1991 SHO sputtering an hesatating when accelerating.

[Bryan]

Okay... So my DIS module may be going on me... The question now is which one should I replace it with? Ford shows they have the original part at $320. SHOSource also seems to stock it as well at $250 (brand not listed, though stated as high quality). Also I checked AutoZone and they stock the same part (Duralast) at $131. NAPA Auto Parts also lists it (Echlin Ignition) at $177. And finally Advanced Auto shows two different ones. BWD Ignition, or Wells Vehicle Electronics at 135 (BWD) or 175 (Wells) respectively.

Also what kind of thermal paste should I use? I have some from when I built my PC and had to apply some to the CPU heat sink. Would that work well enough? And how much is a good amount? Just make sure to cover its entire base right?

 

[SHOdded]

You can get a good used DIS from rcmautomotive.com, they are in PA too. Scroll down on this page: http://rcmautomotive.com/id10.html Much more affordable.

Correct on the paste. You need to use heatsink paste, same as your PC's CPU heatsink paste. Don't lather it on, keep a thin layer (again like the CPU), and you should be fine. Tighten the bolts on the DIS to spec, so you maintain a proper ground. While you are in the vicinity, check to make sure the ground strap from the intake (passenger firewall corner) is intact and connected to the firewall (or some other bare metal in the engine bay, the strut tower being a popular area).

 

[Bryan]

You can get a good used DIS from rcmautomotive.com, they are in PA too. Scroll down on this page: http://rcmautomotive.com/id10.html Much more affordable.

Correct on the paste. You need to use heatsink paste, same as your PC's CPU heatsink paste. Don't lather it on, keep a thin layer (again like the CPU), and you should be fine. Tighten the bolts on the DIS to spec, so you maintain a proper ground. While you are in the vicinity, check to make sure the ground strap from the intake (passenger firewall corner) is intact and connected to the firewall (or some other bare metal in the engine bay, the strut tower being a popular area).

I got my Sub Frame and Strut Rods from RCM. Problem is it took them FOREVER to get back to me and we had a falling out. I'll look into it.

And with the paste thanks for the heads up! I'll make sure to keep a think layer and check that ground strap when I install the new DIS. I take it that it would be a good idea to disconnect the battery when installing the new DIS right?

 

[SHOdded]

Yup, disconnect the battery. Better to go thru a relearn process than take a chance on frying the PCM.

 

[rubydist]

Just pulled the codes and this time I got 24. What does this one mean?

I have never seen a SHO run right if it had that code. For some reason, if the pcm doesn't see an intake air temp it believes, it acts stupid. So, you do need to chase this down and fix it. Typically, it is a dirty connector issue.

I always to go a place like Radio Shack and get regular computer heat sink paste - that has always worked well for me on the DIS.

 

[Bryan]

Update! Got the new DIS installed and the problems have stopped. Car is running great again and the fuel computer in the instrument panel is again showing I am getting the proper amount of fuel economy.

 

[SHOdded]

Awesome Now talk to the car and tell it to keep behaving

 

[Bryan]

Awesome Now talk to the car and tell it to keep behaving

Lol! theres no telling what will blow up next. Found out just today my parking brake is no good as when I got out of my car it decided to roll out of my driveway and try to run me over when I tried to stop it. Managed to get it to stop only after a nice slide across the street.

 

[SHOdded]

So the GO works, the STOP doesn't? The Yin isn't playing well with the Yang on this one!

 

[TimboSHO]

Update! Got the new DIS installed and the problems have stopped. Car is running great again and the fuel computer in the instrument panel is again showing I am getting the proper amount of fuel economy.

Fuel computer? Did you do the digital dash swap?

 

[Bryan]

Fuel computer? Did you do the digital dash swap?

Yup. That and a new EATC as well.

 

[Bryan]

Update: Sad to say but the DIS seems to not have been the issue as now the car is still lacking power and I can hear it misfiring and sputtering. It just feels like it's either not firing on all cylinders or there's not enough spark so the car feels like its working harder to get the same acceleration. Welp guess its back to the drawing board.

DIS: Check. TPS: Check. Next on my list? I really can't change my spark plugs because the valve covers gaskets are bad and oil is seeping in through the plug well seals. And now with another 12 inches of snow expected I think I am going to just park the car and let it sit until all this white stuff melts and warmer weather allows me to work on it.

 

[rubydist]

well of course its going to be down on power if the plug well seals leak and the plugs and wires are wet with oil. the oil breaks down the insulation and allows at least part of the spark to short through the oil to the head, rather than in the combustion chamber. you need new plugs, wires, and valve cover gaskets. once you do that, I expect you will find a resurgence of power.

 

[Bryan]

well of course its going to be down on power if the plug well seals leak and the plugs and wires are wet with oil. the oil breaks down the insulation and allows at least part of the spark to short through the oil to the head, rather than in the combustion chamber. you need new plugs, wires, and valve cover gaskets. once you do that, I expect you will find a resurgence of power.

Yeah I know it needs to be done. Is its difficult to change them?

 

[SHOdded]

From what I have read, aside from getting tried & true replacement parts, the main trick is to make sure the rear valve cover gasket doesn't roll during installation. I guess you could follow the top end 60K process listed on http://www.shophoenixproject.com/upper60k/upper60k.htm . The site even gives you the parts you need for this particular project!