Engine randomly missing after engine bay washed (SOLVED!!!!!!)

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micbrody
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Engine randomly missing after engine bay washed (SOLVED!!!!!!)

Post by micbrody »

So: I hope that tincture of time (evaporation) will help:

I ran car today for at least 45 minutes without problems in the morning.

After it was cool, I decided to clean the engine compartment. I put plastic bags over the alternator and the distributor cap.
I sprayed this engine degreaser stuff by hand all over engine. Let it sit for 10 minutes; then rinse off after 15 minutes. I let car sit for another 30 minutes. In the meantime, I also cleaned the fresh air intake with some light sprays of soapy water; let it dry.

After 30 minutes car started immediately. I let it idle for another 15-20 minutes. Engine bay looked bone dry. And while parked reved up to 3000-4000 without any issues. I went to take it for a ride. About half way down the block, under acceleration and load, the engine started to miss or and rev down under throttle. I was able to go around the block back to garage.

I inspected everything that I thought. The spark plugs looked dry; I pulled distributor cap to see if water sneaked in; nope.
I unmounted coil to see if any water seeped onto ignition control module.

I checked air filter to see if it was saturated with water....nope.

I repeated the same around the block ride; same issue....

Again, hopefully everything will be normal tomorrow......but just really curious where the water is; or what I screwed up?
Last edited by micbrody on Fri Mar 03, 2017 1:29 pm, edited 1 time in total.
AriK
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Re: Engine randomly missing after engine bay washed

Post by AriK »

Yup it will be all normal tomorrow.
But in the meantime if it's bothering you disconnect the high tension leads to the spark plugs and coil terminal and let them air dry overnight and/or spray them with water dispensing WD40. The spark plug wells probably filled up with water and while the drying process was happening some moisture worked its way up spark plug cable(s). As a bonus take a cue tip and spread dielectric grease into the tip of all the cables (not on the terminals).
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

After searching internet, I think Arik explanation seems quite plausible.

The only thing that I can't understand is why it happens when car moving under load; but not when I rev it in driveway.
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

It's been a few days; I let wires dry; sprayed with wd40; dried with q-tips.

Car starts fine. But I still have problem. Car starts fine. Engine accelerates fine when sitting still.
When I go for a drive, it is intermittent; but usually from start from 1st gear and 2nd gear, the engine bogs down. I have to press clutch to disengage; and hit gas for it to not conk out.
It doesn't seem to happen when shifting from 2-3, or 3-4. So: it seems to be associated when engine under high torque load.
AriK
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Re: Engine randomly missing after engine bay washed

Post by AriK »

You still have moisture in the sockets of those fun electrical components that communicate with the ECU. You'll need the disconnect them and let them air dry overnight. You're almost there.
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

I checked all sockets....they look dry.....though I guess there could be water hidden. But why would it happen only when engine under load? Never when reving engine standing still?

I think my oxygen sensor might be bad (I have not checked; but it was heated and cooled repeatedly when trying to disconnect frozen downpipe bolt. Car ran find, though, after reassembled but before washed. Also, would a faulty oxygen sensor cause that much problem?
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

I checked oxygen sensor with voltmeter; the voltages seem to hover around 0.45, which is appropriate.

The problem is still happening; though I perceive it as less often. So probably still related to residual water...... but after 4 days? And most important: why only when engine under high torque load.... from standstill through 2nd gear.

Again, all after cleaning engine (cold engine). And never does it when in neutral.

If something electrical was still wet (arcing of spark?), why would it act up only when engine has a load on it.
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

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micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

another thought:

I think this happened for a week or two last year; but only in the first few clutch shifts in morning. I actually posted the question on the board.
http://www.fiatspider.com/f15/viewtopic.php?f=5&t=31289

I theorized that maybe morning condensation on clutch plate caused it to be slippery. TX82FIAT suggested that maybe it could be oil.

Well I just cleaned the OIL off my engine with WATER.......... maybe it traveled to clutch plate; and its causing friction issues??? Anyone else has this problem?
AriK
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Re: Engine randomly missing after engine bay washed

Post by AriK »

If oil was on your clutch plate then you would be feeling a shudder off 1st gear. What you're experiencing is not a shudder. It also does not indicate wet ignition cables.
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

Not really sure what I would call it, but it is pulsatile when high torque situation. It does usually occur off of 1st gear from a stop; seems to happen when rpms between 2500-3200 when shifting; but not always; and not always reproducible
Any other ideas?
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

Another theory: maybe AFM has a resistive board issue. Specifically:
Under no load and movement, the I don't notice any pulsation; however under load and movement, the vibration is causing sweep arm to intermittently make contact and/or coupled with under load oxygen sensor adjustments to fuel mixture...........

I previously had rehabbed the AFM myself (cleaned resistive surface; moved sweep arm to different part of resistive arc; I do have an extra AFM , though not sure if it works ......but easy switch.

Still would not explain why this happened after engine wash. I did open up cover and did not see any moisture.....but maybe there was; and some oxidation occurred

Anyone following I apologize for my stream of consciousness on this problem! Just trying to understand cause; and execute cure!
AriK
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Re: Engine randomly missing after engine bay washed

Post by AriK »

Nothing to apologize about. Someone will chime in. I'm a carbie kind of guy, so my experience with Bosch L-Jetronic is nil. Nevertheless there's a high volume of views relative to the time of posting so others along with myself are closely following. Keep us posted.
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Re: Engine randomly missing after engine bay washed

Post by rridge »

Rough running after an engine compartment bath is usually the result of an ignition issue. Rough running under load is often a sign that one of the cylinders has a weak spark. I'd look closely at the condition of the ignition wires and their terminals. Wait til evening, idle the engine with hood open and no nearby light source. Look for signs of arcing along the wires, in the spark plug wells and around the distributor cap.
micbrody
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Re: Engine randomly missing after engine bay washed

Post by micbrody »

Rridge,

Thanks for advice. I will check into that.
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