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Discussion Starter #1
I'm looking at a 91 turbo hard top which appears to be in perfect condition. It has about 113k miles on it.The only problem with the car (according to the owner) is that the "header gasket" is bad and this is causing the car to knock. He says as soon as the header gasket is replaced the knocking should go away. He insists that the header gasket is not the head gasket. I'm not familiar with MR2's so I don't know if he is being honest with me or not. Has anyone heard of the "header gasket" and could it be the source of the knocking?
 

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A header is also known as an exhaust manifold. you know the the thing that goes from the cylinder head to the turbo. im not sure how that gasket failing can cause a knock though. som1 might be blowing hot air at you. just have a shop look at the car, its like 100 dollars. if it is a head gasket, i wouldnt buy the car, unless its dirt cheap.
 

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He is blowing hot air up your behind man!

Knocking or detonation, can cause a headgasket to blow, pistons to break, rings to fail, ruin valves etc....

However there might be a missunderstanding on both your parts, if there is a noise coming from the engine, caused by a leaky/faulty manifold gasket, and that is an easy fix indeed.

T
 

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Discussion Starter #5 (Edited)
He says the CEL is on because of the knock, so I dont think its just a wierd noise. But then as I said I dont know about MR2's. The knocking noise he describes is a "tapping noise when you start the car and its cold." Could this be something other than knocking setting off the CEL?

He is asking $4200 for the car. Interior and exterior are near mint. It has an aftermarket exhaust (I dont know what kind). Would this be a fair price for a 91 hard top if there is in fact a knock issue?
 

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If it is a knock issue, you might find yourself deep in a rebuild, or swap real soon....So I wouldnt pay 4200 for a car that is 14 y/o, even if it is a hardtop.

I would say, offer him 4300 if he fixes the knock with a new gasket....(if he is full of bs, he wont take it)

T
 

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really? 4k for a hard top that is in "mint" condition? i think thats an awesome price, even if the engine is f'ed up. do a little research, 5000 is a good price for a mr2 that is in decent condition, and this is a mint hard top (btw did the year 91 turbo really come hard top?), i dont think youll be able to find a better deal than that very easy. even if i had to dump another grand into the enigne id still buy it
 

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Discussion Starter #9
If the header gasket isn't likely to be the cause, any guess what could be causing the engine to knock? It was my understanding that the 3SGTE engine is near bullet proof and that it should last longer than 113k miles.
 

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1) "Knock" (detonation) does NOT trip the CEL. But...a faulty knock sensor will.

2) If you can hear it, its NOT knock (detonation)

3) What you probably have is a faulty exhaust manifold gasket (very common on '91, '92 3sgtes). It will make a knocking sound, especially when cold. But that's NOT knock.

I suspect your seller is really not being dishonest, he's just not very knowledgeable.

bill
 

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Discussion Starter #11
So your saying I likely have a faulty knock sensor and a bad exhaust manifold gasket? If this is the case, how much would it cost to repair? and would $4200 still be a fair price?
 

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No, I didn't say you have a faulty knock sensor, only that the knock sensor is one of about 30 different reasons the CEL will come on.

There is a very simple procedure to read the CEL error codes. No need to guess why its on, the ECU will tell you.

http://www.mr2-tech.com/bgb.htm

Mechanical>EFI>diagnosis

But yes, based on your description (and the known histopry of the 3sgte) you probably have a manifold gasket leak.

bill
 

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Discussion Starter #13
So to get this straight, I use my SST (paper clip?) to connect E1 and TE1. Then it blinks Toyota Morris Code at me. I jot this down and reference it with my handy BGB print out? Sounds easy enough. Thanks for the info.
 

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psycobob said:
So to get this straight, I use my SST (paper clip?) to connect E1 and TE1. Then it blinks Toyota Morris Code at me. I jot this down and reference it with my handy BGB print out? Sounds easy enough. Thanks for the info.
Yeah, you got it.

But remember, the ECU styores all errors forever, unless the are manually cleared. Your first reading might show several codes. And its a good idea to make note of them, even though they may not be valid.

Then you clear the codes (pull the EFI15A fuse for 30-60 seconds), and see if any codes come back. If they do, those are current errors.

bill
 

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Discussion Starter #15
Ok, I'm looking at the instructions and realize that I have no clue where to find terminals E1 and TE1. Where are they located? Is it under the hood or in the cabin?
 

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Discussion Starter #17
Awesome. Thanks for all the help. I'm heading over there when I get out of work tonight to pull the codes. Hopefully I'll get a 52 (the knock sensor) and just have to replace the sensor. I hope to join the ranks of the MR2OC very soon.
 
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