Hesitaion HELP

[syty9933]

My Syclone has had bad hesitaion almost ever since we got it new, but i was little then and my dad worked too much and had enough cars to go to work and didnt have time so it pretty much sat, now i drive it and it still has a hesitaion usuakky from a stop when you hit the gas it dosent go for a second and then it goes. When i swapped my 160 stat out for the stock 195 it didnt have the problem but now its starting to come back even with the 195. ive read all the threads in the search bar. I even found a guy writing this exact same post here http://www.syty.net/forums/showthread.php?t=36838&highlight=hesitation

but i dont think he has had it figured out. I have a stock pump and stock injectors ..My guess is that it is a pump, or fuel filter, how do i go about figuring out if its the pump, sometimes i also see a lil bit of smoke by the egr ??( side note)


any thoughts?

 

[Quickstop [UK]]

Re: Hesitaion HELP

Depending on how long you've had it, a fuel filter is essential and a fuel pump is recomended. An injector failure from what I have read on here is a rare thing. Done the other stuff yet? Cap? Plugs? Rotor? Vac lines?

Have you got Data Master? You need it. Wideband O2? Very recommended.

Awesome you had it in the family and know the history!

Welcome to a small but knowledgeable and friendly welcoming international club!

 

[Quickstop [UK]]

Re: Hesitaion HELP

Depending on how long you've had it, a fuel filter is essential and a fuel pump is recomended. An injector failure from what I have read on here is a rare thing. Done the other stuff yet? Cap? Plugs? Rotor? Vac lines?

Have you got Data Master? You need it. Wideband O2? Very recommended.

Awesome you had it in the family and know the history!

Welcome to a small but knowledgeable and friendly welcoming international club!

 

[JSM]

Re: Hesitaion HELP

you can say that again.

 

[syty9933]

Re: Hesitaion HELP

Depending on how long you've had it, a fuel filter is essential and a fuel pump is recomended. An injector failure from what I have read on here is a rare thing. Done the other stuff yet? Cap? Plugs? Rotor? Vac lines?

Have you got Data Master? You need it. Wideband O2? Very recommended.

Awesome you had it in the family and know the history!

Welcome to a small but knowledgeable and friendly welcoming international club!

Yes i have done all of that except vaccum lines, and a fuel filter and fuel pump, i guess thats next, Thank god its probally not an injector, and yea back in the day he bought a green ty and a black sy brand new and the sy has always had the little hesitation problem , so it used to sit because of lack of time to fix it and because we had and still have at least 10 cars to drive. It only has a lil over 50k which is pretty good, it runs great besides this problem. I guess it is time for a new pump.... But how do the thermostats change the problem and my pump sounds stout to me when priming??


thanks

 

[gkrcr882]

Re: Hesitaion HELP

Need to do a pressure & volume test on the pump to verify its condition. Is it only a slight, momentary hesitation or a pronounced one? I have heard about whats known as "tip in sag" on LT-equipped cars (where we get our throttle body), and an airfoil in the throttle body between the throttle plates remedied the situation. Definitely change out that fuel filter, you'd be surprised how much junk actually gets caught in them.

 

[syty9933]

Re: Hesitaion HELP

Need to do a pressure & volume test on the pump to verify its condition. Is it only a slight, momentary hesitation or a pronounced one? I have heard about whats known as "tip in sag" on LT-equipped cars (where we get our throttle body), and an airfoil in the throttle body between the throttle plates remedied the situation. Definitely change out that fuel filter, you'd be surprised how much junk actually gets caught in them.

aight ill change it and get it tested. Its usually about a whole second, and my fuel pressure sensor is broken for my gauge in my pillar pod( go figure) but ive heard that it suddenly goes from lean to rich in this situation?i guess ill buy an airfoil to fix this too, and how do you think the thermostats affect this?

 

[Sean Krupa]

Re: Hesitaion HELP

I have a hesitation problem to. It only happens when I first start it when it's cold. It goes away after awhile. It doesn't happen all the time. I changed the fuel filter and still has a hesitation. I also turned up the fuel pressure 2psi because I had a knock problem but it still happens. My dad said it was always like this even when he bought it in 94.

Thanks,

 

[syty9933]

Re: Hesitaion HELP

I have a hesitation problem to. It only happens when I first start it when it's cold. It goes away after awhile. It doesn't happen all the time. I changed the fuel filter and still has a hesitation. I also turned up the fuel pressure 2psi because I had a knock problem but it still happens. My dad said it was always like this even when he bought it in 94.

Thanks,

yea same here , when it heats up it usualyy goes away, even new it did that but only in the syclone not in our typhoon?

 

[SY2932]

Re: Hesitaion HELP

You *need* to see what's happening with your fuel pressure. I have done it "hillbilly" style in the past to see if it was the pump or not by road testing my truck minus hood. I rigged up my mechanical fuel pressure gauge that I use to set my fuel pressure so that I could watch it while driving. If it's dropping off when you get on it, you have a fueling issue. Once you get into boost, it had better rise one pound of pressure per one pound of boost or else your will start detonating your engine to death...

If you still have the stock fuel pump in there, it may the pulsator causing you problems too. You can see my "how to" write up for a syclone fuel pump swap here. Check the fuel pressure and let us know what you find out.

 

[Sean Krupa]

Re: Hesitaion HELP

I have my fuel pressure set to 40psi. My knock is a little high right now, (5*) at 12psi boost. I also have a Walbro fuel pump. It doesn't hesitate when I get into boost, only when I'm getting up to speed (normal driving).

 

[gkrcr882]

Re: Hesitaion HELP

First priority IMO is to get that knock under control, there has to be some underlying cause. 5* at 12psi shouldn't happen.

 

[Sean Krupa]

Re: Hesitaion HELP

First priority IMO is to get that knock under control, there has to be some underlying cause. 5* at 12psi shouldn't happen.

I had a whole lot more than that before I turned up the fuel pressure. I had about 11*. I'm thinking if I turn the fuel pressure up 2psi I will get it abit lower.

 

[syty9933]

Re: Hesitaion HELP

I had a whole lot more than that before I turned up the fuel pressure. I had about 11*. I'm thinking if I turn the fuel pressure up 2psi I will get it abit lower.

good luck man youll figure it out, it would be a shame to a have a truck so pretty and clean that gets ruined or cant run to its potential, try some upper cylinder lubricants, or additives, sometimes i throw in a bottle of octane booster

 

[gkrcr882]

Re: Hesitaion HELP

Band-aids such as lubricants and "octane boosters" (which really only raise the octane by a 10th of a percent or two) aren't the answer. By using the trial and error diagnostic routine, you can find out exactly what it takes to make your truck run 100%. There are tons of possibilities for sources of detonation: poor quality gas, carbon deposits, high IATs, incorrect ignition timing, boost pressure spikes, abnormally high cylinder temperatures or pressures, the list goes on. The combustion process is a precisely timed event, and each part must occur at exactly the right time in order for the engine to be efficient and to make power. Detonation, obviously, is the result of this precise timing being interrupted. Detonation, or "knock" is more than just the cylinder firing at the wrong time-thats another entity called a misfire- Knock is when cylinder pressures become many many times greater than they are supposed to be, and the hydrodynamic wedge between the bearing surfaces is actually broken for a brief period of time. Finding out whats causing this problem in this series of events is critical for knock control. As far as the hesitation- it could be an aging fuel system component, poor ignition system components (high resistance or opens), a sensor out of range, the list goes on. If you can get a scantool that displays realtime data, and you know what the sensors should look like (hell, if you can hook up an igniton scope it couldn't hurt) you can find the potential problem. Sorry for the rant, I have a tendency to get in-depth with things of this nature- information/knowledge is power. **steps off soapbox**

 

[syty9933]

Re: Hesitaion HELP

Band-aids such as lubricants and "octane boosters" (which really only raise the octane by a 10th of a percent or two) aren't the answer. By using the trial and error diagnostic routine, you can find out exactly what it takes to make your truck run 100%. There are tons of possibilities for sources of detonation: poor quality gas, carbon deposits, high IATs, incorrect ignition timing, boost pressure spikes, abnormally high cylinder temperatures or pressures, the list goes on. The combustion process is a precisely timed event, and each part must occur at exactly the right time in order for the engine to be efficient and to make power. Detonation, obviously, is the result of this precise timing being interrupted. Detonation, or "knock" is more than just the cylinder firing at the wrong time-thats another entity called a misfire- Knock is when cylinder pressures become many many times greater than they are supposed to be, and the hydrodynamic wedge between the bearing surfaces is actually broken for a brief period of time. Finding out whats causing this problem in this series of events is critical for knock control. As far as the hesitation- it could be an aging fuel system component, poor ignition system components (high resistance or opens), a sensor out of range, the list goes on. If you can get a scantool that displays realtime data, and you know what the sensors should look like (hell, if you can hook up an igniton scope it couldn't hurt) you can find the potential problem. Sorry for the rant, I have a tendency to get in-depth with things of this nature- information/knowledge is power. **steps off soapbox**

oh i totally agree, i wasnt saying it was the answer just some steps in the right direction,some of those "band-aids" can help and yeah the octane booster does suck but trying a lil might show you if its gas related? But Sean will figure it out hes got such a clean setup and hes very knowledgable, thanks again for the airfoil tip, im goin to get a walboro, filter, and air foil tonight with the last of my money haha, and a new throttle body soon too, that should all do it


thanks

 

[Sean Krupa]

Re: Hesitaion HELP

Do you guys thing if I use Top end Cleaner it might help the hesitation?

 

[syty9933]

Re: Hesitaion HELP

Do you guys thing if I use Top end Cleaner it might help the hesitation?

idk but im goin to get some before my new turbo and exhaust swap, and then im getting a new throttle body, fuel pump, filter, and full engine detaill, so it should deffiantly be fixed then