Cold killed the SHO

[freecop]

Well I've looked and I need a hand here.

My 91 SHO will not idle and will sputter and die as soon as the clutch is pushed in. At start up it will run smooth for 20 seconds and then it starts surging and will eventually die out. The key test gives me codes 24, 41, and 91. The run test gives me 12, 13, and 24 and dies out without completing the test.

When the below zero temps hit it fried something and now it has very poor gas mileage and won't idle. I replaced the IAC and ACT sensors but it did nothing. O2 sensors? Going nutty!

 

[Wakeboy1337]

If you have a spare PCM I would try that first.

 

[frosho]

It sounds like you have a substantial vacuum leak. Check for cracked couplers and vac lines.

 

[freecop]

I found a vacuum hose that was plugged laying under the butterfly. Where does it go lol. Gonna go try to find it

 

[frosho]

Pictures would be very helpful.

 

[freecop]

I checked and found out it was a old hose that was replaced already. It went from the throttle body to the cruise control area. It's hesitating on acceleration and is starting to run rough at start up. I got some nasty blue smoke this morning. CPS bad? Frickin water pump is slow to turn when cold. Looks like the whole front has to come off.

 

[freecop]

wakeboy you still sellin that SHO? looks like a good time for a backup

 

[Eric VerValin]

Cruise control area? You talking about the manifold of 4 hoses near where the hood strut mounts to the firewall? Check all of those for cracks... but to me it sounds like your fuel pump might be on the way out. The way it starts, stumbles, and quits... I remember another SHO acting that way a while ago..

What happens if you try to give it gas? Can you keep it alive with the gas pedal? You should also look into running some codes.

What part of Indiana are ya in?

 

[freecop]

eric i'm in northwest indiana near gary. the codes are in my first post {2 digit eec-iv}. with the gas it runs fine but if you let off it surges or dies outright. shotimes says it may be the MAF sensor and that just might sound right since those things usually crap out in freezing weather. i ordered one so we'll see what happens. i drove 120 miles and used a half tank of gas!

fort wayne is like an hour and a half away i believe.

 

[frosho]

Unplug the MAF and run it to see if it makes any difference.

 

[Eric VerValin]

The more I think about it... I know it isnt much, but gasoline does get a little thicker in colder temps.... I wonder if that pushing thru a dirty fuel filter is enough to choke it out.

It's a cheap thing to replace.. and only helps your gas mileage if it hasnt been done in a while.

 

[jayro]

If it runs okay with gas, but will not idle my first thought would be the IAB. I would also check fuel pressure as Eric suggested. Cleaning the MAF is always a good idea as well. Good luck.

 

[freecop]

Put a new MAF sensor and MAP sensor in to no luck. Wires are bad so I got those ordered with autolite double platinum plugs. I'll hose down the butterfly as well . I suppose if I keep replacing stuff I'll eventually get it lol. Thanks for the suggestions and I'm trying each one. I do have a new fuel pump from a couple months ago but isn't there a fuel pressure regulator on the fuel rails? Looks like 1 for each runner.

 

[Eric VerValin]

yes there is, on the passenger side where the fuel lines come in at. The spot where you want to measure is a schrader valve.. looks like a tire stem, has a black cap on it, near the throttle body.

 

[freecop]

OMG my plugs are bathed in oil! Putting new ones and wires in now. Might have been the prob all along.

 

[rubydist]

you will need to change / recondition the valve cover gaskets, or the new plugs and wires will get soaked in oil pdq. at least pull off the valve covers and rtv the gaskets and put them back on.

 

[freecop]

Got a new set of codes. 11 for no trouble and 41 rear bank lean. Runs a **** of a lot better with the wires and plugs but still consuming lots of gas. Damn hood release handle broke off too. What a string of bad luck. Gonna try another idle control valve since the one rock auto sent was a return they resold to me.