not starting no spark

[sajnaj]

ok im not geting a spark when i crank the engine and take off one of the booties and hold it close to a metal ground. i have tryed 2 diferent coil packs,checked icm, 2 dif ckp. and with all of this there was no difernce i have fuel to the rail i just put a new pump in it.

have tooken out the plugs a little black but i cleaned them up and that made no difernce. i checked for a voltage reading at the conector that plugs into the coil pack while cranking the engine i had no voltage.

any sugestion will be apreciated

thanks

jason

 

[MrShorty]

No voltage at the coil pack? Based on the wiring diagram for a '92, it appears that there should be a steady 12V (key on) at one of the wires going to the coil pack (red/lt green wire in a '92). My wiring diagram could be wrong, but if it's right, and you don't have any wire with +12 V at the coil pack, then something is wrong between the coil pack and B+.

 

[cutter]

Was it running and shut off? did you see chk engine lite?I would test codes could be crank or cam sensor or did timing chain break and cam is not spinning what is miles

 

[sajnaj]

when i check for codes i hear a click and nothing happens. it was runnig really crapy one day then i turned it off and parked it and then it would never run right after that.

 

[MrShorty]

Nothing happens? That in itself is a fault. Hows power supply to the computer? Computer's ground?

 

[sajnaj]

i had thought that my computer was the problem but then went on to other therioes. it displays a cel almost all the time but when i conect the jumper i hear a click and nothing happens. i have tooken the computer apart and looked for burnt componets nothing was obvious.

 

[sajnaj]

bad computer

my computer will not give me any codes when i conect the jumper. my light that i use to to display the codes stays litt all the time even when the key is not on but when the key is off it is a little bit dimmer then usual when i turn the key on it brightens up. the light stays on all the time even after and during when i jump the jumper to try and make it display the codes. and it will not start at all. i have no spark what so ever and i have replced the ckp,icm,coil pack so im at my wits end i think its time to put it out to pasture.

 

[410Fortune]

it is very possible your PCM is bad, you can find them used for anywhere from $30 to 100.
Sounds to me like you have a dead short somewhere in the PCM itself or the power supply to it.

I personally have seen 3 PCM's fail, all of them in 91-94 explorer's.
Find a new PCM (computer) with your same calibration code, or borrow one from a friends truck that has the same equipment (91-92, auto or stick) swap them out and see if it runs.

You should check the EEC power relay first however, it is mounted under your fuse box in the engine compartment. the EEC relay supplies power to the computer when the key is turned on.

 

[sajnaj]

i have power to the computer and a ground but i will check the relay.

 

[mechanix]

If you don't have 12 volts at the coil packs you need to figure what you don't. Trace the wire that supplied power to the coil pack. Probably gonna be a relay. I would track this problem down first, it could end up being a bad pcm, but I wouldn't just start changing parts out without knowing first.

On that note: There should be a red/lt green wire comming to the coil pack. This wire gets power from the eec replay. I would check this relay to see if it "clicks" when you attempt to start the vehicle. If it does and you still don't have power at the coil pack the you have a broken wire some place.

Hope this helps. In my Haynes manual on page 12-38 it shows the wiring diagram.

 

[sajnaj]

i checked it wrong i have voltage at the coil pack. is there any way to check the eec its self?

 

[mechanix]

Does you check engine light come on? This is a pretty fast way of checking the pcm. Also you can get a multimeter and check for all the necessary powers and grounds going to and from the pcm.

 

[sajnaj]

the cel comes one but when i check for codes nothing hapens. i have power and a ground to the pcm.

 

[MrShorty]

my computer will not give me any codes when i conect the jumper. my light that i use to to display the codes stays litt all the time even when the key is not on but when the key is off it is a little bit dimmer then usual when i turn the key on it brightens up. the light stays on all the time even after and during when i jump the jumper to try and make it display the codes. and it will not start at all. i have no spark what so ever and i have replced the ckp,icm,coil pack so im at my wits end i think its time to put it out to pasture.

Something's wrong there. Let me see how well I can remember what I see when I pull codes. Note that I use a voltmeter instead of a test light.
1) key off with/without jumper wire -- 12 V
2) key on without jumper wire -- 12 V
3) key on with jumper wire -- 0 V except as the computer sends codes.

It looks to me like there is some electrical fault in the self-test circuit. Can't sayat this point if it's internal to the PCM or external. Check the power & ground to the PCM carefully, check the wiring to the self-test connector. If you satisfy yourself that there are no wiring faults external to the computer, then the problem is probably inside the computer.

 

[sajnaj]

ok replaced the computer but yet still is not runnig. i have checked the wiring and it looked fine . im not shure what else is posible

 

[MrShorty]

Can you get codes, yet?
Is the no start still a lack of spark?

 

[sajnaj]

it sill does the same thing as last time. and no spark

 

[MrShorty]

So, you've replaced the computer, and it hasn't changed the trucks behavior. That suggests that the problem isn't the computer itself.
How have you checked the computer's power? How are you checking the computer ground? How have you checked the integrity of the self-test circuits?

 

[sajnaj]

i have lost my wiring diagram out of my haynes manual wich pins should i check on the computers harnes for a ground and power. is there any hting inbetween the icm and the computer like anohter module.

 

[MrShorty]

The wiring diagrams that are part of the vehicle repair guides at www.autozone.com are an adequate start, and will show you pin assignments for power, ground, STI, STO, SIG RET, and the connections between the computer and the ICM.
Better wiring diagrams can often be found in a library. Many will carry professional manuals (Mitchell and Motor are the ones I see most frequently) which contain more complete wirin diagrams.