951 running rich and flooding

xero · 11-26-2005, 04:53 PM

Hi I just got done installing a new head gasket on my 86 951, the car ran fine before but now It doesn't want to start, I got it started twice and both times it was running very poor and puking huge clouds of black smoke out the back , if i get the rpms up to around 4000rpms it seems to run ok just at that speed only but still does smoke a bit and if I go any higher it runs bad again and loses power.
at the moment the car will not start, spark is good, did a compression test and got 130,130,110,120, which I think is basically ok?
I can crank it and crank it and it will not start but then if I unplug all the injectors and crank it after trying to crank it with the injectors plugged in it will fire up for a second till it burns out the gas in the cylinders and then dies again.
I even tried disconnecting the AFM from the intake boot so that it would see no vacuume and give max lean setting, but it still floods out during startup.
I disconnected the throttle position sensor and the O2 sensor and still flooding?!?! even unplugged the AFM sensor wires with no change .....the only thing I can think of at this point is that there is something wrong with the DME ....I have some performance chips in it by the way, forget the brand offhand, I think it starts with an M ?

xero · 11-26-2005, 04:54 PM

oh also I pulled off the injector rail while someone turned the key and the injectors fire one at a time so they're not like stuck open or anything, but they just injecting way too much fuel

xero · 10:31 AM

the chips I have are weltmister .....also there is some sensor or something that goes into the top of the turbocharger....or maybe it goes into the waterpipe attached to the turbo or something?
it has one wire connected to it and I broke the sensor or whatever this is off while doing the head gasket, I've been trying to find a diagram that will tell me that this part is, does anyone have an idea?

Lawrence Coppari · 11-27-2005, 12:32 PM

Turbocharger has a thermostat in its water jacket. When you shut off the car the auxiliary water pump runs for 30 seconds. After that, if more heat seeps into the turbocharger from the hot exhaust and heats it to thermostat set point, the thermostat triggers the water pump to run for another 30 seconds. This process can repeat several times.

A single wire comes off the turbo water sensor. If you disconnect and ground it - the end that does not go to the thermostat, the pump will run for 30 seconds. Thermostat just completes ground when it senses too high a temperature.

xero · 11-27-2005, 12:57 PM

ok so then it would not effect my fuel it just turns the aux water pump on?

Britwrench · 07:18 PM

Cali56,

Seeing how absolutely NO diagnosis (apart from changing parts without seeing if they work) seems to have been done, therefore no reading of any technical manuals, there's not much point describing why disconnecting one injector might get the motor to start.

If you read my post it said "check the fuel pressure" as the engine possibly has fuel pressure regulator failure.. which is very common in running rich problems. You might also notice that, according to the posts, it hasn't been done yet.

Removing the injector wire leans off the system enough it may run by reducing the total amount of fuel available, but the air amount remains the same. And yes, I do know it is then only a three cylinder motor.
I've done this in car park before when diagnosing non-starts without tools. You can also loosen off the air intake hose to allow more air..on the engine side of the throttle body. It should allow the engine to at least run.. which sort of moves one to the postion of knowing what the fault is rather than guessing.
Most times with fuel presure problems result in the engine cranking, running and then stopping..when cold. At normal operating temperatures it won't start at all because the fuel/air ratio is way too rich.

It all comes back to diagnosis in a logical path. Not doing that takes way longer and tends to be expensive.

Ok, ok where did that cali56 post go?

nynor · 11-27-2005, 08:38 PM

ah, britwrench, i love you. in a platonic way, but i still love you.
xero: just do it and let us know what happens. i forgive very easily.

xero · 11-28-2005, 02:13 AM

britwrench and nynor: don't get me wrong I appreciate any advice but the disconnecting of one injector will not make the other 3 any less rich...however the cylinder with the disconnected injector will fire for a second if it has just been flooded as the extra fuel dissapates and i have gotten my car to fire up previously by removing all 4 injector wires...but then it immediatly dies of course, and I did say that I would look into the fuel pressure as that may be a possability but that disconnecting one injector won't help me.... even if it did start I can't drive it that way so what's the point, I already know it's running way rich if you guys want me to do it that bad I'll give it a try just to satisfy you
also as I mentioned I tried removing the rubber boot from the afm and it still runs rich .....I'm really starting to think this may be a problem with my DME engine temp sensor? going to check that AFTER pulling the wire to one injector :P
the cali 56 posts are an another thread, I posted this to the NA forum after I didn't get any responses at first, thanks
oh and yeah, like britwrench said it will sometimes fire if it's dead cold but if it's warm in the slightest there's nothing

still open to ideas btw, thanks

nynor · 11-28-2005, 07:36 AM

let us know what happens after pulling an injector.

xero · 11-28-2005, 03:16 PM

ok well I tried pulling the wires to one injector and it still wouldn't start (big surprise heh) but anyway I found the problem! (am prepared to be laughed at) my DME temp sensor wire was unplugged!, plugged it in and it started right up....still runs slightly rich...but it was doing that before, I think I have a couple minor vacuume leaks that make it rich when the turbo kicks in thanks guys ttyl

Cali56 · 11-29-2005, 12:29 AM

Thanks for bringing it back up, I deleted it because I thought it was a little rude.. I don't usually do that here I had been awake for 26 some odd hours and a little off canter, will you accept my appology?

Cali56 · 11-29-2005, 12:37 AM

soo were in the mood for diagnostics.. I just had my starter rebuilt and installed it with the battery wire to the starter and the alternator wire also connects to the same starter post and then returns to the battery and the ignition wire goes to the solenoid on the starter and the key goes on and the fuel pump goes on but the starter will not... is this a sign of the DME relay not sensing enough load on the pump to fire the starter? did I connect my solenoid up on the wrong trip wire? there's two posts on the replacement solenoid for the trip wire, aplying a jumper from the power of the battery to the solenoid trip wire also makes the fuel pump come alive... still wondering what is going awwery on the starter/ignition thing... I can jump the starter at the solenoid to crank the motor over but after a few cranks the starter pops back off the ring gear and continues to spin free... tried the fuel pump load to see if that would trigger the starter by pinching off the feed line on the pump but that just about stalled the pump so I hooked the pressure regulator to the feedline and return line hoping it would give the right load to the relay... should I replace the relay or try another post on the solinoid? maybe power to the other post to trigger it?

ronin · 12-13-2005, 09:20 AM

Quote:

Originally posted by Cali56
will you accept my appology?

no, but we'd glady beat you to within an inch of your life...

oh wait, wrong support group

Cali56 · 12-13-2005, 06:33 PM

Quote:

Originally posted by ronin
no, but we'd glady beat you to within an inch of your life...

oh wait, wrong support group

ACK internet stalker! :P

xero · 12-13-2005, 11:08 PM

kick him in the nuts beavis!!

Cali56 · 12-14-2005, 08:22 AM

what if it's not a him!

ronin · 12-18-2005, 01:35 PM

pray you don't lose your foot!

Porsche944 · 01-11-2006, 12:16 PM

Swapping starters is pretty much a "no brainer" because there are only TWO connections to worry about. The big wires go to the big terminal, and the small wire goes to the small terminal.

If the starter does not crank the engine when you turn the key, then you have an open between the battery, ignition switch and the solenoid. The first place to check is the connectors near the brake booster. Look for one with four wires. Make sure this connector is tight and the connections are not corroded or dirty.

If the starter still does not crank the engine, then you may have a faulty ignition switch or you may have an open between the switch and the solenoid.