fuel leak at injectors

looneybin · 12-02-2009, 03:07 PM

I've been chasing a leak from the injectors for 2 days now.
I've installed new o-ring kits on all 4 (2 times now with no luck) & they still won't seal properly.
I have major amounts of fuel still leaking.

I've tried 10 times now to reseat them, but no luck.
I cleaned the ports in both the fuel rail and the intake manifold with carb cleaner and rubbed my pinky finger in the holes & all felt smooth.

I also used ATF to lube the ports during install.
Then i tried something different, i swapped the #3 injector (the leaking one) with the #2 injector, and the major leak also moved.

I have replaced the o ring on this injector 4 different times with the same results.
Is it possible for the injector to go bad and be leaking from the part that the o ring and hat sit on?

I'm at my wits end and my patience is getting thin.

I'm not sure if i should purchase a single injector, are they somewhat of a matched set?

I know the injectors can be a PITA to seal, but come on, this is crazy.

Any kind words are appreciated

John_AZ · 12-02-2009, 04:18 PM

If the fuel lines are not leaking, and the leak moved from #3 to #2 ---orig #3 the leaky injector, you could try to buy a single rebuilt but I think your best financial solution would be to send them to WitchHunter Performance - Injector Cleaning & Flow Testing Services or similiar and have them all tested and balanced.

Pretty fast return time and he can sell you a rebuilt if you need 1 or 4.

The other option is to get a set of 4 new injectors. There are interchanges for our injectors.
It was covered very well here:

Cleaning Injectors Advice

GL
John_AZ
1988 924S +1987 924S

HondaDustR · 12-02-2009, 06:58 PM

According to witchunter, these particular Bosch injectors were known to spring leaks at the joint between the body and the end that has the spray tip. The tip assembly is more or less crimped to the body right above the o-ring. I had one in the set I sent to them turn up leaking right away. I got another replacement which tested good and was cleaned, and a few months later another one springs a leak in the same place! You could take chances on a known good used one, or fork out the bucks for a new one, but that's what they do and it's not really fixable.

I do have some extras if you are interested.

porsche4life · porsche4life's Garage

I sent all 4 of mine to witch hunter and they said that one or more were leaking.... I ended up having to buy 4 of the rebuilts that Pelican sells.... 2 of those sprung leaks on me but they have a 1 yr warranty... Just be sure you have your old ones for cores...

I had witch hunter do the VW though and they did a great job...

looneybin · 12-02-2009, 08:11 PM

Thanks to all for the help,
I have the sinking feeling it is leaking from the joint at the body to the tip assembly,
The tip assembly is loose enough to spin on all 4 injectors, i didn't think that was right.
HondaDustR PM sent on the extras
Thanks

looneybin · 12-02-2009, 08:12 PM

Thanks to all for the help,
I have the sinking feeling it is leaking from the joint at the body to the tip assembly,
The tip assembly is loose enough to spin on all 4 injectors, i didn't think that was right.
HondaDustR PM sent on the extras
Thanks

Mike C5 · 12-03-2009, 04:39 PM

It is possible the injector body is leaking past the molded plastic upper part with the electrical connector. I don't know if this happens often on these injectors but I did experience this on a similar looking injector on my 90 Jeep Cherokee.

porsche4life · porsche4life's Garage

Ya... Thats what I was talking about on mine...

mikepellegrini · mikepellegrini's Garage

I had the injectors in my 951 cleaned by Witchhunter and they did a great job.

But when I reinstalled the injectors, within a few days, I noticed a leak from one of them - it was in the plastic body of the injector, near the top.

I called Witchhunter the next day and told the guy, and he told me that the Bosch injectors just sometimes do that - and it's not something that they - or anyone - can fix. He refunded me the bucks for cleaning on that injector.

He went on to stress that fuel injectors are NOT REBUILDABLE. You cannot disassemble an injector and put it back together. The unit does not come apart.

Witchhunter (and the others, like Pelican) clean injectors and install new O-rings, but that's it. And it certainly can improve performance.

But there is no such thing as a re-built fuel injector (at least for our cars, anyways...).

From the Witchhunter website:

Does WitchHunter Performance "rebuild" fuel injectors?

Nobody actually rebuilds gasoline injectors, since they are a sealed unit and can't be totally disassembled. What we do is inspect, test, ultrasonically clean and replace any serviceable parts, (such as filters, o-rings, & pintle caps). Some companies call this rebuilding, or even remanufacturing and charge over 5 times our price. We replace all the parts that can be replaced. The truth is, you are getting the same thing.

WitchHunter Performance - Injector Cleaning & Flow Testing Services

I ended up buying a new Bosch injector (from here) to replace the leaking one and the car runs just fine.

AA_Ezra · 12-15-2009, 07:23 PM

Ok In Regards to AFJuvat's Tech article, were does one get a charger with a 2mv Or is it 2Mv setting? I can't find one or think of what to use, anybody have any ideas? i just don't want to burn up my injectors even tho they are a spare pair

porsche4life · porsche4life's Garage

Man... Just send them to WitchHunter. They are cheap enough and you know they are spraying right when they are done. Plus they put all new rubber and tips on for you.

AA_Ezra · 12-16-2009, 12:35 AM

Yea. I just want to have the abillity to do it myself since I have everything but the charger. I got an expensive r/c charger I just don't WANs use that

John_AZ · 12-16-2009, 04:54 AM

I used a 12V motorcycle battery charger when I did the AFJuvat procedure-2X+. I have read that a 9V radio battery works. I just tap, tap, tap, tap the wires to simulate the injector firing.
There are a couple of YouTube vids and many DIY injector cleaning sites if you google. One should fit your cautious approach.

I bought my injector seals and hats at a VW parts house. The OEM kits had a different hat size and spacer. NAPA was no help for me. Just compare before you install the new hat on the injector.

GL
John_AZ
1988 924S + 1987 924S

matthewb · 12-16-2009, 06:05 AM

Does anyone know the flow rate on the stock 2.5 N/A injectors in lbs/hr? Why hasn't anyone found a replacement injector from another vehicle?

John_AZ · 12-16-2009, 07:43 AM

Quote:

Originally Posted by matthewb

Does anyone know the flow rate on the stock 2.5 N/A injectors in lbs/hr? Why hasn't anyone found a replacement injector from another vehicle?

Flow rate info:

And alternate injectors.....
From the link I provided in my earlier post:
Porsche & Volkswagen Fuel Injectors - VW Bosch & Lucas Injectors

matthewb · 12-16-2009, 09:38 AM

I do not see that link in an earlier post. but thank you for that link. I think in the other injector thread that is going around the original post-er was having issues finding 2.7 liter injectors because it was a one year engine but this chart says they are the same as the 2.5 liters.

The thing that brought this all up for me is i just picked up an 86 car this weekend that only had one injector working. I couldnt find the extra set of 944 injectors that I am pretty sure I have but I did have some 24lb ford injectors that I went ahead and put in figuring it would be close enough at least to get it running. kinda looks like they are a good pick for the job. It seemed to run fine for me so I may just leave them in.

Thanks

John_AZ · 12-16-2009, 10:40 AM

Quote:

Originally Posted by matthewb

I do not see that link in an earlier post. but thank you for that link. I think in the other injector thread that is going around the original post-er was having issues finding 2.7 liter injectors because it was a one year engine but this chart says they are the same as the 2.5 liters.

The thing that brought this all up for me is i just picked up an 86 car this weekend that only had one injector working. I couldnt find the extra set of 944 injectors that I am pretty sure I have but I did have some 24lb ford injectors that I went ahead and put in figuring it would be close enough at least to get it running. kinda looks like they are a good pick for the job. It seemed to run fine for me so I may just leave them in.

Thanks

Here is my complete source.
I am not sure of the Ford injector impedance values???? The 944 Bosch are "low".
Stan Weiss' - Electronic Fuel Injector (EFI) Flow Data Table

GL
John_AZ

running_cold924 · running_cold924's Garage

+1 for witchhunter, just got mine back and installed onto my 951. I did have a bad injector that was leaking externally, so it had to be replaced. he said its common, so now i have a set of 3....