| Author | Message | ||
| Julio Valladares (Jbanzai)
New member Username: Jbanzai Post Number: 30 Registered: 2-2002 |
Thanks Steve, that makes me feel much better. I checked and both #3 valves are bad, one very little and the other I think is completly open. So I have ordered the 3 valves. Regarding the Slow Down light, once I ensmble those valves I will see. As I said the light come up just at the same time than the noise, so I hope they are somehow related. If not I will continue the search. Could happen that the lambda cable got lose at the same time, but is not probable, that connector goes prety tight. I rather think that cable was not conected back in the last maintenance work 3000 miles ago. Thanks to you I learnt a bit more about my car today  Thank you!!! Julio. | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 2083 Registered: 1-2001 |
I'd say a reasonable average exhaust check valve life isn't way more than ~60K miles so if you've had a failure at 68K miles it's roughly normal IMO (and I doubt you had some other problem that caused them to fail). However, I don't see a strong correlation between bad check valves and the "slow-down" light coming on -- I'd be more suspicious of your disconnected lambda sensor and some other injection problem causing an over-rich A/F ratio. | ||
| Julio Valladares (Jbanzai)
New member Username: Jbanzai Post Number: 29 Registered: 2-2002 |
Thanks Steve, I could deffenitly feel air comming from the hose #10. So I am going to remove that T and see which valve is not working, if not both. After your explanation I understand why the valve have melted, probably with hot exhaust air comming in. Would that also explain the Slow Down light? Also if those valves #3 are bad could that mean that something else in the engine is obstructed? The car is a 'high millage', 68000 miles car, so it might be just tired valves. But I never seen one of those fail before, and that concerns me, should I worry or not? Thanks. | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 2082 Registered: 1-2001 |
Julio -- The check valves #3 should not let hot exhaust gases flow back towards #1. If you get exhaust gas coming out hose #22 or hose #6 then the check valve #3 is bad on that side. | ||
| Julio Valladares (Jbanzai)
New member Username: Jbanzai Post Number: 27 Registered: 2-2002 |
Thanks Kurt, I feel better now. Also I found out what really broke in my car, and I do not think has anything to be with gas quality. I got some time this afternoon and I jacked up may car and started looking for the problem. I could not find anything wrong with the exhaust down the car. So I started looking over. Danm, previous owners have done a lot of crap to the car! I thouigh I had a good car, I bought it 2 years ago, I got the car to fix a coupleof things. An after that I have put on it 15000 miles and made a major maintenance work 3000 miles ago, all this without a glitch until this happened. Today when looking at the car I found out that the test probes tubes (the snail tubes) in the front were removed. I did not noticed before because I did not know they where there, but I know this is this way since I bought it. Paying more attention I found that the holes in the exhaust manifold have been gooped with some kind of ceramic s#1t. I also found that the lambda sensor was disconnected in the connector below the air filter. That 2 of the 4 test probes at the back exhaust manifold also had been gooped, and finally that the silencer cover of the front exhaust manifold have been also gooped in the joints with that ceramic s#1t. But I don't know if I have to be happy or not. The good news is that the noise is not from the exhaust, so I won't have to replace all those expensive parts. The bad news are that the noise comes from this piece #1 in the drawing (part #111704), who was litteraly melted, leving the hoses loose.  The good news are that it is cheap to fix, if I only have to replace that part. But the bad news, once again,is that I have no idea why did it melt, so it can happen again. And I know that the noise comes from there because when I approched the hoses to what was left of the valve the noise disappeared. However I do not know if the Slow Down light that started to ligth at the same time, has something to be with the cause of the problem that I still don't know or is just an effect of it. If I sound like a begginer is becuase I am, but I am learning , any help you guys could provide me with will be appreciated. I might post this as a new post, becuase I know now it has nothing to be with the original post. Thanks. | ||
| Kurt Kjelgaard (Kurtk328)
Junior Member Username: Kurtk328 Post Number: 214 Registered: 3-2001 |
Julio, I have a '86 328GTS US in Europe and has been using 95 unleaded for 5 years now without any problems. | ||
| Julio Valladares (Jbanzai)
New member Username: Jbanzai Post Number: 20 Registered: 2-2002 |
Thanks after your question I searched the web for 'Octane measurment' and I found exactlly what you said. It looks like I should be using 98 instead of the 95 here. I found in some other forum that unleaded 98 was equivalent to 93 US octane, and 95 in Europe would be little less than 91 in the US. So I might have been using low octane gas.  That explains why I notice very very little difference, I was using about the same octane gas than in California. Can pining cause the rupture of a header gasket. today my car started to make a noise like if the exhaust was starting to break, but I could not see anything wrong from below of the car, and the nois was stronger when opening the hood. I think that I might burned a gasket in the back bank of cilinders, I can't see it. The thing is that those gaskets were changed only 3000 miles ago. | ||
| DGS (Dgs)
Member Username: Dgs Post Number: 284 Registered: 5-2003 |
I've never heard it called double detonation, but "pinging", "knocking", "detonation" are all the same phenomenon -- an uneven burn which causes excessive stress on the parts. Most modern turbocharged cars have "knock sensors" to detect detonation, allowing the ECU to retard the ignition timing to compensate for lower octane fuel. | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 2074 Registered: 1-2001 |
Europe = RON US = AKI AKI = (RON + MON)/2 I've read that the sensitivity of modern fuels runs about 10ish (sensitivity = RON - MON = 10), so if you make that assumption, you can do the calculations yourself (e.g., AKI = 91 when RON = 96 if the sensitivity is 10). | ||
| Julio Valladares (Jbanzai)
New member Username: Jbanzai Post Number: 19 Registered: 2-2002 |
First of all thanks Erik for the quick response. I do not notice much difference with California so far, maybe a bit more power, very little. In California I used the highest available that it was like in Idaho, 91 octane. Although I lived in California for 3 years I am acctually a Spaniard. And I am a bit short of mechanics terminology in English, I am not familiar with the term 'ping'. If you don't mind me asking again, is 'ping' the same than double detonation? How do I know if I am pinging? Thanks in advance. | ||
| DGS (Dgs)
Member Username: Dgs Post Number: 283 Registered: 5-2003 |
Anyone know the translation from US "octane" to European "octane"? US pumps report "R+M/2", the average of RON and MON, while european pumps report the higher RON. I've heard that european 96 is equivalent to 92 in the US | ||
| Erik R. K. Jonsson (Gamester)
Member Username: Gamester Post Number: 376 Registered: 11-2000 |
Octane relates to the ability to not ping. Too much will not help "not pinging" if you are already "not pinging" The highest available ocatane in Idaho is 91 and my cars don't ping on that. You should be plenty good with the 95 you have available- or you can simply waste extra money. | ||
| Julio Valladares (Jbanzai)
New member Username: Jbanzai Post Number: 18 Registered: 2-2002 |
Hello, I have a 328 GTS USA version, it was my car in the USA for the last 3 years and I brought it back to Europe when I moved back 3 months ago. Originaly the car was intended to use unleaded 93 octane gasoline. Since I am back in Europe I've been using the closest thing to that available here in Spain, that is unleaded 95 octane. However I have doubts if I should not use the unleaded 98 octane gas. I guess the car will perform slighly better with 98 octane, but does anyone here know if doing that would cause any motor problems in the medium/long term? Thanks. |