fristajlo

Hi guys, hope someone could shed some light over what's happened to my car after my latest. My 944 n/a hasent been running to well ever since I bought it. It was bought as a long time project-car. It has never run particularly well, always felt sluggish. So I decided to clean the injectors. Removed the whole fuel rail, flushed the injectors both ways, ran them in an ultrasonic cleaner and replaced o-rings, filter and caps. Thought it would make a big difference since I flushed out a lot of stuff from the injectors. Installed the whole lot yesterday, all good so far. No leaks whatsoever. I let the fuel pump work a couple of seconds before I started the engine. It fired up right away but runs like s*it. Kind of a diesel feeling. So I managed to make it run worse... I did let it warm up and drove it a bit, hoping it would make it run better. But no, it was still horrible. Lacks power and running rough. The idle is rougher too, was no problem before.
Everything I've done to the car so far has improved its performance and appearance, one small step at the time. But this was a blow to morale and joy.
Can anyone help me to troubleshoot this mess? I know I f****d up, but I don't know what I've f****d up or how.
Have I ruined the injectors? Is there air trapped in the fuel rail (it was completely drained)?
Grateful for ideas how to sort this mess up.

V2Rocket

try unplugging the injectors one at a time, you might have a dead one.

fristajlo

Thanks. I don't have to worry about breaking anything else by doing this? Will try that if safe.

V2Rocket

no...if one is dead, when you unplug it the engine wont change how its running.
unplugging the live ones will make the engine struggle to stay running (only 2 cylinders left)

fristajlo

Thank you. Will try that next time I have the time to work on the car. I'm leaning towards replacing all of the injectors anyway for peace of mind. Is there an affordable option for new injectors? Other than refurbished? I have a 944 85.5 n/a

V2Rocket

I haven't done research to part numbers but there are any number of "other car" fuel injectors that will work in a 944 NA.

Need to be about 220-240cc/min flow rate @ 3 Bar fuel pressure, with impedance/coil resistance of 2.4-2.8 ohms...probably some Volvo or BMW part would work.

curtisr

Did you flush them on the work bench with a device not unlike this?

snb13

Where are you located?

fristajlo

thanks, will start looking into this.

Correct. Also ran the injectors in the ultrasonic cleaner in between flushes.

I live in Stockholm, Sweden.

ealoken

Oh, some old injectors do not like the ultrasonic cleaners.

fristajlo

In that case I've most likely killed them...

Thanks to the lead from v2rocket I've probably sourced some BMW injectors that match mine "perfectly". Very close anyways. Will try these.
Thanks!

Otto Mechanic

FWIW, I had the same problem with my 928 and found two injectors that were just plain bad. I had a spare 928 (the whole car), which helped. Spencer's right saying that it just takes one. It's also my experience that cleaning them can make the whole problem worse. There's a fellow that goes by the name of "Witchhunter" who makes a business of injector cleaning and since these injectors aren't cheap you may want to give him a try. He's in the US though so maybe there's someone else in Europe that does the same sort of thing?

dmjames

Oh holy crap, I had literally the exact same issue come up on my 87 Turbo. Swapped stock chips in, then added some Techron to a new tank of fuel to clean things out since it'd been running rich for years. Now it runs like crap... going to try bench-cleaning the injectors and see if that does it.

Tiger03447

Some GM injectors will work (or so I'm told) can be had for about 50 bucks apiece, new. I think they fit a Buick. Bought a new set at my FLAPS. I have yet to check them out..since all 4 of mine were toast.

Tom M'Guinn

If you pull the connectors on the fuel injectors, you can use a 9v battery to test them. When you apply 9v across the leads, you should hear and feel them snap open. Or, use a multimeter to check the ohms across the leads -- any consistent reading in the low single digit range probably means they are ok -- if they are shorted or open (or lots of resistance) then they are bad. Be sure to check for spark too and/or for mixed up spark plug wires if you removed them when doing the work.