Need to Pick Brains on Problem

mfbarnes · 02-29-2004, 01:06 PM

Finally got the 86 3.2 back on the road after engine/tranny drop. Now the car is seriously down on power. It acts almost as if there is a timing problem, but that can't be it since all timing is automatic. It goes all the way to redline, but takes forever to get there, and had little pull in higher gears.

I checked: idle control valve: tested good.
air flow vale: tested good.
full throttle valve: tested good.
head temp sensor: a little out of spec, read 3.9 ohm when the range should be 1.5 to 3.6 at 65 degrees F.
Did not check speed sensor, but car ran well before drop.

Idle speed is 1100 at start up and drops to 850 when warm. Engine is smooth at cold idle, but not at warm idle....exhibits the same hard to accelerate behavior as on the road when blipping the throttle by hand.

All vacuum lines seem to be in order, in fact improved from before.

I'm stumped....ideas?

MFB
86 carrera

rzepko6194 · rzepko6194's Garage

I see you tested the full throttle valve, but is the throttle opening all the way when pushed by the gas pedal?

Is the ground strap to the tranny clean and tight?

JP

Hetmann · 02-29-2004, 02:33 PM

Did any spark plug wires get pulled off?

dtw · 02-29-2004, 02:40 PM

My ex-3.2 did this once after an engine drop - there was a DME-related connector attached backwards. It's been maaany years now so I can't remember specifics, but check all your connections.

Wil Ferch · 02-29-2004, 04:23 PM

Engine speed and reference sensors...???
I mention these because they could have been affected by an engine drop...almost too coincidental to ignore...either bumped or damaged or not in-spec as to clearance to the flywheel teeth, etc.
---Wil Ferch

3.2 CAB · 02-29-2004, 05:27 PM

I'm with Will. Check the sensor air gaps and connections. Could be that during drop and all, the sensor holder got bumped and moved out of place a little, it does not take much for the adjustment to be wrong with onlya 0.8mm air gap.

mfbarnes · 03-01-2004, 05:02 AM

Well, I am sure the throttle opens fully. Ground straps were cleaned and the connections were cleaned.

I am not sure about the speed and reference sensors. I can check the voltage, but not cannot do the sine check.

I have triple checked all the connectors and don't see any problems.

What is the best test for speed and reference sensors?

Thanks for everyone's help

MFB

3.2 CAB · 03-01-2004, 08:07 AM

MFB, when mine were bad, I tested them with a digital volt/ohm meter, they both tested good according to the Bentley book. I did not have access to a scope so I was not able to check sine. I have a friend who is a Pcar wrench in another state, he told me the really only sure way was with a scope, after seeing the results and then replacing mine I believe him. The bottoms of both sensors were slightly bulged out like they had expanded out toward the bottom, they are supposed to be flat across the bottom. The problem my engine was having was when the outside temp was below about 70 degrees it would crank, but not start, there was no spark, if the temp was above 70 it wouldn't turn over twice before it started. Good luck with it.