Rotten Eggs

[mechanist]

I read a thread on BITOG about fuel and octane a while back; maybe 5 years ago. Basically it was about never running higher than 87 octane unless you need retarded detonation or it can lead to engine damage/failure. It was a few years ago - probably irrelevant to your smell.

 

[mct75]

Higher octane fuel contains less energy, all other things equal.

 

[Funner]

I suppose what has me standing off about the "fuel source" is that the station is by far newer than any of the options in a 5 mile radius and I have two other vehicles that run the same gas from the same pumps in the same octane and they have shown no signs of problems.

Would it hurt to go elsewhere, no, and for the sake of a baseline I will do so.

It's not the gas.

 

[LINUS]

It's not the gas.

It is a variable.

Likely variable, no. But stranger crap has happened. I've watched molten sulfur drip uphill, and chase its' way through pipe threads at a fitting. Nobody said that was going to happen.

 

[Funner]

It is a variable.

Likely variable, no. But stranger crap has happened. I've watched molten sulfur drip uphill, and chase its' way through pipe threads at a fitting. Nobody said that was going to happen.

It's that he has had this issue using a different station previously as well as using this brand spanking new station with numerous vehicles and none of them have this problem.
With the CEL lit up and this being intermittent I suspect electrical problems somewhere that are resulting in fuel/air mismanagement. He needs to resolve the CEL as a starting point. That's what I would do.
I wonder if there are any new codes being thrown since this issue first arose, light wouldn't change there would just be more trouble codes making it illuminate.

 

[LINUS]

^^^Absolutely agree. Chit is tossing a code, prob resides somewhere in that world quite probably. But he seems to think he's tossed enough parts that way.

All we can do is nod & shrug if he's not interested in following that path to fruition & suggest other variables that can be common sources. His 80, not mine - Dan knows I flat re-did my EGR crap with his parts as I refuse to let a CEL light beat me.

Simply doing that means he could rule it out, but it's his 80 - right?

 

[jasheehan]

Higher octane fuel contains less energy, all other things equal.

wha?

Higher octane is strictly an anti-knock property of the fuel. Higher octane fuels withstand higher compression levels before auto-ignition. All fuels have the same (ok, generally) amount of stored chemical energy in their bonds (same C-C single bonds).

 

[amonostereo]

The first place my mind went to with all this was electrical. I had similar symptoms when a ignition coil was going bad really slowly (granted, it was a Jeep). It did pretty much the same sporadic and erratic idle, and sudden loss of power at speed for a couple weeks before just completely giving up. As for the sulfur smell... unburned gas seems to fit with everyone else's theories?
If I remember right, it wasn't even throwing any codes because it was still passing enough voltage. It was a pain to diagnose because the spark tester we were using was still showing spark.
I'd take the coil off and see if the resistance is in spec. Primary: 0.36 - 0.55 Ohms cold, 0.45 - 0.65 Ohms hot; Secondary: 9.0 - 15.4 kOhms cold, 11.4 - 18.1 kOhms hot.

Just my 2 cents.

 

[LINUS]

wha?

Higher octane is strictly an anti-knock property of the fuel. Higher octane fuels withstand higher compression levels before auto-ignition. All fuels have the same (ok, generally) amount of stored chemical energy in their bonds (same C-C single bonds).

It's a whole can 'o worms.

Technically speaking, yes - it's true what he said. If you want to go further you can say E85 is a superior fuel in this vacuum where his statement is true.

It takes more energy to ignite higher octane rated fuel than lower octane, but once lit you get a controlled burn. So yes - lower octane, more fuel efficient in said vacuum. Your bearings & rings don't like it, but that's not the facet where that statement came from.

Saying more is tangential to the strict energy statement made, so I'm stopping there.

 

[Traakon]

OK, first off, this symptom is not throwing any additional codes. The only CEL I have is the one for the EGR and it has had that for over two years. Since it ran just fine with the code before I am not relating the current issues with the EGR one. Besides, when I began tracking the EGR issue when I first bought the 'Cruiser half of the advice I got here was to ignore it because a '93 will run just fine...and it did. If you can demonstrate the link between the EGR code and these current symptoms I am all ears.

amonostereo - I replaced the coil last year with the first round of these issues.

I went to install the ECU water temp sensor I had ordered in the past and when I got the old one out it did not match the new one. (While they both took a 19mm the existing one has a larger dia. threaded section than the one I bought). So it appears that the one I got from Tom and Larry, PN 89422-35010, is one meant for somewhere else. Going to do some looking for the correct PN myself this time.

I have been considering from the start that there is a non visual issue in the engine harness which might be linking both the old EGR problem with the new symptoms.

 

[LINUS]

If I'm remembering correctly - and OBD2 is pretty common- you have 2 temp senders. 1 for the ECU to see, one for the cluster that the ECU can see.

Part of why there's a code for the ECU temp out of range, and a code for ECU seeing conflicting values & going default mode.

If you are getting that code in Toyota world (I know the senders doing OBD1 swaps on BMW's) - then easily you could be in a 'limp-home' fuel-rich/choke run mode that could easily be the cause of a fuel mixture manifesting as this.

 

[Traakon]

If I'm remembering correctly - and OBD2 is pretty common- you have 2 temp senders. 1 for the ECU to see, one for the cluster that the ECU can see.

Part of why there's a code for the ECU temp out of range, and a code for ECU seeing conflicting values & going default mode.

If you are getting that code in Toyota world (I know the senders doing OBD1 swaps on BMW's) - then easily you could be in a 'limp-home' fuel-rich/choke run mode that could easily be the cause of a fuel mixture manifesting as this.

Oh if this were only an OBD II system. I would have so much more information to sort things out. But alas I have a silly blinking light to count.

There is suppose to be one that drives the temp gauge in the dash and one that communicates with the ECU. The one that is "suppose" to be for the ECU is the 2 wire one high/right above the oil filter. That's the one I thought Tom and Larry ordered but as indicated, when I got it out, the existing one did not match the new one. Still trying to see where that PN snafu occurred but so far everything leads me back to the PN of the one I bought.

 

[LINUS]

The 2 temp senders thing applies to the BMW - I only know the 95-97 1FZ to speak on but yeah this is deeply suspect as your core issue.

I hope those parts you changed needed it anyhow. That was a long list.

But yes, I'd pursue this further.

 

[Marine7]

It sounds like your on the right path with the temp sensor snafu..... good luck. I'll be curious as to the final outcome.

 

[BILT4ME]

I'll beat on the fuel ONE more time.....

You're going to NEW stations, using the SAME BRAND (Chevron)

What I'm referring to is a MIX, not "bad fuel" or "contaminated" fuel. It is a given mix used in some areas and maybe the CORPORATE of Chevron specified this MIX in your area.

I know the area I'm in (Kansas City) has a completely different fuel mix in the winter VS summer, based on local regulations for pollution.

Also, depending on WHERE the oil was pulled and processed, it MAY have a higher sulfur content, and the process of combustion in YOUR truck happens to smell very pretty!

OK, I'll stop now.....

Really.....

I promise.....

 

[Traakon]

It sounds like your on the right path with the temp sensor snafu..... good luck. I'll be curious as to the final outcome.

Well, turns out the part number was correct. The "snafu" was all me

In looking at the FSM picture and then what I could see under the intake I removed the wrong sensor the first time. I could not see the correct sensor because it was slightly below and right of the one larger one I pulled. So for those keeping score at home...PN 89422-35010 is correct for the ECM temp sensor and that makes the score Tom and Larry 1 and Me goose-egg.

I will get her out for a long run (hopefully) tomorrow and see what has changed if anything.

 

[Traakon]

OK, a interim update -

Have right at 200 miles and a tank of fuel (No, I did not change locations or grade) run since replacing the ECM temp sensor. "OSO" has run very well with no re-occurrence of the Rotten Eggs or the stutter/stall. But I have been here before.

What I do have is an exhaust leak I have to trace in the new front to back exhaust system. Kind-a thinking what ever set this recent whole thing off popped a flange gasket or one of the joint welds in the exhaust. Going to start crawling around and under/over it tomorrow.