2,4,6 and 8, no spark

[SATAN]

Searched this and found a guy with the exact same problem. He found that the 5 pin connector to the passenger igniter was swapped around with another plug (which is RIGHT NEXT TO THAT ONE) that had 6 pins but clipped in perfectly . Same situation with mine however, that didn't do crap.

Here is what I know.

All coils are seeing 12 volts (passenger & driver, driver is not my concern)Both igniters work when plugged in on drivers sideALL coils fire when plugged in on driver side.Seems as though all injectors are firing, hard to tell 100% though.ECU code = Ignition signal circuit AND knock sensor. Oh and ECT sensor (coolant sensor?)All coils see 12v constantly but get pulsed a ground signal correct?

If the ECU can see that there is an ignition signal circuit that is messed up, that tells me that the ECU is not sending the ground signal to the coils. Does that sound right or no? If this is the case, then is the ECU's driver for spark not good and it just doesn't know it, or is it that there is wiring messed up somewhere.

Thanks for the help guys. Oh sorry, this is a 1990 Q45 if it matters.

Edit: According to Q45 Tech on here, I should test the wires coming out of the ECU that drive the igniter. I should test them in millivolts. Now I just need to find out what the MV range should be. Still searching, chime in if you have answers.
Modified by SATAN at 1:39 PM 1/12/2008

[goody90q45]

There's a ground wired in to each of the spark plug/coil harnesses. It's in the rear near #8 plug (and #7). Did it possibly not get re-attached by the PO? If this isn't the problem and you've already ruled out the igniters (power transistors), I'd be looking to swap in a known good ECU (as you alluded to).

Don't worry about the KS code for now since it's a separate problem unrelated to this. It's not a bad idea though to ohm the fuel injectors and KS though to get an idea of what they're doing. Good luck.

[SATAN]

Ground wire is there and attached. I found that pins 54 53 50 and 44 are for coils 2,4,6 and 8. I am going to try to see if I can pull ANY millivolts off of them to see if they are sending any signal at all. If there is nothing, then I will assume the ECU is bad at that point I guess. I just dont understand why the ECU wouldn't flash a "bad ecu" code.

Now I just have to find out which ones coming out of the ECU those are.

Still searching

[Q451990]

Weren't you having issues with the cam sensors? I can't remember if those play a role or not. I know you rotate them to check for injector pulse, but I don't remember for sure on the spark pulse.

Heath

[SATAN]

Weren't you having issues with the cam sensors? I can't remember if those play a role or not. I know you rotate them to check for injector pulse, but I don't remember for sure on the spark pulse.

Heath

Yes, rotating the cam sensor does both fuel and spark. Mine is missing pieces but is still intact enough to send a signal to the ecu simulating engine rotation.

I will be getting a new CAS soon, but this one works for what I need it for, for now.

[SATAN]

OK, on page 98 and 99 of the fsm in the EF & EC section it says this

Pins 2, 12, 14, and 15 need continuity checked with pins F,G,I and J. In those orders. 2 goes to F, 12 goes to G etc.

It doesn't say anything about millivolts. However since it doesn't specify what to do if those connections are good, I assume that Q45 tech was suggesting finding the millivolts comming out of the ECU to see if the ECU is good. In that code 21 diagnosis it never mentions if you should replace the ECU or not.

So, Q45tech, What are those milli volts supposed to be? I am assuming power should only be visible when the CAS is spinning, or no?

[mxr662]

OK, on page 98 and 99 of the fsm in the EF & EC section it says this

Pins 2, 12, 14, and 15 need continuity checked with pins F,G,I and J. In those orders. 2 goes to F, 12 goes to G etc.

Using your meter set to ohms, the four connections on ecm connector to the power transistor harness should be 0 ohms or very close.

If those four connections are ok goto page ef ec 218

[SATAN]

Right, thats what I did, went to that page. At that point, it tells you to check the igniter. Then it leaves it at that. Doesn't mention anything about if the igniter is good.

My igniter IS good, so if the continuity is good and the igniter is good then is HAS to be the ECU right? Thats why I was wondering what the millivolts are supposed to be comming out of the ECU.

Also, I see the little Ohms symbol on the little multi meters, but in the instructions it doesn't mention resistance that I could see. It just says to check continuity. At least that's what it says in the little table next to the multi meters on that page. Where did you find that you are supposed to check resistance? I must have missed that.

Edit: oh it says if the power transistor is good (the igniter) then to check the connections of the clip to the ecu THEN it leaves it at that, and never mentions the ECU being bad as a possiblility.
Modified by SATAN at 8:26 PM 1/12/2008

[Q451990]

I guess the question is, is that cam turning? If the chain is completely off, then it wouldn't?

Heath

[SATAN]

Oh, that is not what concerns me right now. I have the cam sensor out and just spinning it by hand, that way I dont have to physically crank the engine.

[mxr662]

Also, I see the little Ohms symbol on the little multi meters, but in the instructions it doesn't mention resistance that I could see. It just says to check continuity. At least that's what it says in the little table next to the multi meters on that page. Where did you find that you are supposed to check resistance? I must have missed that.

The ohm symbol means set the meter to ohms. When it says continuity it means either 0 ohms (connected) or infinity (open circuit).

[SATAN]

Gotcha

[Q45tech]

The CAS is the master clock for ecu while it may open the injectors it doesn't fire the coils until a certain rpm is reached hand tuning slower than 150-200 rpms* won't work as serious engine damage could result if CAS was not somewhere in sync with piston position. Why the slot only allows a 45 degree adj range.

The ecu should send 70-140 millivolts to each ignitor transistors BASE connection as per FSM depending on rpm - low at idle with the voltage increase at 2,000 rpm.

[SATAN]

Q45tech, I did not have the coils on the plugs when I was spinning the CAS. Therefore they were not sending spark to the cylinders. I also found that the CAS does not have to be spinning at 75 rpm or more in order to tell the ecu to spark. It will do it anyways spinning slow as hell. At least on my car anyways.

Ok, here's the deal. I was having the exact same problem as the guy I searched.You can plug the igniter into two other clips that have nothing to do with the igniter. Then the two clips that would plug into the igniter, plug into something else (don't know what that something else is at this time, nor do I care right now) The point is, everything can be clipped in and look fine. When in fact it is not. This is only on the passenger side. Which is why I still had spark on the driver side. Chasing my own tail for hours on this stupid crap. How I figured it out was the wire colors from the FSM. They didnt match up like they were supposed to. Then it hit me. Now I have spark where it is supposed to be.

Now, all I need is a good CAS and to pull the front of the engine apart, see if it is still timed, and replace the guides if it is still timed. If not, well, time it and check compression...

Here are the pictures of what I am talking about on the connectors.

These two can swap overAnd these two can swap over

And here is a pic through the access hole showing the tensioner guide backed with metal, which doesn't matter because all of those were metal backed. The blue silicone is what tells me they still need to be done.

[tmorgan4]

Hey Satan,

If you want to try another ECU, I've got an extra one up here in Fort Collins. I thought mine was bad because it wouldn't power on, but it was just a wiring issue.

EDIT: Just re-read the whole thread and looks like you got it figured out. If not, my offer still stands.

[SATAN]

Hey, right on man, Good looking out. Yeah, the ECU is fine now so... I will have to get the cam sensor and the chain guides and see what else it needs after that. Looks like I need a new brake booster hose, which means I probably need to do all the hoses under the plenum. Got any leads on a cam sensor in state for a fair price?

[tmorgan4]

Parts have been really difficult for me to find locally. If I were to do it over, I would have bought an entire parts car myself. I know of ONE Q45 in a junkyard up here in Fort Collins, and they didn't want to part out the engine.

The only place that I've had any luck finding parts was Blake's Auto Salvage out in Erie. All the engines are in pieces but they keep parts organized fairly well (enough that I found the oil pump sprocket I needed).

There's a few guys on this board I'd REALLY recommend if you end up wanting to order used parts. Mike (goody94q45) is probably the best person I've ever bought things from before. If he doesn't have that sensor, there's another guy that I haven't ever bought anything from but he seems to have a ton of VH45 parts...name is Tecni.

[maxnix]

Try PopPop also.

[SATAN]

I haven't noticed a PM function on this forum. Is my best bet to locate them in a thread and ask for their Email?

I assume they would post in the vh45 or the q45 section most of the time right?

[maxnix]

Do a member search then their profile will have an email if they so desire.

Graeter gods of NICO disabled PM to force discussion onto forums, even, alas, when it is inappropriate - i.e., "You've got mail!"

As if the recipient wouldn't know.
Modified by maxnix at 8:20 AM 1/16/2008

[SATAN]

I was wondering why NICO gets so much traffic. Now I know.

[qship96]

Its called BUSINESS MARKETING.... the more posts per day {traffic} , the more advertisers will pay to get their products in front of potential buyers-not much different than what a business pays to locate their shop/store/restaurant on a busy,highly traveled road as compared to a side street....its all about volume

[SATAN]

Yeah, I figured as much. Cool with me. Do what you gotta do. Whatever pays the bills. How many people on here are admins? Or I should say, how many people on here collect a check from NICO? Or is it just like a lot of sites to where any checks that come in manage to be just enough to keep the forum going?

[Q45tech]

Nobody gets paid other than owner and I doubt the ad revenue does more than cover the website cost.............

Too many unaffiliated Nissan forum sites which share advertisers.

I've always suggested that signatures [pictues and crap] should be paid per view beyond one line of text or a single website link.

The last thing a human wants is a public email on a national site can you imagine.