8 inch. I had never seen that before. The colors varied from black to gray, all were clean.
Compressions were 105,100,100, 95.
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Friday, November 20th, 2009 AT 11:10 AM
Tiny
RACEFAN966
  • EXPERT
Ok so are we talking about the plug wires or the spark plugs themselves? As for the compression not good. What I would like you to do is redo the test one dry and one wet. Now this must be done with the engine warm ok. Now first check compression as normal write down the findings, then do a second compression test with a squirt of oil in the cylinder (through the spark plug hole) write down the findings here too. Get both readings back to me. With compression that low and that spread out you will have a miss that can not be fixed. Just for your info minimum compression is 130 per cylinder, I think we are going to find that the engine is just tired.
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Saturday, November 21st, 2009 AT 8:48 AM
Tiny
BARRRY
  • MEMBER
Spark plug GAP, not a mistake, of over.100 in. Can't get motor hot as I have coolant out in order to check crank and cam sensors
Compression this time is 100,110,110,100. All cylinders went up 15-20lbs. When I squirted Brake Clean in cyls. I uses brake clean to as to NOT foul the other spark plug on each cylinder. Compression tester may be reading low because it is hard to tell if it seals enough to get real reading. As I said, the engine runs, albeit with a random miss.
Would really like info about how to tell if PCM, crank, cam, sensors and circuits are working properly. This controls the two coil packs.
Thanks.
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Sunday, November 22nd, 2009 AT 9:53 PM
Tiny
RACEFAN966
  • EXPERT
Is this compression test done cold or hot? If it is done hot then the engine is just tired as the compression is below 130 which is minimum compression to run correctly. With the compression bumping up that much when wet just confirms the engine is tired. The reason for the random missfire is because of the drop in compression. I can give you test procedures if you like but it will not change much with the low compression. Cam shaft sensor- first check power to it- first disconnect it and then (using the diagram below) check for power at the VPWR term should be 10.5 or better with key on engine off. If it is then computer is doing its job and sensor is getting power. Now check resistance between pwr gnd and ground should be 5 ohms or less. Let me know what you find.
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Monday, November 23rd, 2009 AT 7:36 PM
Tiny
BARRRY
  • MEMBER
Compression done cold.
The diagram didn't come through.
What is VPWR?
No power at cam sensor plug, neither terminal.
What do you mean by pwr gnd?
I need to assure customer that bottm end rebuild will solve problem.
Thanks.
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Tuesday, November 24th, 2009 AT 1:28 AM
Tiny
RACEFAN966
  • EXPERT
Sorry I must have forgot to include it. Here is the diagram. Again the customer needs to understand that less then 130 psi per cylinder indicates the engine is needing either replaced with a remanufatured engine (better choise) or rebuilding the one in it. Here is your diagram.


http://www.2carpros.com/forum/automotive_pictures/249564_Graphic_152.jpg

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Tuesday, November 24th, 2009 AT 10:03 AM
Tiny
BARRRY
  • MEMBER
The cam sensor is a 2 prong. This Ranger is a 95 with OBD 2.
One prong has no voltage and the other goes to ground in the PCM.
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Tuesday, November 24th, 2009 AT 10:42 AM
Tiny
RACEFAN966
  • EXPERT
Ok OBD2 started in 96 not 95 with a two prong cam sensor then you do not have a hallofect type that all. So if you would give me the production date it may be a late model. Also on an OBD2 system the camshaft sensor is used to determine camshaft position and when cyl 1 comes to tdc for start up. Now using the diagram below for the 96 model year check the restance on term 91 and term 85 between camshaft sensor and pcm connector should be less then 5 ohms.
Now if resistance checks out ok then check sensor output. To do this truck must be able to start and run. Set you volt meter on AC voltage and check while running voltage between pin 85 on the sensor and term 51 and term 103 at the pcm. If voltage vary's more the .1 volt then replace pcm if voltage don't change more then .1 volt then change the sensor.
Also I must ask why did you drain the antifreeze to check the crank and cam sensors? From what I can tell you only need to drain coolant to remove the crankshaft sensor and it can't be tested that way as it needs to be pluged in for some of the tests. Let me know what you find.

Camshaft sensor


http://www.2carpros.com/forum/automotive_pictures/249564_Graphic_154.jpg



PCM


http://www.2carpros.com/forum/automotive_pictures/249564_Graphic_155.jpg

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Wednesday, November 25th, 2009 AT 10:11 AM

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