Alright... The 7 hasn't started in about a month and a half, and I'm out of ideas. It died on me right after I left my house, ending with me pushing it back a few blocks. What was happening was that it was turning over when you cranked it, but as soon as you moved the key off of the "start" position, it shut off. now I can't even get it to turn over.

1st thing I tried - Replaced the key cylinder, because I thought that might be messed up. It's now push-button start. It was doign the same thing after I got hte push button start working.

2nd thing - replaced the ECu. It had a 236 ECU in it, I accidently ordered a 237 ecu from here. The plugs were the same, and the CAS still fires the spark plugs if you manually turn it, and the 237 appeared to come out of another S4 NA, right? so they should be compatible. same thing happens.

3rd thing - heavy de-flooding. pulled the plugs, cranked for a cumulative 30 seconds (intervals of 10 seconds), until it wasn't blowing anything else out. I put a decent amount of oil in the leading holes, and cranked the engine over by hand quite a few times. Stilll just spins...

So I'm looking at the AFM, possibly? I know it's getting fuel in the engine, the plugs are soaked every time I pull them. I know there's oil in the engine.
Is it possible that the AFM just cut out of me (literally) while I was driving? If so, what do I need to jumper to bypass it temporarily? I know about the fuel pump jumper, but I'd be happy if I could get it to run for 4 seconds by itself.

What else does the AFM do, and should I be looking in this direction?

Thanks.

 

The AFM is pretty much ignored during cranking. You should be able to start the car with it unplugged, though it will stall out a few seconds later.

 

that's what I was thinking (afraid of?). Thanks for confirming, Aaron.

 

Compression test? Pull any codes?

 

What about your BAC setup? You know that vacuum hose that runs from the bottom of the tube that runs from your MAF to your throttle body? Check that to make sure it's seated correctly and there's no leaks along the way to it's destination.

I had that thing pop off on my becuase I didn't put it on tight enough, and the car would do the same thing.

Pull a plug and see if it's producing a spark as well. Hold it close to a piece of bare metal and see if a spark crosses the gap.

 

The airflow meter is one of the primary inputs to the ECU. It is ignored during cranking, but on the '86-88 cars it functions as a fuel pump switch, so if the airflow meter is closed, the fuel pump shuts off.

Have you messed with the airflow meter any recently?

I'd also check for *large* vacuum leaks - like the hoses under the intake tube popping off, the tube itself popping off, etc.

If the airflow meter is somehow bad (they actually are pretty hardy, VERY rare to have one go bad) they are a dime a dozen, should be like $20-30 max for a good used one.

The ECU is no biggie - the only difference between the 326 and 327 ECU's is some minor programming changes in the emissions controls. Fuel and ignition maps are identical.

Dale

 

uRizen - Good idea about the BAC setup.. I'll have to take a look at that tomorrow or the next day. I'm sure it's not a vaccum problem, but I'll check the unit out. I do know that all 4 plugs are fireing properly.

dcfc3s - I'm pretty sure it's not a vacuum leak, I've removed everything non-essential to running, so it's pretty simple now, vaccum wise. The only messing I did with the AFM is to remove it, just to see if that was my problem. Then it started to rain, so that's as far as I got... Thanks for the info on the ECUs.

Thanks guys

 

Maybe the plugs arent getting enough spark and just flooding out everytime. I would think with getting spark and fuel it would mean a problem with the air getting in also. I have an 88 TII engine in mine, and i ran into a similar problem when the afm had the solder on a connection inside break loose. Just a shot n the dark though. Good Luck.

 

you've got air...you've got fuel... I would suggest looking at the ignition system. Check the resistances on the CAS and verrify that you have spark.

 

I know that I have spark, at least visually.. i've pulled the CAS out while all four plugs were on the throttlebody, and turned it. Relatively new plugs (2000 miles?) and brand new wires, too.. Good idea, though.

 

Seems odd then. Could it be the car is either really flooded and not making enough compression for combustion...

 

Flooded. But here's some charts to view.

 

Karte1

 

Hailers - Do you think pull starting is the best bet at this point? and does that mean you support the "it was the ECU" theory of rotortivity?

Thanks for the charts, I will be using them..

 

Cars used to have a component called the ballast resistor. The purpose of this was to send full battery voltage while cranking, but when the key went to "run" the voltage to the ignition components dropped to about 8-9 VDC. When the ballast resistor failed, it would cut voltage to the primary side of the coil.

Modern electronic systems have something similar, but I don't know what the current item is, or where it would be located. It might be part of the ECU.

I don't have the fix, but this may help you find the solution.

 

No. I think it's flooded beyond belief, so to speak. If you keep on cranking with the starter it'll kill the starter sooner than later.

If you have spark and fuel and have not touched/rotated/fiddled with the cas, then maybe pull starting is the way to go.

I'm not a big fan of it (pull starting). Usually disabling the fuel pump by pulling its plug off, then spinning the engine for say ten seconds with the lower plugs removed, then reinstalling the lower plugs and spraying starter fluid into the air filter for a second, maybe two and then cranking the engnine over should start it for a brief moment. That brief moment will help clear the engine. Do it a couple of times then put the fuel pump plug back on and do it again and maybe the thing will stay started.

But if you've a long rope/chain and a helper, pull start it. Then make a fuel cutoff switch for possible future problems.

Did I ever tell you the story about how I tried to help a motorist stranded on the side of the road several years ago? B/t Waco and Ft Worth at 3am. I offered to push start the car. I shoved him up to forty or so mph and noticed his lights would dim occasionaly. It did not start. We pulled over. I asked him how he was trying to start it. He said when I honked my horn at forty he would turn the key to start the engine. It didn't crank over any faster he said. I asked him that maybe the next time if he left the key to on and just let the clutch out in third at forty maybe it'd work better. It did. I don't push strangers cars anymore after that episode.

 

Lol. I used to drop the clutch on my 84 S10 to start it, but it only required the 10mph or so I gained from the front of my driveway to the end (it had a small incline).

What do you attach the chain/rope on to pull start the poor thing? I'm thinking I may have to sue that sometime in the future (knowing how my luck has been lately). Besides, it would be a funny trick to show the guys, lol.

 

The only thing I didn't use is starting fluid, but I'll definately try it.. I've had a fuel cut for a long time, though. when I de-flooded it, i just let everything blow out of the engine until it didn't crank any more mist out. I'm going out armed with starter fluid here's to not blowing up the car!