Ok. this is odd. It started tuesday night, i would drive down the road and the car would cut off.... tach would go down to zero, and then cut back on after a few seconds and drive fine. Odd.. i thought it was the coil pack so i replaced it, had no real problems with it until today, it would do the same thing, but would stay off. I would get under the hood and just fiddle with a few things (play with the coil pack plug, tap the coil pack, tap on the cas ect ect) and shut the hood. Sometimes that would get her to run, sometimes not. So i took the negative off the batt and put it back on. That little trick worked twice in a row (could be coincidence). I limped her home (it wouldn rev past 4K at all, very low on power as well). So that tells me the secondarys werent working.

I get home, i replace the CAS, the coil pack (again) the ECU. It wont start....Same thing, the tach doesn't move while cranking. The tach makes a slight bump when the switch goes "on" which i think tells me the relay is working. The main relay checks out, all the grounds check out, and i even put another ground (for kicks) from the batt to the block to see if that would help. By the way, i have power to the coil pack when this is happing too, and power to the CAS, and everything inside seems to work (idiot lights cut on ect ect).

Does anyone have any idea what the hell is going on here? The only thing i can think of is faulty wiring (something around the CAS), but, the harness is out of a car that used to run like a champ, so i doubt it (but havnt checked for sure, i will probably by the time you are reading this). Does anyone know how to test the *wiring* for the CAS as it seem that this would be the only thing related to spark and fuel timing.

Thanks Guys.

 

Tried pulling error codes from the ECU?&nbsp Bad CAS will usually trigger some kinda code...


-Ted

 

Thanks man, i replaced the CAS, but i will try and see, maybe some fautly wiring will pull up an error code

 

i always heard HAILERS say that S4 ecu's didnt store codes. have i been living a lie?

 

They don't. But if it's a shorted wire, it'll throw an error code regardless.

 

No, the series four does not store codes, so your not a liar. Go out to your car and turn the key on. Now pull the boost sensor plug off. Look at the codes. You'll have a code. Now turn the key off. Put the plug back on. Turn the key on and you don't see any codes. Do any combination you want and it won't store a code. That said, I realize that no one in the above posts really think a series four stores codes. Just doing my finger exercises.

And when you do see a code, it's 99.9 percent sure that that sensor is not bad. The plug has fallen off or......a shorted wire to the sensor. This ECU is bare bones dumb as a rock.

It can't even remember its own name. That's why they wrote N332 on its forehead. In case it gets lost someone will know what its name is, because I guarantee it has forgotten its own name.

 

Uhm... Ok.... That was a little strange. Does the car stay running when the tach hits 0? Or does it complete stall?

 

Ring out the cas per the attachment on this post. Meter on ohms, ring between N and P and T and Q. Both readings should be approx the same. Approx 110-210 ohms. While the meter leads are on the wires, massage the harness and plugs on and around the cas and ECU all the time watching the meter to see if the connection is lost. Then put the meters neg lead on a good ground and one pin at a time such as N, and then see if you have a short to ground. Massage the harness while doing that.

Really sounds to me like the power for the coils, injectors, main relay is being disrupted, more than the cas.



You could take the small plug off the ECU and get on any of the injector wires with the positive lead and a good ground with the negative lead and turn the key on. YOu should see 12v. Now massage the harness around the engine fuse box, the main relay and inbetween. See if the meter loses the 12v while doing that. Too many possibilites to list.

 

When the tach is at zero she stops firing, just coasting.


I can hear/feel the main relay click on, and it stays on, and i have power to the coils and i *should* be able to get power to the injectors as well. The reason why i wondered about the cas is because thats the only thing i can think of that wouldnt tell the coil and injectors to fire, seeming that both have power just not being "told" to operate. I replaced the ECU, this car used to be an Auto and the Automatic N336 was in there, and i replaced with an ECU i had laying around that was also an N336.

Thanks guys, keep em comin'. Heh, still no luck btw.

 

I have had the same problem before on my car but it
would only happen while driving. Turned out the MAF
was just barely hitting the fender well inside the engine
bay. Just a thought, good luck.

mothership

 

Hey man, today im going to replace damn everything i got a spare of, the AFM is on that list. Anything that could possibly be shorted or causing a short will be looked, overlooked, tested, and/or replaced. Thanks man.

 

I'd start with the ECU ground or connector corrosion.

 

About not reving over four grand........I can take my 87n/a (just did this), pull the secondary injector plugs off, and hit six to seven grand in each gear(first thru third) IF I don't slam the pedal to the floor. It's natural that if you slam the pedal down with no secondary injector plugs that it will bogg big time before continuing to accelerate.

So I'm asking .......do you really mean it won't go above four grand????

SureShot has a good point. Sure you grounded the ECU thru the ground ring under the intake manifold?

Even better, mabe the solenoid resistor has a bad contact with the power wire to it.

 

OK, heres the deal. Hailers, im not sure, i couldnt get it to go over 4K, but, i do know that it was TERRIBLY low on power, maybe it would have, but i dont think that has any underlying meaning. I just got back from doing a few test. I get about 2.5V of power to the CAS, and i did the "pull small plug and test" and the only wire that had ANY power was the black wire with a white stripe, that also had only about 2.5V of power. The ECU is grounded under the manifold, as is the one near the transmission. I also ran a spare "just for kicks" ground to the block again as a toss out in deep water, no avail. What do you guys think?

 

AAAAHHHAHAHAHAHAHAHAHHAHAHAHAHAHAHHAHAHAHHAHAHHA BUWAHAHAHAHAHHAHA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !


ok, enough of that. Well.. i found the problem. You know where the ECU is that big *** plug on the right hand kick panel? The bigest one there to replace the harness. Well, i guess a month or so ago when i peiced this car together from parts around and replaced the harness this plug was loosley connect. Well, sorry to bother all you guys, but thanks for the great support. If anything this is a good write up on how to find culprit problems and how simple they may be.

I was doing the test on the injector plug and started playing with the harness, massaging it and that bitch hoped up to 12 and then went back down.. i was like "wtf.. " and then i started jiggling plugs and she stayed.. i cliped it in.. its fine. heh. Thanks again.

 

Hah.... Why is it the problems I always expect to have some interesting solution always are solved so simply!? Oh well, congrats on the find... I guess we should add, *CHECK ALL CONNECTIONS* to our list of things to check first.

 

Lemme hear a AMEN!!

 

hahaha.