No spark 91PAU

[ParkAveUltra]

Hello everyone, the new guy to the site. I've been a long time member to another site and I have so far recongnized a few usernames on this site that use the other site aswell. I'll be sure to pitch in any useful knowledge to this forum, looks like a good month or two's worth of catching up. Anyways..

I've yet to come up with a solution to my problem that I've recently aquired from my 91PAU as a birthday present! Actually was a few hours before my bday. I'm pretty sure my car thinks this is a big joke, and taunts "figure this one out birthday boy! "

So the introduction begins.. I've had the car on the road for 3-4 months, it has been running absolutely perfect.. then out of nowhere.. starting Jan 18th about 8pm.

1st sign. Drive car to work, blowing snow squals, nothing serious. Leave work, start car no problems, runs for about 10-15seconds, DIES, everything else is working fine (lights, heater... etc). Try to restart, just cranks cranks cranks, won't fire, sputter, nothing. So I figured the fuel line froze up. 15-20min later after calling for a ride home, I've decided to run the codes by jumpering the onboard diagnostics, no codes show. Continue to sit there for a minute or two waiting for ride to show up, so I tried to start it once again and it sputtered a bit, so I tried again and it fired up and idled perfect as if nothing was wrong.. drove it home.

2nd sign. Has been 2 days since the first episode. No problems. Leave work car had troubles starting, it would sputter and resisted firing up, but eventually did and then ran and idled fine. Went to friends house to watch some movies and hang out. 4 hrs later I go to leave and it wouldn't start, crank crank crank crank, no fire. Jumpered the diagnostics, no codes, tried to start again and it fired up like brandnew. First I thought it was a fuel problem, but after the second diagnostic mode I figured the ECM was the problem.

3rd sign. Next day, to leave work, car wouldn't start once again, so I figured, oh I'll just run the codes again, then it'll start right up.. nope, didn't work this time. After a good 25mins it eventually and reluctantly sputtered to life, and once running, ran just fine. Brought it home, and there it sits almost 2 weeks later and refuses to start!

Tested for spark and none exists.

Changed coilpack/icm as a unit. ~ nothing.
Changed computer. ~ nothing.
Changed Crank sensor. ~ nothing.

So today out of the blue my neighbour who works at a wrecking yard and has tons of experience with autos, came over and said change the MAP sensor..

I thought for a bit to myself... not recalling ever seeing a MAP sensor on my car. So I got under the hood and sure enough, there's no MAP sensor. Then he points to the MAF sensor and says that this sensor can cause a no spark situation? I thought MAF only controlled fuel delivery, but I got to thinking with the lack of a MAP sensor, would the MAF sensor on my vehicle substitute for both? (has 3 wires).. anyways, I pulled the harness off the MAF and tried cranking it over and still wouldn't fire or sputter.

Then I thought maybe a relay isin't working right, but good luck there since none of the relays under the hood are labelled. Anyone know which relay controls the ignition? From left to right, standing at front of vehicle looking toward relays on the firewall.

Soooo.. wiring problem? Any hot spot I should start with, as in locations, common fail spots for wiring of the ignition? Any help, questions greatly welcomed!! I'm only giving this another day or two before I take it to a shop. I've never had to take a car to a shop before, and I don't want to start!! But if it comes down to it, then so let it be

[maxwedge]

Get a scanner on it and look for cranking rpms, if none inspect wiring from cps to icm, based on waht you have replaced, aslo check for injector pulse if no scanner, if no pulse and no spark, back to connections, I assume all your fuses are good and all the components in the circuit are powered.

[ParkAveUltra]

Well I finally tackled the wiring and found that two of the four CPS wires were caught inbetween the rad hose and fitting, one was grounding out.. replaced those wires, and cleaned up some grounds. Runs like a dream.

[Bassasasin]

Mine had the CPS.. Crankshaft Position Sensor.. started failing.
With No timing no injector gas pulse to injectors.
Tough to diagnose.. Throws Camshaft sensor codes to the computer. Its paralell to the Ignition module somewhat in wiring and can make the computer go wild with dash lights and spedometer jumps. Considering wires is important. THey cram those wires under a plate under the Ignition Module and simple mechanical splices like a stripped wire and punch a hole and feed wire through it and twist are inside those cables.
Of course check for fuel pressure at the rail schrader valve.


You can Disconnect the MAF sensor and It may throw a code and still run.. Have to test that.. I know the sensor on the Air Filter does that. I do that often.. Like pull the O2 sensor cable connector apart.. checking for stuff.

ENJOY