How to resolve some bad gas?

[Martin in Bellevue]

Immediately after filling up at some stop 'n rob I hadn't been to before, it starts pinging & running poorly. Since then, I have pumped out 3/4 of the tank, into garage gas cans & the minivan. I swapped in a new fuel filter just a while ago, after filling up with 92 octane at the usual known gas station. I also replaced the spark plugs, cap & rotor, & reinstalled the original coil & chip. The other ignition coil was a spare from a parted car of last fall. I checked the gap of the crank sensor. The MAF worked on Jeff's car since the pinging started.

I did, immediately after the pinging started, look up Winfred's posts regarding sucking a few ounces of water though the intake. I sucked a few ounces though the intake at above 3,000 rpm. A plume of smoke was created & kinda lingers.

Have I missed anything in resolving this?

Could I have jumped timing on the m30? Does that happen? It will rev up pull to redline, just not happy about off idle through midrange.

[MBXB]

Throw in a can of gas line anitfreeze (Heet). It's just alcohol, mixes with water and burns off. Voila.. Water is gone from your tank.

[Bill R.]

settings on the maf have altered? If you richen it up a notch does it help?
Or could the gas have contaminated your o2 sensor giving you a false reading now... You've looked at all the usual suspects, vacum leak between the maf and the throttle body...or any other manifold vacum leaks...







Immediately after filling up at some stop 'n rob I hadn't been to before, it starts pinging & running poorly. Since then, I have pumped out 3/4 of the tank, into garage gas cans & the minivan. I swapped in a new fuel filter just a while ago, after filling up with 92 octane at the usual known gas station. I also replaced the spark plugs, cap & rotor, & reinstalled the original coil & chip. The other ignition coil was a spare from a parted car of last fall. I checked the gap of the crank sensor. The MAF worked on Jeff's car since the pinging started.

I did, immediately after the pinging started, look up Winfred's posts regarding sucking a few ounces of water though the intake. I sucked a few ounces though the intake at above 3,000 rpm. A plume of smoke was created & kinda lingers.

Have I missed anything in resolving this?

Could I have jumped timing on the m30? Does that happen? It will rev up pull to redline, just not happy about off idle through midrange.

[Martin in Bellevue]

I've checked for vacuum leaks. The MAF ran well on Jeff's car the other day, since the problem started with my car, seeming to not be the cause of problems.

I was stunned at how immediate the problem occurred with the bad gas.

Thanks for the ideas, Bill.


settings on the maf have altered? If you richen it up a notch does it help?
Or could the gas have contaminated your o2 sensor giving you a false reading now... You've looked at all the usual suspects, vacum leak between the maf and the throttle body...or any other manifold vacum leaks...

[mike wong]

I like Techron - in the bottle. Techroline from the gas pump is diluted.
also heard Redline has a similar product.

[thunderman]

I take beano for bad gas

[Bill R.]

MM head right? :p



settings on the maf have altered? If you richen it up a notch does it help?
Or could the gas have contaminated your o2 sensor giving you a false reading now... You've looked at all the usual suspects, vacum leak between the maf and the throttle body...or any other manifold vacum leaks...

[Martin in Bellevue]

So, just as a refresher, how does the m30 run when say, the headgasket fails between a pair of cylinders?

Yeah, I went ahead & put a call in to bma for a gasket, bolts & such. I've been thinking about a "preventative" head gasket job for a while.

The plugs don't read this too likely. I don't think this is necessarily the issue.

[George M]

Martin...I have some bad news. When you and Jeff were doing all the baton passing with your car parts, Jeff dropped the MAF during the hand off. I have no choice but to bench him for the summer games.
George...aka Hanky Sr.

[George M]

oh...and be sure to listen to Thunderman's advice about "bad gas".

[Bill R.]

they typically run poorly on start up for the first 20 seconds or so... I suspect its coolant under pressure migrating into the combustion chamber when the engine is off but the cooling system is still under pressure..
I've seen some that ran fine with a blown headgasket but they would build up pressure in the cooling system for the combustion gases and it would overpressurize the cooling system,then open the relief valve in the radiator cap and dump coolant, as the pressure builds the coolant would keep getting pushed out until the car starts to overheat from lack of coolant... Like you mentioned though the spark plugs will usually indicate if one or more cylinder is leaking... And if its blown between cylinders you can always do a compression test..





So, just as a refresher, how does the m30 run when say, the headgasket fails between a pair of cylinders?

Yeah, I went ahead & put a call in to bma for a gasket, bolts & such. I've been thinking about a "preventative" head gasket job for a while.

The plugs don't read this too likely. I don't think this is necessarily the issue.

[Hector]

blew the first time. The car would feel it was about to fall apart after start up but then when it got warmed up it would run better. I couldn't do more than 80 mi/hr in this condition. Unfortunately, I realized I couldn't go beyond 80 before I was told the HG bit the big one.

After the car had be driven and parked over night, I could hear the hissing sound of pressure being released after opening the rad cap.


they typically run poorly on start up for the first 20 seconds or so... I suspect its coolant under pressure migrating into the combustion chamber when the engine is off but the cooling system is still under pressure..
I've seen some that ran fine with a blown headgasket but they would build up pressure in the cooling system for the combustion gases and it would overpressurize the cooling system,then open the relief valve in the radiator cap and dump coolant, as the pressure builds the coolant would keep getting pushed out until the car starts to overheat from lack of coolant... Like you mentioned though the spark plugs will usually indicate if one or more cylinder is leaking... And if its blown between cylinders you can always do a compression test..

[George M]

Martinator,
Further to what Bill wrote, if you are experiencing cold starting difficulties which is many times symptomatic of a failing gasket...here is a tip off your head gasket is on its last legs. If not leaky injectors...the following is a test you can perform to get a baseline without a lot of effort. After the engine has been running at normal operating temp, shut the engine down and then immediately open the coolant cap to let the pressure vent. (careful) Leave the cap open and let the car stand overnight. The next morning, tighten the coolant cap and start the car. If the car now starts w/ ease (i.e., normally) then it is very likely that your cold start problem is a result of the head gasket beginning to fail. How this test works is...with pressure in the coolant system, as an engine w/ a failing head gasket begins to cool and mating head and block surfaces start to contract and due to an insufficient seal a small amount of coolant will bleed into the cylinders. Then with a bit of coolant in the cylinders, the car will be difficult to start after it has been sitting for several hours. But if you release the pressure within the coolant system after you shut off the engine, coolant will not bleed into the cylinders as readily.
HTH,
George

[Martin in Bellevue]

It doesn't exhibit any starting problems. It just gets very rough. In fact, I think it starts very easily, supporting the loss of compression between a couple cylinders.

The compression test will tell more.



Martinator,
Further to what Bill wrote, if you are experiencing cold starting difficulties which is many times symptomatic of a failing gasket...here is a tip off your head gasket is on its last legs. If not leaky injectors...the following is a test you can perform to get a baseline without a lot of effort. After the engine has been running at normal operating temp, shut the engine down and then immediately open the coolant cap to let the pressure vent. (careful) Leave the cap open and let the car stand overnight. The next morning, tighten the coolant cap and start the car. If the car now starts w/ ease (i.e., normally) then it is very likely that your cold start problem is a result of the head gasket beginning to fail. How this test works is...with pressure in the coolant system, as an engine w/ a failing head gasket begins to cool and mating head and block surfaces start to contract and due to an insufficient seal a small amount of coolant will bleed into the cylinders. Then with a bit of coolant in the cylinders, the car will be difficult to start after it has been sitting for several hours. But if you release the pressure within the coolant system after you shut off the engine, coolant will not bleed into the cylinders as readily.
HTH,
George

[George M]

you can do a compression test...but if you aren't losing any coolant etc...I would go through all the engine management sensors if you can't isolate a particular cylinder by looking at the spark plugs. Could be a bad injector also.
George

[Jeff N.]

ooooooooo. thud thud thud!

[Bill R.]

ooooooooo. thud thud thud!

[Martin in Bellevue]

And maybe the second set of eyes for diagnosis. Maybe there is something glaring that I'm not seeing.


ooooooooo. thud thud thud!

[Jeff N.]

I gots dem der compression gauge at my house. Trade ya for an O2 sensor pigtail from the parts car.

[Jeff N.]

Gonna get this thing sorted out sooner or later.

The plan now is basically:

- stuff in a new O2 sensor,
- finishing wiring in the cabin a/f gauge (almost done, PITA)
- watch the mixture for rich/lean issues in the troublespot
- if that looks bad, work with Mark D on a tweeked chip (since I can't mess with Martin's maf!!)
- if that looks OK, do a mechanical verification of the upper/lower timing relationship via degreeing in the cam
- if that looks OK, work with Mark D on a tweeked chip with more off-cam ignition advance.

[Martin in Bellevue]

Jeffro found the problem with my car! Injectors for #4 & #6 were not fully plugged in. The new spark plugs, when pulled showed #4 to be very dry, compared to the others.

A compression test on the cold motor resulted in a range from 192 to 205 psi, dry. Good times, I am happy. The car runs like a friggin' scalded cat, again. Each of you should drive it sometime.

Martin






I gots dem der compression gauge at my house. Trade ya for an O2 sensor pigtail from the parts car.

[Bill R.]

Jeffro found the problem with my car! Injectors for #4 & #6 were not fully plugged in. The new spark plugs, when pulled showed #4 to be very dry, compared to the others.

A compression test on the cold motor resulted in a range from 192 to 205 psi, dry. Good times, I am happy. The car runs like a friggin' scalded cat, again. Each of you should drive it sometime.

Martin

[Jeff N.]

yeeeeass...now that is a fine question, no?

[Martin in Bellevue]

went in. I guess they got re-plugged in with the intake manifold swaps a while back. They haven't been touched in the last few months for sure, unless as somebody's wife was proposing last night...

[Bill R.]

went in. I guess they got re-plugged in with the intake manifold swaps a while back. They haven't been touched in the last few months for sure, unless as somebody's wife was proposing last night...

[winfred]

Bwahahahah