88 350 TBI cold start stumble.

[kenh]

Have somebody check the radiator for Co2. If it's a head gasket you will have Co2 in the radiator from the combustion process.

Ken

 

[Steven Petersen]

Have somebody check the radiator for Co2. If it's a head gasket you will have Co2 in the radiator from the combustion process.

Ken

I’m almost certain it was the slow leak I found at the heater hose to core connection. Tomorrow after I get everything back together I’m gonna pressurize the system and make sure.

 

[thinger2]

Had the same problem on my 94.
It ended up being badly worn throttle shaft at the linkage end was causing it to suck air at cold start and making the initail air setting to far out of whack for the tps.
I was able to compensate for this by adjusting the initial air a little bit but it was only a temporary fix

 

[Supercharged111]

Had the same problem on my 94.
It ended up being badly worn throttle shaft at the linkage end was causing it to suck air at cold start and making the initail air setting to far out of whack for the tps.
I was able to compensate for this by adjusting the initial air a little bit but it was only a temporary fix

Were you able to get butt ass cold starts with no throttle or stumbles?

 

[thinger2]

Were you able to get butt ass cold starts with no throttle or stumbles?

Yes but keep in mind im in Seattle.
we really dont get butt ass cold.
I made it work in about 25 degrees but it was a really fine line between just enough initial air and the throttle plates sticking in the bores.
It was enough to get it work untill spring but kinda sketch..
I only did it because I had the shop torn down to the studs to set earthquake anchors into the foundation and had to do all vehicle work outside

 

[Steven Petersen]

Yes but keep in mind im in Seattle.
we really dont get butt ass cold.
I made it work in about 25 degrees but it was a really fine line between just enough initial air and the throttle plates sticking in the bores.
It was enough to get it work untill spring but kinda sketch..
I only did it because I had the shop torn down to the studs to set earthquake anchors into the foundation and had to do all vehicle work outside

I’m curious, did you have a scanner hooked up when it did this? If so, were any numbers out of whack?

 

[thinger2]

I’m curious, did you have a scanner hooked up when it did this? If so, were any numbers out of whack?

No, I didnt use the scanner. After finding the play in the throttle shaft I suspected it was scavenging air so I pumped a bunch of heavy grease between the linkage and the throttle body and pushed it into the gap with a really tiny paint brush.
Did a cold start and the problem went away.
Blasted all the grease off with carb cleaner and the problem came back.
A real half assed diagnosis but it told me what I needed to know

 

[Supercharged111]

Yes but keep in mind im in Seattle.
we really dont get butt ass cold.
I made it work in about 25 degrees but it was a really fine line between just enough initial air and the throttle plates sticking in the bores.
It was enough to get it work untill spring but kinda sketch..
I only did it because I had the shop torn down to the studs to set earthquake anchors into the foundation and had to do all vehicle work outside

Mine was money for a 25 degree start. South of that is where my '88 got a little finicky for the first few seconds.

 

[thinger2]

Mine was money for a 25 degree start. South of that is where my '88 got a little finicky for the first few seconds.

I have noticed that the more "new" aftermarket parts I put on the trickier diagnosis becomes.
I have bought several spare parts at auctions and estate sales and sometimes swap them out just to see what happens.
The service manuals are written with 90s parts in mind.
New junk parts dont meet the same parameters.
This is why live data becomes more critical.
So everyone who tells you to get a scanner is right.
Its only gonna get worse.
But we can still do some old school **** on the side of the road too

 

[Steven Petersen]

I have noticed that the more "new" aftermarket parts I put on the trickier diagnosis becomes.
I have bought several spare parts at auctions and estate sales and sometimes swap them out just to see what happens.
The service manuals are written with 90s parts in mind.
New junk parts dont meet the same parameters.
This is why live data becomes more critical.
So everyone who tells you to get a scanner is right.
Its only gonna get worse.
But we can still do some old school **** on the side of the road too

You are right. Most of the Ac Delco parts are made in China now. I buy NOS Delco parts off EBay. Stuff with the original part numbers from my parts catalog.