no start, no fuel, no spark... cps is good - JeepForum.com

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post #1 of 42 Old 10-22-2014, 08:18 PM Thread Starter
airdevil85
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no start, no fuel, no spark... cps is good

ok so its been a while since Ive owned a jeep... I got a good deal on a 98 zj... The engine was blown and the previous owner replaced iot but couldnt get it running...

when I turn on the fuel gauge goes to 1/2 tank then after a few seconds drops to e and the gas light comes on... I know there is gas in it... I put a few gallons in... The check engine comes on and gives a code about fuel...
\The engine cranks over fine but wont start... There is no fuel pressure and no spark... All fuses are good and the asd and fuel fump relay seem to be working, I have swapped them out with known good ones but still the same problem...

The cps has been replaced with a new one and it does test good... I have checked for voltage at the coil and I aqm getting 5 volts...

The ignition coil tests good

The cps, cam pos sensor, map and tps all have their 5 volt reference signal

I just talked to the guy that swapped the motor, He used the flywheel off the new motor and not the original one... The new motor is a 95... not sure if it would make a difference

Im stumped as what to test/check/replace...

any help would be greatly appreciated


1995 XJ - Totaled
1998 XJ - Totaled
1994 YJ - Sold
1998 zJ - Current

Last edited by airdevil85; 10-22-2014 at 08:50 PM. Reason: Forgot some things
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post #2 of 42 Old 10-22-2014, 08:36 PM
ZeeJay1997
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What is the code?

How are you checking the coil voltage, where are your leads?


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post #3 of 42 Old 10-22-2014, 08:58 PM Thread Starter
airdevil85
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P 0463 - Fuel Level sensor A circuit high

The coil seems to be getting 5 volts from the green/orange wire... I dont seem the be getting any signal from the other wire

The leads were red to green/orange and black to neg on batt... the other wire I tested black to the coil signal with red to pos on the batt

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1998 XJ - Totaled
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post #4 of 42 Old 10-22-2014, 09:35 PM
ZeeJay1997
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How are you checking the cps, cam pos sensor, map and tps 5 volt reference signal? If you used battery for the black (negative) lead, go back and check the tps using the black/blue for negative lead and and white/black for positive.

I think something has the sensor ground (black/blue) shorted to voltage. The fuel level signal to the PCM is sensor ground modified by the sending unit in the tank.

From FSM:
If the PCM detects a short or open in
the fuel level sending unit circuit, it sends a message
on the CCD data bus that will cause the instrument
cluster circuitry to position the fuel gauge needle at
the Empty stop.

This tells me the sensor ground circuit is somehow compromised. The check I mentioned above should tell the tale.


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post #5 of 42 Old 10-22-2014, 09:44 PM Thread Starter
airdevil85
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The cps, cam pos, map and tps all were cecked using the wht/blk as pos and the batt as a ground...

Just rechecked... using the blk/blu as a groug I get the same reading 5.18v across all 4 sensors

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1998 XJ - Totaled
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post #6 of 42 Old 10-22-2014, 09:46 PM Thread Starter
airdevil85
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Quote:
Originally Posted by ZeeJay1997 View Post

From FSM:
If the PCM detects a short or open in
the fuel level sending unit circuit, it sends a message
on the CCD data bus that will cause the instrument
cluster circuitry to position the fuel gauge needle at
the Empty stop.
but, would this cause a no start, no spark condition?

1995 XJ - Totaled
1998 XJ - Totaled
1994 YJ - Sold
1998 zJ - Current
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post #7 of 42 Old 10-22-2014, 09:55 PM Thread Starter
airdevil85
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another thing I noticed there is another distributor in the back of the vehicle... Im assuming its possible the person who did the engine sway took the old one out... Once the engine is a tdc and the marks are aligned what is the approximate position the rotor should be in? standing on the pass side of the vehicle looking over the fender it appears to be in the 1 oclock position...

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1994 YJ - Sold
1998 zJ - Current
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post #8 of 42 Old 10-22-2014, 10:18 PM
Uniblurb
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Just curious and I'm sure ZeeJay would know this better than me or maybe you already know airdevil85? Can you install an OBD1 95 engine in a 98 OBD2 w/o electrical issues and which harness/PCM are you using?

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 93 4.0 XJ (spare), 96 4.0 XJ (son's)


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post #9 of 42 Old 10-22-2014, 10:20 PM Thread Starter
airdevil85
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the harness used is the original 98 one... as far as I know the engine is the same with the exception of the sensors

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post #10 of 42 Old 10-23-2014, 12:07 AM
Uniblurb
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Part of the problem could be, if using your existing 98 4.0 PCM which you probably have to, is it only has a 5V output to all the sensors while the 95 PCM has both 5V & 8V sensor outputs. Voltage to the cam, crank and vehicle speed sensors should be 8V on the 95 as can be seen in the below diagram while all the other sensors receive 5V.

This may be why you found an old distributor in the trunk and he could have changed it out to the 98 for the 5V cam sensor. Maybe that's why he also installed the 98 flywheel on the 95 but not sure if you could swap out the crank sensors because there's a good chance they aren't the same. But since a new crank sensor was installed wonder if it's for a 95 or 98 4.0?

PS. the "troublesome" 8V supply again Zee and it must go for the 93-95's.
Attached Thumbnails
ZJ, 95 4.0, 8volts from PCM to cam, crank, vehicle speed sensors, 8W-30-13, 95 FSM, 650x868.jpg  

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 93 4.0 XJ (spare), 96 4.0 XJ (son's)


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post #11 of 42 Old 10-23-2014, 07:08 AM
newfieZJ
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Can you hear the fuel pump prime when you turn the key ?

That code should not cause a no start condition , however , has been said to been a symptom before pump failure . I bought a jeep with an erratic gauge and replaced it after just a few days because of what I read , and I hate not knowing what's in the tank . The light , the ding from the light going on and off was a PITA . Mine ran fine but with the code but , for how much longer is anyone's guess . This being a new to you jeep , you have to take someones word for the history , or , last time it ran . Maybe sitting idle for the time was enough to finish off a failing pump .

Given fuel is one of the 3 components needed to start , and the code , seems to me a logical place to start Also , I'm not sure if fuel pressure is monitored in any way , I don't think it is , so I'm thinking it would be the only code if there were a connection issue for the pump as well . Just saying .

Once we know the pump functions or not , we can go from there . It could be anything from a damaged wire from the engine install to a bad ground in/to the fuse box . Just a matter of ruling out things as you've been doing and trust everything was tested properly . For example , the Cam sensor , was the rotor point straight back when tested ? Did you crank it to make sure it pulsed the signal 0-5v ? Does the ASD click and shut everything down once cranking ? Lots of things to toss at you once I know the pump is priming

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post #12 of 42 Old 10-23-2014, 07:16 AM
ZeeJay1997
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Quote:
Originally Posted by airdevil85 View Post
standing on the pass side of the vehicle looking over the fender it appears to be in the 1 oclock position...
if the #1 piston is on tdc on the compression stroke and the timing mark is on zero, the rotor should be at 5 oclock

Quote:
Originally Posted by airdevil85 View Post
would this cause a no start, no spark condition?.
In this case, it doesnt appear to be causing a problem with the ground circuit.

good point uni. the swap can be made as long as all sensors are changed. cam and crank and one of the speed sensors, i think its the VSS that are 8v on the obd 1. sorry i dont have time to look it up now

i'm still trying to figure out why your getting 5 v at the coil. you should get 12v at injectors and coil while cranking. injectors are same circuit as coil, check it there. use battery for ground.


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post #13 of 42 Old 10-23-2014, 07:26 AM
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Quote:
Originally Posted by newfieZJ View Post
I'm not sure if fuel pressure is monitored in any way , I don't think it is , so I'm thinking it would be the only code if there were a connection issue for the pump as well .
You are right, according to the FSM, it's not monitored.


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post #14 of 42 Old 10-23-2014, 12:20 PM
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Quote:
Originally Posted by ZeeJay1997 View Post
if the #1 piston is on tdc on the compression stroke and the timing mark is on zero, the rotor should be at 5 oclock
Agree on the 5 oclock and I'll post a photo below to show #1 plug wire on the cap.

Quote:
Originally Posted by ZeeJay1997 View Post
good point uni. the swap can be made as long as all sensors are changed. cam and crank and one of the speed sensors, i think its the VSS that are 8v on the obd 1. sorry i dont have time to look it up now

i'm still trying to figure out why your getting 5 v at the coil. you should get 12v at injectors and coil while cranking. injectors are same circuit as coil, check it there. use battery for ground.
Understand your time limits Zee. While searching last night I found a post from someone with a 95 4.0 who was having no-start problems but was reading normal 8V at the distributor connection with ignition on but not cranking. He had to be reading the 8V at the cam sensor connector.

Guess the point is, and searching further, as we were surprised the other other day the 93 4.0 has 8V supply from the PCM for the cam, crank, and vehicle speed senors, so does the 94-95 4.0. That diagram I posted is from the 95 FSM showing 8V supply to the before mentioned sensors. Can see why the cam & crank sensors need changed out for the 98 4.0 5V supply from the PCM.

I'm sure you and Newfie know a whole lot more than me about electrical issues with engine swaps and just passing info along.
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96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 93 4.0 XJ (spare), 96 4.0 XJ (son's)


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post #15 of 42 Old 10-23-2014, 04:31 PM Thread Starter
airdevil85
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correction... the coil isnt getting any voltage while cranking

1995 XJ - Totaled
1998 XJ - Totaled
1994 YJ - Sold
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