Fuel Injector Seal Nightmare
10-30-2018, 10:32 AM
#16
Addict
Rennlist Member
Rennlist Member
It'd have to be leaking at the body down near the pintle cap then. I think there is a seam near #5 in this cutaway:
https://witchhunter.com/images/injectorcutaway.jpg
*edit* looks like a crimp is more visible in this cutaway:
https://www.cprracing.com/wp-content...tor-cutout.png
If there are Design III injectors that'll work IMO waste no time or money messing around with the old potbellied ones.
https://witchhunter.com/images/injectorcutaway.jpg
*edit* looks like a crimp is more visible in this cutaway:
https://www.cprracing.com/wp-content...tor-cutout.png
If there are Design III injectors that'll work IMO waste no time or money messing around with the old potbellied ones.
10-30-2018, 10:55 AM
#17
Did you replace your injector seals with a rebuild kit or have Witch hunter re do them? The pic below shows the 3 seals that come in rebuild kits and the ones that typically show up from rebuilders. The lower seal is what we need in the 928 world for the lower injector on our cars and I can't remember if the 9x4 use the same one. But could be your issue.
10-30-2018, 11:55 AM
#18
Drifting
I install the injectors the Official Workshop Manual way: injectors into the intake manifold first. When I put the injectors into the manifold, they "pop" into place. No, "pop", not fully seated.
Next, I install the fuel rail on top. Finally, with pliers I gently pull up on each injector until I can put the clip on. The clip location is tricky: it actually looks like it goes further down but doesn't.
The problem with putting the injectors into the fuel rail first is you'll have a very hard time "popping" them into the intake manifold. This is because the bolt-down bracket for the rail doesn't allow the rail to be pushed down any further.
Next, I install the fuel rail on top. Finally, with pliers I gently pull up on each injector until I can put the clip on. The clip location is tricky: it actually looks like it goes further down but doesn't.
The problem with putting the injectors into the fuel rail first is you'll have a very hard time "popping" them into the intake manifold. This is because the bolt-down bracket for the rail doesn't allow the rail to be pushed down any further.
10-30-2018, 11:19 PM
#19
If these are old injectors, simply replace them. The plastic welds begin to fail as these things age. I had the same issue on my 951 and new seals will not solve the issue. It's time for new injectors. Replace them all and move on.
10-30-2018, 11:36 PM
#20
Rennlist Member
Thread Starter
I’m believing the “replace and move on” line of thinking. I did not realize there was a joint below the seal. That seems to be a very plausible explanation.
Any opinions on replacement injectors that won’t break the bank?
Any opinions on replacement injectors that won’t break the bank?
10-31-2018, 07:33 AM
#21
Rennlist Member
From my experience chasing similar leaks I would bet my 25 cents on it being the injectors. Check out my thread.
https://rennlist.com/forums/924-931-...know-this.html
As mentioned in my thread I bought 4 used injectors off eBay... 1 of the 4 had the same problem but with the other 3 I got the car back on the road and I think I still have one functional spare.
https://rennlist.com/forums/924-931-...know-this.html
As mentioned in my thread I bought 4 used injectors off eBay... 1 of the 4 had the same problem but with the other 3 I got the car back on the road and I think I still have one functional spare.
10-31-2018, 05:27 PM
#22
Rennlist Member
Some people have had good luck with GM injectors. They apparently seat well and give about 6 sprays out instead of just one. I think some are for Buicks. Just check with your local auto parts store. Take the old injector with you so you can get a good number cross. I think that AutoZone had some for about 40 bucks apiece or so..that's where I used to work (retired now) not a plug for AZ..just sayin...Hope this helps a bit..
10-31-2018, 09:55 PM
#23
Rennlist Member
Thread Starter
I checked out Elgy’s thread again. I know I have read that thread at least two times. Now I understand that his leak problem was the same thing I am experiencing.
Concerning replacement injectors, if there are more modern injectors that would be an improvement over OEM and maybe even be reasonably priced, I would be interested in learning of them. I have read various threads about this injector or that injector may work. Or the coil resistance needs to be this or that and could or might work if you add a resistor....you get my concern.
I have no problem buying standard injectors, I am just thinking that if there were an identifiable injector that is known to be a good replacement, I would go that route, especially if it is reasonably priced.
Any thoughts to add? I appreciate all of you for taking the time to reply. Thanks again.
Concerning replacement injectors, if there are more modern injectors that would be an improvement over OEM and maybe even be reasonably priced, I would be interested in learning of them. I have read various threads about this injector or that injector may work. Or the coil resistance needs to be this or that and could or might work if you add a resistor....you get my concern.
I have no problem buying standard injectors, I am just thinking that if there were an identifiable injector that is known to be a good replacement, I would go that route, especially if it is reasonably priced.
Any thoughts to add? I appreciate all of you for taking the time to reply. Thanks again.
11-02-2018, 12:06 PM
#25
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I didn't read every word of this thread - but I didn't see anywhere the mention of lubricating the o-rings.
Use a drop or two of ATF. Lightly lube all o-rings. It is easy to tear the rings if they are dry and forced into place.
I have also used the rebuild service from Rock Auto. There are other, more reputable places - but I have been happy with RA.
Use a drop or two of ATF. Lightly lube all o-rings. It is easy to tear the rings if they are dry and forced into place.
I have also used the rebuild service from Rock Auto. There are other, more reputable places - but I have been happy with RA.
11-02-2018, 12:50 PM
#26
Rennlist Member
I didn't read every word of this thread - but I didn't see anywhere the mention of lubricating the o-rings.
Use a drop or two of ATF. Lightly lube all o-rings. It is easy to tear the rings if they are dry and forced into place.
I have also used the rebuild service from Rock Auto. There are other, more reputable places - but I have been happy with RA.
Use a drop or two of ATF. Lightly lube all o-rings. It is easy to tear the rings if they are dry and forced into place.
I have also used the rebuild service from Rock Auto. There are other, more reputable places - but I have been happy with RA.
11-03-2018, 10:49 PM
#27
Rennlist Member
Thread Starter
I want to thank everyone for taking the time to post.
I have learned that the original injectors were prone to leaking, not just at the joint between the top plastic section and the metal body, but at the joint between the body and the pintel section just above the plastic spacer and lower O-ring. I did not know about the lower leak point. This leak point is the only thing that could explain such a profuse leak, just above the manifold.
I ordered 4 replacement injectors this past Friday. I will report back the results of the install to close the loop on this saga.
Thanks again to all who offered their experience. It is much appreciated.
I have learned that the original injectors were prone to leaking, not just at the joint between the top plastic section and the metal body, but at the joint between the body and the pintel section just above the plastic spacer and lower O-ring. I did not know about the lower leak point. This leak point is the only thing that could explain such a profuse leak, just above the manifold.
I ordered 4 replacement injectors this past Friday. I will report back the results of the install to close the loop on this saga.
Thanks again to all who offered their experience. It is much appreciated.
11-09-2018, 04:57 PM
#28
Rennlist Member
Thread Starter
I received the replacement injectors from MotorMan on Monday after ordering on the previous Friday morning. Last night I installed them without a hitch. The engine ran rough for a few moments, then cleared right up and purred nicely. And without any leaks. The engine seems much smoother with the refurbished injectors, especially above 4,500 rpm.
The joint between the pintle end and the main body could be spun by hand on the leaking injectors. The two non-leakers did not spin. It seems kind of odd to me that a known issue like leaking injectors, would not have been corrected with a factory recall. Especially in light of the possible consequeces of a fuel leak....FIRE!
Anyhow, this car should be in pretty good shape in that regard now. Once again, I appreciate the input from all those who took the time to post their experience.
The joint between the pintle end and the main body could be spun by hand on the leaking injectors. The two non-leakers did not spin. It seems kind of odd to me that a known issue like leaking injectors, would not have been corrected with a factory recall. Especially in light of the possible consequeces of a fuel leak....FIRE!
Anyhow, this car should be in pretty good shape in that regard now. Once again, I appreciate the input from all those who took the time to post their experience.
11-09-2018, 10:44 PM
#29
Rennlist Member
I received the replacement injectors from MotorMan on Monday after ordering on the previous Friday morning. Last night I installed them without a hitch. The engine ran rough for a few moments, then cleared right up and purred nicely. And without any leaks. The engine seems much smoother with the refurbished injectors, especially above 4,500 rpm.
The joint between the pintle end and the main body could be spun by hand on the leaking injectors. The two non-leakers did not spin. It seems kind of odd to me that a known issue like leaking injectors, would not have been corrected with a factory recall. Especially in light of the possible consequeces of a fuel leak....FIRE!
Anyhow, this car should be in pretty good shape in that regard now. Once again, I appreciate the input from all those who took the time to post their experience.
The joint between the pintle end and the main body could be spun by hand on the leaking injectors. The two non-leakers did not spin. It seems kind of odd to me that a known issue like leaking injectors, would not have been corrected with a factory recall. Especially in light of the possible consequeces of a fuel leak....FIRE!
Anyhow, this car should be in pretty good shape in that regard now. Once again, I appreciate the input from all those who took the time to post their experience.
11-09-2018, 11:00 PM
#30
Rennlist Member
Thread Starter
Grant,
Your post put me on the right track. I knew of the possibility of the leak between the upper plastic end and the metal main body, but knew nothing of the possibility of the lower leak. Thanks again for pointing me in the right direction.
Your post put me on the right track. I knew of the possibility of the leak between the upper plastic end and the metal main body, but knew nothing of the possibility of the lower leak. Thanks again for pointing me in the right direction.