Thorough search on injectors:

original porsche 993 injectors 99360612000 are:
23 lbs/hr or 242 cc/min @ 15.9 ohms @ 3bar (43.5psi)

FJ51 are:
24 lbs/hr or 252 cc/min. @ 14.4 ohms @ 3bar

I am waiting for my porsche injectors before doing anything

 

Good Luck.... hope you get this sorted out!!!!!

 

Hey Geolab - I bet this is frustrating. So really hope you get it sorted.
You pin-pointed my OP sensor issue on my 993 back in Feb, and I was much relieved when it eventually got sorted, after your advice, so am rooting for you.

Phil

 

This may be quite off beat .... but most of the recent Bosch injectors used by Ford are of the 4 orfice, rotating disc design ( Design II and III type designation) vs. the single orfice with a pintle as used in the 993. The newer type is claimed to have superior fuel atomization, and is often used as a performance upgrade. This works well in the 928 S4 for example, and I have done one conversion; however, there is a caveat claiming that the changed shape of the Design II spray pattern may not work well in certain intakes tailored for the conical spray of the pintle type injector.
That argument may be so esoteric as to be meaningless .. I do not know
Regardless, the specs you have are effectively identical for the flow & impedance, so no issue there.

PS: in post #7, I read
"It is so easy to check because plug numbered II-6 for example is on top distributor @ number 6 and hooked on the front left cylinder bottom
but I will check more than once , again , thanks"

Should that be 'front right cyl' vs left? I earlier assumed a simple typo ... but every detail must be scrutinized if baby doesn't run

 

Typo Typo sorry about that, thank you G
And thanks to all for the encouragement, it is really frustrating, Phil take care dude

 

Hey Geo, if timing was off it wouldn't clear up at speed, would it?

What about the fuel regulator? Could it be off and over-pressurizing the injectors?

 

some photos

 

Hey GeoLab... did you get this sorted?

 

Yesterday was an excellent day for sorting my problem.
since last month, I was waiting for my injectors to come back from bosch and they did.
I changed the injectors fired up the car and Vrooom, what a relief, running super smooth.
FJ51 is NOT compatible with Porsche 993 fullstop.
I went for a ride to warm the car a bit, up on the highway for 15 minutes, and realized a big CHANGE.
Before I did all the work, under load, I used to hear the engine randomly pinging.
Yesterday I challenged it to ping, nothing., so that is good news.

Then I realized that the main distributor coil is not functioning.

One ignition coil is functioning while the other is not.
I bought a new dual ignition coil, but it turned out the electric cable feeding the right coil is not functioning.
I have thoroughly looked at the wire sheets in the workshop manual (sheet #5) and it looked that maybe the ignition control switch
was the problem, so I put in a brand new one, still no juice.
Would you think it is possible for me to get the right coil to function,
by connecting the left coil wires to the left and right one together? any idea much appreciated...
when I connect the electric feeding wires to one of the sides of the dual coils, this side works not the other.
I am talking about the electric harness, there are four cables that go out to the dual ignition coils next to the distributors.
The electrical wires going out to my main distributor coil are not functioning.
best regards

 

Check the continuity between the ignitor (next to the ECU) and each pair of wires going to each coil. There is a multi-connector thats part of the engine harness that can be the culprit. In some cases, the spades of the connector lose contact and/or they back out of the connector,............

 

Thank you Steve, I thought "maybe" there was a relay or fuse somewhere between the ignition switch and
the dual coils, but looks like there is none. So since one hour, I measured the ohms going out of the wiring harness to
the coils, the big black wires feed the 12 volts to the coils, and both were functioning.
The other small yellow and green wires, one was reading 124 mvolts with contact on, the other was reading zero.
So I do not know if there is a risk, but I took a wire from the good yellow wire and hooked it to the second coil.
Normally since the load importance is after the coils, I think there should be no problem, any thoughts?
Wow, engine harness on my PET says 1200 euros ...

 

Finally finished the Xmas DIY yesterday, having spent all weekend on the car.
The dual coil problem is solved. The culprit? the new ignition control switch was the problem....and not the wiring harness. This fooled me for a few hours, but with a voltmeter, all went well.
Curiously, if you want to test this switch, you can remove the cable connected under the passenger seat
without removing the seat and plug a new one, squeeze it against a metallic surface and run the motor.
It sounds easier than removing the seat to test.
After searching for the problems, and removed and installed the wheels so many times, I
realized the lugnuts need 11 turns to go out or in. mere 911 coincidence???
Here are some photos...the fan and housing were sandblasted and VHT CLEAR coated only, no colour paint....thanks

 

Congratulations on tracking down the problem.

The fan looks great!


Andreas

 

Great to see you were able to work through all the issues and get it sorted out. Looks awesome too. Thanks for posting.

 

Wow geo, your engine is CLEAN!