4-7 firing issue; posting for a member

[Pete]

Yeap injectors,i initially wrote and guessed that you had FIC's but removed it. LOL
There have been a few ZR-1 guys on here that had FIC injector issues.

Jason don't spend another dime just borrow a set of good injectors from someone and install yourself if all is good then order new Accels

http://www.jegs.com/i/Accel/110/150821/10002/-1
All of the FBI Z's have Accels never had one issue with them and 3 of them are big inch 10 second Z's.

You saved a few bucks on injectors but spend it elsewhere and now will spend more to replace them.Penny smart dollar foolish.

FIC will warranty them the issue i have is the 2 hour labor, $75 gaskets and all the frustration is just not worth the savings for used injectors.

Pete

[-=Jeff=-]

Yes I had/have FICs.. they are rebuilt. I had issues at first but now I have had them on for 4 years.. so far so good. I did have a couple leakers at first and I think I was the first one to buy the injectors for the LT5 from him before he specifically marketed them for our cars.

[Pete]

Originally Posted by Jason 91

I thought that the injectors were RCs, but they actually came from Fuel Injector Connection. The coils are factory and were bought from the dealership.

#4 and #7 have no spark for certain. I was reading further through the FSM tonight (Chart C-4) and it seems like the diagnostic flow goes quickly to a faulty ignition module. I’m a novice (at best), but I can see where if someone wasn’t thorough they might jump to this faulty ignition module conclusion.
Thanks for the ideas you guys are providing here. There’s a lot to be looking for that could be simple and I really hope it is at this point.
Jason

Jason if you don't have spark on 4 & 7 and you already tried IM and ECM only 2 things left spark plug wire or bad coils check simple things first check plugs behind the coil packs maybe when they replaced coils they bend a pin etc.

Pete

[GOLDCYLON]

Originally Posted by Pete

Yeap injectors,i initially wrote and guessed that you had FIC's but removed it. LOL
There have been a few ZR-1 guys on here that had FIC injector issues.

Jason don't spend another dime just borrow a set of good injectors from someone and install yourself if all is good then order new Accels

http://www.jegs.com/i/Accel/110/150821/10002/-1
All of the FBI Z's have Accels never had one issue with them and 3 of them are big inch 10 second Z's.

You saved a few bucks on injectors but spend it elsewhere and now will spend more to replace them.Penny smart dollar foolish.

FIC will warranty them the issue i have is the 2 hour labor, $75 gaskets and all the frustration is just not worth the savings for used injectors.

Pete

Why im running RCs install and forget about em. Accels are great as well. I will never/ever recommend anyones rebuilt injectors. Even if warrentied its a PITA do have to go throught it ALL over again. I agree with you 100% Pete. GC

[Fully Vetted]

Originally Posted by Pete

Yeap injectors,i initially wrote and guessed that you had FIC's but removed it. LOL
There have been a few ZR-1 guys on here that had FIC injector issues.

Jason don't spend another dime just borrow a set of good injectors from someone and install yourself if all is good then order new Accels

http://www.jegs.com/i/Accel/110/150821/10002/-1
All of the FBI Z's have Accels never had one issue with them and 3 of them are big inch 10 second Z's.

You saved a few bucks on injectors but spend it elsewhere and now will spend more to replace them.Penny smart dollar foolish.

FIC will warranty them the issue i have is the 2 hour labor, $75 gaskets and all the frustration is just not worth the savings for used injectors.

Pete

Pete - Do you prefer the Accels over FIC's new SS injectors as well or just their rebuilt ones?

http://fuelinjectorconnection.com/sh...?productid=115

[scottfab]

Originally Posted by Jason 91

...snip...
#4 and #7 have no spark for certain. I was reading further through the FSM tonight (Chart C-4) and it seems like the diagnostic flow goes quickly to a faulty ignition module. I’m a novice (at best), but I can see where if someone wasn’t thorough they might jump to this faulty ignition module conclusion.
Thanks for the ideas you guys are providing here. There’s a lot to be looking for that could be simple and I really hope it is at this point.
Jason

ah ha... now we have data.
As long as you see spark on any other plugs, it's time to focus
on 4 & 7. As Pete has written, wires or coil BUT we can't as of yet rule out the feed wires from the DIS to the coil. So.......

Measure the resistance between the spark boot at 4 to the spark boot at 7. Compare it to spark plug boot 2 and 3. They should be within a few K ohms (a few 1000 ohms)
If they are close you're going to have to jump into the deep end of the pool.
Here is an isolation step.
It does require pulling the plenum. If you're not comfortable doing this maybe a friend or mechanic can do it for you. Or we can guide you through it. There are threads here on the forum or you can look on the club webpage at:
http://www.zr1netregistry.com/Inform...m-Removal.aspx

Once there pull the 4/7 coil and look at the mounting pins.
Look ok? Not bent or busted off?
Fix as necessary else .....continue
Leave the coil out.
Now find the two (three wire) harnesses that plug into the DIS. These are known as connectors C3 and C4. (Note there are two other wire harnesses going to the DIS, one with many pins and one the two. You don't want these.)
You want to focus on the three wire harness called C4.
It will have these wires:
1. dark blue
2. green
3. black
Check the resistance from the drk blue one to the pins that come up to go into the 4/7 coil.
What do you get?

If any of this is not clear, ask away.
Pic added for convenience.

[Pete]

Originally Posted by Fully Vetted

Pete - Do you prefer the Accels over FIC's new SS injectors as well or just their rebuilt ones?

http://fuelinjectorconnection.com/sh...?productid=115

These look the same as the Accels so either will work fine.

Pete

[Jason 91]

David, to answer your question, the injectors are black.

Scott, what you say above makes sense to me. I need to find the time soon to dive in and, as you say, get dirty.

Thanks guys.

Jason

[scottfab]

Originally Posted by Jason 91

David, to answer your question, the injectors are black.

Scott, what you say above makes sense to me. I need to find the time soon to dive in and, as you say, get dirty.

Thanks guys.

Jason

Keep us posted. No spark is a smoking gun.

[Hib Halverson]

This thread makes great reading. The problem sounds obscure. I love **** like this. I wish the car was closer to me so I could help.

That the no-spark situation not intermittent, ie: the two wires are just flat-assed dead, is actually a good thing because it will be easier to isolate the problem.

In re: injectors...there is no such thing as a "rebuilt" injector. That's marketing BS by people who run injectors through an ASNU machine or some other ultrasonic cleaner. They scam people with the "rebuilt" term when, really, all they've done is clean them, replaced the screens and o-rings and maybe flowed them. What do I use? RC Engineering. I put them in in 1997 and never touched them again.

I'd tend to set any injector work aside right now. Since you already know there's no spark for 4 and 7, the problem is unlikely to be a fuel issue. Right now getting off into injectors is a distraction.

Next, I'd take some of ole "Scottfab's" ideas on wiring diagnosis to heart.

I've read the entire thread twice and no where do I see a statement that the existing 4-7 coil has been replaced with a known-good unit as a test. If it was done and not discussed or I missed it, I apologize for the redundant suggestion. If it's not been done, I'd try it.

My guess is this is either a bad coil, two bad plug wires (unlikely) or one of the wiring issues "Scottfab" talks about.

Good luck.