1990 SHO sluggish from stop

[Terrorizer]

My 1990 SHO is very sluggish from a stop, and occasionally the engine will die if I attempt to drive it after a cold start up, I need to let it warm up. If I am at a dead stop the acceleration is TERRIBLE, its almost like there is a disconnect between the pedal and the engine. I'm not sure if is just a coincidence, but it almost seems like I get better acceleration if I push the gas pedal in slightly rather than all the way. Once I get up to speed I have decent acceleration but I still have much less power than normal. Any ideas?

Years ago I had similar issues with a Toyota 4Runner, turned out that there was an issue with the throttle cable and when I floored the pedal the throttle was only about half open. I don't know if SHO's ever have similar issues.

 

[SHOdded]

Let's see. A search of the forum will quickly reveal these following possibilities: finicky TPS, dying fuel pump/regulator, leaky injectors, bad plug wires/plugs, misbehaving DIS, nonexistent grounds, stuck O2 sensors, stuck butterflies, etc etc etc. It might end up being that a multimeter is what you need to attack the problem. BUT first, I would pull codes, clean/verify good ground, clean/grease/verify the DIS, pull the plugs to check for telltale signs.

When did the issues first start, and what is the maintenance history? Any bout of bad fuel in your area? SHO sitting around for any length of time?

 

[rubydist]

always pull the codes first, that gives us some data to use, rather than just wild guesses...

 

[Off Road SHO]

Before you even pull codes, open up the hood and just look around for disconnected hoses or wires. Start with the simple.

Tom

 

[Terrorizer]

Before you even pull codes, open up the hood and just look around for disconnected hoses or wires. Start with the simple.

Tom

Well surprise surprise, on my way to work today one of the small coolant hoses under the throttle body blew. Probably unrelated but that will be my next fix. I should have fixed it already I knew there were a couple hoses down there going bad.

 

[sperold]

Try to get a look at the timing marks on your timing belt, and see if they are all in the right place (if you have no codes).

 

[itwonder]

Lots of possible causes, but another is a cat meltdown clogging the exhaust. You can check that the three timing pulley marks line up correctly, however the marks on the timing belt itself align only when the belt is first installed.

 

[rubydist]

Lots of possible causes, but another is a cat meltdown clogging the exhaust. You can check that the three timing pulley marks line up correctly, however the marks on the timing belt itself align only when the belt is first installed.

That is not true at all. The timing marks (including those on the belt) all align every 155 revolutions of the engine.

 

[Off Road SHO]

Wait, let me set my rev counter to 155 and check to see if that's true. The timing marks line up with their respective pointers (on the backing plate and oil pump housing) every second revolution of the engine, IF the timing belt was installed correctly.

Rubydist, how did you find the 155 number? Please don't say you counted the teeth and spacing and did the math, or you will be crowned nerd of the year in my book.

Tom

 

[rubydist]

well, I'll be in your nerd book for sure, Tom. The belt has 155 teeth, and the crank sprocket has 26. The least common multiple of 155 and 26 turns out to be 155 x 26, so that means it takes 155 revolutions for the belt to be back in its "starting" position. BTW, at 155 revolutions the cams will be out of phase 180* (since it is an odd number of crank revolutions), so to get the cams and the belt lined up it actually would take 310 revolutions. Just a little math to do when you are bored...

 

[itwonder]

Ok guys, I get it, but academic arguments are not going to help the OP; with focus squarely on giving the OP practical advice, the point of post #7 is intended to make it clear that it's not going to work if one tries to check the camshaft timing using stripe alignment on a timing belt after the engine has been run; I'm sure you meant to suggest in post #6 he check pulley to reference mark alignment, not belt stripe alignment.

 

[Terrorizer]

I found a small hose under the throttle body burst, I replaced it, but now the car wont start. There is compression on the first three cylinders, spark, and fuel pressure, but no start, im pretty well stumped at this point. The engine is turning over.

 

[Mike Kelly]

Not trying to be a Ass until you pull the codes your ******* in the wind.

 

[Terrorizer]

I forgot to mention, I pulled the codes, no current ones. I can't remember if any were stored. It was a few weeks ago, I'll have to double check.

 

[Mike Kelly]

Let us know.

 

[Terrorizer]

Just out of curiosity, why wouldn't an engine start if the starter is turning it over, their is spark, compression, and I am spraying starter fluid into it? I would think it would have to start up....