82 928 that starts and runs ok then slowly floods itself.
03-01-2018, 02:39 PM
#1
82 928 that starts and runs ok then slowly floods itself.
hey guys, have a 82 928 that has me pretty stumped. It fires up cold just fine runs well for about 1-2 minutes with no smoke. Slowly starts missing 1 cyl at a time a starts smoking grey until it floods itself and shuts off. If I let it sit I can jump right back in it and same issue. I have searched and tested most everything I have found. Cold start valve, the 3 regulator vacuum lines, plugs are new, relays all seem fine, grounds are ohming ok, water temp sensor cold is 4.5k ohm and warm 1k. Mass air seems ok from my knowledge. Only funny thing I have is the fuel pump relay will buzz but still works and clearly pumps fuel. I have replaced it with another relay and that one buzzes as well. Any other things I may be missing? Any help appreciated.
thanks Steve.
thanks Steve.
03-01-2018, 06:13 PM
#2
Team Owner
put the mityvac on the small port for the blue check valve at the brake booster start the engine and report what your vacuum is.
03-01-2018, 07:17 PM
#4
I'll give it a test with the mityvac and see.
As for the leaky injectors im not sure since it will hot start as long as I start it for 2 mins or less and keep cycling. But I'll run the pump for a minute and see if it gives me trouble.
Got a vid im going to post up as well.
As for the leaky injectors im not sure since it will hot start as long as I start it for 2 mins or less and keep cycling. But I'll run the pump for a minute and see if it gives me trouble.
Got a vid im going to post up as well.
03-01-2018, 08:17 PM
#6
Team Owner
OK find out the vacuum reading ,
first please a picture of the engine.
first please a picture of the engine.
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03-01-2018, 10:25 PM
#9
Rennlist Member
I've spent literally years chasing problems like this, only to have it turn out to be injector problems. For me, and for the price, I would not screw around. Send your injectors to Witchhunters. If they are all OK you will know it and know that you can confidently look beyond that.
One exception: it might be worth checking that the barn door in the AFM is not sticking before you do that. If the car backfires it can bend the door in the AFM and then it will sometimes stick. That would cause over rich condition also. You can push on the door with your finger or something and feel if there is any sticking.
One exception: it might be worth checking that the barn door in the AFM is not sticking before you do that. If the car backfires it can bend the door in the AFM and then it will sometimes stick. That would cause over rich condition also. You can push on the door with your finger or something and feel if there is any sticking.
03-01-2018, 10:44 PM
#10
Team Owner
in addition to the injectors getting cleaned, you also need a new green wire and hot post cover.
Test the temp 2 sensor, the one with the Bosch plug on it in the WBridge
each pin to ground they should give similar ohm readings
Dont keep running it this way the cylinders can rinse down with the fuel this removes the oil and then the bores can be damaged
Test the temp 2 sensor, the one with the Bosch plug on it in the WBridge
each pin to ground they should give similar ohm readings
Dont keep running it this way the cylinders can rinse down with the fuel this removes the oil and then the bores can be damaged
03-01-2018, 11:05 PM
#11
Bit of a noob question but which is the green wire? I'll get on that. The oil has been getting thin so I'll be adding some 20-50w as testing goes on. The temp 2 sensor I tested the 2 pins together but I will test them separately to ground.
as for the injectors I'll get them cleaned but I have dealt with leaky and clogged injectors before and usually have the opposite effect.
I find it so so strange how it fires up nice and clean when cold like nothing is wrong, then as it warms it slowly loads up with fuel as if the injectors are too big. Any afm tests that would be worth doing?
Thanks again for all the imput.
as for the injectors I'll get them cleaned but I have dealt with leaky and clogged injectors before and usually have the opposite effect.
I find it so so strange how it fires up nice and clean when cold like nothing is wrong, then as it warms it slowly loads up with fuel as if the injectors are too big. Any afm tests that would be worth doing?
Thanks again for all the imput.
03-02-2018, 06:32 AM
#12
Rennlist Member
Green wire is the wire that comes out of the back of the distributor and connects to a orangish male 2 pin amp connector on the side of the engine opposite of the distributor.
It to me sounds like the car thinks it is cold even while warm and keeps running rich.
It could be the temp II sensor but it could also be a bad connection on the AFM. It will cause grey/black smoke when it is disconnected and causes the car to run excessively rich.
This connection could get loose the hotter the engine gets.
It wouldn't hurt to pull out the AFM, clean the contacts on the unit and in the plug, and then bend the pins in the connector with a small screwdriver to ensure there is tension.
This costs nothing to do but ~15 minutes of your time.
It to me sounds like the car thinks it is cold even while warm and keeps running rich.
It could be the temp II sensor but it could also be a bad connection on the AFM. It will cause grey/black smoke when it is disconnected and causes the car to run excessively rich.
This connection could get loose the hotter the engine gets.
It wouldn't hurt to pull out the AFM, clean the contacts on the unit and in the plug, and then bend the pins in the connector with a small screwdriver to ensure there is tension.
This costs nothing to do but ~15 minutes of your time.
03-15-2018, 11:46 AM
#13
Hey guys, just an update checked afm, water II sensor, grounds, all connections are clean and corrosion free. Engine cam timing is correct. Still with the same issue runs great for the first minute then slowly starts to flood itself out. Checked all plugs and all 8 are consistent in black color. One from another really have no difference so does not seem like 1 bank is richer then another like I have found in some threads I have searched.
03-15-2018, 01:13 PM
#14
Rennlist Member
Different fueling system(I know), but when my '89 was doing this, it was a bad engine ground. Sure enough, the main engine ground strap under the passenger side, even though hooked up, was not making a good connection. I removed the strap, cleaned it, tested it, and reinstalled it. Never had trouble with it again. It's a cheap fix and well worth the time to check all the grounds. It drove me crazy for most part of a year before I figured it out.
Good Luck
Good Luck
03-15-2018, 05:39 PM
#15
Burning Brakes
I can't really add anything intelligent here but will try anyway :-P I agree with the recommendations to check the green wire, check contacts, clean grounds, and while you're at it wiggle all the fuses and relays to ensure good contact/luck lol. I suppose a bad injection brain might be possible but they seem quite reliable so that's unlikely. One more thing -- I recently pulled out my AFM (I have an '83 with Ljet like yours) and checked out the trace -- is it a variable resistor? -- that the wiper arm moves on. The trace can get worn down after many years which can lead to erroneous AFM outputs. Frankly, I have no clue if that could cause your symptoms, but may be worth checking any way and often helps these cars run better. You can loosen the little PCM board with the trace and -- because the holes drilled for the mounting screws are a little larger than they need to be -- you can move the board just enough to get the wiper to run on a fresh area of the trace. Even 0.5mm will do it. Something to consider!!