hesitation

[freqsho]

i have a 91 sho with 120000 mi,fresh 60k, when vehicle is cold it has a bad hesitation ( spits & sputters) until 3000 to 4000rpm then its balls to the wall. doesnt matter what temp outside it is just if the car is cold, also probably related but after its warm it seems to have a dead spot about 3100 to 3300rpm, all sensors are new except for knock, map, coolant temp for computer, evap purge. theres no codes & because of the year i cant look at data stream w/my scanner i think thats it please help thank you shrug cry

 

[SHO--ripper]

What did you replace with your 60K? If you replaced your plugs+wires which i assume you did i think you should check your fuel pressure. I think you might need to replace your fuel filter and pump. Before you replace anything check the codes. Good luck and welcome to the forum. thumb

 

[AutoSHO]

Check your ECT (Engine Coolant Temp) sensor. They're cheap and easy to replace.

 

[sdpatt]

Refer to the links at the bottom of my signature to learn the simple way to check the codes on the Gen I and Gen II SHO. You will haev to inform us of the services and parts replacements that were performed during your "60K." That term may mean different things to different people. What brand of plugs and wires are on your engine? Are all of the sensors and actuators plugged in? Have you seen the CHECK ENGINE light?

 

[shobikes]

i revived this old thread 'cause i have THE SAME PROBLEM. i've done complete 60k, new plugs/wires, new ECT sensor, new fuel pump, new fuel filter, cleaned MAF repeatedly (K&N), new TPS, new O2 sensors, new CPS, cleaned intake, cleaned IAB, blasted out DIS/MAF/ACT connectors with contact cleaner, and I STILL HAVE THIS!!! shrug
-i usually let it warm up for 5 or more minutes anyway, but if i don't let the engine temp come up out of the blue completely, it runs like butt. it will spit and sputter and generally refuse to GO until it hits 3500-4000 rpm. what's next? ACT sensor? HELP ME I'M GOING TO BLOW IT UP SOON.

<small>[ February 18, 2004, 09:03 PM: Message edited by: shobikes ]</small>

 

[Anthony1238]

Sound like a possible Vacumme leak... Have you ever taken your intake apart to clean it... If so you need to put fresh gaskets on them and a good amount of RTV. That happen to my 89... it was leaking through the primaries but once the secondaries opended at 3900 the air was dirverted to them and it acted normal... Just a sugestion... I think if it was a fuel pump/filter problem it would't go away in higher rpms... or at least it doesn't when your Injectors are bad...

 

[AutoSHO]

Have you checked your fuel pressure?

 

[shobikes]

AutoSHO:
Have you checked your fuel pressure?

i have not actually checked the fuel pressure. i assumed a new pump would fix any pressure issue, but i guess it could be an FPR problem. it used to be hard-starting, but now kicks on the first crank, so i had eliminated that. i'll go by AutoZone and get them to check it, as i don't have the right type of gauge. thanks - if it were fuel pressure, wouldn't it affect the entire RPM range, esp above 4k?

i have never taken the intake apart. i took it off to do the 60k, but used new gaskets and proper torque for reassembly. i did put a 12mm on each of the plenum nuts the last time i had it off, and a few were less than tight, but not loose.

BTW - there are no codes. anybody else?

 

[SonicRiot]

When it is cold outside, the car should run stronger, as the Yamahammer loves cold air. It sounds like a vaccuum leak... when the engine is cold, everything is constricted. As it heats, the leak will dissapear if it is a minor leak.

Try also cleaning the injectors and check the fuel pump.

 

[shobikes]

OK, so I got fuel pressure checked today.

KOEO - 32 psi

KOER - 32 psi

Goose - 40 psi

Key Off - 26 psi

Do I need another FPR?

I will check for vacuum leaks tomorrow.