Newbie question regarding Red/Blue PCMs

[57 Handyman]

Hey Buddrow,

Got back home the other day but couldn't and can't get to the truck until an hour from now. The Navy Hobby shop where I have my S10 has limited hours.

The one thing that is interesting about the EGR is the ECM has NOT set any codes. Also, glad to know the absence of the EGR has minimal impact on how motor runs. Unfortunately, that means the cause of my idle problems is something else.

With regard to the Marine Cam Specs, I did have that information some place...just need to find it. As for the casting numbers for my Vortec heads, I will remove the valve covers and get those to you.

Since I've been away from working on and messing around with the truck for a week or so, that absence will allow me to have a fresher perspective rather than a mindset. Also, I know your insights will help. I'll get back with more info soon. Thanks

[buddrow]

Sounds like its time to hook up(if not already) the correct pcm, a vacuum gauge and a timing light and have a look at things. Also check for any vacuum leaks around the intake ports. Spray some brake cleaner around the port area, listen for a change in idle.

Buddrow

[57 Handyman]

Buddrow,

After doing some digging, I was able to find these cam specs...Elgin Pro E-1033-P:

Valve lift: .403 Intake/.410 Exhaust
Lobe centers: 108/116
SAE duration: .271/.284
.050 duration: .202/.213

Valve springs are stock.

I'll get the head casting info today and additional efforts to find vacuum leaks.

[57 Handyman]

Buddrow,

Finally got around to pulling valve covers and getting cylinder head casting number...10235772. From my online research and reading, these were the "best" 96+ heads to use when rebuilding a Chevy 4.3L V6. As for doing any port-matching of the intake-to-head mating surfaces, I have to admit that I didn't do anything in those areas since I had no previous experience doing that so just ignored it. Were you successful in confirming the potential effects of different heights having an impact? Because this was not a serious performance build, I wasn't concerned with it when I put the motor together.

I found my vacuum gauge and will begin a serious and methodical search for any leaks in the top half of the motor.

Blaine

UPDATE: I hooked up my vac gauge to the EGR vacuum port at the base of the TBI. After several cycles of start, run, rough idle while struggling to keep running, then dying, restart again, struggle, and die once more, the motor finally settled down to running longer than 30 seconds to a minute. With the vac gauge installed, the readings started at 20 lbs, the bounced between 16.5 - 18 lbs. After several restarts, the engine would idle until I turned off the key. What appears to have been a marking point was when the engine temperature reached around 200 deg F which resulted in the radiator fan kicking on. Don't know if the temp is is of any significance but I thought I'd mention it. After letting the engine cool, attempted another restart and it started up and ran fine. After these multiple restart, I am now beginning to under if the ECM "learned" something and is now using those settings to control the motor.

As part of arriving at this somewhat acceptable condition, I did a few other checks:
(1) sprayed starter fluid along the mating surfaces between intake and heads - NO CHANGE
(2) sprayed fluid onto the base of the TBI as well at mating areas for sensors--TPS, IAC, and MAP - NO CHANGE engine started, idled, then died.
(3) disconnected ESC - NO CHANGE engine started, idled, then died.
(4) disconnected TPS - NO CHANGE engine started, idled, then died.

I will return tomorrow attempt to start the engine and continue to monitor performance.

[57 Handyman]

Buddrow,

My apologies and sorry for the extended delay in getting back to you. Well, I did return to the shop the following day and to my great dismay and disappointment, the problems were back! Talk about being pissed...I walked away for several days and went about doing other things. Now, I'm back to getting this darn truck of mine fixed and on the road.

So, where to start???

First, I was able to get a 1227747 on Ebay out of a 90-91 4.3L; it should arrive sometime this week. Do I need to do mods to it before plugging it in? You've stated I need to get the mechanical stuff straight, but I don't know what else to do. Any recommendations?

Thanks for your assistance.

[buddrow]

Double check all grounds. Also, jump diagnostic pins or hook up laptop/tunerpro to gather any codes that may be stored. Could also be valves adjusted a tad too tight.

Buddrow

[ony]

handyman how was it running before it was modified? was the check engine light on or anything. when you are hooked to it datalog and record and save a file then post the file.