1994 Chrysler LHS crank no start

Tiny
ALBARADR
  • MEMBER
  • 1994 CHRYSLER LHS
  • 3.5L
  • V6
  • FWD
  • AUTOMATIC
  • 120,000 MILES
Here is my question

Flipped my pdc over to have a look. Shows that the fuel pump relay socket 85 goes to pin 51 in pcm. Out of same socket 85 there is a separate wire going to socket 85 of asd.

I have constant power on socket 30 on both relays. Power to 86 with key on to both relays. Test with test light clamp on battery pos and probe to socket.

For pin 85 put test light clamp on positive and probed socker 85. With key on light turned off. I think that shows its being grounded.

Relays have been swapped both crank and cam sensors are new.

I have power at pcm on 3 and 9. Grounds a 5 11 and 12.

9 volts on orange at pcm on pin 7 as well as to both crank and cam. Ground and signal wires also are good. All wired from sensor to pcm have continuity and resistance. 03 to.09.

Same with wi red from pdc on both relays.

I jumped both relays from 30 to 87 still nothing

Took off jump to fuel relays sparked into intake leaving asd jumped. Car starred for a few seconds

Guys I'm stumped! Am I not testing something correctly?
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Monday, January 19th, 2015 AT 8:17 PM

3 Replies

Tiny
WRENCHTECH
  • EXPERT
You need to approach this in a different way to get a clearer picture of what is happening.

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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Tuesday, January 20th, 2015 AT 2:20 AM
Tiny
ALBARADR
  • MEMBER
I guess I needed to me more specific

full battery at 12.5 volts

no spark at all eight plugs, checked green and orange wire going from asd relay to coil. No power going to coil. Checked continuity. Good ohms.01

made sure pcm was getting power on pins 5 and 9 both getting 12v. Then checked grounds on 5 11 12. All check out using test light to positive.

Testing hall effect crank and cam

pin 7 at pcm provided 9 volts to each the crank and cam sensors. Both are new. Signal wire verified by cranking engine by hand. Voltage.8-4.8 volts via the windows on wheel. Sensor ground.08 mv. Good on both cam and crank.

Tested both relays

continuity from 30 to 87a, 85 and 86 coil side 76 ohms. Applied voltage to relay on 85 and 86 coil energized armature closed on both asd and fuel pump relay.

Relay socket testing
you probably have them as abcd I have them as pin numbers. Constant power on pins 30. Switched power on 86 with key on. Both. 85 put test light on pos to battery probed 85 socket. With key on it lit then shut off.

Jumped sockets 30 to 87 on asd relay. Got power to coil.
Jumped sockets 30 to 87 on fuel pump got power to pump
still crank no start.

Unplugged fuel pump sprayed starting fluid into intake. With asd jumped car started for a few second.

As stated before. I want to know if a bad fuel pump would cause the no power to coil because the asd and fuel pump share the same driver pin 51 on pcm.
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Tuesday, January 20th, 2015 AT 2:48 AM
Tiny
WRENCHTECH
  • EXPERT
If you want me to help, we have to do this my way.

Do you have injector pulse?

If not, do you have power supply to one side during the first 2 seconds of key on and when cranking?
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Tuesday, January 20th, 2015 AT 3:38 AM

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