Engine doesn't rev up normal!

[Supraflymk3]

I bought my car about a month ago and when I got it it ran fine. Then a couple days after I bought it, if I hit the gas to try to rev it a little it wouldn't rev freely like it should. It would rev really hard, like you could hold the gas part way down and it would seem like it was fighting just to rev up. so i thought maybe the headgasket was blown and coolant might be in the cylinders which would probably do that. So I tore the head off and everything looked ok; cylinders are good, no coolant in cylinder and the headgasket looked good. So if anyone knows what is up just let me know. Thanks alot!

 

[Burntz]

is your cat good? free flowing?

check for codes too, and have you done a tune-up? plugs? wires? fuel filter? clean ur injectors? new/clean filter?

 

[Supraflymk3]

I just got the car. The plugs and wires are good they shouldn't have went out in a day. I tore the exhaust off to get the head off and the inside of the cat looked good. That just leaves the fuel filter, but also I don't see why it would run great one day and then the next day it run like ass.

 

[Burntz]

you never know, usually its a gradual thing w/ injectors, filters, etc.

if its all of a sudden, it makes me think electronic, which is why i said check for codes. tps maybe?

 

[Supraflymk3]

when i did check the codes 52 knock sensor signal came up. when 52 was on on my other 87 it didn't do that, i ended up doing the rewire then it was all good. so i don't think its electronic. I think i'll get a headgasket kit put it back together with a titan 1.4mm arp head studs and greddy timing belt and replace the fuel filter and see if it still does it.

 

[Burntz]

dont put a metal HG on it if you arnt pulling the block and decking it.

also, i forgot, your timing could be a tooth off, or actually anything with your timing.

 

[Supraflymk3]

i put a metal headgasket on my other supra without having it decked and it works fine.

 

[arz]

Yea I have done at least 3 MHG's with no re-surface of the block. If you can find a shop that will deck the head wit out dissassembeling it that would be the fastest and cheapest. Provided you dont need to remove more than .006 inches or so. My machinist buddy did a couple for me and it took about 15-20 to set it up and 5 to actually surface each head, since he took so little material .003 off of my heads he didnt use any coolant and I just sprayed the chips out of the head andf cleaned it as best as I could.

Obviously I checked the valve seats and guides and replaced the valve stem seals and both heads were good to go.

I would have checked to make sure you dont have a boost leak first if your revs changed in one day though. Pulling the head seems like a long way to go to find out you have a boost leak or a blown BOV. If you still have the stock BOV blow into it to see if it still works.

 

[CampbellsChunkySoupra]

1st: plugs, wires, fuel filter [like state above]
2nd: good luck troubleshooting now that it is completely torn apart.

 

[starscream5000]

Wait, wait, wait. You pulled the head off just to make sure you didn't have a blown head gasket? LOL, there are testing kits you can make up to check for a BHG that which would have costs a lot less than what you are going to have to spend now since you've already done it. Might as well take your time now and do things right...

 

[Supraflymk3]

well i was planning on putting a metal headgasket on and arp head studs anyway so i'll do it right. but i think it was rebuilt recently because the cylinders are honed out you can see the cross etching. So I'll just put it together right and hopefully it'll run normal again.

 

[arz]

I have taken a part a bunch of 7M's even one with 240,000 miles and the crosshatching was still plenty visible. Crosshatching missing at the top (or commonly calle a "ridge") usually happend on older carburated motors, because carbs are no good at maintaining good AFR's at idle.

That crosshatching visibility is common, I wouldnt use that as a measure of motor health.

 

[jsnowman76]

its too bad that you tore it apart already. the first thing that I found out when my supra was acting up was that one of my intake pipes had blown a clamp but youll have to put it back together to really find out.

 

[Supraflymk3]

i'm not a fucking idiot i know there are testers but i was lanning on upgrading right of way.