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I never said that they cant be wired any way.
they can,
it doesnt matter
a 9 volt battery soldered to the wires of a 2 pin AMP connector makes it easy to test all the injectors.
So you installed new injectors and you probably didn't check them to see if they were all working before you installed them
Using an IR thermometer to find the dead cylinder(s) is a brilliant idea! Hopefully, that will help me isolate the offending cylinder(s) quickly Tuesday morning.
It's quicker to just go one by one pulling each spark plug boot or injector connector (which isn't all that easy on this intake).
Here is some more backround info for the mechanics.
Its pertinent to this particular series of 928 models with the big plenum intakes.
IMHO The IR gun is the safest way to find a non firing cylinder on a cold engine,
it takes about 40 seconds once the engine is started to find a cold port with the IR gun.
this even works on a hot engine but you can be burned if your not careful;
Once thats determined then you know where to start looking.
See the NOTES for more info.
NOTE Please heed the hi voltage warning RE getting shocked from a hi voltage spark, dont pull the plug wires off without a grounded tool.
NOTE its also possible to damage the engine computer or igniters by pulling off the plug wires while the engine is running on this system. see warning labels on the radiator.
NOTE pulling the plug wires at the distributor cap with the engine running could cause an errant spark to be sent to the adjacent cylinder that is on an intake stroke,
this can blow the intake plenum off.
If this happens with the hood closed then the hood can also be damaged.
Yes this has happened more than a few times with the over fueling tendency with the 85/86 system and bad ignition wires.
NOTE its next to impossible to remove a injector connector or plug wire without first pulling the plenum off with this 85/ 86 intake,
and once the plenum is off then the engine wont run.
NOTE more than likely one or more of the injectors is not firing/working.
use the 9 volt battery/ AMP connector with the plenum removed to find the non working injector.
BUT First, try this easier test ....
NOTE non working injectors can be found with a long screwdriver or Stethoscope placed on the visible injectors and a running engine.
and listening to the other end of the screwdriver or ear buds.
if you hear the clicking then its working.
Using the IR gun data and the screwdriver or stethoscope you can narrow down your fault.
Early this morning, I started the car after it sat all night in my garage. It fired right up and idled somewhat smoothly, hinting one of the brand-new injectors I installed was not working properly. Using my IR Gun, I went across all the cylinders several times but had trouble finding one colder than the others. The car seemed to be responsive without hesitation when I applied gas, so I decided to take it around my block for a shake-down cruise.
Before I could take it for a drive, I first needed to reinstall the air cleaner top and hoses. So, after about 15 minutes of the car idling in my garage and close to operating temp, I shut the engine down to install those components. I installed those three components and attempted to restart the car.
It would just crank but would not start. This was around 9am, so I left my garage to let the car cool to see if it would start later.
At 1pm, I went out to try to restart the car. The engine was still somewhat warm. I tried to restart it and it sounds like it really wants to start, but doesn't. Rather than start throwing tools, I decided to walk away from the car until Wednesday morning and confirm wheyjer it cold starts again before doing any further trouble shooting.
I have my 9 volt battery and old injector connector tester all ready to go.
smell the vacuum lines for fuel ,
with it warm hold your foot to the floor and crank it.
you could also have a leaking injector.
why not put the old injectors back in after you get them cleaned
I specifically spent $325 on a new set of injectors from 928SRus to avoid the potential for cleaned and rebuilt units to leak, especially when Roger's site advertises the new units as "Plug-and-Play."
NOTE on installing any NEW or recently refurbished injectors.
they should be checked for operation prior to installing them.
to do this use a 9 volt battery with a 2 pin AMP connector soldered to the wires.
I put PB blaster into every new set of injectors then test them with the battery
NOTE any injector thats not clicking then I tap the inlet port onto a block of a wood a few times then retest.
The PB blaster should keep the injector from sticking while the installation process is being performed.
I tried to cold start the car just now. It doesn't even hint at trying to start. It makes no sense to me why that would happen when all I did was install the air cleaner top and the two inlet hoses.
So much for driving my 928 to Carlisle with the car on Saturday.
I'm no longer a U-Boat captain as my U-boat is a boat anchor right now.
I tried to cold start the car just now. It doesn't even hint at trying to start. It makes no sense to me why that would happen when all I did was install the air cleaner top and the two inlet hoses.
So much for driving my 928 to Carlisle with the car on Saturday.
I'm no longer a U-Boat captain as my U-boat is a boat anchor right now.
So it cranks but won't fire or won't crank now? If it turns over and you have tach bounce, push the accelerator pedal all the way down and crank it...anything?
I unsuccessfully tried the car with the pedal floored. Not even a hint of starting.
Once again, I removed all of the injectors and using an old connector spliced with a 9 volt battery confirmed that all of the brand new out of the box fuel injectors are working and do not show any signs of leaking. After speaking with Roger at 928SRUS, I'm very comfortable ruling out any of my new fuel injectors being faulty.
I reinspected all of the electrical connections and vacuum lines before putting everything back together.
It still would not start.
I then pulled the spark plugs from cylinders 4 (Passenger Side) and 8 (Driver Side). As you can see in the attached video, I have a strong spark on the passenger side but a weak, intermittent spark on the driver's side. Unless someone on this thread advises me differently, I believe it's another grounding issue. Roger advised me to clean up the coil grounds as well as the engine-to-frame ground, so that will be my next task at transforming my boat anchor back into a U-Boat.
Good news: After cleaning and tightening the two ground wires at the rear of the engine's "V" underneath the two rear fuel dampers, my car has spark and starts.
Thursday, April 25 Update: Roger at 928SRUs suggested (as other have earlier on this thread - thanks!) to switch the amplifiers to isolate the latest no-spark issue. Unfortunately, when I removed each one this morning, the bright metal plates holding the boards inside spilt from the connector! I think it’s safe to assume that’s not supposed to happen (see attached video)? I still tried to switch them and when I did, now I have no spark on either bank.
I’ve already ordered two new units to have delivered on Friday. Hopefully, that’s all it is at this point. I'll post an update on Friday afternoon as soon as I receive and install the replacement parts. Stay tuned!
04-22-2024, 10:32 PM
