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Discussion Starter #1 (Edited)
Yep, as always it was something small and inexpensive that cost me $$$$$

The car blew the side out of a piston after leaning out on the dyno months ago. Together with my mechanic at the time we felt it was more than likely something in the fuel system, ie. injectors or fuel pumps. After having the engine rebuilt and dropping in new 1000cc injectors I proceeded to drive it always under 5000 rpm during the break in period.

Once I had enough miles on it I decided to take it in to have it tuned. This time I had someone else tune the car for me since my builder has been very busy and told me he would be unable to do so. While tuning the car with the wideband we noticed it was leaning out around the same spot it did before on the dyno. Right at around 6100+rpm it would lean out pretty bad. Since I had just dropped the dough for new injectors and felt pretty confident they were not the issue I immediately went to the fuel pumps. We tested both pumps and everything was great. So what the hell could it be? No leaks..good pumps....good injectors....good fuel pressure... :dunno: Turns out this hole thing was due to a faulty VPC Sensor that I had bought a few months ago when I went single. I purchased the VPC from someone I kind of knew so I am confident that it worked fine when removed. Since I never got on my car prior to the night before it blew I had no indications that there was a leaning issue ( and I did not have a Wideband) again everything was fine up until just past the 6000rpm mark. I am confident that the person that sold it to me had no idea that there was a problem.

The reason for this post is to serve as a public service announcement that when you buy used electronics there can be issues that are not noticable. You can't check for oil leaks or compression on these parts. My advice to everyone is that if it can cause big damage when it fails....buy it new!!! I also want to state how important I think a wideband is. If I had one in my car, I would have seen it leaning out the night before when I was playing on the road with a buddy.

Again, I just thought I would share my experience in hopes that it may save someone else some $$ and headaches in the future. :bigthumb:
 

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Glad you have figured out the problem before another problem occurred.

A wideband is one of the most important guages you could have, hopefully you have one in plain view now to prevent running lean.
 

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Hardtopper
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Thats good that you found the problem... sometimes you just learn the hard way.. now you will be more cautious.. and reading all of this makes me want to be extra cautious with my project aswell seeing as I have a used VPC also.. anything could happen. Good to see you found out your problem from before, before it cost you more money.

ps. dallas; my fenders recovered from cancer !!!!!!!!! :bigthumb:
 

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Discussion Starter #4
kirkMKIV said:
Thats good that you found the problem... sometimes you just learn the hard way.. now you will be more cautious.. and reading all of this makes me want to be extra cautious with my project aswell seeing as I have a used VPC also.. anything could happen. Good to see you found out your problem from before, before it cost you more money.

ps. dallas; my fenders recovered from cancer !!!!!!!!! :bigthumb:
That is why I wanted to post. I hope that it might help others.

Glad to here about the fenders!

And yes the wideband is very important!
 

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Well I guess you should replace alot of parts then. Like that cylinder head?



Also just thought of something. Its very possible that the sensor got full of oil from when the motor blew the first time ?
 

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EchoDeDupra
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as I was going through the post... I had this eerie feeling that you blew your motor again.... hehe... glad that that didn;t happen...

thanks for the heads up :bigthumb:
 

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Discussion Starter #7 (Edited)
Horacio Ramos said:
Well I guess you should replace alot of parts then. Like that cylinder head?



Also just thought of something. Its very possible that the sensor got full of oil from when the motor blew the first time ?
Yep. I am actually in the process right now of doing that, but the stock one is fine for right now; however, I am talking about electronics where you have know way of knowing when they go bad (like a VPC chip that I sold someone that turned out to be bad, but was fine while in my car).

Always possible on the sensor, but that would be a great coicidence leaning out only at the same rpm point.
 

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seeya said:
Yep. I am actually in the process right now of doing that, but the stock one is fine for right now; however, I am talking about electronics where you have know way of knowing when they go bad (like a VPC chip that I sold someone that turned out to be bad, but was fine while in my car).

Always possible on the sensor, but that would be a great coicidence leaning out only at the same rpm point.

Well did you replace the sensor? And verify the failure. How much power did it put down and what were the final A/F readings.
 

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Discussion Starter #9 (Edited)
Yes, and yes. Didn't dyno I tuned on the street. 11 through 11:2.

(Any luck on those #ers and receipts?)
 

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seeya said:
Yes, and yes. Didn't dyno I tuned on the street. 11 through 11:2.

(Any luck on those #ers and receipts?)

Tuned on the street . You might want to data log that to make sure there isn't any lean spots. As far as the numbers I have those. I don't know what receipts you talking about you have all those.

Wait a minute. You dyno'd the car there was issues above 6100 rpm's. You replaced the suspect part. Then tuned it on the road. Thats risky. :rolleyes:
 

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Discussion Starter #11
It seems this tread is going in a different direction than in was intented. I posted to simply tell people why my engine blew (alot of people have been curious and concerned) and to say that it is good to be cautious when buying used electronics because you can't always look at them or plug them in and tell they are bad.

This tread was not an open window for people to pick my car and my decisions apart. I have done what I had to to get my car tuned "conservatively" so while doing just slightly more than everyday driving it would be safe until I can get in on the dyno.

Yes I have used parts on my car....yes tuning on the street can be risky (if you are not taking it a couple hundred rpm at a time, like I did.....obviously tuning the car can be dangerous either way (tuned on the dyno....car blew up, tuned on the street...car drives fine)

If anyone would like to say negative things about my car please do so via my pm. My car may not be perfect, but no ones is and that is not the point of this tread.

Thank you.
 

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seeya said:
If anyone would like to say negative things about my car please do so via my pm. My car may not be perfect, but no ones is and that is not the point of this tread.

Thank you.
PM'ed :fawk:

Just messin :bigthumb: Good luck with the car man... and this thread definately will help me be alot more cautious with my setup seeing as mine is under the knife now also
 

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Discussion Starter #13
Can't wait to see it!!!
 

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Discussion Starter #15
Willjs7 said:
I am glad that the car is all back together and broken-in. The car sounds amazing Dallas. :bigthumb:
Thanks! I am getting ready to do alot more so "stay tuned" :bigthumb:
 

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Dallas I dont why you are turning this into a negetive type thread. No one is picking your car apart. You wanted to warn people about buying used parts. Something alot of people here already know about. Do a search on VPC's you will see all sorts of hang up's. Its a risk you take. Whats new.

I guess you and Kirk were the only ones who didn't know. :dunno:


And it is good that you are informing people as to the cause of the failure. No one is knocking you for that. I think you are being a little sensitive.

My only concern is to why you are tuning a motor thats you just spent alot of money to get together on the road. Yes its running ok on the road now from what you can tell. :rolleyes:

Tunning on the dyno is about taking as many pre cations as possible to make sure nothing goes wrong. You need to look at your power band. I know you seen graphs that look like a 5 year old scribbled on it. But the air fuels seem ok. You could be loosing all sorts of torque. Now you look at some graphs were the car is making good power look at the air fuel it varies alot. There can still detonation you dont pick up while tunning on the street. Theres other things to consider. The wideband in your car is to make sure what you tuned for on the dyno stays that way.



Hey its your car... what you do with it is your concern. No sweat of my back. :bigthumb:
 

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Discussion Starter #17
I guess it just came across that way to me. If I was wrong in interpreting it that way then cool. I hear what you are saying about the dyno tuning, but you know I tried to get it tuned through you for a while and with my limited time these days this was the best I could do and it is definately better than nothing at all.

The car is going out of town for a full tune as soon as I can afford the time that it will take to have my car done 2 hrs away. I talked to several people such as Larry in Orlando and they all said for low boost conditions the street tune was recomended until increasing the boost and power. You know me, I am very gentle on the car in times like these.
 
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