87 328--need advice on hard start issue-redux!

Cold start injector does not have anything to do with having spark or not. So, no!

Random eletrical stuff is very hard to troubleshoot. If I were you, I would start a few long term experiments:

1. Remove (at least disable) the after market alarm for a month or two or until the problem resurfaces (and then leave it out until you have it fixed).
2. Change out the master relay controlling the power to ignition control unit
3. Take out the ECU and inspect for cold solder joints (or touch up all of them).

Those are a few things to try, and they cost little.

PM (or wait for him to repsond) Steve Magnusson. He is the master of this sort of thing.

 

When you mention the flywheel sensors "read normal" how have you tested them? Resistance tests wont work if thats what you have done. You need to check the output on an oscilloscope as one might be giving marginal output. I have seen exactly the symptoms you have seen, on other cars with similar sensors and its been either metallic dirt on the sensor or bad contacts on the wiring to them.

Opening the throttle increases the cranking revs just enough to trip the sensor output over the level it needs, as the engine can turn more easily as there is no vacuum to pull against. The car runs OK because at idle RPM the sensor output is more than sufficient.

 

Yes. The sensor output on these simple coil/magnet-type sensors increases with flywheel speed. If they are marginal then there can be enough output when the engine is running but not enough when cranking. You could take them out and check if there is anything metallic stuck to the sensor as this can cause this problem as it interferes with the signal. There are in-line connectors for each sensor and the round bulkhead connector. I would check/clean all pins on the inline and round connector and the rectangular Molex one next to it.

There is no relay in the ignition feed, only the ignition switch. There might be an outside chance its the switch, ie breaking the ignition feed when turned to the crank position but never come across that.

The other possibility is some contact problem or fault in the ignition which is causing it not to work when the supply voltage drops to the 10 or so volts which happens during cranking owing to the starter motor load.

Its worth doing the usual visual inspection of contacts although you might have done this. The ones on the fuse board are terrible quality with a very small contact area and check for any signs of discoloration. The power feeds through connectors behind the passenger footrest so visually check here for any corrosion etc.

 

Do you have a wiring diagram?

Master Relay is Relay U for controlling of key operated devices.
There are 3 other relays next to the ECU in the trunk on the right hand side.

162, relay for the protection of oxygen sensor system (probably not a problem)
164, relay for the throttle microswitch, (at least pull it and test its functionality)
165, Relay for electrovalve controlling frequency cut off valve (likely not your starting problem).

Good luck.

 

Greg,

I know you don't think it is your alarm system but you may want to read this thread to see if you immobilizer was wired in the same manner.

http://www.ferrarichat.com/forum/technical-q/408265-328-starter-non-function-solved.html

 

But its better to concentrate on areas which are directly relevant to the problem. The OP has stated there is no spark. So none of the above relays are implicated in this. If there were no fuelling, ie fuel pump not running then relay U could be a culprit.

Regarding the alarm, its highly unusual that an alarm would only disconnect the starter. To comply with insurance company requirements it must disconnect the starter and the ignition.

 

When you checked for spark (which was negative) did you check it from one or both of the coils? If you have no voltage at the coils it may be an ignition switch issue. If there is voltage at the coil then it is somewhere down the line (crank sensor, etc).

I am also assuming that your lights are strong and the battery connections are tight as well as the connections at the starter.

EDIT: Have you also checked the connections located in the passenger side foot well?

 

Let us know the findings of the coil leads and check the connections in the passenger foot well.

I know this is highly unlikely given your description but look at the hose coming out of the auxiliary air valve (AAV) under the expansion tank. Is it connected and snug?

 

I'm not sure whether this works the same way on a 328, but my QV had a similar (though not identical) issue. Sometimes it would start right away, sometimes it would start after a bunch of cranking (and need some throttle input), sometimes there was absolutely no sign that it would start (although the starter turned without issue). I swapped the fuel pump relay with another identical relay (windows, I think), and the problem has never come back. I will shortly replace all of the relays for good measure. My theory (not tested) is that there is a loose connection inside the relay. When the car started with help from the throttle maybe the pump was working intermittently, causing a low fuel pressure situation that could be overcome with the throttle.

At any rate, it's a very easy and cheap theory to test.

 

On your model, during starter motor cranking, there are two ways that +12V can be supplied to close the fuel pump relay based on the state of the safety switch. Your report that the engine runs fine once going and that opening the throttle plate seems to help when starting, confirms that the primary path running mode (large airflow plate deflection = safety switch open) is working OK (as is the ...113 fuel pump relay), but casts doubt on the other mode (no airflow plate deflection = safety switch closed) -- this other path goes thru a different relay (start injector blah, blah relay -- it's a ...101). Paul_308 has posted a diagram (well) describing both modes -- if you can't find it, give a shout.

Have you tried: unplug safety switch, turn key "on" (engine not running), listen for fuel pump operation (you should hear it buzzing), turn key to "start" and see if starts better?

 

Greg,

I went back and read your entire previous thread and did not see in any of your posts that you confirmed the fuel pump is running with the safety switch (blue connector) unplugged as Steve mentioned in the above post.

I suggest you take Steve's advice and check this and report back. It takes less than five minutes and may be the source of your problem.

 

I am getting a sense of deja-vu here. Seems to be back at step 1 of the original thread where fuel was suspected. Then it was mentioned there was no spark. Then confirmed on this new thread there is no spark. Now there is a spark so we are back to step 1 of the original thread again, ie check the fuel pump runs with safety switch disconnected. There was no result of this test on the original thread.

 

Any updates Greg?

 

Fingers crossed this is your issue as we know the solution.

 

I had trouble getting mine off the first time I tried as well. I couldn't get my fingers down there very well with the air filter box in the way. I finally took off the box and pulled it loose. You just squeeze the sides a bit and wiggle it off. I think it was just stiff, because now I can get just enough grip even with the box in place to pull it off.

The other one you mentioned sounds like the disconnect for the the cold start injector.

Good luck!