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Distributer upgrade to HEI?

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Randy282828

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got a 90 burban with a 5.7 tbi. ive been all thru this engine trying to figure out why it wont stay running, and lopes erratically unless the map sensor hose is off, idles smooth for about 3 minutes, then something changes, and its bogs out and dies. map is new, tps is new, egr is working, o2 is new. no codes. new cap and rotor, plugs and wires, etc. just rebuilt the tbi. still not the problem. couple wheeling buddies(and 1 hot rodder) say to change the distruter(igniter or crack?) so i picked up a HEI to upgrade to, but no instructions on wiring. can someone tell me the wiring to go from my distrubiter to hei?:confused::confused::confused::confused::confused::confused:
 
If it's a tbi, then it's already hei and computer controlled. It sounds like you have a vaccum leak somewhere.

Edit, just realized you might have meant you have a new ignition module or pickup coil and not a whole hei distributor. The ignition module can be changed without removing the distributor. Just use the thermal grease and plug the two colored wires in the same spot they can off. Don't know much about the pickup coil.
 
its not hei yet, just a regular distributer with a external coil pack. got a hei outta a 88 350 buick rivera. hoping it will work for me
 
i thought i had a vacuum leak also, thats why i rebuilt my tbi, cause all the hoses were good, some new, and the old standby didnt work( starter fluid, or carb cleaner) so im at a loss here
 
If it's a stock motor, the small cap tbi systems are all hei already. They just have a separate coil. I don't know anything about buicks, but unless it also has tbi, then it won't work without a ton of work.

I would just replace the ignition module since those supposedly fail a lot and cause that kind of problem. It's way cheaper and less hassle than trying to convert a non-tbi distributor to work with tbi.
 
the buick was carbed, but according to the hot rodder, its just a adapter plug needed to make the wiring work. should i junk yard hunt for a reg stock distributer to see if it solves the issue? was told the big HEI would improve mpg, hp etc
 
The big HEI and the TBI HEI are same-same as far as ignition mojo goes. You definitely will not see performance or mileage increases by retrofitting the older coil in cap version. You will have all sorts of headaches trying to make it work though...

Vac leaks are common at the TBI unit. Ignition module problems are common too.

The Blazer I picked up about 6 months ago had a pretty fun problem where it'd start fine, and run pretty good for about 3-5 minutes...then load up, puke black smoke and die. At that point it wouldn't re-start until it cooled down again. The guy I bought it off of sold it to me for pretty cheap, and judging by the spare parts inside the truck (Q-jet and big cap HEI) he was about to ditch the TBI altogether.

It had a bad coolant temp sensor...which was telling the computer the temp was -60F so as soon as it warmed up a bit it would massively enrichen things to the point it'd flood out and die. 5 minute fix...

Rene
 
Randy282828 said:
the buick was carbed, but according to the hot rodder, its just a adapter plug needed to make the wiring work.
Click to expand...

I guess if there was a plug adaptor to disable the computer controlled ignition you could hook up a vacuum advance, buy it wouldn't do anything for power or mileage. It would probably make it worse in fact.

Randy282828 said:
should i junk yard hunt for a reg stock distributer to see if it solves the issue? was told the big HEI would improve mpg, hp etc.
Click to expand...

That's probably a better option, but there's really only two parts inside those distributors, the ignition module and pickup coil. A new ignition module is easy to replace and pretty cheap too.
 
will look into the ignition module, and the coolant temp sensor. would either one make it lope like a major cam? because with the vacuum line on(the map sensor), it barely idles. will start, go down to almost dying, then rev up to about 1500, and repeat for about 3 minutes, then it'll run smooth for a sec, then flood out and die(or at least it seems like its flooding out). this vehicle sat for 4 years b4 i got it, i did some work on the tranny, ran great for about a week, then started this crap
 
CTS could do that. It really depends on the ambient temp, versus what it's falsely telling the ECM the coolant temp is.

Rene
 
tRustyK5 said:
CTS could do that. It really depends on the ambient temp, versus what it's falsely telling the ECM the coolant temp is.

Rene
Click to expand...

i live in nor cal, and temp has been between 65 and 80 last month or so. so i dunno what its telling the puter. no codes. it wont run long enough to "warm up" to reg temp (was about 195 to 210 till this all started). was driving when it started bogging, and got worse from there quickly
 
Well, might be CTS then. The one I bought would run less than 5 minutes before bogging, flooding, puking black smoke and dying. Definitely not long enough to hit operating temp. It did have a CES light on though...although I'm not 100% it was regarding the CTS. It went out after driving about 10 minutes, and I had replaced the coil, CTS and TPS.

It runs like a dream now...

Rene
 
A plugged fuel filter or a bad fuel pump will give you the symptoms you have.
 
For future reference, the ECM needs to see a crank/RPM signal from the dist for the TBI to function. This is why the 'coil in cap' HEI doesn't work as a swap unit.
 
i imagine that the cts is the cheapest thing to replace first. i will update as soon as i get that done. my fuel pump has got good pressure, and the filter is brand new. thought the same thing when it started acting up. so the cap in coil hei wont work for my tbi? ok, glad i know that before i started splicing wires. if it aint the cts, i will junk hunt for a distributer from the junk yard
 
Okay Randy, All good advice here, now I will invite you to become a member if you are financially capable of doing so.

As you can see, there is a wealth of info and great opportunities to be had by being a part of the "Brotherhood".

Looking forward to a good report on the repair.
 
Randy282828 said:
i imagine that the cts is the cheapest thing to replace first. i will update as soon as i get that done. my fuel pump has got good pressure, and the filter is brand new. thought the same thing when it started acting up. so the cap in coil hei wont work for my tbi? ok, glad i know that before i started splicing wires. if it aint the cts, i will junk hunt for a distributer from the junk yard
Click to expand...

Good fuel pressure is only half the battle. You also need the proper amount of flow at the correct fuel pressure. :deal:
 
will be here in a couple weeks. just got a new job, and they hold back a week. now a update, went cheapest part first(money is tight) with the cts, no change. do i reset the computer or just wait till i get the cash for a pick up coil and module?
 
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