here's my situation, i have a 85 gl-10 turbo wagon with an odd new problem. just recently it has lost all power at anything above a hair throttle, when you lightly step on the gas it will rev a bit very smooth then like a switch will go to tripping over itself. i don't know if i am explaining it right but here's what it does... starts up perfect idles at around 800 rpms and revs clean, sounds really healthy. then the instant i get going even nice and slowly it runs like poop. once i hit about 3000 rpms and hold it with very light throttle it will like cut to running smooth again.

 

if that made sense to anyone at all here's what i've done so far

-checked compression cylinders 2,3,4 at 110 and #1 and 100.

-checked spark seems totally fine and good on all cylinders

-checked injectors, one seemed weird (unplugged it and motor ran about the same) so swapped in one off my spare motor.

-checked timing 1 degree off put it back to 25

-replaced fuel filter (just today right before posting)

 

none of these things helped at all, i am desperate for any suggestions

 

oh yeah on a side note i put the fatty set of tires off my old car on it because the ones on it were super crappy, no fender trimming and only hit the top of the fender on big bumps. i say this because i had to trim my old cars fenders i'm assuming because of the front end damgae it had. 15x8 rims with 205/65r15 tires that's a 25.5" tire!

heres the car

loose baffle in the catalytic converter blocking the flow?

theres no cat, the exhaust is about 4 feet long with only a home made glass pack in it. thanks though

Air intake leak? MAF tube not clamped on?

just checked, it's all nice and tight

theres no cat, the exhaust is about 4 feet long with only a home made glass pack in it. thanks though

 

take off the homemade glass pack, and see if the problem still exists with open exhaust (don't get too rowdy and get a ticket)

sounds like bad MAF/AFM to me

Those compression numbers are low.

 

Doug

they dont seem low for a turbo to me

they dont seem low for a turbo to me

 

I'm thinking the spec is 140 lbs for the turbo.

 

Doug

take off the homemade glass pack, and see if the problem still exists with open exhaust (don't get too rowdy and get a ticket)

the problem came about around a week after i made the exhaust, but i'll try anyways.

 

 

i tried just swapping to my spare motor's maf sensor and it ran the exact same, do they go out very often? could i just have two bad ones??

 

i'm not sure if the compression is the problem because it almost feels like and electric switch that goes off or on to make it run right or crappy. its really hard to explain

 

thank you for all the help so far

mmm well it depends, i had one go out in my maxima, got a j-yard one and stuck it in there and it lasted a week before it crapped out again.

 

which was fine it got me to pay day and through smog testing

run a sweep test on the tps. (analog mutli meter)

I had a similar issue with a bad TPS on a different turbo car.

run a sweep test on the tps. (analog mutli meter)

I had a similar issue with a bad TPS on a different turbo car.

 

so the throttle position sensor might be bad? i didn't even think of that, do you think i should check it out or just put the other one i have on it to see?

Do a resistance test on your injectors.

You don't even need to pull them out of the car.

Just take a multimeter with resistance settings and check all of them for the

same resistance.

If one is off, that's your culprit,

Check your distributor, make sure its functioning properly, no broken points or

anything like that.

 

Twitch

Do a resistance test on your injectors.

You don't even need to pull them out of the car.

Just take a multimeter with resistance settings and check all of them for the

same resistance.

If one is off, that's your culprit,

Check your distributor, make sure its functioning properly, no broken points or

anything like that.

 

Twitch

 

thank you will do

I'm thinking the spec is 140 lbs for the turbo.

 

Doug

 

The book spec:

 

*standard* at 134 to 145 psi.

 

*limit* at 105-117 psi

 

But most of the ones I've tested in the real world are between 110-130, even on fresh rings.

 

So it sounds to me like he has a tired engine, but I doubt that is the source of the running problem he is having.

run a sweep test on the tps. (analog mutli meter)

I had a similar issue with a bad TPS on a different turbo car.

 

x2 do a sweep test on the blue to pos, black to neg. watch for jumps and dead spots. sounds like what mine does, only mine only does it at the highway happy spot lol (right at cruising speed pedal position)

quick update

I drove it to work today and it ran alot better for no reason, i was getting half throttle and way less cut out under load....

 

i'm off to just buy a cap, rotor, wires, and plugs just to totally eliminate that question. then come back and check out the tps (thanks Ricearu and zukiru)

x2 do a sweep test on the blue to pos, black to neg. watch for jumps and dead spots. sounds like what mine does, only mine only does it at the highway happy spot lol (right at cruising speed pedal position)

 

ha yeah mine too... non turbo mpfi though...

problem fixed! i need to learn to double and triple check the easy stuff!! the spark plug wire to cylinder 1 had a bad end at the rotor side, that gave a fine idle but somehow lost connection under load? it wasn't burned up or anything either just kinda disconnected in between the actual wire and the little metal end

 

thanks for all the suggestions everyone

Hey,

 

Good that you got it solved.

 

 

"But most of the ones I've tested in the real world are between 110-130, even on fresh rings."

 

Short of boring, new pistons will bring that up a bit. Fresh ring lands and tight clearance there go a long way.

 

Different cams will up or lower that too.

 

I know of people that's added more boost and whatnot to an engine like that. Doesn't make sense. If the compression isn't up to snuff, what's the point?

 

Doug

 

Short of boring, new pistons will bring that up a bit. Fresh ring lands and tight clearance there go a long way.

 

Different cams will up or lower that too.

 

IDK, I built 2 now with fresh pistons and rings and still the best #s I every have gotten are around 130

 

I know of people that's added more boost and whatnot to an engine like that. Doesn't make sense. If the compression isn't up to snuff, what's the point?

 

Doug

 

The added boost ups the effective compression. It yeilds HP gains even on old engines.....but it is a temporary fix that is more detrimental in the long run than rebuilding the motor and keeping boost stock.

problem fixed! i need to learn to double and triple check the easy stuff!! the spark plug wire to cylinder 1 had a bad end at the rotor side, that gave a fine idle but somehow lost connection under load? it wasn't burned up or anything either just kinda disconnected in between the actual wire and the little metal end

 

thanks for all the suggestions everyone

 

 

hmm maybe I should check that I was really leaning towards my TPS...

 

my wires are from my old Starion but the were fresh and not cheap so I used them on the Subie.

maybe I just need some new wires (that aren't all over the engine bay)