ROUGH RUNNING 2
 

Good Morning !

I am thinking that my rough running symptom when starting with hot engine could be something to do with a cold start system. Can anybody explain how it works on the LT5 ? Also wondering if it is switching to a default mode ? When started cold it will run perfect for hours until it is stopped.

Re: ROUGH RUNNING 2
 

I don't think that would be it, cold start just multiplies the fuel being dumped based upon coolant and intake air temp I believe. I would think that would not be your issue. If it happens when hot I would think more likely injectors, wire, coil or maybe DIS

Re: ROUGH RUNNING 2
 

Hi, thanks for coming back to me.
I initially thought coils and replaced them. This made no difference. I then focused on injectors and used injector cleaner, which did seem to help and I thought I had cured the problem. Do you have any thoughts on what is happening with the injectors, if that is the problem ?

Re: ROUGH RUNNING 2
 

Original Injectors tend to go bad, no cleaners etc will help. Check the resistance across the injector to see if they are consistent.

Re: ROUGH RUNNING 2
 

I believe they are the original injectors, It sounds like I should invest in a new set. Have you any advice on which manufacturer ?
Thanks again.

Re: ROUGH RUNNING 2
 

Hello!

The issue is alcohol; dissolves the insulation of the internal actuator coils in injectors installed before 1993.

Talk to Jon at Fuel Injection Connection and ask for the NEW (not "rebuilt") stainless steel injectors for the LT5.

Or, Summit carries the Accel #150821s (which many of us are using). The Accel units have a plastic tab that needs to be ground off of those to be used for the secondary(?) injectors - no big deal.

Re: ROUGH RUNNING 2
 

Pat,

You have several choices. FIC, RC, and Accels are the more common ones. I believe the FICs are the most cost effective but I would stay away from rebuilts.
I have run the Accels for 5 years w no issues.

Re: ROUGH RUNNING 2
 

Well, maybe don't replace too many parts without doing some diagnostic work. It ain't no picnic, and it's cheaper.

Do you have FSM and a multimeter? Fuel pressure gauge? Check static FP, and leakdown time...

Re: ROUGH RUNNING 2
 

Paul,
Thanks for your thoughts, fascinating !

Re: ROUGH RUNNING 2
 

thanks for that, I am going to do more diagnosis before taking the plunge with a new set of injectors.