My 88 TPI started this hesitation at a stop like it might not be getting enough gas. The injectors have about 30,000 miles on them.It just started doing this out of no where. And it doesn't do it all the time. Anyone got any ideas no codes thrown.

 

First thing I would do is remove the throttle body, clean it and the IAC. Then reset the TPS sensor and IAC. A procedure is on my site, click my name.

Then I would go about checking fuel pressure and spark to each cylinder if it wasn't fixed.

 

Especially the TPS. In carbed engines, it squirts a shot of extra gas each time you pump the throttle to stop a hesitation. Your TPS's job is virtually the same, if it's off its setting, it doesn't tell the computer you just came off idle..

Greg

 

would cleaning the MAF and TB help? Where is the IAC located?

 

Yes, but I doubt it is what you're after.

IAC is just below the TPS..
Tps senses where the throttle is and senses as it is moved. If it isn't set right, computer isn't told right info when you move the throttle. TPS is easy to set. Using pins, connect a digitial meter (analog won't work) to the wires. Ignition on (not running), it should read around 0.5vdc up to 0.6vdc.. (I think 0.54 is target for yours). If it is off either way, loosen the 2 screws that hold it. You can rotate the TPS a hair either way until voltage is correct. Tighten screws while still watching voltage to make sure it didn't move. Once you've set it to base, then slowly move the throttle from idle to full while watching the meter. It should gradually increase the voltage as you move. If it sits on one voltage for a bit, or read 0 then jumps up, it's toast, other wise that part is complete. If still stumbles off idle, then you need to go further into basic tune up.
IAC controls idle and is an anti-stall on decelleration only. Doesn't come into play while driving or hitting the gas. If your idle is good, no point in playing with the IAC unless you know what your doing.. If the pintle gets moved while it's out, you can destroy the IAC when you put it back in.

 

your right it didn't help. Where can I buy a digital meter like autozone? Now when I kick it in the *** from around 30 it boggs down like it's starveing for gas

 

Any electronics shop and most decent hardware stores will have digital meters.. Radio Shack (if they still exist there?) etc..

I thought your bog was just off idle..
You should still verify the TPS, but so much more can come into play when the bog is at different throttle positions.. Starving for gas is amoung them.. Plugged filter, plugged inlet, low pressure from pump, regulator failing to provide proper pressure and plugged injectors (they however usually hit the idle bad too).

Timing is another thing as is all the sensors such a temp, air temp, TPS, MAF etc..

Does it miss, back fire or just plain feel weak?

 

the injectors have about 30,000 on them purchased from john. no miss or back fire just falls flat at a kick down. when you first take off its like starveing for gas and then levels out. then running about 30 or so and when i nail it it boggs down and then catches up. It was running fine and then just out of nowhere it started this crap

 

Can someone tell me why this thing isn't throwing any codes? It is running like crap

 

It can show codes and run great, it can run like crap and not show codes. It isn't that smart. Codes show when some sensor is reading out of range period.. For example, if you set the timing way off, the computer doesn't know that, it will just do the best it can to adjust idle and anti knock anyway..

These were state of the art, for their time, doesn't mean they're capable of pointing right to your trouble!

 

I put new distributer cap and rotor on this morning and now it's running worst. No power and back firing. I numbered the plugs wires and thought I got them back on in the same order? I'm about to use this thing for a hugh flower pot

 

Pretty sure since you made it worse and now have back firing you know the answer to "thought I got them back on in the same order?"

 

I followed the diagram AGENT 86 sent me. Checked it three times I'm really confused as to what the hell is going on. Now it's not even driveable at least before it was driveable

 

Any diagram is only usefull if the distributer was in factory position to start with, it probably isn't..

You need to figure out where number one is on the distributer. Normally standing at the front of the car, the power plugs to the cap would be directly to the drivers side and number one would be the right of the 2 posts closest to the front of the car. Again, that assumes the distributer is still indexed right. If it isn't, #1 could be any of the 8!! If the power plug is not directly to the drivers side, then it certainly is not indexed, if it is, doesn't mean for sure it is indexed..

Finding number 1 is ignorant for a newbie.. Lets assume for now, the distributer is still indexed right..

If done right (again, assuming index is correct) then only 1 wire from each side of the distributer crosses to the other side, other 3 on each side stay on the side they start from.

If the diagram below doesn't work, then your distributer isn't in it's original position and you need to find out which post is indexed to number 1..

To do this, pull the cap. Pull #1 spark plug. Put a socket on the center bolt of the harmonic balancer and begin to turn the engine by hand while holding your thumb over the spark plug hole. Once you feel the compression on the spark plug hole trying to pop your thumb off you can remove your thumb. Now, looking at the harmonic balancer, the slot cut in it should be visible. Turn the engine until this slot is lined up with the 0 mark on the tab welded to the timing chain cover. All of this is extremely hard to see on a Vette and as mentioned, this job really sucks.


Once you have done that, figure out what post on the cap the rotor would be pointing to, that is number one post and wire 1,8,4,3,6,5,7,2 from there. If you've had to do all this, then you just learned something, you will never again remove plug wires without following #1 back and marking the post!

By the way, now that you know where #1 really is, the distributer can be pulled and indexed to the right location but you need a timing light to do this. Other wise the only downside to it not being indexed right is your current problem and plug wires that may not reach nicely to their correct locations, doesn't effect running at all.

 

By the way, if you can get it to Ontario Canada, I will always pay at least $200 for your flower pot!

 

Thanks for all the info. I'll make this my saturday project. It looks like a task just to get a socket on the balancer. As for coming to ontario I'll elpaso on that. Thanks again for your help i appreciate it.

 

since it was not that bad before you "fixed" it. I have miswired my engines more than once.