!!!!!!!!!!!!!!!!!Please Help!!!!!!!!!!!!

Deimos

Registered User
ok,this is complicated sort of,but bare with me for a sec


my friend has a 90 SC with a 5 speed, it expiereinced many major malfuntions wich led to its utterbreakdown. well over the past 2 months we have repaired it back to runnin condition now.heres is a list of what we replaced

harmonic balancer (got the new billet steel one)
oil pump
water pump
power steering pump
power steering lines (all)
solid motor mounts
oil pan
timing chain and gears
cam sensor
crank sensor
underdrive pulleys (no increase on SC yet, stock pulley there)
valve cover gasket ( IC tube side)
all other corresponding gaskets and seals for everything else listed
intercooler tube tape

there are other newer items on the car but have been there 4 months now.



now here is the dillema, after carefully assembling everything the car ran but the RPM gets spastic at WOT, what i mean is that when you floor it it wants to seriously hesitate. now i know this sounds like it could be many things but heres what i have it down to.....

when the car finally broke down the harmonic balancer twisted apart and bent the crank sensor ring that mounts up to it, well upon reassembly we tried to reshape it how it was and it does look pretty good, but it probably is not perfect on a gauge thing. well i know that the book says to space the sensor a matchbooks thickness apart from the ring that passes through there upon turning the motor we noticed that it rubbed slightly, but we had a ols sensor from another SC it it appeared that it was worn down from rubbin as well. so my question is ....does the crank ring have to be perfect or is this not a precise sensor? does it have a range? wahts the out of round limit on the crank ring? is this even causin the misfire's and hesitation or is it somethin else?

please help me, all we want is to make this beast run right!!!!!!
 
It could be the sensor ring, but if it is out-of-round the car shouldn't run at any RPM. It sounds like maybe you have some belt slippage on the supercharger pulley. Does the hesitation feel like stuttering? or, is it more of a smooth "bottoming out" type lag? I think I have an extra sensor ring (from one of the many stock balancers I broke in years gone by) that you can have. I'll check when I get home this evening to be sure. If I can find it, its yours...just let me know where to send it and I'll drop it in the mail to you...
 
Further Investigations

i understand, yeah the car wouldnt run if it was out of round so thats not it,
as far as the belts there really tight and i really doubt theyre slippin

to better describe the problem

its like when you give it gas like half throttle it just runs fine,but when you give it full throttle it like jumps you will be climbing past 3500 and it you will see the tach jump to 5500 in the blink of an eye and then the car will be all hesitating and then it will jump like it starts workin and then keep going back and forth as it climbs through the powerband

we had to take off all the intercooler tubes, but im pretty sure we sealed that good with the tape, do you think its a vacum leak?

as far as the ring, i will get back to you i have to consult the owner im just the mechanic/helper
 
Plugs/wires??
Shuttering under boost is usually caused by a bad plug or wire. Or a wire not completly on the plug. These cars are real sensative to bad plugs/wires.
Just something I'd check on and rule out.
 
Last edited:
Deimos said:
when the car finally broke down the harmonic balancer twisted apart and bent the crank sensor ring that mounts up to it, well upon reassembly we tried to reshape it how it was and it does look pretty good, but it probably is not perfect on a gauge thing. well i know that the book says to space the sensor a matchbooks thickness apart from the ring that passes through there upon turning the motor we noticed that it rubbed slightly, but we had a ols sensor from another SC it it appeared that it was worn down from rubbin as well. so my question is ....does the crank ring have to be perfect or is this not a precise sensor? does it have a range?
Find a used HB from someone somewhere and get an unbent ring off of it. At the engine speeds you're talking about, I would be surprised if it didn't cause a problem. The rubbing is a bad thing :cool:
 
What about a DIS module. I had a problem w/ my car doing that over 3000 rpms but it was because I didn't have the DIS grounded properly. I lost the bolts to it and used little screws to hold it in place but it wasn't tight. Anyways I got some new bolts for it, bolted it down tight, and it ran 10x better. That was after my head gasket job and I had brand new plugs and wires among many other parts.
 
Codes

I hate to be a flat tire but, have you checked for any codes yet? The paperclip trick works everytime for me.


Tyler (Tickler)
1990 SC
 
Real Bad News

well i think i have figured out whats really wrong......apparently theres oil in the water and vice versa, could be a blown head gasket or the timing cover gasket, i hope its the latter will keep everyone posted, about to do a compression test to it today, as far as the codes i have done that and it triggered a 93 and a 21....93 dont even exist in the book? 21 ic coolant sensor out of range
 
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