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Engine & Trans Decisions

wildweaselmi

wildweaselmi

Bra Stress Tester
Joined
May 23, 2016
Posts
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Location
Davison, MI
I have been working on my 91 K5 for years and I have been struggling with two main things.
Engine
Transmission

I purchased a GM crate 383 stroker motor for the torque, power and reliability. I immediately put on the Holly Fuel Injection and that’s when everything started to suck. For reference I had the original 700R4 installed at the beginning.
Anyhow, not changing anything, it was not install and start as advertised.
I needed to buy a new distributor because the one I had wasn’t compatible.
I needed to install ignition box
It still didn’t run so paid Motor City Steel to sync tune it and it finally ran but was stalling when I hit the brakes. Motor City Steel won’t reply to two weeks of calling, emailing and using FB messenger so guess they are out.
I tried a place called Alpha Motorsports and for more than $1000 they made it undriveable after having it for 72 days. I just took it back since they were making it obvious they just didn’t know what they were doing. Now all of a sudden they said one of my cylinders doesn’t have full compression. Seriously WTF..

so I’m exhausted chasing down a way to make my blazer run.

I purchased a new 700R4 trans but I’m not stuck to it if there is a solution that will be reliable and run.

I use my blazer 75% on the highway driving to work and 25% Offroad.

what combo is everyone using? Carb, fuel injection, 700R4, 4L60e, 4L80e (with the electronic trans what computer r u using)

appreciate any input.. what ur happy with, what your not happy with, if you could do it again..
 
Nut shell answer:

4L60s are fragile
Holley Sniper EFI is forgettable

everything else is negotiable


Run a compression check on that engine yourself and see where you really are before you dump more money into the fire
 
Sounds like you are in over your head to me. Too many problems with your drivetrain all at one time. Takes someone with a lot of knowledge and patience to sort them out one at a time. Most auto repair shops are not going to fix your rig because if bolting on a part does not fix it they do not want to mess with it. If this where my rig I would go back to square one, and make sure the timing chain was installed correctly, the valves where adjusted correctly, the distributor was installed correctly and was the correct one for aftermarket fuel injection, no vacuum leaks, and it was getting fuel..air...and fire.
 
If holley sniper unit sounds like the same problems i had . My story of hell is in the injection section here .

I found a easy fix for it . . . Remove it and went edelbrock pro flo 4 . More of a true unit and way better all around . Gm even uses the edelbrock unit on 1 of there engines offered on the crate engine line up .
 
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There was another guy here recently who was having a problem with a Holley Sniper unit, ended up being the location of the water temp sensor putting the fuel injection into limp mode. Maybe he will chime in here.

Me personally, and has already been stated, go back to last known working condition. I have run a 350 off of only 5 and half cylinders before so I kinda doubt one dead cylinder is causing your problems. Do a compression check, check valve timing, ditch the Holley for now and add a known working carb and distributor and tune it. One step at a time buddy. That 383 is a just a teenage small block 400 so its dirt simple, you just have to get it back to dirt simple to get it to run properly. Then add the electronic goodies one at a time.
 
The only problem that I see with going to a carburetor to get it running, is that you can't drive it without setting up the TV cable properly for the transmission. Yes, you probably have too much fuel pressure for a carburetor, but that should be something that can be dealt with.

The 700R4 isn't terribly fragile if built properly. I have close to 50K behind a big block on one of mine, also have a couple of other trucks with them. O know of another guy who had one in a street/strip car for years, all good when it went into his C10.

Anyway, you can make it run and drive with the engine and transmission that you already have, however you are probably going to have to learn how to work on it yourself. Even if you swap another engine and transmission combination into it, there's plenty of ways a shop can cost you a lot of money and headache. This is why @Joel Wilson is spot on that you need to go back to basics, and work your way up.
 
After having both a Holley Sniper and Edelbrock Pro-Flo 4 and having issues with both my future builds are really leaning towards something with factory EFI. A lot of guys here love the Pro-Flo but I'm in the middle of a saga with mine that I will update everyone on once it's resolved, but it's been going on for several months now. I've had a few issues with the Sniper as well, but overall it's worked pretty good for me. It's just that once you get into a situation where there's a problem you can't figure out, it can be hard to get help. At least with a factory EFI setup, there are usually lots of people and shops familiar with how to fix it.

I have a 4L80e with a US Shift Quick 4 controller. I really love the set up for what I do. I drive it on a lot of highway plus trail running and it gives me a lot of control and versatility.
 
mrk5 said:
After having both a Holley Sniper and Edelbrock Pro-Flo 4 and having issues with both my future builds are really leaning towards something with factory EFI. A lot of guys here love the Pro-Flo but I'm in the middle of a saga with mine that I will update everyone on once it's resolved, but it's been going on for several months now. I've had a few issues with the Sniper as well, but overall it's worked pretty good for me. It's just that once you get into a situation where there's a problem you can't figure out, it can be hard to get help. At least with a factory EFI setup, there are usually lots of people and shops familiar with how to fix it.

I have a 4L80e with a US Shift Quick 4 controller. I really love the set up for what I do. I drive it on a lot of highway plus trail running and it gives me a lot of control and versatility.
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While I have never used a Sniper system, and I am not 100% pleased with my PF4, I have never had the PF4 die and fail to restart. (At least so far, knock on wood)
Even with a leak above the O2 sensor, it would run and drive, just lacking in performance.
My '01 GMC with a LQ9 that has a Texas Speed cam installed, has been reliable, even though it appears to be having an internal ECM problem. Small tweaks to the engine and transmission map have been very precise as well. There are definite advantages to a more capable computer and system.
 
in the long run i wish i had just done a LS in my budget beater build . then i could of run a 4L80-e trans easy . then swap to electric plow pump over my current belt drive plow pump .

i like my pro flo 4 but i dont play with it much as i just drive it . it has been hands down better than the sniper sh!t box unit i had for sure tho .

there is something to be said about FACTORY EFI set to stand alone use :deal:
 
6872xtc said:
While I have never used a Sniper system, and I am not 100% pleased with my PF4, I have never had the PF4 die and fail to restart. (At least so far, knock on wood)
Even with a leak above the O2 sensor, it would run and drive, just lacking in performance.
My '01 GMC with a LQ9 that has a Texas Speed cam installed, has been reliable, even though it appears to be having an internal ECM problem. Small tweaks to the engine and transmission map have been very precise as well. There are definite advantages to a more capable computer and system.
Click to expand...
That is true, the PF4 hasn't left me stranded. I've been towed once due to Sniper failure when the coil driver module had a melt down. The ECU on the Sniper failed in the driveway but to Holley's credit they replaced it even though I was out of the warranty period. The other issue I've had with the Sniper is the injector connector coming loose which is a known issue and relatively easy to fix. It doesn't leave you stranded, but just kills the engine power for obvious reasons. I think the injector connector problem is the most egregious design flaw in that system.

If a person is debating between a Sniper and PF4, here's my thoughts. The Sniper is cheaper, but you are accepting more likelihood of operating issues. The PF4 multi-port fuel injection is more efficient, but I can tell you from experience it is not flawless. There are a lot more tuning parameters the Sniper offers that the PF4 does not. The PF4 is definitely friendlier for someone that wants to just install it and let the system do most of the thinking. The Sniper gives you few more parameters to play with, which could actually be a down side for some people. If I were to consider a cheap aftermarket EFI, I would be okay with another Sniper because I know what its foibles are. If I wanted a better system in the $2000 range, I'd probably look at a Holley Terminator Stealth system. You get the tunability and the capability of controlling an electronic transmission. I know you lose some efficiency with the throttle body type injection, but I only picked up 1mpg going from carb to PF4 in my C10. Another thing I like about the Terminator system is that you get the ECU off the throttle body and away from the engine heat.

I've not fully investigated, but I've always thought it would run around $2500 to do a complete LS type swap. I know a lot the cost depends on the price of the engine itself and I'm sure there are ways people have found to mitigate that cost. You can also save money if you're willing to put in the time to do the harness work yourself. But I feel like it would be easier to get help with issues. A lot more people have experience with those engines and factory EFI setup.
 
mrk5 said:
After having both a Holley Sniper and Edelbrock Pro-Flo 4 and having issues with both my future builds are really leaning towards something with factory EFI. A lot of guys here love the Pro-Flo but I'm in the middle of a saga with mine that I will update everyone on once it's resolved, but it's been going on for several months now. I've had a few issues with the Sniper as well, but overall it's worked pretty good for me. It's just that once you get into a situation where there's a problem you can't figure out, it can be hard to get help. At least with a factory EFI setup, there are usually lots of people and shops familiar with how to fix it.

I have a 4L80e with a US Shift Quick 4 controller. I really love the set up for what I do. I drive it on a lot of highway plus trail running and it gives me a lot of control and versatility.
Click to expand...
When you went to the 4L80e I know you have to move your trans support back and shorten the driveshaft. With my K5 its a pretty short wheelbase (especially with the 6" suspension lift). Curious if you get any vibrations hitting highway speeds. I drive mine alot on the highway to work and back (150miles a day) and of course have fun on the weekends (of course its been years since I've been having so many issues).

Before I went the 4L80e I am really hoping to identify any reason NOT to go to an electronic trans from the 700R4. My understanding is the 4L80e has overdrive just like the 700R4 does, its built a bit heavier duty than the 700R4 but requires a module that you can either get that plugs into the Holly computer so the fuel injection, distributor and all that know what gear you are in. "Supposedly" moving to an electronic trans is "suppose" to help how the Blazer drives but again, I just research whats on forums and what Holly says and the shops. I have enough knowledge to be dangerous with... which is why I prefer a professional to dial in the tune using a Dyno. If they can't dial it in with the engine and trans as is, then I'll have to go to the next step (whatever that is).
 
I have a crew cab pickup so the rear driveshaft is not really comparable to yours. I also have fabricated crossmembers. This truck started out as a 2wd with an SM465, then a 700r4, and now the 4L80e.

Personally I'd rather have the standalone transmission controller versus using aftermarket EFI module. There is a lot of customization you can do with the Quick 4 that I utilize. One of the big needs I have is the 4 speed transfer case. The Quick 4 allows you to program for each of the 3 low ranges. The controller comes with several tables you can load for the transmission so you don't have to be a wizard on programming the transmission. You can load a table to looks close and then tweak things from there. For example, I like nice firm shifts so I increased the line pressures a little to get that nice sharp shift. The Quick 4 has the ability to load 4 different tables so you can try different setups to see if there are changes you like but you aren't stuck with 1. You could also make a table for different driving conditions and choose the table you want to use while driving. Then there's the ability to do all sorts of programming with the torque converter lockup which helps control transmission temperatures. And for the trail I like using the manual mode where the transmission runs in what ever gear you have selected. In manual mode, if you have the gear selector in 3rd, it will be in 3rd gear right from the start. That's more useful if you have the double-reduction gear boxes like a Doubler or Magnum. I could list more things I like about the controller, but it would turn into a small book.

I had a 700r4 for a lot of years. I really don't like them for aftermarket fuel induction. The only time I felt like the throttle valve was set properly was when I had it connected to a factory TBI setup designed to work with the 700r4. Then all of the geometry was correct. When I had a Holley carb and then the Holley Sniper EFI connected to the 700r4, I never felt like the throttle valve cable was set up quite right. I would be okay using it with a factory TBI or Quadrajet that had the 700r4 from factory, but I'd much rather have one of the electronic transmissions with a stand alone controller for any other setup.
 
If you're not setting all this up and tuning it yourself maybe the best thing to do is first find someone local who is competent and that you trust. Put it together with the stuff he's familiar/comfortable with.

You may end up with a better result faster and cheaper then cobbling together the best of what all the keyboard commandos think you need and then trying to find someone who can make it driveable...
 
update is I found someone who will help me with the move from a 700R4 mated to a NP241c transfer case changed to 4L80e mated to the same transfer case.
I’m choosing to use Motor City Steel here in Michigan to help with replacement.
Because I have the more expensive version of the Holly Fuel Injection I don’t have to purchase another computer to help with that part. The Holly computer can talk directly to the transmission.

NEEDS:
find the correct year 4L80e (still not positive on what year 4L80e I need to find that works with the Holly and will work with this change)

Will need to shorten rear drive shaft and lengthen front and balance them.

re-tune Holly Fuel Injection

currently awaiting price from Motor City Steel.

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83ChevyK5Blazer said:
You will need to swap the input to your tcase as well, 700r4 is 27 spline, 4l80 is 32 spline.
Its an easy swap over
Click to expand...
i might be good on this since I use the Slip Yoke Eliminator so If I twist a drive shaft I can just remove the driveshaft without loosing any fluid
 
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