OK guys just trying to trouble shoot at the moment...Did the water pump replacement the first time..leaked again...So i did it again last night..new O rings and permatex ....now Car skips when idling under load..cruise control at 60....didn't do it as bad when at 65..and it also skips while idling park.... Didn't do it last night bad when I drove it around but did do it minor....This morning was pretty bad...

Anybody know what could have happened?

 

I assume that something went wrong when the timing chain went back on? Did it skip a tooth?


Zack

 

you ****ed up yer timing.

 

As far as i know it didn't but evidently it did..

What do I do as far as timeing?

 

messed with it some today...the skip isn't the exact same..like i can give it gas and cruise at 60 for a few minutes and then it'll start skipping after a few minutes..wouldn't it be the same deal if 2 and 3 weren't firing as it would be if the timing is off? also at the back of the motor i can here like a chugging noise ...it also seems to be audible in the exhaust...any help

 

This is a long shot but perhaps a sensor for the injection that's in the coolant is airbound or has become damaged when the water pump went out.

 

I don't understand what you mean when you say the engine skips. When you are idle or driving, you feel it or see the RPM needle drop down for a brief second?? If so, that would not have anything to do with your water pump. You would be looking at your coil packs. Check to see if you have any codes stored even though the light is not on.

 

No I'm just saying the skipping started after I changed the water pump. And I mean that I can accelerate without it doing much but if I put it on cruise it'll be ok for a minute but then it'll start jerking...It just doesn't seem to be a constant thing like I would think the timing being off would be with 2 and 3 not firing.

 

do you see the tach acting up? does it feel like it downshifts, then upshifts?

 

No it's just jerking is the best way to explain it..but it only really starts being bad until i put the cruise on 60 and leave it for a minute...I also hear sort of a tapping noise at the rear of the motor...

 

We need a video of this showing how the tach is reacting and possibly the sound it is making. Do you have any codes stored??

 

Ok guys an update on this issue...I took it to a very nice guy's shop in town and he agreed to look into the basics for free...However he just called and says he can not communicate with the computer to get the codes...Is this a good sign that the computer could be the root of my problems? If so were is a good place to buy one cheap? What all do I have to do to change out computers?
Thanks,

 

An ECU failure is rare, I'd get a 2nd opinion. Seems you have a misfire.
Have you tried to check for codes yourself by using the set screw on the side on the ECU? There are clear instructions in the sticky's in the top of this forum.
Also make sure that the ECU set screw is in the correct center position.
And I think there might be a fuse for the OBDII port as well,(somebody correct me if I'm wrong) make sure thats not blown.

 

unfortunately I broke the screw. Sounds like that fuse...Would it just be in the fuse block or is it a in-line deal?

 

I spoke with the guy and he said he checked the fuse and everything had power but he would double check...If I broke the screw can the position of it still hinder reading with a scanner?

I also spoke with a friend of mine who is a GM master tech..he seems to think the guys an idiot but it seems like a pretty good shop that does alot of business...

I'm hoping for the cheapest situation but not sure if this guy is competent or not first time working with them but again he is doing everything for free and is a very nice guy.

 

To me it would seem obvious that if your Max wasn't doing this before you did the WP, then you fuucked something up when you installed the new WP. I would be looking into this area myself. I know nobody wants 2 go over the steps they took doing the WP but that's what has 2 be done. Good wrenching.

 

ok not saying this is the answer to your problem but it maybe, try getting a maf sensor cleaner for a discount auto parts store and clean you maf sensor first it may settle it for the knocking i couldnt tell you unless being near the engine, and always remember when one sensor goes bad it will sometimes read as a bunch of sensors and rarely a bad comp system in car, but i would try the maf sensor cleaner first.

 

Agreed!

Bypassing the filters for language will earn you a ban ...

Also, are you texting here, or do you acutally use a full keyboard and PC?


MAF isn't a bad idea to check / clean. You should start by pulling codes in one way or another. Not sue if the set screw (btw - how did you break that? ) being off center will affect the OBD II or not - I would think it might.

 

you might have to change your timming chain

 

If he did skip a tooth with timing wouldn't a timing light help out to see if hes still at 15 BTDC?

Also aren't these motors done if they skip a tooth?

 

hey did you ever get this problem resolved?? I am having the same problems. I just replaced the water pump on my 1995 nissan maxima and mines is skipping ive been told its the coilback , did you resolve the problem

 

Had very similar experience a long time ago....most likely you had some slack in the timing chain and caused it to skip a tooth when it tightened. It should drive terrible, and they won't be able to find any codes - at least none that would directly relate to the issue at hand. Good luck.

http://www.asashop.org/autoinc/jan2001/techtips.htm

Timing Chain Being Off One Tooth
Can Cause Ignition Coils Not to Fire

Posted 1/16/2001
By Paul Kujawa
“Since the problem occurred right after the water pump was replaced, I wondered if the camshaft and crankshaft position sensor signals were out of phase with each other, since the timing chain must be taken off to replace the water pump.”
Vehicle: 1996 Nissan Maxima. VQ30DE

Symptom: Misfires. No spark from the coils for cylinders No. 2 and No. 3. The cam timing is off a tooth.

The problem began with a leaking water pump. After the water pump was replaced, ignition coils No. 2 and No. 3 did not fire.

This Nissan's engine is equipped with a distributorless ignition system (DIS), with a separate power transistor mounted with each one of the six coils. This gives each cylinder one coil and one power transistor. A separate signal from the powertrain control module (PCM) to the base of each of the power transistors turns the power transistors on and off. The power transistors pulse coil negative to ground, based on those signals from the computer.

The technician verified that the signals from the PCM to the base of the power transistors for the other four working cylinders were good. He found no signal from the PCM to the base of the power transistors for cylinders No. 2 and No. 3 at the power transistors. The harness was checked for opens and shorts between the computer and those two coils' power transistors. The signals at the PCM were checked as well. The technician tried running new wires between the PCM and the power transistors, and also tried new coil/power transistor assemblies for those two cylinders, as well as a used PCM. There were still no signals from the PCM to the base of those two power transistors. The camshaft position sensor (phase) and crankshaft position sensor (reference) signals were both scope-checked and had nice, consistent sine wave type patterns with proper amplitude for both signals.

Since the problem occurred right after the water pump was replaced, I wondered if the camshaft and crankshaft position sensor signals were out of phase with each other, since the timing chain must be taken off to replace the water pump. This engine has a main timing chain and two camshaft timing chains. The camshaft timing chains go around the smaller intake and exhaust camshaft sprockets. The main timing chain goes around the crankshaft sprocket, and then up around two larger camshaft sprockets that mount on the end of the intake camshafts, outside of the smaller intake camshaft sprockets that the camshaft timing chains go around. The main timing chain is the one that needs to be removed to replace the water pump.

When I asked the technician to check the engine mechanical cam timing, he found the timing chain was off one tooth. He corrected the cam timing and the two coils started firing once again.

So if you get a couple of coils with no spark and there are no signals to the base of their power transistors, make sure the timing chain is not off a tooth.

 

I'm presently working on replacing my water pump, and, was having quite a bit of difficulty getting enough slack to remove the pump. So, frustrated, I started moving the crank backwards then forwards again. This did give me the slack I needed... but, I have a concern that the noise that I heard from inside the timing chain cover might have been the timing chain disengaging from the crank sprocket.

As I've got what seems like a _lot_ of parts off the side of the engine already, is there a quick way to check if the cams and crank are still in sync? Or, is my best bet to bolt it back up and hope for the best?

Is there any way to fix this without removing the front engine cover? (I really don't want to do that, especially as I barely think the car is worth the time I'm putting in for the WP).