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.
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.
Last edited by 57 Handyman; 08-21-2017 at 05:02 AM. Reason: added information
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.
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
If it don't fit force it, if it don't force fit f&%@ it!
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.
Last edited by ony; 09-06-2017 at 03:50 PM.
Hey Anthony,
When I first started the motor, it was a fresh rebuild with all the internal engine mods. It ran just fine with the 4288 ECM. Then, something happened when I attached the ECM-to-PCM adapter I made as a means to hook up the 8625. I went the adapter route because I wanted to have an easy escape route to go back to the 4288 in the event I screwed up tuning the 8625. However, since the motor wouldn't start with the 8625, I decided to go back to using the 4288. Unfortunately, that is when all the problems with rough idle, struggling to stay running, and shutdowns/dying surfaced. These problems even persisted when I inserted the PROMs you sent.
Interestingly enough, for some reason, I don't get any check engine lights unless I disconnect a sensor.
lastly, I have not done any data logging because: (1) I am still learning how to get my computer to sync with the AutoProm, (2) then connect via the ALDL. Besides that, the motor won't stay running long enough to attempt any data logging.
If it isn't one thing, it is another...
Last edited by 57 Handyman; 09-09-2017 at 11:29 PM.
I made a adapter and got 1 wire wrong and blowed the modgul in the dist. truck wouldn't start with the 288 reinstalled.it is a possiblityyou may have damaged the modgule most of the time the vehecele don't run at all but it might run badly.if there is a orielys or auto zone over they can check it. tell them to load it heavy when its checked. if it is bad or going bad it wont turn on the cel light. all the red underlines I must not be speling very good this morning.
This seems to be an important piece of the puzzle. Ran fine with '288 initially then like you said the problems came after the '8625. In one of your post, I noticed you said the E-fan kicked on 200dF. The data log you posted, yeah rich and engine temp never got over 140dF. Anyway, I have a few '747s that you can try out. The only V6 one I have is missing the PROM chip so I need to make one. I'll prolly burn the one you posted in one your threads. I can also bring my antiquated laptop and see if there's anything that seems amiss. Just let me know when the next time you're gonna go play!Originally Posted by 57 Handyman
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