euthorus

So a good friend of my mom has been having some problems with her van and I volunteered to help. It's a standard distributor Chevrolet 4.3 V6. The spider injector had sprung a leak, so I replaced it along with the return lines, and plenum gasket. All was well until a few days later the van started stumbling at idle and eventually chocked dumping a bunch of fuel on the ground.

The engine hydrolocked with fuel in most cylinders - another intake plenum gasket and a failed oring at inlet line right at the spider. Changed the oring, cleaned everything out, dumped fuel from the cylinders, new plugs and wires. The van ran like a champ, went for a test drive and all is well. Next day started it up and it is stumbling at idle - checked the fuel pressure and it's holding at 52PSI, cleaned the IAC, cleaned the EGR, checked all connections and vacuum lines, still crappy idle with eventual stalling.

Replaced the IAC, cleaned the EGR again, replaced the TPS, rechecked plugs, checked FPR with bleed down, sprayed carb cleaner all over thinking there is a vacuum leak I somehow missed. Still stumbling after 30 secs or so and eventually stalls. No engine codes, does not feel like an electric miss, the fuel pressure goes up as the IAC attempts to compensate but still stalling.

I am a bit stumped - what am I missing ?

cardana24

Is 52 psi with the vacuum line hooked up to the regulator or not? I am not sure what the pressure is supposed to be on that vehicle, but if that reading is with the vac line hooked up I know that is a high reading compared to stuff I have worked on before. Once the vehicle shuts off have you pulled a plug to see if it is soaked in fuel?

euthorus

52-60ish psi is its happy range. Leaving the gage on and letting it sit for 10mins still hold 50psi. I am starting to wonder if my map sensor is toast or I have a major compression loss or perhaps somehow the timing is off. But mostly think its MAP since I restored 2-3 broken vacuum lines and it's pulling a lot more vacuum now than it had in years.

cardana24

Yeah, I looked around a little more after I replied to the thread earlier because I am not that familiar with throttle body injection. What about the coolant temp sensor, that would have some bearing over the amount of fuel being delivered. Are the plug soaked once it dies?

euthorus

not a real sensor - just a reference plug. Found my MAP wires and connector are messed up as well as thewires going into the spider...joy

euthorus

Well, finally gave up and took it to a shop. It's been there one week now and they dont know whats wrong with it :/

type-r coup

There is a module in the dizzy that goes bad a lot. I'm sure its been check/replaced

euthorus

Need to take a second look, now it runs fine until it warms up then stalls, start up fine and immediately stall

NasTHatch

any news on this yet ?

euthorus

All of the plugs are firing like they are supposed to, the ICM under the dizzy is not a suspect in my opinion as I am not getting any trouble starting at all. The searching idle seriously feels like fuel or air but I can't find a fault with either. I am at a loss with this cursed thing.