finally got tthe new engine in. misses bad

[mnracer550]

Im gonna start with a history on the 87 turbo supra i bought. i bought it thinking it needed a new head. it sounded like a exhaust valve dropped on cylinder 2 and was missing really bad. when i got it home i ripped it apart and diagnosed the rod bearing was absolutely gone. so i found a donor car for a new engine. Ok so after all my dumb little issues i got the engine out of my 89 turbo auto and into my 87 turbo manual. so im running the 89 turbo wiring harness and a 90 turbo auto ecu. started up rite away but had a light miss. i figured it was probably dude to 6 month old gas. so i drove it up to the gas station and it ran pretty decent until around 3500 rpms and it would miss pretty bad. after i shut if off put some 92 oct in it then started it, it was worse. was missing all the time. so im thinking it has to be one of the moduels on the 87 supra body since the car was missing with the old engine as well and then ran awesome in the 89 donor car. i just tried the ignitor from the the 89 and there was no difference. anyone else have any ideas?

 

[mnracer550]

I forgot to add...
i used the following from the running 7m out of the 89 donor car.
-o2 sensor
-afm
-cps
-knock sensors
-tps
-coil, plugs, wires
- cold start injector
-turbo

i also forgot to mention im using a aem wideband. afrs look good. blips lean just a little when it misses.

 

[mnracer550]

Another update. went out to the garage this morning to move the supra and it ran good and reved free of misfire for like a few seconds then i put it in reverse and it started missing again. its not just a load or boost related like eveyone else seems to post about. its always there. i have no check engine light and havnt checked my codes yet. it couldnt be timing since it was good in the other car. this car is drivin me crazy!

 

[89nasupra]

Did you check to make sure all the injectors are firing? I had the same issue after i did my swap. I started it and pulled one injector at a time untill I found the one that was not working.

 

[mnracer550]

im gonna have to start doin that now, i jus checked for codes. nothing. its just weird that it would be an injector since that would be a "constant" since they were fine in the other car. again timing also seems like it would be a "constant" im lookin for the variables but im gonna start checkin everything anyways, but im sure most of you are must more experienced so any more idea would be great

 

[hvyman]

Check:
Codes,
Spark plugs,
coil packs,
spark plug wires,
fuel pump,
injectors.

 

[89nasupra]

What ever you find let us know what the problem was. The injectors were fine in my donor car also, after the swap and I got it running one was toast.

 

[mnracer550]

alright i pulled the plug wired and plug 5 and 6 were drowning in water that somehow got in there. so i took it out for a drive and it is fine till it makes a few pounds of boost. under no load in neutral or with clutch in it revs freely also. so around 3500 rpms it starts missing again and just sputters. im gonna try my spare afm, maybe try my spare boost pressure sensor also.

 

[hvyman]

Boost pressure sensor on the drivers side fender well only goes to the gauge.

 

[mnracer550]

lol thanks for clearing that up. couldnt find any good info..... would explain the vaccum line going to it. seems like a few people have had this problem but no real answers. i had a small vaccum leak from one hose but only helped a very small amount

 

[hvyman]

Do you have coolant inside the cylinders or just around the plugs?

There are 3 14mm allen plugs between each sets of 2 plugs that coolant can leak out of.

 

[metaphysico]

Check all the ic hoses and pipes to make sure there tight and not torn.

 

[mnracer550]

no it was from when i washed the engine. no coolant. just went through all hoses. checked all vaccum lines. spark plugs look like there burning decent. black with a tint of brown. i noticed. i can run like 1/3 throttle and get it up to about 5k rpm before it starts missing. it definitly and issue one its full throttle or boost. maybe the sparkin can ignite all the fuel it send once i hit boost?

 

[mnracer550]

ok guys jus pulled plugs 1,4,5,6. there lookin pretty white. but that usually indacates a lean situation. and my mafrs are good. 10.5-11.5 wot. 13.5-15 crusing. idles 14.7. does the misfiring cause this.

 

[hvyman]

Hard to tell from the pics but what is the gap on the one on the left and how old are the plugs

 

[boostcraver]

I'm surprised no one has suggested to check the adjustment on the TPS. If you haven't checked it yet, you should as it sounds like it's been off and reinstalled. TPS out of whack= poor running vehicle. Mine displayed similar symptoms to what you are describing till I re-adjusted the TPS. Not saying that is your problem, just my.02. Please keep us posted an good luck.

 

[mnracer550]

thanks guys. well i found a huge problem, i didnt have the upper vaccum line for the fuel vsv hooked up. made a massive diffference. actually can make boost and power now but still misfire under anything more then half throttle. gonna check tps rite now. it will run decent half throttle. can get full boost but under boost it runs pretty rich low 10s will even hit 10.0 and stay there on full boost in 5th gear. i have a light misfire on idle and misfires a little when letting off the gas.

 

[supraguy@aol]

Any- and I mean ANY- water around the plugs will cause the spark energy to ground to the head instead of the plug.
The missing under load that you describe is the exact issue i had when coolant got into the valley. If you haven't already, make sure that all the plug boots
are absolutely bone dry.

 

[mnracer550]

i havnt checked 2 and 3 cauee im lazy and drunk working on the surpa. but is seperat so im not seein it happen. ill check when im sober in the morning. but it sounds like vaccum leak to me. lean at idle. rich at wot. no good. fuckinn supra.....

 

[supraguy@aol]

Well, when YOU dry out, make sure sure your plug valley is dried out.
And spray a little starting fluid or carb cleaner in isolated parts of the engine, to see if there's a vacuum leak.
popular spots for this are- the throttle body gasket, and the lower intake manifold gasket.