pasa

Hi everyone
I just finished an extensive resto on my 1990 928Gt which included, all new engine hoses including power steering, air pump and A/C hoses , rebuilt brakes + new rotors, alternator, air pump,steering rack and A/C compressor. New power steering pump , motor mounts,oil pan gasket Devek aluminium rad, belly pan,starter, new leads,plugs and caps and a complete top end refresh kit including Bosch/Ford fuel injectors. I powder coated the intake, cam covers front cross member,sway bars, front tow hooks,and the tube connecting the front lights. I also replaced ever single visible bolt and nut with stainless steel. I started the project in Nov 2004 and just finished yesterday. I started the car up yesterday and it fired up right away and idled well. The only problem was a slight miss. I first suspected the ignition system and proceeded to test everything electrical and all was as it should be. I removed all the plugs and noticed the number one plug was still brand new exactly the same as when I placed it into the engine, all the rest were slightly golden brown. This indicated to me that no combustion was taking place in the number one cylinder. I proceeded to disconnect the number one fuel injector from it's harness and it made no difference in the engines idle, it continued to run as before. I tested the injector harness for the number one cylinder by plugging one of the old injectors into the harness while the car was running and I could feel the old injector pulsing. I know that there is power at the harness connector. I tested the fuel pressure and it was rock steady at 46 PSI. I also tested the resistance at the injector itself and it was 14.6 Ohm's. After all that I suspect the number one injectors is faulty. My question is " can I test the injector while it's still on the car? and how likely is it that a new injector is bad? have I missed something? Any help would be greatly appreciated.

Dan 1990 928GT RHD soon to be exported to Canada

P.S. I plan to post pictures soon.

jyoon

get a stethoscope and listen to it while running. it shouldb be easy to hear it clicking.

Bill51sdr

Try putting one of the replaced plugs back in that cylinder & see what happens. I've had new plugs not function once in a great while... very quick and simple test!

pasa

Hi Guys,

Thanks for all of your suggestions.

I have tried a different spark plug and no difference is noted. No combustion. I have also tried listening to the injector and I am not sure if it is ticking or not. The number 2 injector makes a rather loud ticking noise and while I try to listen to the number 1, the clicking is not as loud but I can't be sure if it's the number 2 injector that I'm hearing?!

Thanks,
Dan 1990 928 GT

jyoon

if you get a cheap stethoscope from autozone or whereever (around $10), you stick the metal probe directly on the injector. there should be absolutley no mistaking if it's a different injector clicking.

pasa

I'll buy a stethoscope and report back tonight


Regards Dan 1990 928GT

pasa

bought the stethoscope and a harness tester kit tonight and ran the engine. The harnesss definitely has power going to it and the stethoscope is silent when placed on the injector" its dead". What a pain!!! How common is it to have a bad new injector?



Regards Dan 1990 928 GT

Adam C

Last time this happened to me I had unknowingly cracked the plastic plug part that connects to the distributor. Get an Ohm meter and put it on the plug wire to see if it does indeed have continuity. Replaced my plug wire and I was back in business.

pasa

if the tester light pulses when its pluged into the harness do I still have to test for continuity?




Regards Dan 1990 928 GT

Bill51sdr

Nope!

pasa

thanks for the info Guy's, I have a new injector ordered and I'll keep everyone posted on how it all works out.

Regards Dan 1990 928GT

pasa

Hi everyone just a quick update I put the new injector in tonight . The engine fired up right away and idle perfectly , no miss; what a difference!



Regards Dan 1990 928GT

Garth S