New Accel Injectors, same problem different hole.

[RZR]

Originally Posted by tccrab

Ray:

The trick is to leave so much tire rubber that they can't see the little puff of oil smoke.

TomC
'90ZR1 #792

I LIKE IT!! Great suggestion and you know, with Sumitomo's being $107 a pop for the 17x11's, I can light 'em up at every stop!!

[tccrab]

Originally Posted by RZR

I LIKE IT!! Great suggestion and you know, with Sumitomo's being $107 a pop for the 17x11's, I can light 'em up at every stop!!

Boy was I glad to see the price on the Sumitomos.
I've got a complete set of GoodYear GSC's on my Z and I was deathly afraid of having to replace them earlier than the usual 10,000 miles.

TomC
90ZR1 #792

[tccrab]

Originally Posted by RZR

Tom,
One other issue related to the failed injectors I experienced and wanted to see if you experienced the same. When my primary injector(s) failed, the car mis-fired, bucked and kicked pretty good - I thought I had broken the motor. Shortly afterwards I pulled over, shutdown and noticed what sounded and smelled like a catalytic converter meltdown - loud ticks and a lot of heat from the underside. A few days later I heard clunking sounds from underneath the car during idle and low speed driving. I assumed this to be pieces of the cat dispersing within the exhaust system. I am planning my approach to solving this but thought I'd run it by you to see what you did if anything. I thought about just replacing the cats but now am faced with the possibility of a blocked muffler as well.
thanks,
Ray

Ray:
OMG, it must have been AWFUL.
My experience with failed injectors was nothing like that.
I took Girlfriend (that's what my wife calls my Z, for obvious reasons... ) for a drive to a buddy's house about 25 miles up the mountain.
When I went to leave about half an hour later, it started fine, but I noticed a slight miss as soon as I pulled out onto the road. By the time I got home it was missing big time, at idle you could hear the dual mass flywheel rattle and you could feel the engine shaking the car.
I didn't drive it after that, was too afraid of hurting her more than she already was.

TomC
'90ZR1 #792

[tccrab]

Well, think I found it.
Check out these two pics, the first is Cylinder 8's fuel injectors, the second is Cylinder 6 (my dead hole).
The image might be too small to see the detail, but I won't know until I submit the post, so here goes.
Think this is my miss?

Hint: it's something to do with the secondary injector.

TomC
90ZR1 #792

[RZR]

INTERESTING! So that one injector in cylinder 6 looks like it isnt seated all the way. But if it is squirting fuel, will that make for a complete miss? It would make sense though since more air is being introduced into the cylinder so it should feel like a miss - I am just thinking out loud here.....
Tom, I would be really happy for you if thats all you have to do to fix it. I will then cross my fingers and hope to find the same situation in my car.
GOOD LUCK and I cant wait for your next report after you push that baby in all the way!
Ray

[tccrab]

Originally Posted by RZR

INTERESTING! So that one injector in cylinder 6 looks like it isnt seated all the way. But if it is squirting fuel, will that make for a complete miss? It would make sense though since more air is being introduced into the cylinder so it should feel like a miss - I am just thinking out loud here.....
Tom, I would be really happy for you if thats all you have to do to fix it. I will then cross my fingers and hope to find the same situation in my car.
GOOD LUCK and I cant wait for your next report after you push that baby in all the way!
Ray

Ray:

Thanks!
I think whats happening is that the 'O' ring is actually pushed up out of the seat on the injector and just barely setting in the top of the injector hole. It's letting in gobs of air and throwing the air/fuel mixture way lean. So lean that the spark plug can't ignite the mixture until the secondary injector kicks in and squirts in gobs more gas.

It's as good a theory as any, I'm going with it.
Tomorrow after work I'll yank that fuel rail and replace the 'O' ring on that fuel injector and button 'er back up.


Wish me luck!

TomC
'90ZR1 #792

[tccrab]

Well, getting closer.
#6 firing just fine now.
Idle is much smoother.

trouble is, now it's clear that #4 & #7 aren't firing all that well, and guess what? They're both on the same coil pack.

Need to figure out how to diagnose coil packs or sensors or wires.

Ideas?

TomC
'90ZR1 #792

[RZR]

Tom, really sorry to hear that you're still having issues. Not sure how to check coils/wires other than checking for a good spark while cranking. Are there any misfire codes? Not sure if you have a means to data log your car but I believe there is a way to check for any DTC codes thrown by the ECM. If so all it might tell you is that you have a misfire and you already know that. Really hope you get to the bottom of this as I bet its getting rather frustrating. I know, I have been in that spot recently and still kinda there.....

[tccrab]

Originally Posted by RZR

Tom, really sorry to hear that you're still having issues. Not sure how to check coils/wires other than checking for a good spark while cranking. Are there any misfire codes? Not sure if you have a means to data log your car but I believe there is a way to check for any DTC codes thrown by the ECM. If so all it might tell you is that you have a misfire and you already know that. Really hope you get to the bottom of this as I bet its getting rather frustrating. I know, I have been in that spot recently and still kinda there.....

Ray:

Actually, it's not so bad.
I've learned a lot and by the time I have the plenum off and back on for the third time I hope to be pretty good at it.

I'm beginning to think that I had two problems, one obvious, which was bad/going bad fuel injectors, and a more subtle problem being a weak spark on cylinders 4 & 7.
The coil or sensor or whatever is causing the weak spark has probably been going on for quite a while and I just never noticed that the power was a few percent down. I have never raced Girlfriend, just an occasional first gear through third gear "back road boogie" to blow out the carbon and feel the power. Otherwise I drive it like a regular car, which may be part of my downfall. From all I've read, the harder you drive these cars, the better they perform.
When the fuel injector went, it caused a big miss, and coupled with the other two cylinders not firing well made Girfriend shake and rattle like a wet dog.

Now to find out about coil packs and what makes them work. There's gotta be some way to nail down either the coil pack or the electronics that drive them, sensors, etc. Time to dig through the archives...


TomC
'90ZR1 #792

[tccrab]

It was a dark and stormy night...
Oh, wrong story.
Saga of the mystery miss continues...


With the engine cold I've checked the coils at the plugs and they read:
1/6 = 19.68k Ohm
2/3 = 19.91k Ohm
4/7 = 18.05k Ohm
5/8 = 17.92k Ohm

I bought one of those little inline spark test lights and the glow is no different between cylinders.

Yet I clearly still have a miss, and pulling plug wires one at a time with the engine idling STRONGLY suggests that #4 & #7 aren't firing.

I've manually tested each primary fuel injector and verified BY SIGHT that each primary fuel injector squirt gas into each cylinder when I ground the appropriate pin at the ECM connector. (thanks for that NIFTY tip Mark Haibeck).

I've verified that the circuit to each primary fuel injector is continious and each injector coil measures +/- .2 ohms of each other.

No vacuum leaks, the engine idles at 500-600 when warm, but it's clearly not hitting on all 8.

Is there an easy to tell if the ECM is causing the fuel injectors to fire without using a scope?

Am I missing something?

HELP!

TomC
'90ZR1 #792