auzivision

Today the car ran great, tonight it won’t start. I drove it about 70 miles this AM no problem, out for 10 miles a lunch (hard driving), then back another 70 miles this evening. Everything was great. Stop off on my way home for a cold one and the starter hesitated for a split second after sitting 30 minutes. On the way home, the voltage gauge wouldn’t push past 12V, turned off both A/Cs and the stereo, but still even 12 (roughly 2 volts less than normal).

Got home and thought I’d try to charge it a little. It was drawing 7 Amps for 45 minutes. Decided to take in for a quick alternator check and drove it to Pep Boys. They pulled it into the garage and that where it sits now. Cranks great, but won’t fire. This is the third time in three years this has happened (once last summer and once last week when I went to pick it up after an alighnment).


Thought the most probable cause was the fuel pump or LH relay so I replaced them both. Started and ran just fine until tonight. I thought it could be the EZK relay, so I swap that relay with a couple others (breaking it in the process) and still nothing. So I pulled a plug wire and l placed it against the cam cover and could see a spark.

Obviously it’s either not getting fuel or not getting spark (or both). I’d bet money that tomorrow morning it will fire right up. What are common causes of intermittent ignition/fuel problems? I don’t think it’s the relays. The brains aren’t making any peculiar sounds and when it runs it runs flawlessly. It seems to be temperature dependant (hot = no go). It’s all or none, either it fires right away or absolutely nothing… no sputter or spit, but cranks hard.

Would not even fire or spit with a quick spray of carb cleaner (can you believe Pep boys was completely out of ether). I’m guessing both are bad ideas. I was desperate… Tomorrow we are supposed to leave on a weekend trip to Lake Michigan and my car is all locked up at Pep Boys till morning.

Anybody have similar problems? What the most logical way to trouble shoot? My thoughts were see if it start (which it probably will). If not, I’ll bring an ignition checker. If that doesn’t work I’ll probably have it towed to my mechanic (I could almost push it there, it’s closer to him than it is to me).

Intuition makes me think fuel, maybe a faulty pump or regulator or LH or something. Possibly ignition, but what is heat sensitive on that side? Any thoughts, ideas, or words of encouragement would be much appreciated at this time. I also think the car may have an after market auto alarm partially uninstalled.

I’m mainly fishing for ideas that cause an all or none failure.



87 S4 Auto

auzivision

Quick edit...

I could NOT see a spark when cranking with the plug wire sitting on the cam cover.

heinrich

Alarm.

Shark Attack

ahhh, no you're not. I see conflicts all over that statement

macreel

Green wire ? Fuse ?

Wet caps/wires, etc ?

Rotors turn when cranking ??

G'luck.

heinrich

unlock the car with the key!!!

WICruiser

I would guess spark, should be able to check with a tester or timing light. Not sure how it relates to the low voltage but I suspect they are related. I know it is not much but maybe a direction.

Bill Ball

If you see no spark, it could be the crank position sensor. Sits on the top of the bellhousing under the the air filter box. Locate and check its plug into a harness socket which is down there just to the right of it, as I recall, on the back of the block. Careful, those plugs can crumble at this age. When I saw this happen in a bud's 90 S4, we used a series of tiewraps interlocking around the plug and socket to keep it togther.

auzivision

I can’t figure out the quote option, so I’ll do it manually:

Alarm.

I keep thinking Alarm because the PO couldn’t explain why a couple of wires under the hood weren’t connected to anything. He said he thought they were left over from another owner’s alarm system. The two wires dangle to this day right around the manual headlight raise mechanisms. They appear like they could be for a horn/speaker, but they almost appear to be factory wires. Only other clue is a red led light drilled into the lower pod unit that says “Clifford” on it. If I can find the rest, I’ll have it removed.


ahhh, no you're not. I see conflicts all over that statement

Have more than one vehicle, but also have a preference as to which would be the most fun. It’s our anniversary and I’ve already paid for the room… so one way or another I’m going.

Green wire ? What green wire

Fuse ? They either work or need replaced. Never heard of a blown fuse coming back to line

Wet caps/wires, etc ? Everything is dry. Used to have bad wires and the engine ran rough when wet

Rotors turn when cranking ?? Haven’t checked, but will in the AM

Unlock the car with the key!!!
Interesting and worth a try.

Thanks all for suggestions and still open to more...

fraggle

Sounds like crank sensor to me. No spark...

The wires and connector get VERY brittle!!! Mine were going going gone. First the occasional wierd no start (wires were shorting to the block) Enough vibration and things would fire up. Eventually, the wires were worn enough I couldn't get anything fired up.

Bill Ball

87s don't have a green wire.

jassekhon

Mine did the same - it turned out it was the ECU.

John Speake

If the EZK is getting power and there's no spark, then it could be the crank sensor as stated, or possibly the output stages which are near the hood latch, at front of car.

Check you have spark at both distributors....

Most likely cause is crank sensor.

auzivision

Okay, plan is see if it will fire. Drive it and hope it doesn’t do it again this weekend. My wife reminded me that this is the fourth time it has acted up. The first time was in front of my house. I’d call for a wrecker and then got it restarted a few hours latter while waiting. That was a couple years and thousands of miles ago.

If it doesn’t start, check for spark with a tool (i.e. not just looking for arch from a disconnected plug wire). If no spark double check that EZK is getting power. Other then the EZK relay is there anything else to check? I didn’t see any fuses listed for this. Make sure distributor is rotating. Check the crank sensor how? Anything else in this department I should check?

If it does have spark, assume fuel, which is mostly like pump or injector related. Pour some gas in tank just to eliminate that possibility and check and/or jumper the relays to the LH and fuel pump. Regarding fuel pump, how do you troubleshoot. I know it should make a little noise. Is there a simple way to check for pressure? Anything else I should check in this department?

If all else fails call a for a flat bed and transport the car either home or to the mechanic. The old time versus money conundrum again.

John Speake

As it is intermittant, then it is most unlikely to be either EZK or LH failure.

The only fuse needed to get it started is the one for fuelpump/O2 sensor.

Check the flywheel sensor lead and connector under trhe engine airfilter. It should be possible to check for output from the sensor with a digital voltamer, on ac volts measure between p9ins 1 and 2 while someone cranks the motor.

The meter will be calibrated for sine wave volts, and the sensor waveform is more like a square wave, but you should get a reading of more than 5v ac when cranking. The EZK won't respond unless it has sufficient amplitude.

Good luck !