test and tune with propain

[Bill_Ritter]

I went to the track for some test and tune last saturday. when i began tuning the propain in, and increasing the boost, i lost a cylinder. the rear passenger side cylinder wall was completely washed down and had absolutely 0psi of compression when i tested it. so i squirted a little oil in there and fired it back up and everything was fine. My car has been set up exactly the same for the past 5 or 6 months, i havent changed the fuel pressure or anything. is it possible that the propane is what washed the wall down??? i cant see how it could do it since it is in a gas form when injected, and not a liquid. I dunno, mabey i was using too much propane or something, but i dont think so. I used the 86 jet at 50% duty cycle, and 39psi (static) fuel pressure. Have any of you guys had any problems similar to this?

 

[Two Lane]

One theoretical might be that the rings contracted from a hyper-cold blast, temporarily giving no seal.

Bizarre & intriguing!

 

[Bill_Ritter]

hmmm... i never thought of that. But the car sat for a good hour or so after the last use of propane before i finally got around to doing the compression test.

 

[Turbo__Tim]

Hmmm, something is not right here Bill. People have pu tempreature sensors and found no change in the input charge temperature. Propane is only 10 percent of the fuel, or mixture so I don't see how it could have that much of an impact.

After posting this somewhat alarming information, you now need to do some further testing to see what the problem really is.

Something is not right here, and it will be up to you to find what the problem really is.

I'm not convinced the propane could have had anything to do with what hapened. Tho I don't know what else you can do at this point.

Sorry to hear of your problems, and I hope somebody can come up with some suggestions.

 

[Bill_Ritter]

I dont think it was the propane, but it was the only changed factor. I was just wondering if it was a possibility. i cut back my fuel pressure and it seems to be just fine now with the propane. Im hoping it was just some kind of fluke, but im going to keep a close eye on it as i drive it this week (daily driver) with my turbolink.

If anyone who is considering propane is reading this, i dont mean to scare you or anything. By all means this is a GREAT system to use, I just need to take some more time to tune it in slowly. Like i said above, i dont think my problem was the result of using propane, i was just wondering if it were a possibility.

 

[EclipseTurbo]

you need to consider what is in your cylinder as a mixture.

Normal you have air and gasoline

now

you have air gasoline and propane.

the 2nd mixture is harder to ignite, because it is so rich.

If it doesn't ignite the fuel just stay there and wash the cylinder.

When I first used propane I had to dial the gasoline back because it would drown the ignition and sputter. This is either caused by me engaging the system at too low boost, or injecting too high pressure of propane. Very easy to happen on my tiny 2.0L engine.

Although I do not think your incident had to do with the propane, I do not think it is rich enough to wash the cylinder down to 0 compression. Did you do a 2nd compression test?

 

[JayC]

Washing it down to 0 PSI would be quite a feat. I've seen pistons with the skirts busted all to hell that had some compression. It doesn't sound like you were injecting enough propane to cause an over rich condition like that judging by the numbers you posted. Very odd, indeed but I seriously doubt it was propane related.

 

[WSLN 6]

It's a long shot, but maybe the injector harness was pinched near the injector causing it to go wide open.
It's an easy way to find a driver side header leak.......(don't ask me how I know )

 

[Bill_Ritter]

Originally posted by EclipseTurbo
Although I do not think your incident had to do with the propane, I do not think it is rich enough to wash the cylinder down to 0 compression. Did you do a 2nd compression test?

Yes, i tested compression in every cylinder twice, and on the one with no compression 5 times. I couldnt believe it myself either but there was seriously 0psi compression there. after i squirted oil in it there was 130psi of compression (which matched all of the other cylinders) and there still is after 3 days of driving.

I have cut my fuel pressure back some more today (now down to 36psi) and the 02's still look good, so i guess i was running a little rich. It kinda puzzles me though because at 39psi my 02's were in the 820-840 range, and at 36psi there are still around 810-820.
What is the lowest you guys would recommend running your fuel pressure? Im kinda worried about going too low.

Thanks guys

 

[EclipseTurbo]

Probably don't want to lower the fuel pressure than 36 PSI.

The pressure helps the fuel atomization. Too low and you can run into problems. This applies to all FI cars.

 

[bruce]

Originally posted by GNnut
the rear passenger side cylinder wall was completely washed down

and had absolutely 0psi of compression when i tested it.

What leads you to believe the cylinder was WASHED down?.
Washing a cylinder down galls the ring(s) to the piston, it's permanent and final.

Guage may have been fubar'd on the first attempt.

How many miles did you drive in 5-6 months?.
Did you first baseline the car without the propane after the 5-6 months?. If not then you didn't have a ground 0 to start with.

When you add something.
the first past afterward should be a sanity check to as close as possible to the last KNOWN.

For any testing to be accurate, it has to be planned.

 

[TurboBob]

What brand of fuel were you running?


Octane?

When did you purchase it?

Bob

I have to find the details but there were some stuck-valve issues with some ohio area premium fuel last year. Excessive detergent built up on the intake valve stem making them stick open.

 

[Bill_Ritter]

Re: Re: test and tune with propain

Originally posted by bruce
What leads you to believe the cylinder was WASHED down?.
Washing a cylinder down galls the ring(s) to the piston, it's permanent and final.

Its just my hypothesis based on my previous experiences racing dirtbikes and motorcycles.

Originally posted by bruce
How many miles did you drive in 5-6 months?.
Did you first baseline the car without the propane after the 5-6 months?. If not then you didn't have a ground 0 to start with.

The car is driven daily, so approximately 8-9K miles. Yes i baselined the car. i ran a 13.53 (1.8 60' time) w/o propane or slicks on 94 octane gas alone.

I took the car back to the track again Saturday, with better results this time. I ran 110psi regulated, with 160psi bottle pressure.
My best pass was with the smallest jet, 50% duty cycle, 33psi fuel pressure (static), and 17psi of boost. I had 1.5 degrees of KR during the 2-3 shift. I ran a 13.4. I tried to add more fuel pressure but my 02's went into the upper 870's, so i figured that was too rich already.