Almost no power and exhaust smokes up through the hood

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Pseudoduck

New Member
Feb 25, 2013
13
0
0
Washington
Sup guys. Pretty desperate here. I bought a 86.5 Supra with 7mge about 6 months ago. Had a blown head gasket so I decided it was time to replace it. Now, I have everything timed and it seems to idle okay (sometimes it gets kinda low to 500 rpms). I took it for a drive and it has crap acceleration now. Sometimes when I'm trying to rev in 2nd gear, it will start bucking until a certain rpm, but it just doesn't have the power like it used to. So we took it back to the garage and there's ALOT of white smoke coming out from my exhaust somewhere between the cat and the headers, and it billows up through my hood and out. It's almost like fuel is being dumped into my exhaust and it's on fire just burning in it. It smells really bad like burned rubber or plastic or something weird. This will be my 4th time disassembling the engine. Only this time I just don't know where to look or what to do. I refuse to give up but at the same time I'm just so stumped I almost want to give up. Any ideas guys? Thanks in advance.

Also I timed everything to their zero marks. So it's exactly at zero at the cams and crank. And it's also giving me a code 51 and 52.
 
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Pseudoduck

New Member
Feb 25, 2013
13
0
0
Washington
Oh wow haha. I didn't know knock sensors were that important. I thought they just... sensed shit for the ecu lol. Alright I'll go check it out. Is there a plug for it? Cuz there's a brown plug near the rear of my engine that's just hanging there and a green plug in the front underneath my intake, and I have no idea where those go.
 
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Pseudoduck

New Member
Feb 25, 2013
13
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Washington
Okay so I got the green plug into the knock sensor underneath the first runner on my intake. Did some research and I guess there's another one near the rear of the engine on the same side of the block. Do all 7mge's have this second knock sensor or is that only for 7mgte?
 
suprasick

suprasick

Hey look...a Supra!
Mar 17, 2006
291
0
16
Milton, Washington
Every 7MGE I have worked on only had one knock sensor towards the middle of the block. And every GTE I have seen, regardless of year, has had two knock sensors one in front and one towards the rear.
 
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Pseudoduck

New Member
Feb 25, 2013
13
0
0
Washington
Alright after hours of feeling up my engine block and finger prodding it I think you guys are right. So after I got that knock sensor plugged in I took it for another test drive and my acceleration came back just like what IndigoMKII said. Now I just need to figure out this fuel leak thing. There's not as much white smoke coming out of the exhaust but it still smells like burnt rubber or plastic when I drive it. There's hardly any smoke coming out the hood. I don't have a compression check tool so I will have to borrow one from a friend and have him show me how to use it.
 
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Pseudoduck

New Member
Feb 25, 2013
13
0
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Washington
Just did a compression check like you said. I think it's fine but here's the results:
Cyl 1: 170
Cyl 2: 165
Cyl 3: 170
Cyl 4: 175
Cyl 5: 180
Cyl 6: 180
 
IndigoMKII

IndigoMKII

New Member
May 9, 2011
2,181
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Madison, Virginia
Okay, the smell you are smelling is probably from your dirty hands touching everything under the hood and being slowly cooked off. Did you fix your code 51? Was the a/c on? Was your foot on the throttle? Code 51=tps alignment is wrong, a/c was on or your throttle body isn't closed.

Not to mention, cylinder 2 is right at the limit of compression difference per cylinder. http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=EM&P=20
 
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Pseudoduck

New Member
Feb 25, 2013
13
0
0
Washington
All codes are fixed. My car didn't come with a/c or previous owner took it out. It's no longer smoking through the hood and the smell is gone. I don't give it any throttle unless I have it in gear and intend to drive it. So far everything's good. It's in good running condition except for the life of me I absolutely CANNOT get my injectors to seat in right. My 2nd injector keeps pushing fuel out and I can hear pressure bubbling and pushing out from the seals. It's making puddles on my intake :mad:. Am I the only one that's struggling to get my injectors to seat in right?

Also I just wanna say thanks again for the help guys. I really appreciate it this is some really good info.
 
Grandavi

Grandavi

Active Member
Sep 25, 2008
2,664
6
38
Calgary, Alberta, Canada
^^ what Indigo suggested. Best to get that perfect.. otherwise its going to be either a long term headache or a short term Supra burn...

For what its worth, my car smelt like "burnt plastic" for about 3 days after the build. Of course.. I was leaking oil via the turbo, but it was an odd type of smell that disappeared as the engine broke in. No smell now.
 
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Pseudoduck

New Member
Feb 25, 2013
13
0
0
Washington
Yep. The 2nd injector had a pinched o-ring. It's running good now. Thanks Indigo and everyone for your inputs. I looked up a bit more info so I could do the injectors properly and someone suggested using petroleum jelly instead of gas for lubing up the seals. Did just that and it works fine. My car overheats ALOT now though so I will be doing a pressure check on the coolant and flushing it out a bunch. My dumbass didn't cover anything on the block when I scraped off the old gasket so pieces of it could be floating around in my coolant somewhere. But the engine runs so hot, that if I get a tiny puddle of water in one of my star shaped bolts near the valve covers, it boils it away. It seems like I always fix one problem and then BAM another one pops up.
 
Grandavi

Grandavi

Active Member
Sep 25, 2008
2,664
6
38
Calgary, Alberta, Canada
At this point I would be taking it to a qualified mechanic. Some of the things you have stated your doing is scaring me. First... you scraped off the old gasket.. but I am wondering how well you inspected the block and head surfaces. The head gasket is the weak point on these engines, if not done properly.. headaches later. Stuff floating in the water jackets could cause you more problems later if its really contaminated, so a good flush should be in order just to be safe. Did you touch the head at all while it was off? (recondition it?)

Running our vehicles to get to a very hot point when nothing obvious is wrong is a very bad idea as you can cause head warpage because of the differences between the block and the head in expansion due to heat.. higher heat = higher differences. The engine should not overheat "just because". To be honest, because my skills aren't what I would call up to snuff for a simple rebuild (these engines aren't that complex, but if you have a few tiny things wrong it can cause a lot of problems for you) I paid someone to do my full build. I have read far too many threads of people doing good work to have it all crater later. Scared me enough to just throw money at it instead of time. (although.. I really wish I could have done all the work myself.. much more pride in that)

Just make sure you know when to quit before you cause major issues and get help (either a mechanic or perhaps someone who is very familiar with the engine that lives close to you if your lucky... there may be a forum member near you).

Wondering why your compression is so high on cylinder 2 as well. Just from reading, there seems to be something you overlooked that could be causing you headaches past just getting the injectors running correctly. As I said, my skills aren't great enough to advise, but now that you are getting fuel and its overheating, it could be that your timing is out enough to cause that. Thats a guess though. Photos help. Would have been nice to see a pic of the pistons, cylinders and head while it was off.
 
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