91 Coupe replaced injectors now blowing smoke

[jamesmdx1]

Hello
I replaced all 8 of my injectors on my 91 coupe 4.9L
the resistance was low on them .. and the car was not running smooth, after changing all the obvious..(plugs, wires, fuel filter, battery)
I had 2 delco new injectors and 6 GB REMANUFACTURING Remanufactured MULTI PORT INJECTORs from rock auto...
after putting it all back together I started the car and it was running rough and blowing white/blue smoke from the tailpipe.. when I stepped on the gas it was bowing alot more smoke and was smelling bad...
resistance on all the new injectors is 18 ohms
I don't know what to do.. I'm not sure if I did anything wrong.. I followed the FSM and replaced all the o-rings...
please I need help...

[Sevillian273]

Bluish smoke usually indicates oil being burned. Oil may be getting into the combustion chamber somehow. However I dont know how the injector job could cause that... It would be a far-fetched coincidence...

[jamesmdx1]

could the smoke be from too much fuel entering the combustion chamber...its also hard to start the car

[drewsdeville]

Well I'm not sure of the real procedure to replacing fuel injectors on these engines, but on both of mine I had to remove the rear hose from the water neck to get the fuel rail off. This spills coolant onto the intake manifold if you aren't careful. I just let it run all over the intake both times. Then when you remove the fuel rail, the coolant puddled on the back side of your intake runs into the rear injector ports. When you get it all back together, it stumbles and blows smoke until it clears up and the fuel rail is purged of air after 20 seconds or so. I got the same result on both cars...

Not sure if this is what you experienced. Did you let it run long enough to confirm that this isn't whats happening? If you shut it off right away, let it run for a minute and see what happens

[jamesmdx1]

yes i let it run for a while...and took it around the block .. blow alot of smoke...smells like there is gas that is not burning..

[drewsdeville]

Did you forget to plug in the coolant temp switch or map sensor (and it's vacuum line)? These both are vital tools for fuel management and must be disconnected to remove the fuel rail.

[Sevillian273]

If you smell gas out the tailpipe, its running rich. One or more of those injectors might be stuck open. You can check by applying a 9volt batt to each one of them and listen for a click.

[jamesmdx1]

yes i plugged back in all the connectors and lines and double checked them.... I guess I will have to take it apart again and maybe I have a bad "new" injector..the car ran fairly smooth before I changed the injectors and never blow any smoke...I did have a few low resistance injectors and I hoped that after replacing them it would run flawlessly now, but it looks like it needs more attention....
only has 60K on it - old lady driven car.

[Sevillian273]

My oem's failed early like yours at 67k miles. They are a bad design...(google 'MULTEC') and i bet the ones from rockauto that were listed for your car were also of that design. The ones you want are called Bosch III's - theyre a bit skinnier and have a better spray pattern. There around 150 rebuilt or 300 new.

The 9volt test is a good way to find the bad one. Another method would be to lift the rail with the injectors attached and turn the ignition on and watch the spray. This is super dangerous for obvious reasons but you'll know for sure. Its likely that the rest are fine and the bad one is just dumping fuel into one cylinder with the other 7 cylinders keeping the engine running. If you leave it like that it will foul up the spark plug and oxygen sensors with carbon soot and will make your cat converter turn red hot and fail. Also a high risk of backfire and balooning the muffler.

[drewsdeville]

To blow smoke due to a rich condition, I'm pretty sure it would take more than leaking injectors. The volume of fuel has to be quite large. Generally leaking injectors cause a slight misfire and drivability symptoms, but this seems to be beyond that. I suppose the whole batch could be leaking, but I think your odds of winning the lottery are better than having a complete new set of injectors leak. If they all leaked, I'm sure you'd have one hell of a time even getting it running.

If you are positive that you have everything hooked up correctly, I have to ask this. I know it might seem silly...

Are you sure you were given the correct injectors?

Incorrect injectors will fit. Injectors of the same brand all look the same externally and fit many applications. However, what you can't see is the injectors flow characteristics and lbs/hr.

If you are unsure, take a look around the top of the body if it is a Rochester injector or look at the plastic electrical connection if it's a bosch injector. Report back with the part number you find.

[jamesmdx1]

thanks for all the replys:
these are the injectors that I installed in the car
they are AC Delco injectors...4 of them I bought off ebay...from online new car parts seller...he stated that they were new ACdelco but when I received them they each came sealed in plastic in a brown box.. I wasn't really happy with them because I wanted new ACdelco originals..(part # stamped on them is 17102119 (ACdelco # 217-296), he assured me that they were "new"
I then found 2 brand NEW Acdelco's on line and bought them.. same #'s as above...
So then I purchased 2 from ROCK auto GB manufacturing injectors which were refurbished to new and look it too..and they also have the same part #'s as above... so to me that is a matching set..all have normal ohms.

So now I think that the 4 I bought off ebay, 1 or all of them may be bad.. so I have have gone ahead and ordered 4 more from rock auto and will replace those...
I have exposed the fuel rail again..looking for any obvious problems, but haven't found any... I'll pull the injectors when the new ones arrive.
Looking in the throttle body I can see what looks like gas in the bottom only on 1 side though..(the side closed to the front of the car.. does that mean the leak is in the 1,3,5,7 injectors?

Is there anything that I coulld have done wrong when installing them?
I followed the FSM
I used the correct injectors, I didn't want to use the ford or the other ones because I didn't want any problems.. or should I have used another brand?
How can I find the bad injector?..
thanks for all the help.

[Sevillian273]

Originally Posted by drewsdeville

To blow smoke due to a rich condition, I'm pretty sure it would take more than leaking injectors.

I agree, that's why I think hes got just one leaking profusely. As in a steady spray.

Originally Posted by jamesmdx1

How can I find the bad injector?..

As said above: 9volt batt test, pressurize the rail while it is out of the engine, OR put a large flathead screwdriver on the top of each injector (engine running) and listen at the handle for the ticking sound. One probably isnt 'ticking', just spraying a steady stream.

I would also tell you to check the ohm's of each unit but you said they all read 18 ohms so it sounds like the coils are healthy but one unit is stuck open or otherwise mechanically defective.

You bought from 3 different vendors so thats 3 different origins of the parts and 3 different groups of folks that could have screwed something up on their end.

Are you getting any codes? -just curious. Im guessing you have E44, E45, or E80. Its hard to start because as soon as you turn the key, the rail pressurizes and starts dumping fuel into the engine through the bad injector. Its flooding out...

[drewsdeville]

There's an easy way to tell if you have a stuck or leaking injector if you have a fuel pressure gauge handy. Hook up the gauge to the rail and cycle the key a couple times to let the fuel pump run. Turn the key off and observe the gauge. The pressure should not bleed off...

[jamesmdx1]

no I didn't get any codes...
I tried the 9 volt battery on the old injectors to try to get them to click so I know what to look for on the new injectors, its was hard to connect the battery to the injectors, I finally tired with wires with double ended alligator clips..didnt get it to click so I tried it with the car battery and got it to click...not sure if the 9 volt was weak. Can I test the new injectors with the 12v battery?

[Sevillian273]

Of course, thats what they get in the car. Its easier to do if you can get an old connector from a junkyard.