I have a 305 TPI that runs perfectly when it’s cold. However when it warms up it runs like s***, and hesitates like crazy under any kind of remotely hard acceleration. Sometimes it’ll stall entirely too. I just put new plugs in and the wires are about to follow (both are Delco), as well as a temp control sensor which seemed to help a bit. Does this sound like injectors?

 

My 92 Z28 5.7 kinda dose the same thing it seem fine when you crank it up but after driving it for a little while it starts to have a hesitation in the accelerating . I was also wondering if it might be the injectors .

 

Sounds just like mine. Starts and idles perfectly, until it gets warm, then it will hesitate and buck under acceleration. I'm definitely a trouble shooting amateur so I don't know how to test the injectors

 

Yeah sounds just like mine . I'm wondering if I have a leaking injector because I have replaced the gas tank and new fuel pump and even the fuel pressure regulator . I hooked up a fuel pressure gauge and primed the pump and the pressure starts to slowly drop from about 42 PSI to the mid to low 30's . Well you might check to see if all your injectors are working by taking a long screw driver and while the car is running take the flat end of the screwdriver and touch the injectors and then put your ear to the other end and see if you hear the injectors clicking its not fool prof but if you don't hear anything it could be a bad injector. And it wouldn't hurt to get a fuel pressure gauge they don't cost much.

 

The old injectors used in these have known problems when hot. You can pull them and have them bench tested or you can just replace them. Having a new set on hand alleviates the need to wait for them to be bench tested and if they are original there's a high likelyhood they are garbage and it will be a waste of time any money anyway. Get some Bosch injectors from South Bay injector.

Fuel pumps are a known failure item also but generally aren't any better when cold.

GD

 

Check your ignition system first( coil,distributor,icm) these components once warmed up is when.you notice failing. Especially the icm in the distributor.

 

Hey tealman92 that's a good point I have change out the distributor cap and button and even the coil but I didn't think to check the ICM.

 

You need at least a cheapo ebay scan tool to get fuel trim numbers and see what the O2 sensor is putting out

 

Agree. Otherwise you are just guessing. This is "Electronic" Fuel Injection. If you ignore the electronics you are just flailing around in the dark. If you are going to own and work on these cars, you MUST have the right tools.

 

Something like this? --



https://play.google.com/store/apps/d...droid&hl=en_US


and

https://www.ebay.com/itm/12-Pin-ALDL...00623.m-1#rwid

 

Yeah those work but it's a lot of setup and messin around. I have one and it's cool but a commercial wired tool would be easier. Depends on how technical you are.

 

Well I just got back from having the ICM tested and if the guy at Autozone did it right the ICM tested bad so I got another one so we'll see how it go's. And thanks tealman for bring that up I don't know why I didn't think of having it tested sooner.

 

Don’t forget to put on the thermal paste under the icm.

 

Will do and thanks for reminding me . Knowing me I would have forgot to do it. lol

 

I have the second one as a backup to my laptop. Its very easy to use, and also comes with a special app in the play store. It was easy to sync up with my phone/tablet. Once synced up and car is running, you select the car type and hit play. You will see any codes on screen, as well as all PIDs refreshing live. Theres another button that if you tap, it will begin to log everything to a CSV file that you can later open as a spreadsheet. There is also a button to "reset ECM".
Also if you have any issues, John. who wrote the app and I believe made the hardware, will get back with you within a day.

Supposedly it will work with tunerpro also if your laptop has bluetooth (if not then just get a USB dongle).