Hesitation question

[firstgen89sho]

Alright, first of all, I have used the search function

second of all I want to run this past some of you SHO owners since most of you have alot more experience with these cars

The car is an 89, with 92,000 on the odometer (unknown if it has rolled yet, most likley)

What's happening, is when cold, when accelerating from an idle, the car really hesitates and almost stalls or stalls, when warm, you can feel it but not as bad

I brough it into the shop today and was checking it out, the MAF was clean, tested with another one just in case this one was defective, that was not the case, checked for any vaccuum leaks (with my favorite substance Brake Clean, yes I know how to do it, don't worry) there were no vaccumm leaks, and obviously it's not the O2 sensors because it does it in closed loop and open loop.

Put a voltmeter on the TPS, was getting about .85v, seems ok, no breakdown of the TPS, as for oil in the plug wells, I pulled one plug out (I know, there are 5 more that might have oil in them) and it was fairly dry, dunno on when the 60 k was done or if it ever was done

I will be doing on saturday, the front 60k, along with the plugs, (Timing belt, Cam seals, Crank seals, water pump, thermostat (all Ford parts execpt the WP), The upper 60k will be done early next year

Now, what I have come to wonder is, when I let the car idle in the shop untill the temp gauge was in the middle (it hasn't been reaching that range here due to the -20c weather we have been getting here) the hesitation goes away, now I'm wondering if it could possibly be the Coolant Temprature Sensor (I havn't had a chance to test out my throry yet with a voltmeter) becasue og how the hesitation went away with the engine warm (oh yeah pulled codes, and there were note, and also there is no data link

what are you opinions?

TIA

 

[rangerj]

If you got .85v at closed throttle that may be contributing to your problem. The TPS should read .6v at closed throttle. The TPS is not adjustable, per se, but there is enought play in the screw holes for a slight adjustment.

If the milage on the car is correct I would say you have a bunch of original 16 year old sensors. Spend some time disconnecting, checking and reconnecting connections. Do yourself a favor and invest in new hoses. Replace the hoses when you do the front 60K.

There are a number of little hoses around the throttle body, there is a 2 inch long(approximately) by 2 inch in diameter(approximately) hose to the right of the thermostat (when looking in from the drivers side). The ideal time to replace this is when you do the water pump. There are a couple of hoses down by the oil filter. You may also want to consider replacing the throttle body gaskets. You can do this when you do the upper 60K.

rangerj

 

[91whiteshoplus]

ive had low rpm hesitation (misfires) on two occasions, both from different sources.

1st time it was the oil in the spark plug well. this misfire got worse as the engine warmed up.

2nd time it was a lot harder to find and fix. it was a loose main timing belt gear on the crank. this misfire got worse when the engine was cold. what happens is that the timing belt gear key on the crank shaft breaks, causing the gear to rock around and throw off the valve timing. the key broke because i had been stressing the motor while doing some racing, and i had not tightened the big main front crankshaft nut enough. the solution was a new crank key and main timing belt pulley gear, since the inside collar of the gear had spalled out from all of the rocking back and forth. Fortunately, there was no damage to the crank shaft itself.

since you are doing the 60k you might want to pull off that gear and have a look at it.

there may be a faq on shotimes.com, i am not sure.

 

[SHO_Driver]

Are you getting a CEL? If not its more likely the plugs and wires.

 

[firstgen89sho]

No CEL, (only time I had a CEL is when I disconnected the MAF)

 

[firstgen89sho]

Alright, I thank you for your help, it was the CTS, I replaced it with an OEM Ford unit, and the problem went away, the CTS that was in there was fully encased in plastic, now tell me, how are you suppose to read an proper temrature thriough plastic, the OEM Ford unit was brass, now that conducts heat a little better