Goin' TBI

Well guys, specifically Silicon... I'm probably going back to the ECM. Different this time though. I originally removed the ECM and all components including emissions to put in the 350 I built into my '84 Caprice with old fashioned parts like a regular carburetor and vacuum advance distributor. I like to tinker around, and adjust things etc. It's fun for me and I just couldn't get that with an ECM contolled engine. But as most of you already know I've since ruined that engine. I'm now taking a good solid running 350 from a '92 Chevy Silverado and am gonna drop it into the Caprice. I don't really have time anymore to tinker like I want to, and I'd rather be able to drive my Caprice with an ECM than not at all. So I'm considering transplanting the entine ECM TBI system from the truck to the Caprice. It's already emission-less aside from the EGR valve and PCV valve, but since it's a 2500 pickup, emissions were very limited then, just the way I like it :evillol:. Those two pieces of environmental controls I'll keep on the engine as to not screw with the ECM.

But anyway, this story has a point, or a question rather... In this '92 pickup and also in my '89 GMC (which both look almost identical under the hood) at startup the computer automatically and immediately revs the engine up very briefly to 2000 RPM then drops down to a normal idle. During that rev my '89 rattles a bit until you see the oil pressure jump up and then it's quiet. I hate how it does that though, but theres no way for me to control it. Is there anything I can do to stop it from doing that? Everytime I start it up i feel like I'm hurting the engine. With a carbureted engine that doesn't happen unless you have your foot on the pedal, but with TBI you don't even have to touch the pedal no matter how cold the engine is.

P.S. Now that I think about it, my '89 GMC revs more drastically than the '92 Chevy. They both run great, the '92 it just rotted beyond belief.

Make sure you have the right AC-Delco oil filter on there. PF1218.

There is supposed to be a valve that holds the oil pressure up built into the fitler. Some aftermarket ones don't have it or don't have a good one....

I've used Fram for years, but next oil change I'll try an AC and see how it goes. I've recently changed the oil pump and oil pump driveshaft. It's a stock pump, but I'm already getting 58 PSI at idle cold and 27-ish PSI at idle hot so oil pressure may not be an issue.

If yo only get the noise at start up it's probably one of two things...

Either that oil filter or your crank bearings are worn.

I've used Fram for years, but next oil change I'll try an AC and see how it goes.
Definitely try the A C Delco. I'm sure if you do some research on this site you'll see the bad press Fram has nowadays. Check out this study that was done on oil filters and see what they found out. Especially read the review for Fram and the Delco one:http://minimopar.knizefamily.net/oilfilterstudy.html

From the "Engine Oil Study": Even so, I have received testimonials that the AC Delco stops the valve train noise problems associated with the Fram filter

I'll definately keep posted here as to if the A/C Delco makes a difference. And I always thought Fram was supposed to be good.

I started this thread regarding transplanting and entire TBI system into my '84 Caprice. Now I want to go back to the for a moment... What are some things or problems I may run into. I don't know if anyone here has ever turned a carbureted engine into a TBI engine. Since the truck also had a 4L80, will the computer be "confused" no longer being hooked up to a transmission?

I'll definately keep posted here as to if the A/C Delco makes a difference. And I always thought Fram was supposed to be good.

I started this thread regarding transplanting and entire TBI system into my '84 Caprice. Now I want to go back to the for a moment... What are some things or problems I may run into. I don't know if anyone here has ever turned a carbureted engine into a TBI engine. Since the truck also had a 4L80, will the computer be "confused" no longer being hooked up to a transmission?

So, you're using the '92 for the engine source?

I am not sure about the 4L80E circuitry. You may want to use that engine with an older PCM, say from an '89 or '90 9C1 or other 350-powered car.

As for Fram, they let way too much stuff get by them. Plus, as others have noted, the drainback valves don't always function as designed. AC Delco All the Way.

I'm also considering converting my car to EFI as well - I'm going to try to stick with the 9C1/Caprice 5.7 stuff.

The reason I'm using the '92 Pickup as a source is because I purchased the truck stricktly for parts for my '89 GMC Pickup. They're both 2500, both with the 5.7 liter 350, but the difference lies in the drive train... my '89 has a TH 400 and it's a 4x4. The '92 has a 4L80 and is only 2WD. I found that his "engine problem" was nothing but a vacuum leak, so I want to use this perfectly running engine in my car. The ECMs on both trucks look identical, but obviously are not. Could I get a PROM from and older truck and use it with the '92 ECM?

BTW - The '92 4L80 is probably NOT an "E" variant, and thus has minimal involvement with the ECM. The transmission should shift itself with input from only the TV cable, and the ECM only gets input from a top gear switch and controls the TCC lockup. The transmissions are going to be different in the tail extension housing and shaft (to accommodate the transfer case) and may not be convertible.

The idle increase on initial start is programmed into the ECM, although is should be more on the order of 1,300-1,500 RPM than 2,000 RPM. The higher startup idle can be programmed out in a custom PROM for that ECM.

Okay, I think the transmission os a 4L80-E, but I'm not positive. It's got three plugs going into it, two little, 2-lead ones and one big round one that has a bunch (10-ish) wires coming from it. Would that indicate a 4L80-E or just a 4L80?

That would likely be the "E" variant. IIRC, the system used a separate TCM in '91-93, and went to ECM/PCM control in later years. You're going to have a bit of a project to convert to that trans from a hydraulically shifted unit. All you need should be on the donor truck, so it doesn't have to cost a lot in components, just time.

If it were mine, I'd be more inclined to restore the '89 ECM and wiring, use a TH700, and program it for the larger TBI (or consider TPI or a batch-fired LT1 or Mini Ram).

If it were mine, I'd be more inclined to restore the '89 ECM and wiring, use a TH700, and program it for the larger TBI (or consider TPI or a batch-fired LT1 or Mini Ram).

I think you misunderstood me, I bought the '92 Chevy Pickup for parts for my '89 GMC. BUT... I'm taking the engine w/ the TBI from the '92 Chevy Pickup and putting that into my EMC-less '84 Caprice Classic. My '89 GMC pickup is completely stock, and still has it's ECM. I'm leaving all that alone.

Anyway, how specifically can I make this ECM (From the '92) run with a 700-R4 in the place of the 4L80-E?

What ECM is in the '92 (there should be a 7- or 8-digit part number on the label, like 1228747 or 16146299) ?

The only 8-Digit number I could find was: 16147060. The only other number was a long @ss barcode number. It says it was remanufactured, which is consistant with what the previous owner said about having to have the computer replaced.

Well, here is is. It doesn't look like much, but trust me it's a very nicely running engine. I'm hoping to use the serpentine belt system as well. Sure beats the multiple V-belt setup.
http://www.freewebs.com/petea/bigblueengine.JPG