I'm at my limit of frustration on a TBI to TPI swap. I am using a BIG cam 230/260 at 0.050, so I realize the poor vacuum signal is a major cause of flooding by dumping gas into the system, thereby causing the flood.

So far, I've got $300.00 into custom chips by tuners that I won't mention here. The first tuner knowing the mods gave me two stinking stock chips in a row, with Vats turned off. Un..beleivable He should have known better thatthat about vacuum issue. I sent the chips to someone else who reported he is more on the learning curve of big cams. I'm more hopeful his work will help. He reported the problem of stock chips to me.

Having opened the NEW file from the latest tuner in Tunerpro RT, I can see he did infact change the VE and spark tables consideably with the exception af a few questionable spikes at the 1600 rpm overlap between tables. That should be easy to edit andresolve if I could actually fire up and keep running. I beleive he's giving me his best effort, based on what I can feebly tell him, but I need more help. It's not the money, it's the frustration.

I've spun the engine with the fuel pump disconnected, plugs out, coil unplugged to clear the cylinders. I blew air into each for several minutes to dry them further, cleaned plugs MANY times Nine months of this crap and I'm frustrated and weary of it.

With the newly burned in the ECM this morning, I had two cold cylinders, 4&8 cleaned them out again and refired, Now there are seven cold cylinders.

Even though I've purchased a Prominator, I haven't installed it yet. If I can't a base program to get 8 cylinders to fire, having 8 programs or a hundred available doesn't help much. It's a crap shoot at this point.

I open the floor to you guys to help me get this lawn ornament started and running for more than 20 seconds between foulings.

My sincere thanks for any bone you can throw this old dog.

 

Sounds like you need to install your Prominator and load up the S_AUJP file (or a stock file for that matter)
Create several of these files with different injector constants defined.
Start with a larger sized constant (to give less fuel) and switch them in smaller until you find one that "seems" to not flood and provide enough fuel.
Do this only to get started then go back and figure out where it should be and start again.
Going into "Limp" mode by having the chip out, etc will flood easily if you have higher than stock injectors or higher fuel pressure.
IMO,The only thing that keeps the flooding under control in those situations is a really strong ignition or an MSD box.
Holding the throttle over 80% during cranking will shut off the fuel. May help if you start with the pedal down and crank.
Are you sure your Fuel pressure is not too high, everything else mechanically OK and the distributor is set right at 6*BTDC?

You haven't described enough of your combination to gain other input.

 

I've definitely been there - it sucks. The chip I received from the shop that built my engine was a POS (only tuned for WOT). Then I spent $365 on a custom chip from a good tuner, but after a few variations, it still wasn't ideal, ESPECIALLY at cold start / open loop operation. It was pig rich - I can't tell you how many sets of plugs I went through. Finally, I was convinced to tune it myself, so I bought the AutoProm / TunerPro RT combo and am just now starting to sort it out myself. Big cams are definitely tough to tune via mail order, and now I understand why.

Anyway - enough of my saga. What size / brand injectors are you using? Are they in good working condition? I would perform a fuel line pressure test to see if they are leaking. Leaking / malfunctioning injectors could cause major headaches.

If they check out ok, then I would approach as JP86SS suggested. What bin / chip are you using to run the car now? If you are using a stock bin with larger than stock injectors, it will definitely run pig rich in open loop.

 

Fuel Pressure was at 35lbs. Fuel injectors were changes from the original 32 ponders (overkill) down to 24 pounders.

I'm not trying to mooch here, but I'm sure you can guage my frustration level by this time. Maybe someone of the senior members can see where the file could be improved or at least what areas may be of concern fromtheir perspective
.
Can't say I'm willing to try holding the pedal down long for fear of shrapnel wounds and flying parts. Right now the cyl's are airing out again.

 

That zip file doesn't look right ' Won't let mr reload twice ,

'll try again under a different file name.

Nope that isn't working any better than my car.

 

I'm having the exact same problem. With my tuning efforts PW constants haven't done anything, but I've been told that the VE tables need to be leaned out at idle. Tomorrow night I'll try it and report back.

 

If the FP is still that low then you must have another problem.
Check your base timing and then plug the "bypass" back in when your done.
There must be a problem in the ignition.

I don't think you should post up a purchased bin in an open forum.
Not sure on the issues that can cause but just doesn't seem right to me.
Send it by person to person methods if you need advice on it rather than out for all to grab someones work for free. Maybe just some of the parameter settings for some advice but not the whole thing.
Not that I'm for mail order tunes myself, its just there are some guys that are not out to sell junk and have put effort into trying to do this for people who haven't learned to do it themselves.
Plus somebody out there will try to run it not understanding the effects it could have.
Probly get flamed for that but, just my $0.02

 

Good point on the Zip file.. I didn't consider that aspect of things. But now that you mention it...

If the Moderator can pull the file off I'd be appreciative of that.

I 've been trying to be protective of who has been doing what for me. There are a lot of honest people out there who have good intentions and good ethics and I beleive the latest source meets that criteria. I have been caught up in the frustration of still having a 4500lb stone in the driveway. I'm not looking to take food away from someones kid. In a previous thead I tried to point out that I'm not here to slam people, just looking for help.

I still need lots of it.

 

Might try reading the stickies a few more times...

Try lowering the VE values if the 40-70 K/Pa areas, at the idle range RPM.
Let's guess you have an idle MAP of 60 K/Pa, at say 800 RPM..
What is your VE entry there?.
Subtract 15% from it, and enter it in the 40-70 K/Pa areas.
Try starting the motor.
If still rich drop it another 5%.
Repeat as necessary till you get it to at least idle.
The slowly work you way up in the rpm range.
The try driving it.

 

Thanks Grumpy, for all your help and again and again on my behalf. It'll take me few days (months, years) to get all this shi...stuff under my belt.

" try driving it" Hell, I'm to the point that I hope you like the steaks I owe you cooked over a hickory stuffed B-body wagon!

Grump, in the past you've mentioned a modified ignition system in your car. Maybe, I'm barking up the wrong tree in thinking it's only or mostly a fuel problem. Part of the problem could be maybe I need more juice to fire the fuel. I've got a new square Accel Supercoil separated from the small cap HEI. Is there a stronger/better spark source you'd recommend as well?

 

While there's no such thing as too good of ignition in my book, it's not to be used to cover up problems. I currently have 6 GM TBI remote coils being fired by 6 ACCEL 300 CD ignition modules. It's an extreme ignition system, but the car is somewhat extreme in nature.

The oem GM TBI coils are excellent units. The only down side is that they have a slow saturation time, but, firing them with a CD type igntion module cures that. As it stands now, The TBI coil, ACCEL 300 combo is the best combo I've tried to date.

 

Grumpy, Since it's my own thread I guess I can get off topic for a second to verify that:

1) this is the system you are referring to at Summit

"http://store.summitracing.com/partdetail.asp?autofilter=1&part=ACC%2D49321&N=400020+302257+115&autoview=sku"

2) that it is compatible with a 730ECM computer controlled TPI system.

The plugs appear to be identical. It would be worth having it if it would help fire very rich (semi flooded) conditons. You been monitoring my issues for several weeks now on differnet threads (Thank you) If Grumpy says it would help and it's worth having, I'll get it.

 

I get invalid URL.

The ACCEL 300's have two leads for the coil, a 12v, ground, and sense wire. I just cut, solder, heatshrink them to the appropriate leads.
With the faster rise time, a CD can fire a pretty rich mixture, but, again, counting on it to cure a serious problem, might not work.

 

I'm having issues with posting latety, don't know if it's a setting or what. Haven't learned all the posting quirks here yet. I'll try without the "parse links setting"


I saw this on the Summit sight. Is this what you are speaking of?

www.summitracing.com


type in this part # acc-49321

It appears to be a conversion kit for TPI or TBI units.



(it finally posted)

 

Could use MSD's box. I'm running a "6A" now.
Here's a link to how they are wired.
Probably similar.
https://www.thirdgen.org/forums/alte...?highlight=MSD

 

I wouldn't go spending money on your ignition unless you know it has a problem. There are plenty of people with more motor than you running the same ignition.
Do as Grumpy says and you should be able to get it going.
That assumes you have everything in proper working order. Double check...
A bad FPR would make your situation even worse.
If possible, test your dist/coil in another car. It will do wonders for your confidence in what isn't the problem....
You also want to raise your idle up if you haven't already. You'll have a hard time with it otherwise.

 

I'm trying to get my prominator hooked up at the moment. From the Laptop using the prominator softeare I keep getting fairly consistant "upload failure" reports listing several locations afterward.

I sware someone has cursed this car! (probably my wife)

I'll post the prominator issues as a new thread

 

A friend came over to help sort out the engine issues today. I had mentioned changing over previously from 32lb/hr injectors to 24lb/hr , before I had a new chip burned. Although the 32's were new, the 24's were used, with 60k or more miles on them. We both have a suspicion at this point of faulty or clogged injectors as being a likely issue of some of the cold/fouled cylinders.

I used the Tuner's ''burn" to fire things up. There seems to be general improvement in the motor trying to run, but dying off. I'm left with three cylinders that seem to be consistantly cold. The other five seem to be firing, based on hot header pipes from the respective cylinders.

We replace both the plugs and wires to the suspect cylinders and the problem remained with those same cylinders. Our conclusion or suspicions is those three injectors have issues. Since two of the three plugs become fuel fouled, the thought is the harnesses are working, otherwise no fuel would have been injected to begin with. I'd suspect those two cyl's have a poor spray pattern, more like a stream than atomization.

The third header pipe only gets warm and the plug does not seem fouled, almost dry. There, it would seem the injector itself may be dirty to the point that it is incapable of properly feeding the cylinder and can't foul itself out like the other two, but doesn't have enough fuel to fire properly either. Before I try any datalogging it would seem imperative to get all the cylinders firing. Five are already firing now.


Finally here's my question. I already own the new set of 32lb/hr injectors, and would have to purchase a new set of 24's. Since I now have the ability to load a .bin file for the ECM via the prominator, can I expect reasonable results from working original "burn" by simply changing the injector constant in the file to match the 32 lb/ hr injectors. or would the areas of the VE map for idle likely need to be further supressed? .

 

Having mechanical issues will not help anything when trying to tune.
Even if the 32's give you problems at idle (which should be managable) they will be better than faulty 24's.
I would set them according to your fuel pressure and maybe just a little bigger to be sure you don't flood again right away. After some logging you will see if you can put them to the correct value.
Belive me, don't try to run long term with incorrect injector size. It comes back to haunt you later. Only if you have proven the need to do so should you keep it that way, unless you are happy enough with the results of course.
Jp

 

With what you've done so far, at this stage, I'd start with the basics and do a leak down test next.
Yes.
Yes, changing the injector size isn't going to be that much more tuning.

You've picked a hellva cam to start to learn EFI tuning with. <sigh>

 

From JP
" I would set them according to your fuel pressure and maybe just a little bigger to be sure you don't flood again right away. After some logging you will see if you can put them to the correct value."

If I follow your thought correctly, Put a value of 33 or 34 in the injector size constant to help reduce flooding? Change it slowly back to a more accurate number as datta logging and file changes are created?

From Grumpy "You've picked a hellva cam to start to learn EFI tuning with."

It's like brain surgery before I learn how to put a bandage on a cut. I didn't know my learning curve would resemble an overlapped cam pattern!

 

That helped me figure out my regulator problem when all I got was lots of fuel and couldn't make it run decent. Once I changed it higher and the fuel came roughly into what was a normal operating region, things could be checked easier to find the problem.
Its just a band-aid to keep you from changing plugs each time you don't get it started quickly.
You may not even need to do it since the larger injectors are "fresh' (not that new ones are perfect either) but the bad 24's were probably most of your problem.
A 34 setting wouldn't hurt to start with if your FP is at 43. Once it runs and you see the logs adding fuel you can put the number down to 32 where it should be.

 

Last time I checked the FP at the rail it was at 37 psi, not at 43.

That was seconds before the Accel fuel rail mounted guage at the Schrader sprung a leak behind the guage and started a fire in the engine bay. Luckly all that fired was some silicone vacuum hose and some convoluted tubing covering the harness.

Needless to say... the guage is now a part of the local landfill reclaiming project.

 

Unbeleivable! I'm stunned!


I was in the middle of tearing down the TPI system to change injectors. I had cold cylinders on 2 & 8, and cyl 1 was barely warm. I beleived I had some fouling caused by bad injectors. To change injectors with the SLP siamesed runners I have to puill the valve covers.

If you've been following or helping me in this thread, here's what I found.

I found the roller rockers on cylinders 2 & 8 floating loose and flopping around. The hold down screws were about to fall off. Cylinder 1 was loose to the touch........Freaking amazing!.

I'll be draining and changing the oil as well. I can't emagine how much blow by gasoline must already be in the crank case.

Grumpy thank you for telling me to go back to basics!

Well, at least I found the problem. I realize this is not a EFI/ DIY question, but can I, or should I have used locktight to keep the lockdown screws tight?

 

Most roller rocker setups come with poly locks. These have a set-screw in the top center. After adjustment the set screw is snugged down against the top of the stud, then the poly lock is turned a hair more to lock it in place.

If you don't have the poly-locks, best to get a set.

RBob.

 

Thanks RBob. I do have the polylocks, and that's what loosened up. I'm wondering if I wouldn't be better off adding a drop of Locktite to them to keep them set. I thought just cranking on the setscrew would have done it as well, but they were flopping around.

Maybe I need to eat my wheaties!

 

It is this last step that locks them down "then the poly lock is turned a hair more to lock it in place."

During adjustment I use an offset box wrench and a T handle hex at the same time. One on the poly and the other in the set screw. Once adjusted put a slight tightening pressure on the set screw and snug the poly lock a hair tighter.

Try it on a couple and see how hard it is to loosen them. To un-lock them I usually use both a wrench on the poly and the hex key on the set screw.

I wouldn't use the locktite for a number of reasons. First is that the threads need to be free of oil.

RBob.

 

thanks for the lesson in technique. After digging futher, i've found a few bend pushrods, with no apparent damage to rockers or lifters.
I visited a local engine builder today before I say you reply. He said essentially the same thing, that the final pull is made on both polylock and set screw together. His technique was go to zero lash, take a half turn more on the lock, noting final position. Then back off 1/4 turn, run up the set screw, then add the final 1/4 turn back in on both set and lock at the same time. He mentioned the T-handles worked great as well.

I ordered a half set of rods and picked up some t-handles, and should be able to go at it again later this week.


Thanks for all for help and your continued interest!


Dave Buchholz, Rochester,NY

 

The question I'd want an answer to is: "Why do I have bent pushrods? What caused that?"

 

[QUOTE=vernw]The question I'd want an answer to is: "Why do I have bent pushrods? What caused that?"[/QUOTE

... cause I'm a rookie.

Improper techinique for securing the polylocks did it. The loosened enough to the point where the pushrods shot around and whacked things.

That kind of explains two cold cylinders fasirly well. The valves weren't opening. All I had was fuel and spark, no air.
While I had things apart I noticed some slapping of the bottom of the rocker by the spring plate where there was interference. The silver spot on the purple rockers was easy to see. The've now been clearanced, and new Manley high performance pushrods are going in.

I found out there would have been issues later anyways with stock pushrods against hardened guide plates. That and the wear pattern was slighly off center so I have PROPERLY sized and matched parts going in. Yup, I'm a rookie... I'm learning my mistakes on the old motor though, before the 400 block gets rebuilt and stuffed in spring of 2008.

By then I'll have a better handle on tuning as well as building by screwing things up on the 350 instead.