random missing but clears up
#1
random missing but clears up
Got kind of a strange problem. Car started out of the blue missing one day for a few seconds but cleared up and was fine all the way home. I even romped on it a few times to make sure. I have been able to make it happen only 2 other times. 1st and 2nd times were with full take of fuel. 2nd time big loss of power and spitting and spudering for about 10 seconds on and off the gas to see if it changed, NO CHANGE in power or missing then it cleared up and ran like a bat out hell all the way home again. I wanted to check the codes with my code reader when I got home so I hooked it up and it would not communicate with pcm. This car is a 97 but has 95 PCM and knock sensor with mad tuner tune. I am almost positive I have hooked this code reader up to this combo before and it communicated just fine but I'm no 100% sure. Since I could not scan it I decided to do a data log with Data master and threw a fuel pressure gauge on it. Mind you this car has run great for two years since the tune. I have had zero problems with this PCM and tune. Data master communicated just fine and I did the log and was able to feel the car miss again for about 5 seconds but like before it cleared up and ran fine the rest of the way home and the fuel pressure staed constant except for when engine vac changed like normal. The log shows NO DTC except 1 for MALF 66: A/C Press Sensor Open/Short. I dont have A/C on the car right now so that should explain that. I looked at the log but to be honest I have no real idea of what I am looking at. I see all the values and understand half of them but the rest are a foreign language. Can someone look at it and tell me what you think. I know when the misfires happened in the log since it is 12 min long so I can point you to the right spot and it only happened for a few seconds and then I jumped on it and it cleared up and never came back.
#5
TECH Fanatic
iTrader: (4)
You said 2x it was after filling up the tank. Sounds like you may have gotten fuel into the evap/ charcoal cannister lines and disrupted the purge flow. Some cars have a pair of valves there by the tank filler neck (2-way valve, purge valve for getting air out of the fuel lines when you fill up). Sometimes topping off as much as you can put in the tank upsets those, and on the Hondas I've worked on, it can ruin the shed valve from 'topping off' the tank, over time.
As soon as the fuel is purged off and returned to the tank via the return line your brief symptoms pass, as you've described. My .02.
Hope your daughter is doing well, BTW.
As soon as the fuel is purged off and returned to the tank via the return line your brief symptoms pass, as you've described. My .02.
Hope your daughter is doing well, BTW.
#6
See the canister and Evap system is something I dont understand exactly how it the plumbing works but I know people have said that if the cap vent as you open it the canister may be bad and mine has done that for a while but since it never affected anything I just never worried about it.
Now I figure if there was a problem with the opti it would have shown up in the data log and I'm not sure what to look for other then a DTC. The canister duty cycle did go to like 40 when the miss fires happend but with out having someone who knows what to look at on this data log it is kind of usless to me unless there is a smoking gun. If someone could take a look at it maybe point out some oddities for me and I can work and learn from there.
Now I figure if there was a problem with the opti it would have shown up in the data log and I'm not sure what to look for other then a DTC. The canister duty cycle did go to like 40 when the miss fires happend but with out having someone who knows what to look at on this data log it is kind of usless to me unless there is a smoking gun. If someone could take a look at it maybe point out some oddities for me and I can work and learn from there.